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Sample records for basic protein peptide

  1. Effects of active immunisation with myelin basic protein and myelin-derived altered peptide ligand on pain hypersensitivity and neuroinflammation.

    Science.gov (United States)

    Perera, Chamini J; Lees, Justin G; Duffy, Samuel S; Makker, Preet G S; Fivelman, Brett; Apostolopoulos, Vasso; Moalem-Taylor, Gila

    2015-09-15

    Neuropathic pain is a debilitating condition in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). Specific myelin basic protein (MBP) peptides are encephalitogenic, and myelin-derived altered peptide ligands (APLs) are capable of preventing and ameliorating EAE. We investigated the effects of active immunisation with a weakly encephalitogenic epitope of MBP (MBP87-99) and its mutant APL (Cyclo-87-99[A(91),A(96)]MBP87-99) on pain hypersensitivity and neuroinflammation in Lewis rats. MBP-treated rats exhibited significant mechanical and thermal pain hypersensitivity associated with infiltration of T cells, MHC class II expression and microglia activation in the spinal cord, without developing clinical signs of paralysis. Co-immunisation with APL significantly decreased pain hypersensitivity and neuroinflammation emphasising the important role of neuroimmune crosstalk in neuropathic pain.

  2. Properties of a Small Basic Peptide from Pumpkin Seeds 1

    Science.gov (United States)

    Naisbitt, Gary H.; Lu, Mao-Rong; Gray, William R.; Vernon, Leo P.

    1988-01-01

    A small basic peptide with an unusual amino acid composition has been isolated from the seeds of pumpkin, Cucurbita maxima. Amino acid analysis and sequence data show the protein to be about 36 residues in length, with an approximate composition Lys1, Arg14, Asp3, (Glu + Gln)15, Gly1, Pro1, Trp1. On the basis of composition, the molecular weight is approximately 5000 daltons and the nitrogen content by weight is 20.4%. Twelve amino acids are entirely lacking. The peptide is slightly toxic to mouse B-16 melanoma cells, but its in vivo function is unknown. It does not appear to be derived from cucurbitin, the pumpkin storage globulin; however, it could be a storage peptide involved in nitrogen mobilization during the early stages of germination. Images Fig. 3 PMID:16666381

  3. Peptides and proteins

    Energy Technology Data Exchange (ETDEWEB)

    Bachovchin, W.W.; Unkefer, C.J.

    1994-12-01

    Advances in magnetic resonance and vibrational spectroscopy make it possible to derive detailed structural information about biomolecular structures in solution. These techniques are critically dependent on the availability of labeled compounds. For example, NMR techniques used today to derive peptide and protein structures require uniformity {sup 13}C-and {sup 15}N-labeled samples that are derived biosynthetically from (U-6-{sup 13}C) glucose. These experiments are possible now because, during the 1970s, the National Stable Isotope Resource developed algal methods for producing (U-6-{sup 13}C) glucose. If NMR techniques are to be used to study larger proteins, we will need sophisticated labelling patterns in amino acids that employ a combination of {sup 2}H, {sup 13}C, and {sup 15}N labeling. The availability of these specifically labeled amino acids requires a renewed investment in new methods for chemical synthesis of labeled amino acids. The development of new magnetic resonance or vibrational techniques to elucidate biomolecular structure will be seriously impeded if we do not see rapid progress in labeling technology. Investment in labeling chemistry is as important as investment in the development of advanced spectroscopic tools.

  4. Human Antimicrobial Peptides and Proteins

    OpenAIRE

    Guangshun Wang

    2014-01-01

    As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified ...

  5. Peptides: Basic determinants of reproductive functions.

    Science.gov (United States)

    Celik, Onder; Aydin, Suleyman; Celik, Nilufer; Yilmaz, Musa

    2015-10-01

    Mammalian reproduction is a costly process in terms of energy consumption. The critical information regarding metabolic status is signaled to the hypothalamus mainly through peripheral peptides from the adipose tissue and gastrointestinal tract. Changes in energy stores produce fluctuations in leptin, insulin, ghrelin and glucose signals that feedback mainly to the hypothalamus to regulate metabolism and fertility. In near future, possible effects of the nutritional status on GnRH regulation can be evaluated by measuring serum or tissue levels of leptin and ghrelin in patiens suffering from infertility. The fact that leptin and ghrelin are antagonistic in their effects on GnRH neurons, their respective agonistic and antagonistic roles make them ideal candidates to use instead of GnRH agonist and antagonist. Similarly, kisspeptin expressing neurons are likely to mediate the well-established link between energy balance and reproductive functions. Exogenous kisspeptin can be used for physiological ovarian hyperstimulation for in-vitro fertilization. Moreover, kisspeptin antagonist therapy can be used for the treatment of postmenapousal women, precocious puberty, PCOS, endometriosis and uterine fibroids. In this review, we will analyze the central mechanisms involved in the integration of metabolic information and their contribution to the control of the reproductive function. Particular attention will be paid to summarize the participation of leptin, kisspeptin, ghrelin, NPY, orexin, urocortin, VIP, insulin, galanin, galanin like peptide, oxytocin, agouti gene-related peptide, and POMC neurons in this process and their possible interactions to contribute to the metabolic control of reproduction. PMID:26074346

  6. Antihypertensive Peptides from Milk Proteins

    Directory of Open Access Journals (Sweden)

    Heikki Vapaatalo

    2010-01-01

    Full Text Available Dietary proteins possess a wide range of nutritional and functional properties. They are used as a source of energy and amino acids, which are needed for growth and development. Many dietary proteins, especially milk proteins, contain physiologically active peptides encrypted in the protein sequence. These peptides may be released during gastrointestinal digestion or food processing and once liberated, cause different physiological functions. Milk-derived bioactive peptides are shown to have antihypertensive, antimicrobial, immunomodulatory, antioxidative and mineral-binding properties. During the fermentation of milk with certain lactobacilli, two interesting tripeptides Ile-Pro-Pro and Val-Pro-Pro are released from casein to the final product. These lactotripeptides have attenuated the development of hypertension in several animal models and lowered blood pressure in clinical studies. They inhibit ACE in vitro at micromolar concentrations, protect endothelial function in vitro and reduce arterial stiffness in humans. Thus, milk as a traditional food product can after certain processing serve as a functional food and carry specific health-promoting effects, providing an option to control blood pressure.

  7. Human Antimicrobial Peptides and Proteins

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2014-05-01

    Full Text Available As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32 can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized

  8. Protein identification by peptide mass fingerprinting

    DEFF Research Database (Denmark)

    Hjernø, Karin

    2007-01-01

      Peptide mass fingerprinting is an effective way of identifying, e.g., gel-separated proteins, by matching experimentally obtained peptide mass data against large databases. However, several factors are known to influence the quality of the resulting matches, such as proteins contaminating the s...

  9. Recent trends in protein and peptide drug delivery systems

    Directory of Open Access Journals (Sweden)

    Gupta Himanshu

    2009-01-01

    Full Text Available With the discovery of insulin in 1922, identification and commercialization of potential protein and peptide drugs have been increased. Since then, research and development to improve the means of delivering protein therapeutics to patients has begun. The research efforts have followed two basic pathways: One path focused on noninvasive means of delivering proteins to the body and the second path has been primarily aimed at increasing the biological half-life of the therapeutic molecules. The search for approaches that provide formulations that are stable, bioavailable, readily manufacturable, and acceptable to the patient, has led to major advances in the development of nasal and controlled release technology, applicable to every protein or peptide. In several limited cases, sustained delivery of peptides and proteins has employed the use of polymeric carriers. More successes have been achieved by chemical modification using amino acid substitutions, protein pegylation or glycosylation to improve the pharmacodynamic properties of certain macromolecules and various delivery systems have been developed like the prolease technology, nano-particulate and microparticulate delivery systems, and the mucoadhesive delivery of peptides. The needle and syringe remain the primary means of protein delivery. Major hurdles remain in order to overcome the combined natural barriers of drug permeability, drug stability, pharmacokinetics, and pharmacodynamics of protein therapeutics. In our present review we have tried to compile some recent advances in protein and peptide drug delivery systems.

  10. Myelin Basic Protein-Induced Production of Tumor Necrosis Factor-α and Interleukin-6, and Presentation of the Immunodominant Peptide MBP85-99 by B Cells from Patients with Relapsing-Remitting Multiple Sclerosis.

    Science.gov (United States)

    Nielsen, Claus H; Börnsen, Lars; Sellebjerg, Finn; Brimnes, Marie K

    2016-01-01

    B cells are involved in driving relapsing-remitting multiple sclerosis (RRMS), as demonstrated by the positive effect of therapeutic B-cell depletion. Aside from producing antibodies, B cells are efficient antigen-presenting and cytokine-secreting cells. Diverse polyclonal stimuli have been used to study cytokine production by B cells, but here we used the physiologically relevant self-antigen myelin basic protein (MBP) to stimulate B cells from untreated patients with RRMS and healthy donors. Moreover, we took advantage of the unique ability of the monoclonal antibody MK16 to recognize the immunodominant peptide MBP85-99 presented on HLA-DR15, and used it as a probe to directly study B-cell presentation of self-antigenic peptide. The proportions of B cells producing TNF-α or IL-6 after stimulation with MBP were higher in RRMS patients than in healthy donors, indicating a pro-inflammatory profile for self-reactive patient B cells. In contrast, polyclonal stimulation with PMA + ionomycin and MBP revealed no difference in cytokine profile between B cells from RRMS patients and healthy donors. Expanded disability status scale (EDSS) as well as multiple sclerosis severity score (MSSS) correlated with reduced ability of B cells to produce IL-10 after stimulation with MBP, indicative of diminished B-cell immune regulatory function in patients with the most severe disease. Moreover, EDSS correlated positively with the frequencies of TNF-α, IL-6 and IL-10 producing B cells after polyclonal stimulation. Patient-derived, IL-10-producing B cells presented MBP85-99 poorly, as did IL-6-producing B cells, particulary in the healthy donor group. B cells from MS patients thus present antigen to T cells in a pro-inflammatory context. These findings contribute to understanding the therapeutic effects of B-cell depletion in human autoimmune diseases, including MS. PMID:26756931

  11. Peptide Mass Fingerprinting of Egg White Proteins

    Science.gov (United States)

    Alty, Lisa T.; LaRiviere, Frederick J.

    2016-01-01

    Use of advanced mass spectrometry techniques in the undergraduate setting has burgeoned in the past decade. However, relatively few undergraduate experiments examine the proteomics tools of protein digestion, peptide accurate mass determination, and database searching, also known as peptide mass fingerprinting. In this experiment, biochemistry…

  12. Peptides from milk proteins and their properties.

    Science.gov (United States)

    Kilara, Arun; Panyam, Dinakar

    2003-01-01

    This review has attempted to study the literature pertaining to peptides derived from milk proteins. Hydrolysis of milk proteins to generate peptides has been practiced for a long time and it was recognized early on in this process that the taste of hydrolyzates might hinder use of these products in food formulations. Modification of protein is necessary to form a more acceptable or utilizable product, to form a product that is less susceptible to deteriorative reactions and to form a product that is of higher nutritionall quality. Modifications may be achieved by a number of chemical and enzymatic means. This review has considered only enzymatic modification of dairy proteins. Modified proteins contain peptides and some of these peptides have been purified and their functionalities have been compared with unmodified proteins. This paper has examined the literature pertaining to improvement in functionality of enzyme-modified proteins. Improvements in solubility, emulsification, foaming and gelation were examined. There is limited information available on the sequence of the peptides necessary to improve the functional characteristics of proteins. Knowing the sequences of desirable functional peptides can lead to genetic alteration of proteins to improve functionality. Addition of synthetic peptides to intact proteins may be another way in which the functionality of proteins can be augmented. Some of the peptides in milk proteins are capable of affecting biological functions of an organism. These effects can be antimicrobial and probiotic, i.e., prevent the growth and proliferation of undesirable and pathogenic organisms, or they may promote the growth of desirable bacteria in the digestive tract of humans and animals. Peptides derived from milk protein have been shown to exert digestive and metabolic effects as well. They may also influence the immune system. These biological effects may play an important role in the development of medical foods that treat or

  13. Uptake and presentation of myelin basic protein by normal human B cells

    DEFF Research Database (Denmark)

    Brimnes, Marie Klinge; Hansen, Bjarke Endel; Nielsen, Leif Kofoed;

    2014-01-01

    were capable of binding the MS-associated self-antigen myelin basic protein (MBP) and of presenting the immunodominant peptide MBP85-99, as determined by staining with the mAb MK16 recognising the peptide presented by HLA-DR15-positive cells. In the presence of serum, however, the majority of B cells...

  14. Peptide-enhanced oral delivery of therapeutic peptides and proteins

    DEFF Research Database (Denmark)

    Kristensen, Mie; Foged, Camilla; Berthelsen, Jens;

    2013-01-01

    Systemic therapy upon oral delivery of biologics, such as peptide and protein drugs is limited due to their large molecular size, their low enzymatic stability and their inability to cross the intestinal epithelium. Ways to overcome the epithelial barrier include the use of peptide-based excipients...... throughout the gastrointestinal (GI) tract, chemical stability is an inherent challenge when employing amino acid-based excipients for oral delivery, and multiple approaches have been investigated to improve this. The exact mechanisms of transepithelial translocation are discussed, and it is believed...... that CPP-mediated translocation involves transcytosis and/or direct translocation through the epithelial cells; whereas TJMP-mediated translocation is dependent on interaction with transmembrane or peripheral TJ proteins. This review focuses on the CPPs and the TJMPs currently employed as excipients...

  15. Bioactive peptides and proteins in disease

    OpenAIRE

    Refai, Essam

    2004-01-01

    Regulatory peptides and marker proteins are important to study in order to understand disease mechanisms. This applies of course also to our common diseases where all relationships are not yet known. Cancer and diabetes are two such complex diseases that affect hundreds of millions of people worldwide. This thesis addresses particular aspects of these two diseases, regarding one regulatory peptide (VIP, vasoactive intestinal polypeptide) that may be useful for tumor tracing ...

  16. Use of Galerina marginata genes and proteins for peptide production

    Energy Technology Data Exchange (ETDEWEB)

    Hallen-Adams, Heather E.; Scott-Craig, John S.; Walton, Jonathan D.; Luo, Hong

    2016-03-01

    The present invention relates to compositions and methods comprising genes and peptides associated with cyclic peptides and cyclic peptide production in mushrooms. In particular, the present invention relates to using genes and proteins from Galerina species encoding peptides specifically relating to amatoxins in addition to proteins involved with processing cyclic peptide toxins. In a preferred embodiment, the present invention also relates to methods for making small peptides and small cyclic peptides including peptides similar to amanitin. Further, the present inventions relate to providing kits for making small peptides.

  17. The complete amino acid sequence of the basic nuclear protein of bull spermatozoa

    NARCIS (Netherlands)

    Coelingh, J.P.; Monfoort, Cornelis H.; Rozijn, Thomas H.; Gevers Leuven, Jan A.; Schiphof, R.; Steyn-Parvé, Elizabeth P.; Braunitzer, Gerhard; Schrank, Barbara; Ruhfus, Annette

    1972-01-01

    The complete amino acid sequence of the basic nuclear protein of bull spermatozoa has been established. The sequence was partially deduced by characterization of peptides isolated from thermolysine and chymotryptic digests of the reduced and S-aminoethylated protein. The complete sequence of the fir

  18. Effects of glycinin basic peptide on physicochemical characteristics and microbial inactivation of pasteurized milk.

    Science.gov (United States)

    Zhao, Guo-Ping; Li, Ying-Qiu; Sun, Gui-Jin; Mo, Hai-Zhen

    2016-07-01

    The effects of glycinin basic peptide (GBP) on physicochemical characteristics and microbial inactivation of pasteurized milk were investigated over 21d of storage at 4°C. Sensory properties, total bacterial count, pH, alcohol levels, lactose content, and protein changes of pasteurized milk differentially treated with GBP were analyzed periodically during refrigerated storage. Compared with the control, reductions for total bacterial count and specific bacterium (Staphylococcus aureus) in pasteurized milk treated with GBP during storage were found. However, sensory scores, pH, lactose, and protein contents of pasteurized milk treated with GBP were much higher than those of the control. A concentration of 0.015% (wt/vol) GBP could effectively inhibit the growth and reproduction of bacteria in pasteurized milk, enhance its sensory and physicochemical properties, and extend its shelf life to 15d. Thus, GBP has good potential to be a natural milk preservative. PMID:27157568

  19. Bioorganic Chemistry: Peptides and Proteins (edited by Sidney M. Hecht)

    Science.gov (United States)

    Anthony-Cahill, Spencer

    1999-07-01

    Sidney M. Hecht, Ed. Oxford University Press: New York, 1998. 532 pp. ISBN 0-19-508468-3. $75.00. The second volume in the Bioorganic Chemistry series edited by Sidney Hecht is an outstanding addition to the collections of all scientists who teach and/or do research in the field of protein chemistry. The coverage of current research is up to date and thus the book is of great relevance to all chemists with interest in proteins, not just to academicians. As an instructor I found numerous references to current research, which I have included in my lecture notes for the undergraduate Biochemistry course and a senior-level Protein Engineering course taught at WWU. In addition to the chapters covering a broad spectrum of protein chemistry, there are two chapters (protein structural analysis, site-directed mutagenesis) which are excellent introductions to laboratory procedures in protein chemistry and molecular biology. The first chapter is an overview of basic protein biochemistry and serves as an introduction to the rest of the book. This chapter is dispensable for readers familiar with introductory biochemistry. The chapter on chemical synthesis of peptides is an exhaustive review of solution and solid-phase methods, with numerous references. I was struck by the abundance of figures showing structures of reactants but the general lack of organic chemical mechanisms. This is true for the rest of the book as well. Presumably the chemistry is known to the intended reader (grad students, advanced undergrads); however, as a devoted pusher of electrons, I was expecting to see more mechanisms in this and subsequent chapters. Instructors will have to present this aspect of the chemistry in lecture. The relevance of peptide chemistry is underscored by accompanying chapters on peptide hormones and peptidomimetics. Taken together these three chapters provide an excellent introduction to pharmaceutical peptide chemistry. The chapter on total synthesis of proteins is one of my

  20. Protein-peptide interactions in mixtures of whey peptides and whey proteins

    NARCIS (Netherlands)

    Creusot, N.; Gruppen, H.

    2007-01-01

    The effects of several conditions on the amounts and compositions of aggregates formed in mixtures of whey protein hydrolysate, made with Bacillus licheniformis protease, and whey protein isolate were investigated using response surface methodology. Next, the peptides present in the aggregates were

  1. Facilitating protein solubility by use of peptide extensions

    Science.gov (United States)

    Freimuth, Paul I; Zhang, Yian-Biao; Howitt, Jason

    2013-09-17

    Expression vectors for expression of a protein or polypeptide of interest as a fusion product composed of the protein or polypeptide of interest fused at one terminus to a solubility enhancing peptide extension are provided. Sequences encoding the peptide extensions are provided. The invention further comprises antibodies which bind specifically to one or more of the solubility enhancing peptide extensions.

  2. Peptiderive server: derive peptide inhibitors from protein-protein interactions.

    Science.gov (United States)

    Sedan, Yuval; Marcu, Orly; Lyskov, Sergey; Schueler-Furman, Ora

    2016-07-01

    The Rosetta Peptiderive protocol identifies, in a given structure of a protein-protein interaction, the linear polypeptide segment suggested to contribute most to binding energy. Interactions that feature a 'hot segment', a linear peptide with significant binding energy compared to that of the complex, may be amenable for inhibition and the peptide sequence and structure derived from the interaction provide a starting point for rational drug design. Here we present a web server for Peptiderive, which is incorporated within the ROSIE web interface for Rosetta protocols. A new feature of the protocol also evaluates whether derived peptides are good candidates for cyclization. Fast computation times and clear visualization allow users to quickly assess the interaction of interest. The Peptiderive server is available for free use at http://rosie.rosettacommons.org/peptiderive. PMID:27141963

  3. Predicting protein-ligand and protein-peptide interfaces

    Science.gov (United States)

    Bertolazzi, Paola; Guerra, Concettina; Liuzzi, Giampaolo

    2014-06-01

    The paper deals with the identification of binding sites and concentrates on interactions involving small interfaces. In particular we focus our attention on two major interface types, namely protein-ligand and protein-peptide interfaces. As concerns protein-ligand binding site prediction, we classify the most interesting methods and approaches into four main categories: (a) shape-based methods, (b) alignment-based methods, (c) graph-theoretic approaches and (d) machine learning methods. Class (a) encompasses those methods which employ, in some way, geometric information about the protein surface. Methods falling into class (b) address the prediction problem as an alignment problem, i.e. finding protein-ligand atom pairs that occupy spatially equivalent positions. Graph theoretic approaches, class (c), are mainly based on the definition of a particular graph, known as the protein contact graph, and then apply some sophisticated methods from graph theory to discover subgraphs or score similarities for uncovering functional sites. The last class (d) contains those methods that are based on the learn-from-examples paradigm and that are able to take advantage of the large amount of data available on known protein-ligand pairs. As for protein-peptide interfaces, due to the often disordered nature of the regions involved in binding, shape similarity is no longer a determining factor. Then, in geometry-based methods, geometry is accounted for by providing the relative position of the atoms surrounding the peptide residues in known structures. Finally, also for protein-peptide interfaces, we present a classification of some successful machine learning methods. Indeed, they can be categorized in the way adopted to construct the learning examples. In particular, we envisage three main methods: distance functions, structure and potentials and structure alignment.

  4. Protein Folding: Search for Basic Physical Models

    Directory of Open Access Journals (Sweden)

    Ivan Y. Torshin

    2003-01-01

    Full Text Available How a unique three-dimensional structure is rapidly formed from the linear sequence of a polypeptide is one of the important questions in contemporary science. Apart from biological context of in vivo protein folding (which has been studied only for a few proteins, the roles of the fundamental physical forces in the in vitro folding remain largely unstudied. Despite a degree of success in using descriptions based on statistical and/or thermodynamic approaches, few of the current models explicitly include more basic physical forces (such as electrostatics and Van Der Waals forces. Moreover, the present-day models rarely take into account that the protein folding is, essentially, a rapid process that produces a highly specific architecture. This review considers several physical models that may provide more direct links between sequence and tertiary structure in terms of the physical forces. In particular, elaboration of such simple models is likely to produce extremely effective computational techniques with value for modern genomics.

  5. Origination of the Protein Fold Repertoire from Oily Pluripotent Peptides

    OpenAIRE

    Mannige, Ranjan V.

    2014-01-01

    While the repertoire of protein folds that exists today underlies most of life’s capabilities, our mechanistic picture of protein fold origination is incomplete. This paper discusses a hypothetical mechanism for the emergence of the protein fold repertoire from highly dynamic and collapsed peptides, exemplified by peptides with high oil content or hydrophobicity. These peptides are called pluripotent to emphasize their capacity to evolve into numerous folds transiently available to them. As e...

  6. SuperMimic – Fitting peptide mimetics into protein structures

    Directory of Open Access Journals (Sweden)

    Schmidt Ulrike

    2006-01-01

    Full Text Available Abstract Background Various experimental techniques yield peptides that are biologically active but have unfavourable pharmacological properties. The design of structurally similar organic compounds, i.e. peptide mimetics, is a challenging field in medicinal chemistry. Results SuperMimic identifies compounds that mimic parts of a protein, or positions in proteins that are suitable for inserting mimetics. The application provides libraries that contain peptidomimetic building blocks on the one hand and protein structures on the other. The search for promising peptidomimetic linkers for a given peptide is based on the superposition of the peptide with several conformers of the mimetic. New synthetic elements or proteins can be imported and used for searching. Conclusion We present a graphical user interface for finding peptide mimetics that can be inserted into a protein or for fitting small molecules into a protein. Using SuperMimic, promising locations in proteins for the insertion of mimetics can be found quickly and conveniently.

  7. SuperMimic – Fitting peptide mimetics into protein structures

    Science.gov (United States)

    Goede, Andrean; Michalsky, Elke; Schmidt, Ulrike; Preissner, Robert

    2006-01-01

    Background Various experimental techniques yield peptides that are biologically active but have unfavourable pharmacological properties. The design of structurally similar organic compounds, i.e. peptide mimetics, is a challenging field in medicinal chemistry. Results SuperMimic identifies compounds that mimic parts of a protein, or positions in proteins that are suitable for inserting mimetics. The application provides libraries that contain peptidomimetic building blocks on the one hand and protein structures on the other. The search for promising peptidomimetic linkers for a given peptide is based on the superposition of the peptide with several conformers of the mimetic. New synthetic elements or proteins can be imported and used for searching. Conclusion We present a graphical user interface for finding peptide mimetics that can be inserted into a protein or for fitting small molecules into a protein. Using SuperMimic, promising locations in proteins for the insertion of mimetics can be found quickly and conveniently. PMID:16403211

  8. Stabilized helical peptides: a strategy to target protein-protein interactions.

    Science.gov (United States)

    Klein, Mark A

    2014-08-14

    Protein-protein interactions are critical for cell proliferation, differentiation, and function. Peptides hold great promise for clinical applications focused on targeting protein-protein interactions. Advantages of peptides include a large chemical space and potential diversity of sequences and structures. However, peptides do present well-known challenges for drug development. Progress has been made in the development of stabilizing alpha helices for potential therapeutic applications. Advantages and disadvantages of different methods of helical peptide stabilization are discussed.

  9. PeptideMine - A webserver for the design of peptides for protein-peptide binding studies derived from protein-protein interactomes

    Directory of Open Access Journals (Sweden)

    Gopal Balasubramanian

    2010-09-01

    Full Text Available Abstract Background Signal transduction events often involve transient, yet specific, interactions between structurally conserved protein domains and polypeptide sequences in target proteins. The identification and validation of these associating domains is crucial to understand signal transduction pathways that modulate different cellular or developmental processes. Bioinformatics strategies to extract and integrate information from diverse sources have been shown to facilitate the experimental design to understand complex biological events. These methods, primarily based on information from high-throughput experiments, have also led to the identification of new connections thus providing hypothetical models for cellular events. Such models, in turn, provide a framework for directing experimental efforts for validating the predicted molecular rationale for complex cellular processes. In this context, it is envisaged that the rational design of peptides for protein-peptide binding studies could substantially facilitate the experimental strategies to evaluate a predicted interaction. This rational design procedure involves the integration of protein-protein interaction data, gene ontology, physico-chemical calculations, domain-domain interaction data and information on functional sites or critical residues. Results Here we describe an integrated approach called "PeptideMine" for the identification of peptides based on specific functional patterns present in the sequence of an interacting protein. This approach based on sequence searches in the interacting sequence space has been developed into a webserver, which can be used for the identification and analysis of peptides, peptide homologues or functional patterns from the interacting sequence space of a protein. To further facilitate experimental validation, the PeptideMine webserver also provides a list of physico-chemical parameters corresponding to the peptide to determine the feasibility of

  10. Constraining cyclic peptides to mimic protein structure motifs

    DEFF Research Database (Denmark)

    Hill, Timothy A.; Shepherd, Nicholas E.; Diness, Frederik;

    2014-01-01

    Many proteins exert their biological activities through small exposed surface regions called epitopes that are folded peptides of well-defined three-dimensional structures. Short synthetic peptide sequences corresponding to these bioactive protein surfaces do not form thermodynamically stable pro...

  11. Peptide segment ligation:A new method for synthesis of peptide and protein

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ The protein structure-function relationships are always highlighted in the field of life science. Protein synthesis from genomic sequence data is gaining significance in the "post-genomic era" of biomedical research by providing direct access to functional proteins. The manually or automatically stepwise solid phase peptide synthesis (SPPS) allows peptide of up to 60 residues to be routinely constructed in good yield and high purity[1,2]. The assembly of longer proteins via the gene engineering technology (e.g. recombinant DNA-based molecular biology or site- directed mutagenesis) and convergent peptide synthesis are necessary. Although the current biosynthetic method allows unnatural amino acids to be incorporated into proteins or peptides[3], only ?-peptide in the protein backbone can be obtained. A lot of problems associated with the classic convergent peptide synthesis approach, such as the poor solubility, inadequate purification techniques, and limited characterization methods with the fully protected segment[6]. However, totally chemical synthetic method can easily obtain ?- or ?-peptide[4] and even branch peptide[5].

  12. Information-driven modeling of protein-peptide complexes.

    Science.gov (United States)

    Trellet, Mikael; Melquiond, Adrien S J; Bonvin, Alexandre M J J

    2015-01-01

    Despite their biological importance in many regulatory processes, protein-peptide recognition mechanisms are difficult to study experimentally at the structural level because of the inherent flexibility of peptides and the often transient interactions on which they rely. Complementary methods like biomolecular docking are therefore required. The prediction of the three-dimensional structure of protein-peptide complexes raises unique challenges for computational algorithms, as exemplified by the recent introduction of protein-peptide targets in the blind international experiment CAPRI (Critical Assessment of PRedicted Interactions). Conventional protein-protein docking approaches are often struggling with the high flexibility of peptides whose short sizes impede protocols and scoring functions developed for larger interfaces. On the other side, protein-small ligand docking methods are unable to cope with the larger number of degrees of freedom in peptides compared to small molecules and the typically reduced available information to define the binding site. In this chapter, we describe a protocol to model protein-peptide complexes using the HADDOCK web server, working through a test case to illustrate every steps. The flexibility challenge that peptides represent is dealt with by combining elements of conformational selection and induced fit molecular recognition theories. PMID:25555727

  13. Affinity purification of copper chelating peptides from chickpea protein hydrolysates.

    Science.gov (United States)

    Megías, Cristina; Pedroche, Justo; Yust, Maria M; Girón-Calle, Julio; Alaiz, Manuel; Millan, Francisco; Vioque, Javier

    2007-05-16

    Chickpea protein hydrolysates obtained with alcalase and flavourzyme were used for purification of copper chelating peptides by affinity chromatography using copper immobilized on solid supports. The chelating activity of purified peptides was indirectly measured by the inhibition of beta-carotene oxidation in the presence of copper. Two protein hydrolysates, obtained after 10 and 100 min of hydrolysis, were the most inhibitory of beta-carotene oxidation. Purified copper chelating peptides from these protein hydrolysates contained 19.7 and 35.1% histidine, respectively, in comparison to 2.7 and 2.6% in the protein hydrolysates. Chelating peptides from hydrolysate obtained after 10 min of hydrolysis were the most antioxidative being 8.3 times more antioxidative than the hydrolysate, while chelating peptides purified from protein hydrolysate obtained after 100 min were 3.1 times more antioxidative than its hydrolysate. However, the histidine content was higher in peptides derived from the 100 min hydrolysate (19.7 against 35.1% in 10 min hydrolysate), indicating that this amino acid is not the only factor involved in the antioxidative activity, and other factors such as peptide size or amino acid sequence are also determinant. This manuscript shows that affinity chromatography is a useful procedure for purification of copper chelating peptides. This method can be extended to other metals of interest in nutrition, such as calcium, iron, or zinc. Purified chelating peptides, in addition to their antioxidative properties, may also be useful in food mineral fortification for increasing the bioavailability of these metals.

  14. Peptides Interfering 3A Protein Dimerization Decrease FMDV Multiplication.

    Directory of Open Access Journals (Sweden)

    Mónica González-Magaldi

    Full Text Available Nonstructural protein 3A is involved in relevant functions in foot-and-mouth disease virus (FMDV replication. FMDV 3A can form homodimers and preservation of the two hydrophobic α-helices (α1 and α2 that stabilize the dimer interface is essential for virus replication. In this work, small peptides mimicking residues involved in the dimer interface were used to interfere with dimerization and thus gain insight on its biological function. The dimer interface peptides α1, α2 and that spanning the two hydrophobic α-helices, α12, impaired in vitro dimer formation of a peptide containing the two α-helices, this effect being higher with peptide α12. To assess the effect of dimer inhibition in cultured cells, the interfering peptides were N-terminally fused to a heptaarginine (R7 sequence to favor their intracellular translocation. Thus, when fused to R7, interference peptides (100 μM were able to inhibit dimerization of transiently expressed 3A, the higher inhibitions being found with peptides α1 and α12. The 3A dimerization impairment exerted by the peptides correlated with significant, specific reductions in the viral yield recovered from peptide-treated FMDV infected cells. In this case, α2 was the only peptide producing significant reductions at concentrations lower than 100 μM. Thus, dimer interface peptides constitute a tool to understand the structure-function relationship of this viral protein and point to 3A dimerization as a potential antiviral target.

  15. Chemical Methods for Peptide and Protein Production

    Directory of Open Access Journals (Sweden)

    Istvan Toth

    2013-04-01

    Full Text Available Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported a-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.

  16. The interaction of amino acids, peptides, and proteins with DNA.

    Science.gov (United States)

    Solovyev, Andrey Y; Tarnovskaya, Svetlana I; Chernova, Irina A; Shataeva, Larisa K; Skorik, Yury A

    2015-01-01

    Amino acids that carry charges on their side groups can bind to double stranded DNA (dsDNA) and change the strength of the double helix. Measurement of the DNA melting temperature (Tm) confirmed that acidic amino acids (Glu, Asp) weaken the H-bonds between DNA strands, whereas basic amino acids (Arg, Lys) strengthen the interaction between the strands. A rank correlation exists between the amino acid isoelectric points and the observed changes in Tm. A similar dependence of the hyperchromic effect on the isoelectric point of a protein (pepsin, insulin, cortexin, and protamine) was observed for DNA-protein complexes at room temperature. Short peptides (KE, AEDG, and KEDP) containing a mixture of acidic and basic amino acid residues also affect Tm and the stability of the double helix. A model for binding Glu and Lys to dsDNA was explored by a docking simulation. The model shows that Glu, in an untwisted shape, binds to dsDNA in its major groove and disrupts three H-bonds between the strands, thereby destabilizing the double helix. Lys, in an untwisted shape, binds to the external side of the dsDNA and forms two bonds with O atoms of neighboring phosphodiester groups, thereby strengthening the DNA helix.

  17. Ribonuclease S-peptide as a carrier in fusion proteins.

    OpenAIRE

    J.S. Kim; Raines, R. T.

    1993-01-01

    S-peptide (residues 1-20) and S-protein (residues 21-124) are the enzymatically inactive products of the limited digestion of ribonuclease A by subtilisin. S-peptide binds S-protein with high affinity to form ribonuclease S, which has full enzymatic activity. Recombinant DNA technology was used to produce a fusion protein having three parts: carrier, spacer, and target. The two carriers used were the first 15 residues of S-peptide (S15) and a mutant S15 in which Asp 14 had been changed to Asn...

  18. Peptide folding in the presence of interacting protein crowders

    Science.gov (United States)

    Bille, Anna; Mohanty, Sandipan; Irbäck, Anders

    2016-05-01

    Using Monte Carlo methods, we explore and compare the effects of two protein crowders, BPTI and GB1, on the folding thermodynamics of two peptides, the compact helical trp-cage and the β-hairpin-forming GB1m3. The thermally highly stable crowder proteins are modeled using a fixed backbone and rotatable side-chains, whereas the peptides are free to fold and unfold. In the simulations, the crowder proteins tend to distort the trp-cage fold, while having a stabilizing effect on GB1m3. The extent of the effects on a given peptide depends on the crowder type. Due to a sticky patch on its surface, BPTI causes larger changes than GB1 in the melting properties of the peptides. The observed effects on the peptides stem largely from attractive and specific interactions with the crowder surfaces, and differ from those seen in reference simulations with purely steric crowder particles.

  19. [Peptide synthesis aiming at elucidation and creation of protein functions].

    Science.gov (United States)

    Futaki, S

    1998-11-01

    The recent development of molecular biology has been elucidating outlines of the cross-talk of biomolecules. The understanding of the function of these biomolecules from the viewpoint of chemistry is now demanded not only for the understanding of biological systems but also for the creation of novel functional molecules. Here two topics are described about peptide synthesis aiming at the elucidation and the creation of protein functions. The first topic is the development of approaches for the synthesis of Tyr (SO3H)-containing peptides. Tyrosine sulfation is one of the most popular protein post-translational modifications. Synthetic peptides are of great help for the elucidation of the biological significance of tyrosine sulfation. We have developed two approaches for the efficient synthesis of tyrosine sulfate [Tyr (SO3H)]-containing peptides. The first approach employs a dimethylformamide-sulfur trioxide (DMF-SO3) complex as a sulfating agent and safety-catch protecting groups for the selective sulfation of tyrosine in the presence of serine. The second approach employs the direct introduction of Tyr(SO3H) into the peptide chain in the form of Fmoc-Tyr(SO3Na) followed by deprotection at 4 degrees C in trifluoroacetic acid. These approaches were successfully applied for the synthesis of cholecystokinin (CCK)-related peptides. The second topic deals with new approaches for the creation of artificial proteins through assembling alpha-helical peptides via selective disulfide or thioether formation. Approaches to assemble individual peptide segments on a peptide template were also developed. Four peptides corresponding to the transmembrane segments of the sodium channel (S4 in repeat I-IV) were assembled on a peptide template to give a protein having ion channel activity with rectification.

  20. Administration of Myelin Basic Protein Peptides Encapsulated in Mannosylated Liposomes Normalizes Level of Serum TNF-α and IL-2 and Chemoattractants CCL2 and CCL4 in Multiple Sclerosis Patients

    Directory of Open Access Journals (Sweden)

    Yakov Lomakin

    2016-01-01

    Full Text Available We have previously shown that immunodominant MBP peptides encapsulated in mannosylated liposomes (Xemys effectively suppressed experimental allergic encephalomyelitis (EAE. Within the frames of the successfully completed phase I clinical trial, we investigated changes in the serum cytokine profile after Xemys administration in MS patients. We observed a statistically significant decrease of MCP-1/CCL2, MIP-1β/CCL4, IL-7, and IL-2 at the time of study completion. In contrast, the serum levels of TNF-α were remarkably elevated. Our data suggest that the administration of Xemys leads to a normalization of cytokine status in MS patients to values commonly reported for healthy subjects. These data are an important contribution for the upcoming Xemys clinical trials.

  1. Gas Phase Radical Migration in Peptides and Proteins

    OpenAIRE

    Moore, Benjamin Nathan

    2013-01-01

    Radical chemistry represents a powerful set of reactions in which unstable odd electron species can undergo rapid and spontaneous chemical rearrangements. These reactions have recently found analytical use in the dissociation of peptides and proteins in mass spectrometry. In this dissertation, the factors controlling radical migration and dissociation are explored in detail through examination of model peptides and proteins by mass spectrometry and quantum mechanical calculation. Understandin...

  2. Origination of the Protein Fold Repertoire from Oily Pluripotent Peptides

    Directory of Open Access Journals (Sweden)

    Ranjan V. Mannige

    2014-03-01

    Full Text Available While the repertoire of protein folds that exists today underlies most of life’s capabilities, our mechanistic picture of protein fold origination is incomplete. This paper discusses a hypothetical mechanism for the emergence of the protein fold repertoire from highly dynamic and collapsed peptides, exemplified by peptides with high oil content or hydrophobicity. These peptides are called pluripotent to emphasize their capacity to evolve into numerous folds transiently available to them. As evidence, the paper will discuss previous simulation work on the superior fold evolvability of oily peptides, trace (“fossil” evidence within proteomes seen today, and a general relationship between protein dynamism and evolvability. Aside from implications on the origination of protein folds, the hypothesis implies that the vanishing utility of a random peptide in protein origination may be relatively exaggerated, as some random peptides with a certain composition (e.g., oily may fare better than others. In later sections, the hypothesis is discussed in the context of existing discussions regarding the spontaneous origination of biomolecules.

  3. Interaction between the C-terminal region of human myelin basic protein and calmodulin: analysis of complex formation and solution structure

    Directory of Open Access Journals (Sweden)

    Hayashi Nobuhiro

    2008-02-01

    Full Text Available Abstract Background The myelin sheath is a multilamellar membrane structure wrapped around the axon, enabling the saltatory conduction of nerve impulses in vertebrates. Myelin basic protein, one of the most abundant myelin-specific proteins, is an intrinsically disordered protein that has been shown to bind calmodulin. In this study, we focus on a 19-mer synthetic peptide from the predicted calmodulin-binding segment near the C-terminus of human myelin basic protein. Results The interaction of native human myelin basic protein with calmodulin was confirmed by affinity chromatography. The binding of the myelin basic protein peptide to calmodulin was tested with isothermal titration calorimetry (ITC in different temperatures, and Kd was observed to be in the low μM range, as previously observed for full-length myelin basic protein. Surface plasmon resonance showed that the peptide bound to calmodulin, and binding was accompanied by a conformational change; furthermore, gel filtration chromatography indicated a decrease in the hydrodynamic radius of calmodulin in the presence of the peptide. NMR spectroscopy was used to map the binding area to reside mainly within the hydrophobic pocket of the C-terminal lobe of calmodulin. The solution structure obtained by small-angle X-ray scattering indicates binding of the myelin basic protein peptide into the interlobal groove of calmodulin, while calmodulin remains in an extended conformation. Conclusion Taken together, our results give a detailed structural insight into the interaction of calmodulin with a C-terminal segment of a major myelin protein, the myelin basic protein. The used 19-mer peptide interacts mainly with the C-terminal lobe of calmodulin, and a conformational change accompanies binding, suggesting a novel mode of calmodulin-target protein interaction. Calmodulin does not collapse and wrap around the peptide tightly; instead, it remains in an extended conformation in the solution structure

  4. Identification of a nuclear transport inhibitory signal (NTIS) in the basic domain of HIV-1 Vif protein.

    Science.gov (United States)

    Friedler, A; Zakai, N; Karni, O; Friedler, D; Gilon, C; Loyter, A

    1999-06-11

    The HIV-1 auxiliary protein Vif contains a basic domain within its sequence. This basic region,90RKKR93, is similar to the prototypic nuclear localization signal (NLS). However, Vif is not a nuclear protein and does not function in the nucleus. Here we have studied the karyophilic properties of this basic region. We have synthesized peptides corresponding to this positively charged NLS-like region and observed that these peptides inhibited nuclear transport via the importin pathway in vitro with IC50values in the micromolar range. Inhibition was observed only with peptides derived from the positively charged region, but not from other regions of the Vif protein, showing sequence specificity. On the other hand, the Vif inhibitory peptide Vif88-98 did not confer karyophilic properties when conjugated to BSA. The inactive Vif conjugate and the active SV40-NLS-BSA conjugate both contained a similar number of peptides conjugated to each BSA molecule, as was determined by amino acid analysis of the peptide-BSA conjugates. Thus, the lack of nuclear import of the Vif peptide-BSA conjugate cannot be attributed to insufficient number of conjugated peptide molecules per BSA molecule. Our results suggest that the HIV-1 Vif protein carries an NLS-like sequence that inhibits, but does not mediate, nuclear import via the importin pathway. We have termed such signals as nuclear transport inhibitory signals (NTIS). The possible role of NTIS in controlling nuclear uptake, and specifically during virus infection, is discussed herein. Our results raise the possibility that NLS-like sequences of certain low molecular weight viral proteins may serve as regulators of nucleocytoplasmic trafficking and not neccessarily as mediators of nuclear import.

  5. Lipid membrane association of myelin proteins and peptide segments studied by oriented and synchrotron radiation circular dichroism spectroscopy.

    Science.gov (United States)

    Muruganandam, Gopinath; Bürck, Jochen; Ulrich, Anne S; Kursula, Inari; Kursula, Petri

    2013-12-01

    Myelin-specific proteins are either integral or peripheral membrane proteins that, in complex with lipids, constitute a multilayered proteolipid membrane system, the myelin sheath. The myelin sheath surrounds the axons of nerves and enables rapid conduction of axonal impulses. Myelin proteins interact intimately with the lipid bilayer and play crucial roles in the assembly, function, and stability of the myelin sheath. Although myelin proteins have been investigated for decades, their structural properties upon membrane surface binding are still largely unknown. In this study, we have used simplified model systems consisting of synthetic peptides and membrane mimics, such as detergent micelles and/or lipid vesicles, to probe the conformation of peptides using synchrotron radiation circular dichroism spectroscopy (SRCD). Additionally, oriented circular dichroism spectroscopy (OCD) was employed to examine the orientation of myelin peptides in macroscopically aligned lipid bilayers. Various representative peptides from the myelin basic protein (MBP), P0, myelin/oligodencrocyte glycoprotein, and connexin32 (cx32) were studied. A helical peptide from the central immunodominant epitope of MBP showed a highly tilted orientation with respect to the membrane surface, whereas the N-terminal cytoplasmic segment of cx32 folded into a helical structure that was only slightly tilted. The folding of full-length myelin basic protein was, furthermore, studied in a bicelle environment. Our results provide information on the conformation and membrane alignment of important membrane-binding peptides in a membrane-mimicking environment, giving novel insights into the mechanisms of membrane binding and stacking by myelin proteins.

  6. Dinosaur Peptides Suggest Mechanisms of Protein Survival

    Energy Technology Data Exchange (ETDEWEB)

    San Antonio, James D.; Schweitzer, Mary H.; Jensen, Shane T.; Kalluri, Raghu; Buckley, Michael; Orgel, Joseph P.R.O. (Harvard-Med); (IIT); (NCSU); (UPENN); (Manchester); (Orthovita)

    2011-09-16

    Eleven collagen peptide sequences recovered from chemical extracts of dinosaur bones were mapped onto molecular models of the vertebrate collagen fibril derived from extant taxa. The dinosaur peptides localized to fibril regions protected by the close packing of collagen molecules, and contained few acidic amino acids. Four peptides mapped to collagen regions crucial for cell-collagen interactions and tissue development. Dinosaur peptides were not represented in more exposed parts of the collagen fibril or regions mediating intermolecular cross-linking. Thus functionally significant regions of collagen fibrils that are physically shielded within the fibril may be preferentially preserved in fossils. These results show empirically that structure-function relationships at the molecular level could contribute to selective preservation in fossilized vertebrate remains across geological time, suggest a 'preservation motif', and bolster current concepts linking collagen structure to biological function. This non-random distribution supports the hypothesis that the peptides are produced by the extinct organisms and suggests a chemical mechanism for survival.

  7. Alzheimer's disease against peptides products of enzymatic cleavage of APP protein. Forming and variety of fibrillating peptides - some aspects.

    Science.gov (United States)

    Marszałek, Małgorzata

    2016-01-01

    Various and different peptides products resulting from enzymatic protein cleavage of Amyloid Precursor Proteins (APP) are the main agents in the pathophysiology of Alzheimer's disease (AD). Although relatively well-known, they still arouse interest leading to further intense and wide-ranging research. Their biology and physico-chemical properties still are challenging for basic, experimental research and are matter of scientific debate. The APP itself and its functions are still somewhat enigmatic and therefore it is also called the All Purpose Protein. Apart from well known amyloidogenic and antiamyloidogenic (non-amyloidogenic) enzymatic cleavage pathways of APP protein this paper deals with issues connected with other, alternative pathways that seem to be interesting and important as well. They lead to other than Aβ forms of peptide products such as: N-APP, N-terminally cleavage products of APP (N-terminally truncated ) Aβ', γ- secretase-independent pathway products that involve concerted cleavages of APP by α- and β-secretase or products that emerge after caspase activity. Presence of all these peptides in CSF, ISF, blood serum and urine of the AD patients is crucial for successful diagnosis, giving rise to hope of their better detection and potentially better treatment of AD. Therefore, newly discovered products of the AβT domain cleavage (Aβ total i.e. full fibrillating domain of APP), Aβ type products and other peptides because of their biology and physico-chemical properties are very intriguing and deserve further experimental research. On the other hand after better recognition and better understanding their biology they might be enormously useful in the future for diagnosis and therapy for example Alzheimer's disease. PMID:27383575

  8. Self-assembling peptides form nanodiscs that stabilize membrane proteins

    DEFF Research Database (Denmark)

    Midtgaard, Søren Roi; Pedersen, Martin Cramer; Kirkensgaard, Jacob Judas Kain;

    2014-01-01

    -assemble in combination with phospholipids to form discoidal shaped particles that can stabilize membrane proteins. In the present study, we have investigated an ApoA1 mimetic peptide with respect to its solution structure when in complex with phospholipids. This was achieved using a powerful combination of small-angle X...... show that, like the ApoA1 and derived nanodiscs, these peptide discs can accommodate and stabilize a membrane protein. Finally, we exploit their dynamic properties and show that the 18A discs may be used for transferring membrane proteins and associated phospholipids directly and gently...

  9. Peptides interfering 3A protein dimerization decrease FMDV multiplication

    OpenAIRE

    Mónica González-Magaldi; Ángela Vázquez-Calvo; de la Torre, Beatriz G; Javier Valle; David Andreu; Francisco Sobrino

    2015-01-01

    Nonstructural protein 3A is involved in relevant functions in foot-and-mouth disease virus (FMDV) replication. FMDV 3A can form homodimers and preservation of the two hydrophobic ??-helices (??1 and ??2) that stabilize the dimer interface is essential for virus replication. In this work, small peptides mimicking residues involved in the dimer interface were used to interfere with dimerization and thus gain insight on its biological function. The dimer interface peptides ??1, ??2 and that span...

  10. Synthetic peptides and ribosomal proteins as substrate for 60S ribosomal protein kinase from yeast cells

    DEFF Research Database (Denmark)

    Grankowski, N; Gasior, E; Issinger, O G

    1993-01-01

    Kinetic studies on the 60S protein kinase were conducted with synthetic peptides and ribosomal proteins as substrate. Peptide RRREEESDDD proved to be the best synthetic substrate for this enzyme. The peptide has a sequence of amino acids which most closely resembles the structure of potential...... phosphorylation sites in natural substrates, i.e., acidic ribosomal proteins. The superiority of certain kinetic parameters for 60S kinase obtained with the native whole 80S ribosomes over those of the isolated fraction of acidic ribosomal proteins indicates that the affinity of 60S kinase to the specific protein...

  11. Self-Assembled Proteins and Peptides as Scaffolds for Tissue Regeneration.

    Science.gov (United States)

    Loo, Yihua; Goktas, Melis; Tekinay, Ayse B; Guler, Mustafa O; Hauser, Charlotte A E; Mitraki, Anna

    2015-11-18

    Self-assembling proteins and peptides are increasingly gaining interest for potential use as scaffolds in tissue engineering applications. They self-organize from basic building blocks under mild conditions into supramolecular structures, mimicking the native extracellular matrix. Their properties can be easily tuned through changes at the sequence level. Moreover, they can be produced in sufficient quantities with chemical synthesis or recombinant technologies to allow them to address homogeneity and standardization issues required for applications. Here. recent advances in self-assembling proteins, peptides, and peptide amphiphiles that form scaffolds suitable for tissue engineering are reviewed. The focus is on a variety of motifs, ranging from minimalistic dipeptides, simplistic ultrashort aliphatic peptides, and peptide amphiphiles to large "recombinamer" proteins. Special emphasis is placed on the rational design of self-assembling motifs and biofunctionalization strategies to influence cell behavior and modulate scaffold stability. Perspectives for combination of these "bottom-up" designer strategies with traditional "top-down" biofabrication techniques for new generations of tissue engineering scaffolds are highlighted. PMID:26461979

  12. Semi-wet peptide/protein array using supramolecular hydrogel

    Science.gov (United States)

    Kiyonaka, Shigeki; Sada, Kazuki; Yoshimura, Ibuki; Shinkai, Seiji; Kato, Nobuo; Hamachi, Itaru

    2004-01-01

    The protein microarray is a crucial biomaterial for the rapid and high-throughput assay of many biological events where proteins are involved. In contrast to the DNA microarray, it has not been sufficiently established because of protein instability under the conventional dry conditions. Here we report a novel semi-wet peptide/protein microarray using a supramolecular hydrogel composed of glycosylated amino acetate. The spontaneous gel-formation and amphiphilic properties of this supramolecular hydrogel have been applied to a new type of peptide/protein gel array that is compatible with enzyme assays. Aqueous cavities created in the gel matrix are a suitable semi-wet reaction medium for enzymes, whereas the hydrophobic domains of the fibre are useful as a unique site for monitoring the reaction. This array system overcomes several drawbacks of conventional protein chips, and thus can have potential applications in pharmaceutical research and diagnosis.

  13. Multienzyme Modification of Hemp Protein for Functional Peptides Synthesis

    Directory of Open Access Journals (Sweden)

    Ranjana Das

    2015-01-01

    Full Text Available Functional foods and nutraceuticals are of special importance, particularly for their impact on human health and prevention of certain chronic diseases. Consequently, the production and properties of bioactive peptides have received an increasing scientific interest over past few years. Present work intends to compare the competence of metalloendopeptidases (“Protease N” and “Protease A” with papain for getting functional peptides from hemp seed meal, which is an obligatory waste of hemp fiber production industry. As a measure of the functional potential hemp protein hydrolysates were analyzed for their antiradical properties in DPPH system. “Protease N” modified protein hydrolysate exhibited comparatively superior radical scavenging activity in DPPH system. Overall findings represent the importance of “Protease N,” as endopeptidase in getting peptides of good antiradical properties from various protein sources.

  14. Peptide and protein loading into porous silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Prestidge, C.A.; Barnes, T.J.; Mierczynska-Vasilev, A.; Kempson, I.; Peddie, F. [Ian Wark Research Institute, University of South Australia, Mawson Lakes (Australia); Barnett, C. [Medica Ltd, Malvern, Worcestershire, UK WR14 3SZ (United Kingdom)

    2008-02-15

    The influence of peptide/protein size and hydrophobicity on the physical and chemical aspects of loading within porous silicon (pSi) wafer samples has been determined using Atomic Force Microscopy (AFM) and Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS). Both Gramicidin A (a small hydrophobic peptide) and Papain (a larger hydrophilic protein) were observed (ToF-SIMS) to penetrate across the entire pSi layer, even at low loading levels. AFM surface imaging of pSi wafers during peptide/protein loading showed that surface roughness increased with Papain loading, but decreased with Gramicidin A loading. For Papain, the loading methodology was also found to influence loading efficiency. These differences indicate more pronounced surface adsorption of Papain. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Peptide-peptide and protein-peptide interactions in mixtures of whey protein isolate and whey protein isolate hydrolysates

    NARCIS (Netherlands)

    Creusot, N.P.; Gruppen, H.; Koningsveld, van G.A.; Kruif, de C.G.; Voragen, A.G.J.

    2006-01-01

    The extent of aggregation in whey protein isolate (WPI) hydrolysates induced by Bacillus licheniformis protease was quantified as a function of degree of hydrolysis (DH), temperature and ionic strength. The capacity of the hydrolysates to aggregate added intact protein was also studied. The amount o

  16. Binding of acylated peptides and fatty acids to phospholipid vesicles: pertinence to myristoylated proteins.

    Science.gov (United States)

    Peitzsch, R M; McLaughlin, S

    1993-10-01

    We studied the binding of fatty acids and acylated peptides to phospholipid vesicles by making electrophoretic mobility and equilibrium dialysis measurements. The binding energies of the anionic form of the fatty acids and the corresponding acylated glycines were identical; the energies increased by 0.8 kcal/mol per number of carbons in the acyl chain (Ncarbon = 10, 12, 14, 16), a value identical to that for the classical entropy-driven hydrophobic effect discussed by Tanford [The Hydrophobic Effect (1980) Wiley, New York]. The unitary Gibbs free binding energy, delta Gou, of myristoylated glycine, 8 kcal/mol, is independent of the nature of the electrically neutral lipids used to form the vesicles. Similar binding energies were obtained with other myristoylated peptides (e.g., Gly-Ala, Gly-Ala-Ala). The 8 kcal/mol, which corresponds to an effective dissociation constant of 10(-4) M for myristoylated peptides with lipids, provides barely enough energy to attach a myristoylated protein in the cytoplasm to the plasma membrane. Thus, other factors that reduce (e.g., hydrophobic interaction of myristate with the covalently attached protein) or enhance (e.g., electrostatic interactions of basic residues with acidic lipids; protein-protein interactions with intrinsic receptor proteins) the interaction of myristoylated proteins with membranes are likely to be important and may cause reversible translocation of these proteins to the membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Reaction mechanisms in the radiolysis of peptides, polypeptides and proteins

    International Nuclear Information System (INIS)

    The purpose of this review is to bring together and to correlate the wide variety of experimental studies that provide information on the reaction products and reaction mechanisms involved in the radiolysis of peptides, polypeptides and proteins (including chromosomal proteins) in both aqueous and solid-state systems. The comparative radiation chemistry of these systems is developed in terms of specific reactions of the peptide main-chain and the aliphatic, aromatic-unsaturated and sulfur-containing side-chains. Information obtained with the various experimental techniques of product analysis, competition kinetics, spin-trapping, pulse radiolysis and ESR spectroscopy is included. 147 refs

  18. Specific interaction of central nervous system myelin basic protein with lipids effects of basic protein on glucose leakage from liposomes

    NARCIS (Netherlands)

    Gould, R.M.; London, Y.

    1972-01-01

    The leakage from liposomes preloaded with glucose was continuously monitored in a Perkin-Elmer Model 356 dual beam spectrophotometer using an enzyme-linked assay system. The central nervous system myelin basic protein (A1 protein) caused a 3–4-fold increase in the rate of leakage from liposomes prep

  19. A New Peptide with Membrane-permeable Function Derived from Human Circadian Proteins

    Institute of Scientific and Technical Information of China (English)

    Tao PENG; Ying-Hui LIU; Chun-Lei YANG; Chao-Min WAN; Yao-Qi WANG; Zheng-Rong WANG

    2004-01-01

    Basic peptides such as human immunodeficiency virus type 1 (HIV- 1) Tat-(48-60) and Drosophila Antennapedia-(43-58) have been reported to have a membrane permeability and a carrier function for intracellular protein delivery. Based on the fluorescence microscopic observations of the vascular endothelial cells (ECV-304) and the primary cultured neuroglial ceils, we found that human Clock protein DNA-binding peptide [residue 35-47, hClock-(35-47)] had a translocation activity very similar to Tat-(48-60). The cellular uptake of hClock-(35-47) increases with the increase of incubation time and concentration. The internalization effect at 4 ℃ was same as that at 37 ℃. Internalization of hClock-(35-47) was saturable and could be inhibited by the excess of the other MPPs. Moreover, The uptake of these peptides were significantly inhibited in the presence of heparan sulfate. These results strongly suggested that the hClock-(35-47) shared a common or very similar internalization pathway with other MPPs. Furthermore, we injected rat through the common carotid artery with hClock-(35-47)-FITC peptide, and cryostat sections of the brain were prepared and observed using a fluorescence microscope. Result showed that the peptide had the ability to translocate through the blood-brain barrier. It is promising to provide a new safe carrier for the intracellular and encephalic treatment.

  20. Signal peptides and protein localization prediction

    DEFF Research Database (Denmark)

    Nielsen, Henrik

    2005-01-01

    In 1999, the Nobel prize in Physiology or Medicine was awarded to Gunther Blobel “for the discovery that proteins have intrinsic signals that govern their transport and localization in the cell”. Since the subcellular localization of a protein is an important clue to its function, the characteriz......In 1999, the Nobel prize in Physiology or Medicine was awarded to Gunther Blobel “for the discovery that proteins have intrinsic signals that govern their transport and localization in the cell”. Since the subcellular localization of a protein is an important clue to its function...

  1. Proteins and Peptides in Biomimetic Polymeric Membranes

    DEFF Research Database (Denmark)

    Perez, Alfredo Gonzalez

    2013-01-01

    This chapter discusses recent advances and the main advantages of block copolymers for functional membrane protein reconstitution in biomimetic polymeric membranes. A rational approach to the reconstitution of membrane proteins in a functional form can be addressed by a more holistic view by usin...

  2. Preparation of antioxidative corn protein hydrolysates, purification and evaluation of three novel corn antioxidant peptides.

    Science.gov (United States)

    Jin, Du-Xin; Liu, Xiao-Lan; Zheng, Xi-Qun; Wang, Xiao-Jie; He, Jun-Fang

    2016-08-01

    Corn gluten meal is a major co-product of corn wet milling. Corn gluten meal was hydrolyzed with Alcalase, Flavourzyme, Alcalase+Flavourzyme and Flavourzyme+Alcalase. At the substrate concentration of 10%, corn protein hydrolysate catalyzed by Alcalase had a degree of hydrolysis of 17.83%, which was higher than that by Flavourzyme (3.65%). The hydrolysate catalyzed by Alcalase+Flavourzyme exhibited better antioxidant activities and was further purified. Three novel antioxidant peptides were purified by a series of chromatographic techniques. Sequences of the three peptides were identified as Cys-Ser-Gln-Ala-Pro-Leu-Ala, Tyr-Pro-Lys-Leu-Ala-Pro-Asn-Glu and Tyr-Pro-Gln-Leu-Leu-Pro-Asn-Glu, respectively. Among the three peptides, Cys-Ser-Gln-Ala-Pro-Leu-Ala exhibited good reducing power and excellent scavenging capacities for DPPH radical and superoxide anion radical, with IC50 values of 0.116 and 0.39mg/ml, respectively. The results from our study indicate antioxidant potency of corn protein hydrolysates and peptides separated from corn gluten meal and can provide basic understanding for the application of corn protein hydrolysates as natural antioxidants. PMID:26988521

  3. Anti-biofilm and sporicidal activity of peptides based on wheat puroindoline and barley hordoindoline proteins.

    Science.gov (United States)

    Shagaghi, Nadin; Alfred, Rebecca L; Clayton, Andrew H A; Palombo, Enzo A; Bhave, Mrinal

    2016-07-01

    The broad-spectrum activity of antimicrobial peptides (AMPs) and low probability of development of host resistance make them excellent candidates as novel bio-control agents. A number of AMPs are found to be cationic, and a small proportion of these are tryptophan-rich. The puroindolines (PIN) are small, basic proteins found in wheat grains with proposed roles in biotic defence of seeds and seedlings. Synthetic peptides based on their unique tryptophan-rich domain (TRD) display antimicrobial properties. Bacterial endospores and biofilms are highly resistant cells, with significant implications in both medical and food industries. In this study, the cationic PIN TRD-based peptides PuroA (FPVTWRWWKWWKG-NH2 ) and Pina-M (FSVTWRWWKWWKG-NH2 ) and the related barley hordoindoline (HIN) based Hina (FPVTWRWWTWWKG-NH2 ) were tested for effects on planktonic cells and biofilms of the common human pathogens including Pseudomonas aeruginosa, Listeria monocytogenes and the non-pathogenic Listeria innocua. All peptides showed significant bactericidal activity. Further, PuroA and Pina-M at 2 × MIC prevented initial biomass attachment by 85-90% and inhibited >90% of 6-h preformed biofilms of all three organisms. However Hina, with a substitution of Lys-9 with uncharged Thr, particularly inhibited Listeria biofilms. The PIN based peptides were also tested against vegetative cells and endospores of Bacillus subtilis. The results provided evidence that these tryptophan-rich peptides could kill B. subtilis even in sporulated state, reducing the number of viable spores by 4 log units. The treated spores appeared withered under scanning electron microscopy. The results establish the potential of these tryptophan-rich peptides in controlling persistent pathogens of relevance to food industries and human health. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:27238815

  4. Enhanced Information Output From Shotgun Proteomics Data by Protein Quantification and Peptide Quality Control (PQPQ)

    OpenAIRE

    Forshed, J.; Johansson, H. J.; Pernemalm, M; Branca, R. M. M.; Sandberg, A.; Lehtio, J.

    2011-01-01

    We present a tool to improve quantitative accuracy and precision in mass spectrometry based on shotgun proteomics: protein quantification by peptide quality control, PQPQ. The method is based on the assumption that the quantitative pattern of peptides derived from one protein will correlate over several samples. Dissonant patterns arise either from outlier peptides or because of the presence of different protein species. By correlation analysis, protein quantification by peptide quality contr...

  5. Systematic discovery of new recognition peptides mediating protein interaction networks

    DEFF Research Database (Denmark)

    Neduva, Victor; Linding, Rune; Su-Angrand, Isabelle;

    2005-01-01

    Many aspects of cell signalling, trafficking, and targeting are governed by interactions between globular protein domains and short peptide segments. These domains often bind multiple peptides that share a common sequence pattern, or "linear motif" (e.g., SH3 binding to PxxP). Many domains...... molecular details of how interaction networks are constructed, and can explain how one protein is able to bind to very different partners. Here we show that binding motifs can be detected using data from genome-scale interaction studies, and thus avoid the normally slow discovery process. Our approach based...... that binds Translin with a KD of 43 microM. We estimate that there are dozens or even hundreds of linear motifs yet to be discovered that will give molecular insight into protein networks and greatly illuminate cellular processes.Many aspects of cell signalling, trafficking, and targeting are governed...

  6. Nanoparticles in relation to peptide and protein aggregation

    Directory of Open Access Journals (Sweden)

    Zaman M

    2014-02-01

    Full Text Available Masihuz Zaman, Ejaz Ahmad, Atiyatul Qadeer, Gulam Rabbani, Rizwan Hasan Khan Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India Abstract: Over the past two decades, there has been considerable research interest in the use of nanoparticles in the study of protein and peptide aggregation, and of amyloid-related diseases. The influence of nanoparticles on amyloid formation yields great interest due to its small size and high surface area-to-volume ratio. Targeting nucleation kinetics by nanoparticles is one of the most searched for ways to control or induce this phenomenon. The observed effect of nanoparticles on the nucleation phase is determined by particle composition, as well as the amount and nature of the particle's surface. Various thermodynamic parameters influence the interaction of proteins and nanoparticles in the solution, and regulate the protein assembly into fibrils, as well as the disaggregation of preformed fibrils. Metals, organic particles, inorganic particles, amino acids, peptides, proteins, and so on are more suitable candidates for nanoparticle formulation. In the present review, we attempt to explore the effects of nanoparticles on protein and peptide fibrillation processes from both perspectives (ie, as inducers and inhibitors on nucleation kinetics and in the disaggregation of preformed fibrils. Their formulation and characterization by different techniques have been also addressed, along with their toxicological effects, both in vivo and in vitro. Keywords: amyloid formation, inducer, inhibitor, nanoparticle, nucleation, toxicity

  7. Chicken Egg Shell Membrane Associated Proteins and Peptides.

    Science.gov (United States)

    Makkar, Sarbjeet; Liyanage, Rohana; Kannan, Lakshmi; Packialakshmi, Balamurugan; Lay, Jack O; Rath, Narayan C

    2015-11-11

    Egg shells are poultry industry byproducts with potential for use in various biological and agricultural applications. We have been interested in the membranes underlying the calcareous shell as a feed supplement, which showed potential to improve immunity and performance of post hatch poultry. Therefore, to determine their protein and peptide profiles, we extracted the egg shell membranes (ESM) from fresh unfertilized eggs with methanol and guanidine hydrochloride (GdHCl) to obtain soluble proteins for analysis by mass spectrometry. The methanol extract was subjected to matrix-assisted laser desorption ionization (MALDI), electrospray ionization (ESI), high-performance reverse phase liquid chromatographic separation (HPLC), and tandem mass spectrometry (MS/MS) to determine its peptide and protein profiles. The GdHCl extract was subjected to ESI-HPLC-MS/MS following trypsin digestion of reduced/alkylated proteins. Nine proteins from the methanol extract and >275 proteins from the GdHCl extract were tentatively identified. The results suggested the presence of several abundant proteins from egg whites, such as ovoalbumin, ovotransferrin, and lysozyme as well as many others associated with antimicrobial, biomechanical, cytoskeletal organizational, cell signaling, and enzyme activities. Collagens, keratin, agrin, and laminin were some of the structural proteins present in the ESM. The methanol-soluble fraction contained several clusterin peptides and defensins, particularly, two isoforms of gallin. The ratios of the two isoforms of gallin differed between the membranes obtained from brown and white eggs. The high abundance of several antimicrobial, immunomodulatory, and other bioactive proteins in the ESM along with its potential to entrap various microbes and antigens may make it a suitable vehicle for oral immunization of post hatch poultry and improve their disease resistance. PMID:26485361

  8. Chicken Egg Shell Membrane Associated Proteins and Peptides.

    Science.gov (United States)

    Makkar, Sarbjeet; Liyanage, Rohana; Kannan, Lakshmi; Packialakshmi, Balamurugan; Lay, Jack O; Rath, Narayan C

    2015-11-11

    Egg shells are poultry industry byproducts with potential for use in various biological and agricultural applications. We have been interested in the membranes underlying the calcareous shell as a feed supplement, which showed potential to improve immunity and performance of post hatch poultry. Therefore, to determine their protein and peptide profiles, we extracted the egg shell membranes (ESM) from fresh unfertilized eggs with methanol and guanidine hydrochloride (GdHCl) to obtain soluble proteins for analysis by mass spectrometry. The methanol extract was subjected to matrix-assisted laser desorption ionization (MALDI), electrospray ionization (ESI), high-performance reverse phase liquid chromatographic separation (HPLC), and tandem mass spectrometry (MS/MS) to determine its peptide and protein profiles. The GdHCl extract was subjected to ESI-HPLC-MS/MS following trypsin digestion of reduced/alkylated proteins. Nine proteins from the methanol extract and >275 proteins from the GdHCl extract were tentatively identified. The results suggested the presence of several abundant proteins from egg whites, such as ovoalbumin, ovotransferrin, and lysozyme as well as many others associated with antimicrobial, biomechanical, cytoskeletal organizational, cell signaling, and enzyme activities. Collagens, keratin, agrin, and laminin were some of the structural proteins present in the ESM. The methanol-soluble fraction contained several clusterin peptides and defensins, particularly, two isoforms of gallin. The ratios of the two isoforms of gallin differed between the membranes obtained from brown and white eggs. The high abundance of several antimicrobial, immunomodulatory, and other bioactive proteins in the ESM along with its potential to entrap various microbes and antigens may make it a suitable vehicle for oral immunization of post hatch poultry and improve their disease resistance.

  9. Dendrimer effects on peptide and protein fibrillation

    DEFF Research Database (Denmark)

    Heegaard, Peter M. H.; Boas, Ulrik; Otzen, Daniel E.

    2007-01-01

    , they offer numerous possibilities for interactions with and responses to biological macromolecules and biostructures including cell membranes and proteins. By way of their multiple functional surface groups, they allow the design of surfaces carrying a multitude of biological motifs and/or charges giving...... rise to quite significant biological and physico-chemical effects. Here we describe the surprising ability of dendrimers to interact with and perturb polypeptide conformations, particularly efficiently towards amyloid structures; that is, the structures of highly insoluble polypeptide aggregates...

  10. Generation of GFP Native Protein for Detection of Its Intracellular Uptake by Cell-Penetrating Peptides.

    Science.gov (United States)

    Kadkhodayan, S; Sadat, S M; Irani, S; Fotouhi, F; Bolhassani, A

    2016-01-01

    Different types of lipid- and polymer-based vectors have been developed to deliver proteins into cells, but these methods showed relatively poor efficiency. Recently, a group of short, highly basic peptides known as cell-penetrating peptides (CPPs) were used to carry polypeptides and proteins into cells. In this study, expression and purification of GFP protein was performed using the prokaryotic pET expression system. We used two amphipathic CPPs (Pep-1 and CADY-2) as a novel delivery system to transfer the GFP protein into cells. The morphological features of the CPP/GFP complexes were studied by scanning electron microscopy (SEM), Zetasizer, and SDS-PAGE. The efficiency of GFP transfection using Pep-1 and CADY-2 peptides and TurboFect reagent was compared with FITC-antibody protein control delivered by these transfection vehicles in the HEK-293T cell line. SEM data confirmed formation of discrete nanoparticles with a diameter of below 300 nm. Moreover, formation of the complexes was detected using SDS-PAGE as two individual bands, indicating non-covalent interaction. The size and homogeneity of Pep-1/GFP and CADY-2/GFP complexes were dependent on the ratio of peptide/cargo formulations, and responsible for their biological efficiency. The cells transfected by Pep-1/GFP and CADY-2/GFP complexes at a molar ratio of 20 : 1 demonstrated spreading green regions using fluorescent microscopy. Flow cytometry results showed that the transfection efficiency of Pep-based nanoparticles was similar to CADY-based nanoparticles and comparable with TurboFect-protein complexes. These data open an efficient way for future therapeutic purposes. PMID:27516189

  11. Contextual specificity in peptide-mediated protein interactions.

    Directory of Open Access Journals (Sweden)

    Amelie Stein

    Full Text Available Most biological processes are regulated through complex networks of transient protein interactions where a globular domain in one protein recognizes a linear peptide from another, creating a relatively small contact interface. Although sufficient to ensure binding, these linear motifs alone are usually too short to achieve the high specificity observed, and additional contacts are often encoded in the residues surrounding the motif (i.e. the context. Here, we systematically identified all instances of peptide-mediated protein interactions of known three-dimensional structure and used them to investigate the individual contribution of motif and context to the global binding energy. We found that, on average, the context is responsible for roughly 20% of the binding and plays a crucial role in determining interaction specificity, by either improving the affinity with the native partner or impeding non-native interactions. We also studied and quantified the topological and energetic variability of interaction interfaces, finding a much higher heterogeneity in the context residues than in the consensus binding motifs. Our analysis partially reveals the molecular mechanisms responsible for the dynamic nature of peptide-mediated interactions, and suggests a global evolutionary mechanism to maximise the binding specificity. Finally, we investigated the viability of non-native interactions and highlight cases of potential cross-reaction that might compensate for individual protein failure and establish backup circuits to increase the robustness of cell networks.

  12. Electrospinning of peptide and protein fibres: approaching the molecular scale.

    Science.gov (United States)

    Nuansing, Wiwat; Frauchiger, Daniela; Huth, Florian; Rebollo, Amaia; Hillenbrand, Rainer; Bittner, Alexander M

    2013-01-01

    For the example of peptides and proteins, we contrast "natural" self-assembly, i.e. aggregation in solutions, with "forced" assembly by electrospinning, i.e. by application of strong electrical fields to concentrated solutions. We were able to spin fibres that contain short stretches of diameters down to 5 nm; the ultimate aim is a fibre of the size of a single molecule. Besides their wide biochemical relevance, small peptides can assemble to defined supramolecular structures such as fibres and tubes. While the main driving mechanism in electrospinning is certainly based on electrostatics, aromatic groups in peptides might play a directing role. We used fluorenyl and phenyl, whose i-stacking is not manifested in vibrational spectra, but is clearly visible in their crystal structures. The main differences between solid phases and single molecules are found for O-H and N-H stretching and bending vibrations, due to extensive hydrogen bonding in solids. However, we found that only proteins, but not peptides, can be spun into ultrathin fibres. Therefore, nanoscale analysis by SEM and AFM, and by infrared near-field microscopy are especially useful. The comparison of the amide bands from the infrared and Raman spectra, combined with circular dichroism spectroscopy, allowed us to assign secondary structures. Our results are not only useful for interpreting and refining current theories of self-assembly and electrospinning, but also for creating new scaffolds for the growth of sensitive cells. PMID:24611278

  13. Protein/Peptide Aggregation and Amyloidosis on Biointerfaces

    Directory of Open Access Journals (Sweden)

    Qi Lu

    2016-08-01

    Full Text Available Recently, studies of protein/peptide aggregation, particularly the amyloidosis, have attracted considerable attention in discussions of the pathological mechanisms of most neurodegenerative diseases. The protein/peptide aggregation processes often occur at the membrane–cytochylema interface in vivo and behave differently from those occurring in bulk solution, which raises great interest to investigate how the interfacial properties of artificial biomaterials impact on protein aggregation. From the perspective of bionics, current progress in this field has been obtained mainly from four aspects: (1 hydrophobic–hydrophilic interfaces; (2 charged surface; (3 chiral surface; and (4 biomolecule-related interfaces. The specific physical and chemical environment provided by these interfaces is reported to strongly affect the adsorption of proteins, transition of protein conformation, and diffusion of proteins on the biointerface, all of which are ultimately related to protein assembly. Meanwhile, these compelling results of in vitro experiments can greatly promote the development of early diagnostics and therapeutics for the relevant neurodegenerative diseases. This paper presents a brief review of these appealing studies, and particular interests are placed on weak interactions (i.e., hydrogen bonding and stereoselective interactions that are also non-negligible in driving amyloid aggregation at the interfaces. Moreover, this paper also proposes the future perspectives, including the great opportunities and challenges in this field as well.

  14. Evaluating Peptide Mass Fingerprinting-based Protein Identification

    Institute of Scientific and Technical Information of China (English)

    Senthilkumar Damodaran; Troy D. Wood; Priyadharsini Nagarajan; Richard A. Rabin

    2007-01-01

    Identification of proteins by mass spectrometry (MS) is an essential step in pro- teomic studies and is typically accomplished by either peptide mass fingerprinting (PMF) or amino acid sequencing of the peptide. Although sequence information from MS/MS analysis can be used to validate PMF-based protein identification, it may not be practical when analyzing a large number of proteins and when high- throughput MS/MS instrumentation is not readily available. At present, a vast majority of proteomic studies employ PMF. However, there are huge disparities in criteria used to identify proteins using PMF. Therefore, to reduce incorrect protein identification using PMF, and also to increase confidence in PMF-based protein identification without accompanying MS/MS analysis, definitive guiding principles are essential. To this end, we propose a value-based scoring system that provides guidance on evaluating when PMF-based protein identification can be deemed sufficient without accompanying amino acid sequence data from MS/MS analysis.

  15. Competition between bound and free peptides in an ELISA-based procedure that assays peptides derived from protein digests

    Directory of Open Access Journals (Sweden)

    Pace Umberto

    2006-05-01

    Full Text Available Abstract Background We describe an ELISA-based method that can be used to identify and quantitate proteins in biological samples. In this method, peptides in solution, derived from proteolytic digests of the sample, compete with substrate-attached synthetic peptides for antibodies, also in solution, generated against the chosen peptides. The peptides used for the ELISA are chosen on the basis of their being (i products of the proteolytic (e.g. tryptic digestion of the protein to be identified and (ii unique to the target protein, as far as one can know from the published sequences. Results In this paper we describe the competition assay and we define the optimal conditions for the most effective assay. We have performed an analysis of the kinetics of interaction between the four components of the assay: the plastic substratum to which the peptide is bound, the bound peptide itself, the competing added peptide, and the antibody that is specific for the peptide and we compare the results of theoretical simulations to the actual data in some model systems. Conclusion The data suggest that the peptides bind to the plastic substratum in more than one conformation and that, once bound, the peptide displays different affinities for the antibody, depending on how it has bound to the plate

  16. Novel basic protein, PfN23, functions as key macromolecule during nacre formation.

    Science.gov (United States)

    Fang, Dong; Pan, Cong; Lin, Huijuan; Lin, Ya; Zhang, Guiyou; Wang, Hongzhong; He, Maoxian; Xie, Liping; Zhang, Rongqing

    2012-05-01

    The fine microstructure of nacre (mother of pearl) illustrates the beauty of nature. Proteins found in nacre were believed to be "natural hands" that control nacre formation. In the classical view of nacre formation, nucleation of the main minerals, calcium carbonate, is induced on and by the acidic proteins in nacre. However, the basic proteins were not expected to be components of nacre. Here, we reported that a novel basic protein, PfN23, was a key accelerator in the control over crystal growth in nacre. The expression profile, in situ immunostaining, and in vitro immunodetection assays showed that PfN23 was localized within calcium carbonate crystals in the nacre. Knocking down the expression of PfN23 in adults via double-stranded RNA injection led to a disordered nacre surface in adults. Blocking the translation of PfN23 in embryos using morpholino oligomers led to the arrest of larval development. The in vitro crystallization assay showed that PfN23 increases the rate of calcium carbonate deposition and induced the formation of aragonite crystals with characteristics close to nacre. In addition, we constructed the peptides and truncations of different regions of this protein and found that the positively charged C-terminal region was a key region for the function of PfN23 Taken together, the basic protein PfN23 may be a key accelerator in the control of crystal growth in nacre. This provides a valuable balance to the classic view that acidic proteins control calcium carbonate deposition in nacre. PMID:22416139

  17. NNanomechanical characteristics of proteins and peptides in amyloid

    OpenAIRE

    Boayue, Nya Mehnwolo

    2012-01-01

    ......The understanding of the aggregation of amyloid fibrils is essential as they are linked to a number of diseases such as Alzheimer and Parkston’s disease. Amy- loids from different proteins or peptides have common characteristics such as core β-sheet structure, green birefringence upon binding to Congo red, and fibrillar mor- phology. In this thesis, I report single molecule analysis of TTR105−115 a fragment of transthyretin, a serum and cerebrospinal fluid carrier of ...

  18. Constrained Cyclic Peptides as Immunomodulatory Inhibitors of the CD2:CD58 Protein-Protein Interaction.

    Science.gov (United States)

    Sable, Rushikesh; Durek, Thomas; Taneja, Veena; Craik, David J; Pallerla, Sandeep; Gauthier, Ted; Jois, Seetharama

    2016-08-19

    The interaction between the cell-cell adhesion proteins CD2 and CD58 plays a crucial role in lymphocyte recruitment to inflammatory sites, and inhibitors of this interaction have potential as immunomodulatory drugs in autoimmune diseases. Peptides from the CD2 adhesion domain were designed to inhibit CD2:CD58 interactions. To improve the stability of the peptides, β-sheet epitopes from the CD2 region implicated in CD58 recognition were grafted into the cyclic peptide frameworks of sunflower trypsin inhibitor and rhesus theta defensin. The designed multicyclic peptides were evaluated for their ability to modulate cell-cell interactions in three different cell adhesion assays, with one candidate, SFTI-a, showing potent activity in the nanomolar range (IC50: 51 nM). This peptide also suppresses the immune responses in T cells obtained from mice that exhibit the autoimmune disease rheumatoid arthritis. SFTI-a was resistant to thermal denaturation, as judged by circular dichroism spectroscopy and mass spectrometry, and had a half-life of ∼24 h in human serum. Binding of this peptide to CD58 was predicted by molecular docking studies and experimentally confirmed by surface plasmon resonance experiments. Our results suggest that cyclic peptides from natural sources are promising scaffolds for modulating protein-protein interactions that are typically difficult to target with small-molecule compounds. PMID:27337048

  19. Role of Nanotechnology in Delivery of Protein and Peptide Drugs.

    Science.gov (United States)

    Patil, Sushilkumar; Vhora, Imran; Amrutiya, Jitendra; Lalani, Rohan; Misra, Ambikanandan

    2015-01-01

    The advent of recombinant DNA technology and computational designing has fueled the emergence of proteins and peptides as a new class of modern therapeutics such as vaccines, antigens, antibodies and hormones. Demand for such therapeutics has increased recently due to their distinct pharmacodynamic characteristics of specificity of action and high potency. However, their potential clinical applications are often hindered by involvement of factors which impact their therapeutic potential negatively. Large size, low permeability, conformational fragility, immunogenicity, metabolic degradation and short half-life results in poor bioavailability and inferior efficacy. These challenges have encouraged researchers to devise strategies for effective delivery of proteins and peptides. Recent advances made in nanotechnology are being sought to overcome aforesaid problems and to offer advantages such as higher drug loading, improved stability, sustained release, amenability for non-parenteral administration and targeting through surface modifications. This review focuses on elaborating the role of nanotechnology based formulations and associated challenges in protein and peptide delivery, their clinical outlook and future perspective. PMID:26323432

  20. Prediction of Peptide and Protein Propensity for Amyloid Formation.

    Science.gov (United States)

    Família, Carlos; Dennison, Sarah R; Quintas, Alexandre; Phoenix, David A

    2015-01-01

    Understanding which peptides and proteins have the potential to undergo amyloid formation and what driving forces are responsible for amyloid-like fiber formation and stabilization remains limited. This is mainly because proteins that can undergo structural changes, which lead to amyloid formation, are quite diverse and share no obvious sequence or structural homology, despite the structural similarity found in the fibrils. To address these issues, a novel approach based on recursive feature selection and feed-forward neural networks was undertaken to identify key features highly correlated with the self-assembly problem. This approach allowed the identification of seven physicochemical and biochemical properties of the amino acids highly associated with the self-assembly of peptides and proteins into amyloid-like fibrils (normalized frequency of β-sheet, normalized frequency of β-sheet from LG, weights for β-sheet at the window position of 1, isoelectric point, atom-based hydrophobic moment, helix termination parameter at position j+1 and ΔG° values for peptides extrapolated in 0 M urea). Moreover, these features enabled the development of a new predictor (available at http://cran.r-project.org/web/packages/appnn/index.html) capable of accurately and reliably predicting the amyloidogenic propensity from the polypeptide sequence alone with a prediction accuracy of 84.9 % against an external validation dataset of sequences with experimental in vitro, evidence of amyloid formation. PMID:26241652

  1. Prediction of Peptide and Protein Propensity for Amyloid Formation.

    Directory of Open Access Journals (Sweden)

    Carlos Família

    Full Text Available Understanding which peptides and proteins have the potential to undergo amyloid formation and what driving forces are responsible for amyloid-like fiber formation and stabilization remains limited. This is mainly because proteins that can undergo structural changes, which lead to amyloid formation, are quite diverse and share no obvious sequence or structural homology, despite the structural similarity found in the fibrils. To address these issues, a novel approach based on recursive feature selection and feed-forward neural networks was undertaken to identify key features highly correlated with the self-assembly problem. This approach allowed the identification of seven physicochemical and biochemical properties of the amino acids highly associated with the self-assembly of peptides and proteins into amyloid-like fibrils (normalized frequency of β-sheet, normalized frequency of β-sheet from LG, weights for β-sheet at the window position of 1, isoelectric point, atom-based hydrophobic moment, helix termination parameter at position j+1 and ΔG° values for peptides extrapolated in 0 M urea. Moreover, these features enabled the development of a new predictor (available at http://cran.r-project.org/web/packages/appnn/index.html capable of accurately and reliably predicting the amyloidogenic propensity from the polypeptide sequence alone with a prediction accuracy of 84.9 % against an external validation dataset of sequences with experimental in vitro, evidence of amyloid formation.

  2. Role of Nanotechnology in Delivery of Protein and Peptide Drugs.

    Science.gov (United States)

    Patil, Sushilkumar; Vhora, Imran; Amrutiya, Jitendra; Lalani, Rohan; Misra, Ambikanandan

    2015-01-01

    The advent of recombinant DNA technology and computational designing has fueled the emergence of proteins and peptides as a new class of modern therapeutics such as vaccines, antigens, antibodies and hormones. Demand for such therapeutics has increased recently due to their distinct pharmacodynamic characteristics of specificity of action and high potency. However, their potential clinical applications are often hindered by involvement of factors which impact their therapeutic potential negatively. Large size, low permeability, conformational fragility, immunogenicity, metabolic degradation and short half-life results in poor bioavailability and inferior efficacy. These challenges have encouraged researchers to devise strategies for effective delivery of proteins and peptides. Recent advances made in nanotechnology are being sought to overcome aforesaid problems and to offer advantages such as higher drug loading, improved stability, sustained release, amenability for non-parenteral administration and targeting through surface modifications. This review focuses on elaborating the role of nanotechnology based formulations and associated challenges in protein and peptide delivery, their clinical outlook and future perspective.

  3. Gastrointestinal endogenous proteins as a source of bioactive peptides--an in silico study.

    Directory of Open Access Journals (Sweden)

    Lakshmi A Dave

    Full Text Available Dietary proteins are known to contain bioactive peptides that are released during digestion. Endogenous proteins secreted into the gastrointestinal tract represent a quantitatively greater supply of protein to the gut lumen than those of dietary origin. Many of these endogenous proteins are digested in the gastrointestinal tract but the possibility that these are also a source of bioactive peptides has not been considered. An in silico prediction method was used to test if bioactive peptides could be derived from the gastrointestinal digestion of gut endogenous proteins. Twenty six gut endogenous proteins and seven dietary proteins were evaluated. The peptides present after gastric and intestinal digestion were predicted based on the amino acid sequence of the proteins and the known specificities of the major gastrointestinal proteases. The predicted resultant peptides possessing amino acid sequences identical to those of known bioactive peptides were identified. After gastrointestinal digestion (based on the in silico simulation, the total number of bioactive peptides predicted to be released ranged from 1 (gliadin to 55 (myosin for the selected dietary proteins and from 1 (secretin to 39 (mucin-5AC for the selected gut endogenous proteins. Within the intact proteins and after simulated gastrointestinal digestion, angiotensin converting enzyme (ACE-inhibitory peptide sequences were the most frequently observed in both the dietary and endogenous proteins. Among the dietary proteins, after in silico simulated gastrointestinal digestion, myosin was found to have the highest number of ACE-inhibitory peptide sequences (49 peptides, while for the gut endogenous proteins, mucin-5AC had the greatest number of ACE-inhibitory peptide sequences (38 peptides. Gut endogenous proteins may be an important source of bioactive peptides in the gut particularly since gut endogenous proteins represent a quantitatively large and consistent source of protein.

  4. Synergistic interactions of lipids and myelin basic protein

    Science.gov (United States)

    Hu, Yufang; Doudevski, Ivo; Wood, Denise; Moscarello, Mario; Husted, Cynthia; Genain, Claude; Zasadzinski, Joseph A.; Israelachvili, Jacob

    2004-09-01

    This report describes force measurements and atomic force microscope imaging of lipid-protein interactions that determine the structure of a model membrane system that closely mimics the myelin sheath. Our results suggest that noncovalent, mainly electrostatic and hydrophobic, interactions are responsible for the multilamellar structure and stability of myelin. We find that myelin basic protein acts as a lipid coupler between two apposed bilayers and as a lipid "hole-filler," effectively preventing defect holes from developing. From our protein-mediated-adhesion and force-distance measurements, we develop a simple quantitative model that gives a reasonably accurate picture of the molecular mechanism and adhesion of bilayer-bridging proteins by means of noncovalent interactions. The results and model indicate that optimum myelin adhesion and stability depend on the difference between, rather than the product of, the opposite charges on the lipid bilayers and myelin basic protein, as well as on the repulsive forces associated with membrane fluidity, and that small changes in any of these parameters away from the synergistically optimum values can lead to large changes in the adhesion or even its total elimination. Our results also show that the often-asked question of which membrane species, the lipids or the proteins, are the "important ones" may be misplaced. Both components work synergistically to provide the adhesion and overall structure. A better appreciation of the mechanism of this synergy may allow for a better understanding of stacked and especially myelin membrane structures and may lead to better treatments for demyelinating diseases such as multiple sclerosis. lipid-protein interactions | myelin membrane structure | membrane adhesion | membrane regeneration/healing | demyelinating diseases

  5. Applications and Challenges for Use of Cell-Penetrating Peptides as Delivery Vectors for Peptide and Protein Cargos

    DEFF Research Database (Denmark)

    Kristensen, Mie; Birch, Ditlev; Mørck Nielsen, Hanne

    2016-01-01

    -penetrating peptides (CPPs) constitute a promising tool and have shown applications for peptide and protein delivery into cells as well as across various epithelia and the blood-brain barrier (BBB). CPP-mediated delivery of peptides and proteins may be pursued via covalent conjugation of the CPP to the cargo peptide...... or protein or via physical complexation obtained by simple bulk-mixing of the CPP with its cargo. Both approaches have their pros and cons, and which is the better choice likely relates to the physicochemical properties of the CPP and its cargo as well as the route of administration, the specific...... barrier and the target cell. Besides the physical barrier, a metabolic barrier must be taken into consideration when applying peptide-based delivery vectors, such as the CPPs, and stability-enhancing strategies are commonly employed to prolong the CPP half-life. The mechanisms by which CPPs translocate...

  6. Surface peptide mapping of protein I and protein III of four strains of Neisseria gonorrhoeae

    Energy Technology Data Exchange (ETDEWEB)

    Judd, R.C.

    1982-08-01

    Whole cells and isolated outer membranes (OMs) of four strains of gonococci were surface radioiodinated with either lactoperoxidase or Iodogen (Pierce Chemical Co., Rockford, Ill.). These preparations were solubilized in sodium dodecyl sulfate and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Surface-radioiodinated protein I (PI) and PIII bands were excised from the sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels and digested with alpha-chymotrypsin, and the resultant /sup 125/I-peptide fragments were resolved by high-voltage electrophoresis and thin-layer chromatography (i.e., surface peptide mapping). Radioemitting peptidic fragments were visualized by autoradiography. Results demonstrated that the PI molecule of each gonococcal strain studied had unique iodinatable peptides exposed on the surface of whole cells and OMs, whereas PIIIs appeared to have the same portion of the molecule exposed on the surface of bacteria or OMs, regardless of the gonococcal strain from which they were isolated. Many more radiolabeled peptides were seen in surface peptide maps of PIs from radiolabeled OMs than in those from radioiodinated whole cells, whereas different peptidic fragments were seen in the surface peptide maps of PIIIs from radiolabeled OMs than were seen in those from radiolabeled whole cells. These data suggest that PI may contribute strain-specific antigenic determinants and PIII may contribute cross-reactive determinants and that the surface exposure of PI and PIII is different in isolated OMs than in the OM of intact gonococci.

  7. Inhaled protein/peptide-based therapies for respiratory disease.

    Science.gov (United States)

    Fellner, Robert C; Terryah, Shawn T; Tarran, Robert

    2016-12-01

    Asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) are all chronic pulmonary diseases, albeit with different etiologies, that are characterized by airflow limitation, chronic inflammation, and abnormal mucus production/rheology. Small synthetic molecule-based therapies are commonly prescribed for all three diseases. However, there has been increased interest in "biologicals" to treat these diseases. Biologicals typically constitute protein- or peptide-based therapies and are often more potent than small molecule-based drugs. In this review, we shall describe the pros and cons of several different biological-based therapies for respiratory disease, including dornase alfa, a recombinant DNAase that reduces mucus viscosity and short palate lung and nasal epithelial clone 1 (SPLUNC1)-derived peptides that treat Na(+) hyperabsorption and rebalance CF airway surface liquid homeostasis. PMID:27098663

  8. Direct and indirect radioiodination of protein: comparative study of chemotactic peptide labeling

    International Nuclear Information System (INIS)

    The development of simple methods for protein radioiodination have stimulated the use of radioiodinated peptides in vivo. There are two basic methods for labeling proteins with radioiodine: direct labeling, reaction of an electrophilic radioiodine with functional activated groups on protein, like the phenol ring in the tyrosine residue, and the conjugation of a previously radioiodinated molecule to the protein, referred as indirect method. The great problem related to the direct radioiodination of proteins is the in vivo dehalogenation. This problem can be minimized if a non-phenolic prosthetic group is used in the indirect radioiodination of the peptide. The ATE prosthetic group, N-succinimidyl 3-(tri-n-butylstannyl) benzoate, when radioiodinated by electrophilic iododestannilation produces N-succinimidyl 3-[123l/131l] iodine benzoate (SIB) that is subsequently conjugated to the protein by the acylation of the lysine group. There are many radiopharmaceuticals employed in scintigraphic images of infection and inflammation used with some limitations. These limitations stimulated the improvement of a new class of radiopharmaceuticals, the receptor-specific related labeled peptides, as the mediators of the inflammatory response, that presents high affinity by receptors expressed in the inflammation process, and fast clearance from blood and non-target tissues. One of these molecules is the synthetic chemotactic peptide fNleLFNIeYK that presents potent chemotaxis for leukocytes, with high affinity by the receptors presented in polymorphonuclear leukocytes and mononuclear phagocytes. The objective of this work included the synthesis of ATE prosthetic group and comparative radioiodination of the chemotactic peptide fNleLFNIeYK by direct and indirect methods, with radiochemical purity determination and evaluation of in vivo and in vitro stability of the compounds. This work presented an original contribution in the comparative biological distribution studies of the

  9. Peptide Mimicrying Between SARS Coronavirus Spike Protein and Human Proteins Reacts with SARS Patient Serum

    Directory of Open Access Journals (Sweden)

    K.-Y. Hwa

    2008-01-01

    Full Text Available Molecular mimicry, defined as similar structures shared by molecules from dissimilar genes or proteins, is a general strategy used by pathogens to infect host cells. Severe acute respiratory syndrome (SARS is a new human respiratory infectious disease caused by SARS coronavirus (SARS-CoV. The spike (S protein of SARS-CoV plays an important role in the virus entry into a cell. In this study, eleven synthetic peptides from the S protein were selected based on its sequence homology with human proteins. Two of the peptides D07 (residues 927–937 and D08 (residues 942–951 were recognized by the sera of SARS patients. Murine hyperimmune sera against these peptides bound to proteins of human lung epithelial cells A549. Another peptide D10 (residues 490–502 stimulated A549 to proliferate and secrete IL-8. The present results suggest that the selected S protein regions, which share sequence homology with human proteins, may play important roles in SARS-CoV infection.

  10. Basic Endochitinases Are Major Proteins in Castanea sativa Cotyledons.

    Science.gov (United States)

    Collada, C; Casado, R; Fraile, A; Aragoncillo, C

    1992-10-01

    Basic endochitinases are abundant proteins in Castanea sativa Mill. cotyledons. Three basic chitinases were purified with molecular masses of 25, 26, and 32 kD (Ch1, Ch2, and Ch3) and with isoelectric points between 8 and 9.5. Antibodies raised against Ch1 cross-reacted with Ch2 and Ch3. However, Ch3 showed differences when compared with the other two enzymes, especially in its higher cysteine content. The size, amino acid composition, and N-terminal sequence of Ch1 indicate that it is a class II endochitinase and, therefore, has no cysteine-rich hevein domain. Ch1 inhibits the growth of the fungus Trichoderma viride. The biological role of these endochitinases is discussed.

  11. Indirect readout in protein-peptide recognition: a different story from classical biomolecular recognition.

    Science.gov (United States)

    Yu, Hua; Zhou, Peng; Deng, Maolin; Shang, Zhicai

    2014-07-28

    Protein-peptide interactions are prevalent and play essential roles in many living activities. Peptides recognize their protein partners by direct nonbonded interactions and indirect adjustment of conformations. Although processes of protein-peptide recognition have been comprehensively studied in both sequences and structures recently, flexibility of peptides and the configuration entropy penalty in recognition did not get enough attention. In this study, 20 protein-peptide complexes and their corresponding unbound peptides were investigated by molecular dynamics simulations. Energy analysis revealed that configurational entropy penalty introduced by restriction of the degrees of freedom of peptides in indirect readout process of protein-peptide recognition is significant. Configurational entropy penalty has become the main content of the indirect readout energy in protein-peptide recognition instead of deformation energy which is the main source of the indirect readout energy in classical biomolecular recognition phenomena, such as protein-DNA binding. These results provide us a better understanding of protein-peptide recognition and give us some implications in peptide ligand design.

  12. Studying protein-protein interactions using peptide arrays

    NARCIS (Netherlands)

    Katz, C.; Levy-Beladev, L.; Rotem-Bamberger, S.; Rito, T.; Rudiger, S.G.D.; Friedler, A.

    2010-01-01

    Screening of arrays and libraries of compounds is well-established as a high-throughput method for detecting and analyzing interactions in both biological and chemical systems. Arrays and libraries can be composed from various types of molecules, ranging from small organic compounds to DNA, proteins

  13. Ubiquitin-independent proteosomal degradation of myelin basic protein contributes to development of neurodegenerative autoimmunity.

    Science.gov (United States)

    Belogurov, Alexey; Kuzina, Ekaterina; Kudriaeva, Anna; Kononikhin, Alexey; Kovalchuk, Sergey; Surina, Yelena; Smirnov, Ivan; Lomakin, Yakov; Bacheva, Anna; Stepanov, Alexey; Karpova, Yaroslava; Lyupina, Yulia; Kharybin, Oleg; Melamed, Dobroslav; Ponomarenko, Natalia; Sharova, Natalia; Nikolaev, Eugene; Gabibov, Alexander

    2015-05-01

    Recent findings indicate that the ubiquitin-proteasome system is involved in the pathogenesis of cancer as well as autoimmune and several neurodegenerative diseases, and is thus a target for novel therapeutics. One disease that is related to aberrant protein degradation is multiple sclerosis, an autoimmune disorder involving the processing and presentation of myelin autoantigens that leads to the destruction of axons. Here, we show that brain-derived proteasomes from SJL mice with experimental autoimmune encephalomyelitis (EAE) in an ubiquitin-independent manner generate significantly increased amounts of myelin basic protein peptides that induces cytotoxic lymphocytes to target mature oligodendrocytes ex vivo. Ten times enhanced release of immunogenic peptides by cerebral proteasomes from EAE-SJL mice is caused by a dramatic shift in the balance between constitutive and β1i(high) immunoproteasomes in the CNS of SJL mice with EAE. We found that during EAE, β1i is increased in resident CNS cells, whereas β5i is imported by infiltrating lymphocytes through the blood-brain barrier. Peptidyl epoxyketone specifically inhibits brain-derived β1i(high) immunoproteasomes in vitro (kobs/[I] = 240 M(-1)s(-1)), and at a dose of 0.5 mg/kg, it ameliorates ongoing EAE in vivo. Therefore, our findings provide novel insights into myelin metabolism in pathophysiologic conditions and reveal that the β1i subunit of the immunoproteasome is a potential target to treat autoimmune neurologic diseases.

  14. Pharmacokinetics of biotech drugs: peptides, proteins and monoclonal antibodies.

    Science.gov (United States)

    Lin, Jiunn H

    2009-09-01

    With the advances in recombinant DNA biotechnology, molecular biology and immunology, the number of biotech drugs, including peptides, proteins and monoclonal antibodies, available for clinical use has dramatically increased in recent years. Although pharmacokinetic principles are equally applicable to the large molecule drugs and conventional small molecule drugs, the underlying mechanisms for the processes of absorption, distribution, metabolism and excretion (ADME) of large molecule drugs are often very different from that of small molecule drugs. Therefore, a good understanding of the ADME processes of large molecule drugs is essential in support of the development of therapeutic biologics. The purpose of this article is to review the current knowledge of the ADME processes that govern the pharmacokinetics of biotech drugs. The challenges encountered by orally administered peptide and protein drugs, and the nature of lymphatic absorption after subcutaneous administration will be discussed. In addition, molecular mechanisms of biodistribution, metabolism and renal excretion of biotech drugs will also be discussed. Finally, approaches used for prediction of human pharmacokinetics of protein drugs will be briefly discussed.

  15. Towards generation of bioactive peptides from meat industry waste proteins: Generation of peptides using commercial microbial proteases.

    Science.gov (United States)

    Ryder, Kate; Bekhit, Alaa El-Din; McConnell, Michelle; Carne, Alan

    2016-10-01

    Five commercially available food-grade microbial protease preparations were evaluated for their ability to hydrolyse meat myofibrillar and connective tissue protein extracts to produce bioactive peptides. A bacterial-derived protease (HT) extensively hydrolysed both meat protein extracts, producing peptide hydrolysates with significant in vitro antioxidant and ACE inhibitor activities. The hydrolysates retained bioactivity after simulated gastrointestinal hydrolysis challenge. Gel permeation chromatography sub-fractionation of the crude protein hydrolysates showed that the smaller peptide fractions exhibited the highest antioxidant and ACE inhibitor activities. OFFGEL electrophoresis of the small peptides of both hydrolysates showed that low isoelectric point peptides had antioxidant activity; however, no consistent relationship was observed between isoelectric point and ACE inhibition. Cell-based assays indicated that the hydrolysates present no significant cytotoxicity towards Vero cells. The results indicate that HT protease hydrolysis of meat myofibrillar and connective tissue protein extracts produces bioactive peptides that are non-cytotoxic, should be stable in the gastrointestinal tract and may contain novel bioactive peptide sequences. PMID:27132822

  16. Enzymatic hydrolysis of whey protein concentrates : peptide HPLC profiles

    OpenAIRE

    Mota, M. V. T.; Ferreira, I. M. P. L. V. O.; Oliveira, M. B. P.; Rocha, Cristina M. R.; J. A. Teixeira; Torres, D; M. P. Gonçalves

    2004-01-01

    Hydrolysis of whey protein concentrates (WPCs) at different temperatures and pHs, using three enzymes: pepsin, trypsin, and Alcalase®, was monitored during more than 5 hr by reversed phase HPLC/UV, using a column containing a polystyrene-divinylbenzene copolymer-based packing, and an elution gradient from 8% to 80% acetonitrile containing 0.1% TFA. Peptides were separated according to their polarity and size, and degradation of α-lactalbumin (α-la) and β-lactoglobulin (β-lg) ...

  17. Non-protein amino acids in peptide design

    Indian Academy of Sciences (India)

    S Aravinda; N Shamala; Rituparna S Roy; P Balaram

    2003-10-01

    An overview of the use of non-protein amino acids in the design of conformationally well-defined peptides, based on work from the author’s laboratory, is discussed. The crystal structures of several designed oligopeptides illustrate the use -aminoisobutyric acid (Aib) in the construction of helices, D-amino acids in the design of helix termination segments and DPro-Xxx segments for nucleating of -hairpin structures. - and -amino acid residues have been used to expand the range of designed polypeptide structures.

  18. The immunogenicity of MUC1 peptides and fusion protein.

    Science.gov (United States)

    Apostolopoulos, V; Pietersz, G A; Xing, P X; Lees, C J; Michael, M; Bishop, J; McKenzie, I F

    1995-03-23

    Mucin 1 (MUC1) is highly expressed in breast cancer, has an ubiquitous distribution and, due to altered glycosylation, peptides within the VNTR are exposed. These peptides are the target for anti-MUC1 antibodies, which give a differential reaction on cancer compared with normal tissue. The amino acids, APDTR or adjacent amino acids, are highly immunogenic in mice for antibody production (after immunisation with either breast cancer cells, human milk fat globule (HMFG) or the VNTR peptide). In addition, human studies show that this region of the MUC1 VNTR functions as target epitopes for cytotoxic T cells. We have performed preclinical and clinical studies to examine the immune responses to MUC1 in mice and humans: (a) MUC1+ 3T3 or P815+ 3T3 cells in syngeneic mice are rejected, with the generation of both cytotoxic T lymphocyte (CTL) and DTH responses and a weak antibody response and a weak antibody responses; this type of immunity gives rise to total resistance to re-challenge with high doses of these tumors; (b) immunisation with peptides (VNTR x 2), a fusion protein (VNTR x 5), or HMFG leads to no CTLs, DTH, good antibody production and weak tumour protection (to 10(6) cells, but not 5 x 10(6) cells) (possibly a TH2 type response); (c) immunisation with mannan-fusion protein (MFP) gives rise to good protection (resistance to 50 x 10(6) cells), CTL and DTH responses and weak antibody responses (possibly a TH1 type response, similar in magnitude to that obtained after tumor rejection); (d) established tumors can be rapidly rejected by delayed treatment of MFP; (e) the CTL responses are MHC restricted (in contrast to the human studies); (f) APDTR appears not to be the T cell reactive epitope in mice. On the basis of these findings, two clinical trials are in progress: (a) VNTR x 2 (diphtheria toxoid) which gives rise to some T cell proliferation, DTH and antibody responses in some patients and (b) an MFP trial. The ability to alter the immune response towards

  19. Measurement of guinea pig eosinophil major basic protein by radioimmunoassay

    International Nuclear Information System (INIS)

    Guinea pig eosinophil major basic protein (MBP) was measured by radioimmunoassay (RIA) using 131I-MBP. Two critical features of the assay were: (1) alkylation of the MBP with iodoacetamide prior to radioiodination and (2) inclusion of another basic protein, either protamine or histone, in the phosphate buffer. Freshly isolated non-alkylated MBP was immunologically deficient when compared to alkylated or reduced MBP, but its reactivity could be redtores by reduction with dithiothreitol and alkylation. Reduction and alkylation also restored the immunoreactivity of polymerized MBP. MBP levels were not elevated in sera from guinea pigs parasitized with Trichinella spiralis and having peripheral blood eosinophilia. Muscle extracts from Trichinella infected animals showed significantly higher levels of MBP activity than normal controls. MBP was measurable in extracts of untreated eosinophils, but reduction and alkylation of these extracts increased MBP activity several fold. The RIA permits detection of MBP in body fluids and tissues at levels as low as 2 ng./ml. The RIA is useful in assessing increased or decreased levels of MBP activity in samples from experimental animals when compared to samples from controls. (author)

  20. Self-assembling peptide and protein nanodiscs for studies of membrane proteins

    DEFF Research Database (Denmark)

    Midtgaard, Søren Roi

    of proteins encoded by the human genome. G-protein coupled receptors mediate the majority of hormone and neurotransmitter signals as well as being responsible for perception of light, smell and taste in the human body, and a number of Nobel prizes has been awarded based on their study. Structural...... membrane proteins. A minimalistic approach was tested where the ApoA1 protein was mimicked my small amphipathic helical peptides. The resulting discs were very similar to ApoA1 based discs in size and in their ability to stabilize incorporated membrane proteins. Furthermore, due to their enhanced dynamical...

  1. The role of metals in protein conformational disorders - The case of prion protein and Aβ -peptide

    Science.gov (United States)

    De Santis, E.; Minicozzi, V.; Morante, S.; Rossi, G. C.; Stellato, F.

    2016-02-01

    Protein conformational disorders are members of a vast class of pathologies in which endogenous proteins or peptides undergo a misfolding process by switching from the physiological soluble configuration to a pathological fibrillar insoluble state. An important, but not yet fully elucidated, role in the process appears to be played by transition metal ions, mainly copper and zinc. X-ray absorption spectroscopy is one of the most suitable techniques for the structural characterization of biological molecules in complex with metal. Owing to its chemical selectivity and sensitivity to the local atomic geometry around the absorber, it can be successfully used to study the environment of metal ions in complex with proteins and peptides in physiological conditions. In this paper we present X-ray absorption spectroscopy studies of the metal ions coordination modes in systems where metals are complexed with specific amyloidogenic proteins and peptides. In particular, we show results concerning the Amyloid β peptide, that is involved in Alzheimer's disease, and the Prion protein, that is responsible for the Transmissible Spongiform Encephalopathy. Our findings suggest that the copper and zinc ions may play a crucial role in the aggregation and fibril formation process of these two biomolecules. Elucidating this kind of interaction could be a key preliminary step before any viable therapy can be conceived or designed.

  2. Deimination of the myelin basic protein decelerates its proteasome-mediated metabolism.

    Science.gov (United States)

    Kuzina, E S; Kudriaeva, A A; Glagoleva, I S; Knorre, V D; Gabibov, A G; Belogurov, A A

    2016-07-01

    Deimination of myelin basic protein (MBP) by peptidylarginine deiminase (PAD) prevents its binding to the proteasome and decelerates its degradation by the proteasome in mammalian cells. Potential anticancer drug tetrazole analogue of chloramidine 2, at concentrations greater than 1 µM inhibits the enzymatic activity of PAD in vitro. The observed acceleration of proteasome hydrolysis of MBP to antigenic peptides in the presence of PAD inhibitor may increase the efficiency of lesion of the central nervous system by cytotoxic lymphocytes in multiple sclerosis. We therefore suggest that clinical trials and the introduction of PAD inhibitors in clinical practice for the treatment of malignant neoplasms should be performed only after a careful analysis of their potential effect on the induction of autoimmune neurodegeneration processes. PMID:27599511

  3. Transmissible gastroenteritis virus; identification of M protein-binding peptide ligands with antiviral and diagnostic potential

    Science.gov (United States)

    The membrane (M) protein is one of the major structural proteins of coronavirus particles. In this study, the M protein of transmissible gastroenteritis virus (TGEV) was used to biopan a 12-mer phage display random peptide library. Three phages expressing TGEV-M-binding peptides were identified and ...

  4. EKylation: Addition of an Alternating-Charge Peptide Stabilizes Proteins.

    Science.gov (United States)

    Liu, Erik J; Sinclair, Andrew; Keefe, Andrew J; Nannenga, Brent L; Coyle, Brandon L; Baneyx, François; Jiang, Shaoyi

    2015-10-12

    For nearly 40 years, therapeutic proteins have been stabilized by chemical conjugation of polyethylene glycol (PEG), but recently zwitterionic materials have proved to be a more effective substitute. In this work, we demonstrate that genetic fusion of alternating-charge extensions consisting of anionic glutamic acid (E) and cationic lysine (K) is an effective strategy for protein stabilization. This bioinspired "EKylation" method not only confers the stabilizing benefits of poly(zwitterions) but also allows for rapid biosynthesis of target constructs. Poly(EK) peptides of different predetermined lengths were appended to the C-terminus of a native β-lactamase and its destabilized TEM-19 mutant. The EK-modified enzymes retained biological activity and exhibited increased stability to environmental stressors such as high temperature and high-salt solutions. This one-step strategy provides a broadly applicable alternative to synthetic polymer conjugation that is biocompatible and degradable. PMID:26407134

  5. Identification of an amyloidogenic peptide from the Bap protein of Staphylococcus epidermidis.

    Science.gov (United States)

    Lembré, Pierre; Vendrely, Charlotte; Martino, Patrick Di

    2014-01-01

    Biofilm associated proteins (Bap) are involved in the biofilm formation process of several bacterial species. The sequence STVTVT is present in Bap proteins expressed by many Staphylococcus species, Acinetobacter baumanii and Salmonella enterica. The peptide STVTVTF derived from the C-repeat of the Bap protein from Staphylococcus epidermidis was selected through the AGGRESCAN, PASTA, and TANGO software prediction of protein aggregation and formation of amyloid fibers. We characterized the self-assembly properties of the peptide STVTVTF by different methods: in the presence of the peptide, we observed an increase in the fluorescence intensity of Thioflavin T; many intermolecular β-sheets and fibers were spontaneously formed in peptide preparations as observed by infrared spectroscopy and atomic force microscopy analyses. In conclusion, a 7 amino acids peptide derived from the C-repeat of the Bap protein was sufficient for the spontaneous formation of amyloid fibers. The possible involvement of this amyloidogenic sequence in protein-protein interactions is discussed.

  6. Identification of an amyloidogenic peptide from the Bap protein of Staphylococcus epidermidis.

    Science.gov (United States)

    Lembré, Pierre; Vendrely, Charlotte; Martino, Patrick Di

    2014-01-01

    Biofilm associated proteins (Bap) are involved in the biofilm formation process of several bacterial species. The sequence STVTVT is present in Bap proteins expressed by many Staphylococcus species, Acinetobacter baumanii and Salmonella enterica. The peptide STVTVTF derived from the C-repeat of the Bap protein from Staphylococcus epidermidis was selected through the AGGRESCAN, PASTA, and TANGO software prediction of protein aggregation and formation of amyloid fibers. We characterized the self-assembly properties of the peptide STVTVTF by different methods: in the presence of the peptide, we observed an increase in the fluorescence intensity of Thioflavin T; many intermolecular β-sheets and fibers were spontaneously formed in peptide preparations as observed by infrared spectroscopy and atomic force microscopy analyses. In conclusion, a 7 amino acids peptide derived from the C-repeat of the Bap protein was sufficient for the spontaneous formation of amyloid fibers. The possible involvement of this amyloidogenic sequence in protein-protein interactions is discussed. PMID:24354773

  7. A feedback framework for protein inference with peptides identified from tandem mass spectra

    Directory of Open Access Journals (Sweden)

    Shi Jinhong

    2012-11-01

    Full Text Available Abstract Background Protein inference is an important computational step in proteomics. There exists a natural nest relationship between protein inference and peptide identification, but these two steps are usually performed separately in existing methods. We believe that both peptide identification and protein inference can be improved by exploring such nest relationship. Results In this study, a feedback framework is proposed to process peptide identification reports from search engines, and an iterative method is implemented to exemplify the processing of Sequest peptide identification reports according to the framework. The iterative method is verified on two datasets with known validity of proteins and peptides, and compared with ProteinProphet and PeptideProphet. The results have shown that not only can the iterative method infer more true positive and less false positive proteins than ProteinProphet, but also identify more true positive and less false positive peptides than PeptideProphet. Conclusions The proposed iterative method implemented according to the feedback framework can unify and improve the results of peptide identification and protein inference.

  8. Topical Delivery of Protein and Peptide Using Novel Cell Penetrating Peptide IMT-P8

    Science.gov (United States)

    Gautam, Ankur; Nanda, Jagpreet Singh; Samuel, Jesse S.; Kumari, Manisha; Priyanka, Priyanka; Bedi, Gursimran; Nath, Samir K.; Mittal, Garima; Khatri, Neeraj; Raghava, Gajendra Pal Singh

    2016-01-01

    Skin, being the largest organ of the body, is an important site for drug administration. However, most of the drugs have poor permeability and thus drug delivery through the skin is very challenging. In this study, we examined the transdermal delivery capability of IMT-P8, a novel cell-penetrating peptide. We generated IMT-P8-GFP and IMT-P8-KLA fusion constructs and evaluated their internalization into mouse skin after topical application. Our results demonstrate that IMT-P8 is capable of transporting green fluorescent protein (GFP) and proapoptotic peptide, KLA into the skin and also in different cell lines. Interestingly, uptake of IMT-P8-GFP was considerably higher than TAT-GFP in HeLa cells. After internalization, IMT-P8-KLA got localized to the mitochondria and caused significant cell death in HeLa cells signifying an intact biological activity. Further in vivo skin penetration experiments revealed that after topical application, IMT-P8 penetrated the stratum corneum, entered into the viable epidermis and accumulated inside the hair follicles. In addition, both IMT-P8-KLA and IMT-P8-GFP internalized into the hair follicles and dermal tissue of the skin following topical application. These results suggested that IMT-P8 could be a potential candidate to be used as a topical delivery vehicle for various cosmetic and skin disease applications. PMID:27189051

  9. Topical Delivery of Protein and Peptide Using Novel Cell Penetrating Peptide IMT-P8.

    Science.gov (United States)

    Gautam, Ankur; Nanda, Jagpreet Singh; Samuel, Jesse S; Kumari, Manisha; Priyanka, Priyanka; Bedi, Gursimran; Nath, Samir K; Mittal, Garima; Khatri, Neeraj; Raghava, Gajendra Pal Singh

    2016-01-01

    Skin, being the largest organ of the body, is an important site for drug administration. However, most of the drugs have poor permeability and thus drug delivery through the skin is very challenging. In this study, we examined the transdermal delivery capability of IMT-P8, a novel cell-penetrating peptide. We generated IMT-P8-GFP and IMT-P8-KLA fusion constructs and evaluated their internalization into mouse skin after topical application. Our results demonstrate that IMT-P8 is capable of transporting green fluorescent protein (GFP) and proapoptotic peptide, KLA into the skin and also in different cell lines. Interestingly, uptake of IMT-P8-GFP was considerably higher than TAT-GFP in HeLa cells. After internalization, IMT-P8-KLA got localized to the mitochondria and caused significant cell death in HeLa cells signifying an intact biological activity. Further in vivo skin penetration experiments revealed that after topical application, IMT-P8 penetrated the stratum corneum, entered into the viable epidermis and accumulated inside the hair follicles. In addition, both IMT-P8-KLA and IMT-P8-GFP internalized into the hair follicles and dermal tissue of the skin following topical application. These results suggested that IMT-P8 could be a potential candidate to be used as a topical delivery vehicle for various cosmetic and skin disease applications. PMID:27189051

  10. N-terminal peptides from unprocessed prion proteins enter cells by macropinocytosis

    International Nuclear Information System (INIS)

    A peptide derived from the N-terminus of the unprocessed bovine prion protein (bPrPp), incorporating the hydrophobic signal sequence (residues 1-24) and a basic domain (KKRPKP, residues 25-30), internalizes into mammalian cells, even when coupled to a sizeable cargo, and therefore functions as a cell-penetrating peptide (CPP). Confocal microscopy and co-localization studies indicate that the internalization of bPrPp is mainly through macropinocytosis, a fluid-phase endocytosis process, initiated by binding to cell-surface proteoglycans. Electron microscopy studies show internalized bPrPp-DNA-gold complexes residing in endosomal vesicles. bPrPp induces expression of a complexed luciferase-encoding DNA plasmid, demonstrating the peptide's ability to transport the cargo across the endosomal membrane and into the cytosol and nucleus. The novel CPP activity of the unprocessed N-terminal domain of PrP could be important for the retrotranslocation of partly processed PrP and for PrP trafficking inside or between cells, with implications for the infectivity associated with prion diseases

  11. Isolation of Camelid Single-Domain Antibodies Against Native Proteins Using Recombinant Multivalent Peptide Ligands.

    Science.gov (United States)

    Alturki, Norah A; Henry, Kevin A; MacKenzie, C Roger; Arbabi-Ghahroudi, Mehdi

    2015-01-01

    Generation of antibodies against desired epitopes on folded proteins may be hampered by various characteristics of the target protein, including antigenic and immunogenic dominance of irrelevant epitopes and/or steric occlusion of the desired epitope. In such cases, peptides encompassing linear epitopes of the native protein represent attractive alternative reagents for immunization and screening. Peptide antigens are typically prepared by fusing or conjugating the peptide of interest to a carrier protein. The utility of such antigens depends on many factors including the peptide's amino acid sequence, display valency, display format (synthetic conjugate vs. recombinant fusion) and characteristics of the carrier. Here we provide detailed protocols for: (1) preparation of DNA constructs encoding peptides fused to verotoxin (VT) multimerization domain; (2) expression, purification, and characterization of the multivalent peptide-VT ligands; (3) concurrent panning of a non-immune phage-displayed camelid VHH library against the peptide-VT ligands and native protein; and (4) identification of VHHs enriched via panning using next-generation sequencing techniques. These methods are simple, rapid and can be easily adapted to yield custom peptide-VT ligands that appear to maintain the antigenic structures of the peptide. However, we caution that peptide sequences should be chosen with great care, taking into account structural, immunological, and biophysical information on the protein of interest.

  12. β-Propeller blades as ancestral peptides in protein evolution.

    Directory of Open Access Journals (Sweden)

    Klaus O Kopec

    Full Text Available Proteins of the β-propeller fold are ubiquitous in nature and widely used as structural scaffolds for ligand binding and enzymatic activity. This fold comprises between four and twelve four-stranded β-meanders, the so called blades that are arranged circularly around a central funnel-shaped pore. Despite the large size range of β-propellers, their blades frequently show sequence similarity indicative of a common ancestry and it has been proposed that the majority of β-propellers arose divergently by amplification and diversification of an ancestral blade. Given the structural versatility of β-propellers and the hypothesis that the first folded proteins evolved from a simpler set of peptides, we investigated whether this blade may have given rise to other folds as well. Using sequence comparisons, we identified proteins of four other folds as potential homologs of β-propellers: the luminal domain of inositol-requiring enzyme 1 (IRE1-LD, type II β-prisms, β-pinwheels, and WW domains. Because, with increasing evolutionary distance and decreasing sequence length, the statistical significance of sequence comparisons becomes progressively harder to distinguish from the background of convergent similarities, we complemented our analyses with a new method that evaluates possible homology based on the correlation between sequence and structure similarity. Our results indicate a homologous relationship of IRE1-LD and type II β-prisms with β-propellers, and an analogous one for β-pinwheels and WW domains. Whereas IRE1-LD most likely originated by fold-changing mutations from a fully formed PQQ motif β-propeller, type II β-prisms originated by amplification and differentiation of a single blade, possibly also of the PQQ type. We conclude that both β-propellers and type II β-prisms arose by independent amplification of a blade-sized fragment, which represents a remnant of an ancient peptide world.

  13. β-Propeller Blades as Ancestral Peptides in Protein Evolution

    Science.gov (United States)

    Kopec, Klaus O.; Lupas, Andrei N.

    2013-01-01

    Proteins of the β-propeller fold are ubiquitous in nature and widely used as structural scaffolds for ligand binding and enzymatic activity. This fold comprises between four and twelve four-stranded β-meanders, the so called blades that are arranged circularly around a central funnel-shaped pore. Despite the large size range of β-propellers, their blades frequently show sequence similarity indicative of a common ancestry and it has been proposed that the majority of β-propellers arose divergently by amplification and diversification of an ancestral blade. Given the structural versatility of β-propellers and the hypothesis that the first folded proteins evolved from a simpler set of peptides, we investigated whether this blade may have given rise to other folds as well. Using sequence comparisons, we identified proteins of four other folds as potential homologs of β-propellers: the luminal domain of inositol-requiring enzyme 1 (IRE1-LD), type II β-prisms, β-pinwheels, and WW domains. Because, with increasing evolutionary distance and decreasing sequence length, the statistical significance of sequence comparisons becomes progressively harder to distinguish from the background of convergent similarities, we complemented our analyses with a new method that evaluates possible homology based on the correlation between sequence and structure similarity. Our results indicate a homologous relationship of IRE1-LD and type II β-prisms with β-propellers, and an analogous one for β-pinwheels and WW domains. Whereas IRE1-LD most likely originated by fold-changing mutations from a fully formed PQQ motif β-propeller, type II β-prisms originated by amplification and differentiation of a single blade, possibly also of the PQQ type. We conclude that both β-propellers and type II β-prisms arose by independent amplification of a blade-sized fragment, which represents a remnant of an ancient peptide world. PMID:24143202

  14. Collagen peptide-based biomaterials for protein delivery and peptide-promoted self-assembly of gold nanoparticles

    Science.gov (United States)

    Ernenwein, Dawn M.

    2011-12-01

    Bottom-up self-assembly of peptides has driven the research progress for the following two projects: protein delivery vehicles of collagen microflorettes and the assembly of gold nanoparticles with coiled-coil peptides. Collagen is the most abundant protein in the mammals yet due to immunogenic responses, batch-to-batch variability and lack of sequence modifications, synthetic collagen has been designed to self-assemble into native collagen-like structures. In particular with this research, metal binding ligands were incorporated on the termini of collagen-like peptides to generate micron-sized particles, microflorettes. The over-arching goal of the first research project is to engineer MRI-active microflorettes, loaded with His-tagged growth factors with differential release rates while bound to stem cells that can be implemented toward regenerative cell-based therapies. His-tagged proteins, such as green fluorescent protein, have successfully been incorporated on the surface and throughout the microflorettes. Protein release was monitored under physiological conditions and was related to particle degradation. In human plasma full release was obtained within six days. Stability of the microflorettes under physiological conditions was also examined for the development of a therapeutically relevant delivery agent. Additionally, MRI active microflorettes have been generated through the incorporation of a gadolinium binding ligand, DOTA within the collagen-based peptide sequence. To probe peptide-promoted self-assemblies of gold nanoparticles (GNPs) by non-covalent, charge complementary interactions, a highly anionic coiled-coil peptide was designed and synthesized. Upon formation of peptide-GNP interactions, the hydrophobic domain of the coiled-coil were shown to promote the self-assembly of peptide-GNPs clustering. Hydrophobic forces were found to play an important role in the assembly process, as a peptide with an equally overall negative charge, but lacking an

  15. Uptake and presentation of myelin basic protein by normal human B cells.

    Directory of Open Access Journals (Sweden)

    Marie Klinge Brimnes

    Full Text Available B cells may play both pathogenic and protective roles in T-cell mediated autoimmune diseases such as multiple sclerosis (MS. These functions relate to the ability of B cells to bind and present antigens. Under serum-free conditions we observed that 3-4% of circulating B cells from healthy donors were capable of binding the MS-associated self-antigen myelin basic protein (MBP and of presenting the immunodominant peptide MBP85-99, as determined by staining with the mAb MK16 recognising the peptide presented by HLA-DR15-positive cells. In the presence of serum, however, the majority of B cells bound MBP in a complement-dependent manner, and almost half of the B cells became engaged in presentation of MBP85-99. Even though complement receptor 1 (CR1, CD35 and CR2 (CD21 both contributed to binding of MBP to B cells, only CR2 was important for the subsequent presentation of MBP85-99. A high proportion of MBP85-99 presenting B cells expressed CD27, and showed increased expression of CD86 compared to non-presenting B cells. MBP-pulsed B cells induced a low frequency of IL-10-producing CD4+ T cells in 3 out of 6 donors, indicating an immunoregulatory role of B cells presenting MBP-derived peptides. The mechanisms described here refute the general assumption that B-cell presentation of self-antigens requires uptake via specific B-cell receptors, and may be important for maintenance of tolerance as well as for driving T-cell responses in autoimmune diseases.

  16. Peptides and proteins in matter wave interferometry: Challenges and prospects

    Science.gov (United States)

    Sezer, Ugur; Geyer, Philipp; Mairhofer, Lukas; Brand, Christian; Doerre, Nadine; Rodewald, Jonas; Schaetti, Jonas; Koehler, Valentin; Mayor, Marcel; Arndt, Markus

    2016-05-01

    Recent developments in matter wave physics suggest that quantum interferometry with biologically relevant nanomaterials is becoming feasible for amino acids, peptides, proteins and RNA/DNA strands. Quantum interference of biomolecules is interesting as it can mimic Schrödinger's cat states with molecules of high mass, elevated temperature and biological functionality. Additionally, the high internal complexity can give rise to a rich variety of couplings to the environment and new handles for quantitative tests of quantum decoherence. Finally, matter wave interferometers are highly sensitive force sensors and pave the way for quantum-assisted measurements of biomolecular properties in interaction with tailored or biomimetic environments. Recent interferometer concepts such as the Kapitza-Dirac-Talbot-Lau interferometer (KDTLI) or the Optical Time-domain Matter Wave interferometer (OTIMA) have already proven their potential for quantum optics in the mass range beyond 10000 amu and for metrology. Here we show our advances in quantum interferometry with vitamins and peptides and discuss methods of realizing cold, intense and sufficiently slow beams of synthetically tailored or hydrated polypeptides with promising properties for a new generation of quantum optics.

  17. Neurotrophic effects of amyloid precursor protein peptide 165 in vitro.

    Science.gov (United States)

    Yao, Jie; Ma, Lina; Wang, Rong; Sheng, Shuli; Ji, Zhijuan; Zhang, Jingyan

    2016-01-01

    Diabetic encephalopathy is one of the risk factors for Alzheimer's disease. Our previous findings indicated that animals with diabetic encephalopathy exhibit learning and memory impairment in addition to hippocampal neurodegeneration, both of which are ameliorated with amyloid precursor protein (APP) 17-mer (APP17) peptide treatment. Although APP17 is neuroprotective, it is susceptible to enzymatic degradation. Derived from the active sequence structure of APP17, we have previously structurally transformed and modified several APP5-mer peptides (APP328-332 [RERMS], APP 5). We have developed seven different derivatives of APP5, including several analogs. Results from the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human neuroblastoma SH-SY5Y cells in the present study showed that P165 was the most neuroprotective APP5 derivative. Furthermore, we tested the effects of APP5 and P165 on the number of cells and the release of lactate dehydrogenase. Western immunoblot analyses were also performed. The digestion rates of P165 and APP5 were determined by the pepsin digestion test. P165 resisted pepsin digestion significantly more than APP5. Therefore, P165 may be optimal for oral administration. Overall, these findings suggest that P165 may be a potential drug for the treatment of diabetic encephalopathy. PMID:26551064

  18. Iodination of monoclonal antibodies, proteins and peptide using iodogen

    International Nuclear Information System (INIS)

    The use of the iodinating reagent 1,3,4,6-tetrachloro-3α, 6α-diphenylglycholuril (Iodogen) to label monoclonal antibodies (McAbs). Proteins and peptides was invesrigated with McAbs identified as mouse IgG and IgM, arginine-vasopressin (AVP), glucagon (Glu), human insulin(hI) and albumin(Alb). The labeled products were purified by gel chromatography and their immunoreactivity were detected by RIA or IRMA> Comparison of the Iodogen method with the lactoperoxides and chloramine-T methods showed that the Iodogen method had a number of advantages: 1) technically simpler ; 2) a high labeling efficiency could be obtained; 3) the immunoreactivity of the products was minimally affected; 4) the products were stable for up to 4 months

  19. Boost protein expression through co-expression of LEA-like peptide in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Shinya Ikeno

    Full Text Available The boost protein expression has been done successfully by simple co-expression with a late embryogenesis abundant (LEA-like peptide in Escherichia coli. Frequently, overexpression of a recombinant protein fails to provide an adequate yield. In the study, we developed a simple and efficient system for overexpressing transgenic proteins in bacteria by co-expression with an LEA-like peptide. The design of this peptide was based on part of the primary structure of an LEA protein that is known hydrophilic protein to suppress aggregation of other protein molecules. In our system, the expression of the target protein was increased remarkably by co-expression with an LEA-like peptide consisting of only 11 amino acid residues. This could provide a practical method for producing recombinant proteins efficiently.

  20. Interaction of actinides with amino acids: from peptides to proteins

    International Nuclear Information System (INIS)

    Structural information on complexes of actinides with molecules of biological interest is required to better understand the mechanisms of actinides transport in living organisms, and can contribute to develop new decorporation treatments. Our study is about Th(IV), Np(IV), Pu(IV) and uranyl(VI) cations, which have a high affinity for some protein domains, and Fe(III), which is the natural cation of these biological systems. In this work, chelation of actinides has been brought to light with UV-visible-Near Infra Red spectroscopy, NMR, EPR, and ultrafiltration. Determination of the structure of the complexation site has been undertaken with Exafs measurements, and of the tertiary structure of the protein with SANS measurements. The first approach was to describe the interaction modes between actinides and essential chemical functions of proteins. Thus, the Ac-AspAspProAspAsp-NH2 peptide was studied as a possible chelate of actinides. Polynuclear species with μ-oxo or μ-hydroxo bridges were identified. The iron complex is binuclear, and the actinide ones have a higher nuclearity. The second approach was to study a real case of complexation of actinide with a protein: transferrin. Results show that around physiological ph a mononuclear complex is formed with Np(IV) and Pu(IV), while transferrin does not complex Th(IV) in the same conditions. Characteristic distances of M-transferrin complexes (M = Fe, Np, Pu) were determined. Moreover, the protein seems to be in its close conformation with Pu(IV), and in its open form with Np(IV) and UO22+. (author)

  1. Physicochemical Changes of Antioxidant Peptides Hydrolyzed From Porcine Plasma Protein Subject to Free Hydroxyl Radical System

    OpenAIRE

    Hehong Yang; Yanqing Li; Peijun Li; Qian Liu; Baohua Kong; Xu Huang; Zengbao Wu

    2013-01-01

    Antioxidant peptides have attracted much attention for potential application as natural food ingredients but the fate of them, as well as oxidized proteins in foods during processing, is still poorly understood. Physicochemical changes in antioxidant peptides hydrolysated from porcine plasma protein were discussed in a free hydroxyl radical-mediated oxidation system. Porcine Plasma Protein Hydrolysates (PPH) was prepared by hydrolyzing porcine plasma protein with Alcalase for 5 h at pH 8.0, 5...

  2. The Structure-Activity Relationship of the Antioxidant Peptides from Natural Proteins

    Directory of Open Access Journals (Sweden)

    Tang-Bin Zou

    2016-01-01

    Full Text Available Peptides derived from dietary proteins, have been reported to display significant antioxidant activity, which may exert notably beneficial effects in promoting human health and in food processing. Recently, much research has focused on the generation, separation, purification and identification of novel peptides from various protein sources. Some researchers have tried to discover the structural characteristics of antioxidant peptides in order to lessen or avoid the tedious and aimless work involving the ongoing generated peptide preparation schemes. This review aims to summarize the current knowledge on the relationship between the structural features of peptides and their antioxidant activities. The relationship between the structure of the precursor proteins and their abilities to release antioxidant fragments will also be summarized and inferred. The preparation methods and antioxidant capacity evaluation assays of peptides and a prediction scheme of quantitative structure–activity relationship (QSAR will also be pointed out and discussed.

  3. The Structure-Activity Relationship of the Antioxidant Peptides from Natural Proteins.

    Science.gov (United States)

    Zou, Tang-Bin; He, Tai-Ping; Li, Hua-Bin; Tang, Huan-Wen; Xia, En-Qin

    2016-01-12

    Peptides derived from dietary proteins, have been reported to display significant antioxidant activity, which may exert notably beneficial effects in promoting human health and in food processing. Recently, much research has focused on the generation, separation, purification and identification of novel peptides from various protein sources. Some researchers have tried to discover the structural characteristics of antioxidant peptides in order to lessen or avoid the tedious and aimless work involving the ongoing generated peptide preparation schemes. This review aims to summarize the current knowledge on the relationship between the structural features of peptides and their antioxidant activities. The relationship between the structure of the precursor proteins and their abilities to release antioxidant fragments will also be summarized and inferred. The preparation methods and antioxidant capacity evaluation assays of peptides and a prediction scheme of quantitative structure-activity relationship (QSAR) will also be pointed out and discussed.

  4. Monoclonal antibodies against a synthetic peptide from human immunodeficiency virus type 1 Nef protein

    DEFF Research Database (Denmark)

    Steinaa, L; Wulff, A M; Saermark, T

    1994-01-01

    Monoclonal antibodies against a synthetic peptide (aa 138-152) from HIV-1 Nef protein were produced and characterized. Three hybridoma lines producing monoclonal antibodies (MAbs) against the synthetic peptide were generated by fusion between P3-X63 Ag8.653 myeloma cells and BALB/c splenocytes from...... mice immunized with the synthetic peptide coupled to keyhole limpet hemocyanin (KLH). The hybridomas were screened and selected by ELISA with the peptide coupled to bovine serum albumin (BSA) immobilized to the polystyrene surface and specificity for the peptide was confirmed by competitive ELISA...

  5. Monoclonal antibodies against a synthetic peptide from human immunodeficiency virus type 1 Nef protein

    DEFF Research Database (Denmark)

    Steinaa, L; Wulff, A M; Saermark, T

    1994-01-01

    Monoclonal antibodies against a synthetic peptide (aa 138-152) from HIV-1 Nef protein were produced and characterized. Three hybridoma lines producing monoclonal antibodies (MAbs) against the synthetic peptide were generated by fusion between P3-X63 Ag8.653 myeloma cells and BALB/c splenocytes from...... mice immunized with the synthetic peptide coupled to keyhole limpet hemocyanin (KLH). The hybridomas were screened and selected by ELISA with the peptide coupled to bovine serum albumin (BSA) immobilized to the polystyrene surface and specificity for the peptide was confirmed by competitive ELISA with...

  6. Peptide based DNA nanocarriers incorporating a cell-penetrating peptide derived from neurturin protein and poly-L-lysine dendrons.

    Science.gov (United States)

    Rosli, Nurlina; Christie, Michelle P; Moyle, Peter M; Toth, Istvan

    2015-05-15

    Multicomponent gene delivery systems incorporating cell-penetrating peptides (CPP) from the human neurturin protein (NRTN-30, NRTN(132-161); NRTN-17, NRTN(145-161)) and a poly-l-lysine (PLL) dendron, were synthesized and characterized for plasmid DNA (pDNA) delivery. Acetylated NRTN peptides (Ac-CPP) and peptides conjugated to a PLL dendron (DEN-CPP) efficiently condensed and stabilized pDNA. Complexes between pDNA and DEN-CPP formed smaller and more stable nanoparticles. Flow cytometry experiments showed that pDNA-DEN-CPPs were taken up more efficiently into HeLa cells. There was also no significant difference between NRTN-30 and NRTN-17 for pDNA uptake, indicating that the truncated peptide alone is sufficient as a CPP for pDNA delivery.

  7. Computational Framework for Prediction of Peptide Sequences That May Mediate Multiple Protein Interactions in Cancer-Associated Hub Proteins.

    Directory of Open Access Journals (Sweden)

    Debasree Sarkar

    Full Text Available A considerable proportion of protein-protein interactions (PPIs in the cell are estimated to be mediated by very short peptide segments that approximately conform to specific sequence patterns known as linear motifs (LMs, often present in the disordered regions in the eukaryotic proteins. These peptides have been found to interact with low affinity and are able bind to multiple interactors, thus playing an important role in the PPI networks involving date hubs. In this work, PPI data and de novo motif identification based method (MEME were used to identify such peptides in three cancer-associated hub proteins-MYC, APC and MDM2. The peptides corresponding to the significant LMs identified for each hub protein were aligned, the overlapping regions across these peptides being termed as overlapping linear peptides (OLPs. These OLPs were thus predicted to be responsible for multiple PPIs of the corresponding hub proteins and a scoring system was developed to rank them. We predicted six OLPs in MYC and five OLPs in MDM2 that scored higher than OLP predictions from randomly generated protein sets. Two OLP sequences from the C-terminal of MYC were predicted to bind with FBXW7, component of an E3 ubiquitin-protein ligase complex involved in proteasomal degradation of MYC. Similarly, we identified peptides in the C-terminal of MDM2 interacting with FKBP3, which has a specific role in auto-ubiquitinylation of MDM2. The peptide sequences predicted in MYC and MDM2 look promising for designing orthosteric inhibitors against possible disease-associated PPIs. Since these OLPs can interact with other proteins as well, these inhibitors should be specific to the targeted interactor to prevent undesired side-effects. This computational framework has been designed to predict and rank the peptide regions that may mediate multiple PPIs and can be applied to other disease-associated date hub proteins for prediction of novel therapeutic targets of small molecule PPI

  8. Computational Framework for Prediction of Peptide Sequences That May Mediate Multiple Protein Interactions in Cancer-Associated Hub Proteins.

    Science.gov (United States)

    Sarkar, Debasree; Patra, Piya; Ghosh, Abhirupa; Saha, Sudipto

    2016-01-01

    A considerable proportion of protein-protein interactions (PPIs) in the cell are estimated to be mediated by very short peptide segments that approximately conform to specific sequence patterns known as linear motifs (LMs), often present in the disordered regions in the eukaryotic proteins. These peptides have been found to interact with low affinity and are able bind to multiple interactors, thus playing an important role in the PPI networks involving date hubs. In this work, PPI data and de novo motif identification based method (MEME) were used to identify such peptides in three cancer-associated hub proteins-MYC, APC and MDM2. The peptides corresponding to the significant LMs identified for each hub protein were aligned, the overlapping regions across these peptides being termed as overlapping linear peptides (OLPs). These OLPs were thus predicted to be responsible for multiple PPIs of the corresponding hub proteins and a scoring system was developed to rank them. We predicted six OLPs in MYC and five OLPs in MDM2 that scored higher than OLP predictions from randomly generated protein sets. Two OLP sequences from the C-terminal of MYC were predicted to bind with FBXW7, component of an E3 ubiquitin-protein ligase complex involved in proteasomal degradation of MYC. Similarly, we identified peptides in the C-terminal of MDM2 interacting with FKBP3, which has a specific role in auto-ubiquitinylation of MDM2. The peptide sequences predicted in MYC and MDM2 look promising for designing orthosteric inhibitors against possible disease-associated PPIs. Since these OLPs can interact with other proteins as well, these inhibitors should be specific to the targeted interactor to prevent undesired side-effects. This computational framework has been designed to predict and rank the peptide regions that may mediate multiple PPIs and can be applied to other disease-associated date hub proteins for prediction of novel therapeutic targets of small molecule PPI modulators. PMID

  9. Ribosome reinitiation at leader peptides increases translation of bacterial proteins.

    Science.gov (United States)

    Korolev, Semen A; Zverkov, Oleg A; Seliverstov, Alexandr V; Lyubetsky, Vassily A

    2016-04-16

    Short leader genes usually do not encode stable proteins, although their importance in expression control of bacterial genomes is widely accepted. Such genes are often involved in the control of attenuation regulation. However, the abundance of leader genes suggests that their role in bacteria is not limited to regulation. Specifically, we hypothesize that leader genes increase the expression of protein-coding (structural) genes via ribosome reinitiation at the leader peptide in the case of a short distance between the stop codon of the leader gene and the start codon of the structural gene. For instance, in Actinobacteria, the frequency of leader genes at a distance of 10-11 bp is about 70 % higher than the mean frequency within the 1 to 65 bp range; and it gradually decreases as the range grows longer. A pronounced peak of this frequency-distance relationship is also observed in Proteobacteria, Bacteroidetes, Spirochaetales, Acidobacteria, the Deinococcus-Thermus group, and Planctomycetes. In contrast, this peak falls to the distance of 15-16 bp and is not very pronounced in Firmicutes; and no such peak is observed in cyanobacteria and tenericutes. Generally, this peak is typical for many bacteria. Some leader genes located close to a structural gene probably play a regulatory role as well.

  10. Targeting of proteins to the thylakoid lumen by the bipartite transit peptide of the 33 kd oxygen-evolving protein.

    OpenAIRE

    Ko, K.; Cashmore, A. R.

    1989-01-01

    Various chimeric precursors and deletions of the 33 kd oxygen-evolving protein (OEE1) were constructed to study the mechanism by which chloroplast proteins are imported and targeted to the thylakoid lumen. The native OEE1 precursor was imported into isolated chloroplasts, processed and localized in the thylakoid lumen. Replacement of the OEE1 transit peptide with the transit peptide of the small subunit of ribulose-1,5-bisphosphate carboxylase, a stromal protein, resulted in redirection of ma...

  11. Oral delivery of peptides and proteins using lipid-based drug delivery systems

    DEFF Research Database (Denmark)

    Li, Ping; Nielsen, Hanne Mørck; Müllertz, Anette

    2012-01-01

    INTRODUCTION: In order to successfully develop lipid-based drug delivery systems (DDS) for oral administration of peptides and proteins, it is important to gain an understanding of the colloid structures formed by these DDS, the mode of peptide and protein incorporation as well as the mechanism...... by which intestinal absorption of peptides and proteins is promoted. AREAS COVERED: The present paper reviews the literature on lipid-based DDS, employed for oral delivery of peptides and proteins and highlights the mechanisms by which the different lipid-based carriers are expected to overcome the two...... most important barriers (extensive enzymatic degradation and poor transmucosal permeability). This paper also gives a clear-cut idea about advantages and drawbacks of using different lipidic colloidal carriers ((micro)emulsions, solid lipid core particles and liposomes) for oral delivery of peptides...

  12. Anticancer and antioxidant activities of the peptide fraction from algae protein waste.

    Science.gov (United States)

    Sheih, I-Chuan; Fang, Tony J; Wu, Tung-Kung; Lin, Peng-Hsiang

    2010-01-27

    Algae protein waste is a byproduct during production of algae essence from Chlorella vulgaris. There is no known report on the anticancer peptides derived from the microalgae protein waste. In this paper, the peptide fraction isolated from pepsin hydrolysate of algae protein waste had strong dose-dependent antiproliferation and induced a post-G1 cell cycle arrest in AGS cells; however, no cytotoxicity was observed in WI-38 lung fibroblasts cells in vitro. The peptide fraction also revealed much better antioxidant activity toward peroxyl radicals and LDL than those of Trolox. Among these peptides, a potent antiproliferative, antioxidant, and NO-production-inhibiting hendecapeptide was isolated, and its amino acid sequence was VECYGPNRPQF. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce anticancer peptides. PMID:19916544

  13. Detection of trans–cis flips and peptide-plane flips in protein structures

    Energy Technology Data Exchange (ETDEWEB)

    Touw, Wouter G., E-mail: wouter.touw@radboudumc.nl [Radboud University Medical Center, Geert Grooteplein-Zuid 26-28, 6525 GA Nijmegen (Netherlands); Joosten, Robbie P. [Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Vriend, Gert, E-mail: wouter.touw@radboudumc.nl [Radboud University Medical Center, Geert Grooteplein-Zuid 26-28, 6525 GA Nijmegen (Netherlands)

    2015-07-28

    A method is presented to detect peptide bonds that need either a trans–cis flip or a peptide-plane flip. A coordinate-based method is presented to detect peptide bonds that need correction either by a peptide-plane flip or by a trans–cis inversion of the peptide bond. When applied to the whole Protein Data Bank, the method predicts 4617 trans–cis flips and many thousands of hitherto unknown peptide-plane flips. A few examples are highlighted for which a correction of the peptide-plane geometry leads to a correction of the understanding of the structure–function relation. All data, including 1088 manually validated cases, are freely available and the method is available from a web server, a web-service interface and through WHAT-CHECK.

  14. Aggregation of peptides in soy protein isolate hydrolysates : the individual contributions of glycinin- and ß-conglycinin-derived peptides

    NARCIS (Netherlands)

    Kuipers, B.J.H.

    2007-01-01

    Keywords: Soy proteins, glycinin, β-conglycinin, enzymatic hydrolysis, peptides, aggregation, gelation, identification, mass-spectrometry, mappingThe aim of the work presented in this thesis is to understand howlimited e

  15. Putative signal peptides of two BURP proteins can direct proteins to their destinations in tobacco cell system.

    Science.gov (United States)

    Tang, Yulin; Ou, Zhonghua; Qiu, Jianbin; Mi, Zilan

    2014-11-01

    Plant-specific BURP family proteins have a diverse subcellular localization with different functions. However, only limited studies have investigated the functions of their different domains. In the present study, the role of the N-terminal putative signal peptide in protein subcellular localization was investigated using a tobacco cell system. The results showed that SALI3-2 was present in vacuoles, whereas AtRD22 was directed to the apoplast. The N-terminal putative signal peptides of both proteins were confirmed to be the essential and critical domains for targeting the proteins to their destinations. We also demonstrate that the expression and accumulation of mGFP in tobacco cells was increased when mGFP was fused to the putative signal peptide of SALI3-2. The findings offer the potential application of this short peptide in protein production in plants. PMID:25048229

  16. Production and characterization of polyclonal antibody against a synthetic peptide from β-actin protein

    OpenAIRE

    Nazila Amini; Mohadeseh Naghi Vishteh; Omid Zarei; Reza Hadavi; Negah Ahmadvand; Hodjattallah Rabbani; Mahmood Jeddi-Tehrani

    2014-01-01

    Objective(s):Antibodies against actin, as one of the most widely studied structural and multifunctional housekeeping proteins in eukaryotic cells, are used as internal loading controls in western blot analyses. The aim of this study was to produce polyclonal antibody against a synthetic peptide derived from N-terminal region of β-actin protein to be used as a protein loading control in western blot and other assay systems. Materials and Methods: A synthetic peptide derived from β-actin protei...

  17. Design of cationic microspheres based on aminated gelatin for controlled release of peptide and protein drugs.

    Science.gov (United States)

    Morimoto, Kazuhiro; Chono, Sumio; Kosai, Tadashi; Seki, Toshinobu; Tabata, Yasuhiko

    2008-02-01

    Two different types of cationized microspheres based on a native cationic gelatin (NGMS) and aminated gelatin with ethylendiamine (CGMS) were investigated for the controlled release of three model acidic peptide/protein drugs with different molecular weights (MWs) and isoelectric points (IEPs). Recombinant human (rh)-insulin (MW: 5.8 kDa, IEP: 5.3), bovine milk lactoalbumin, BMLA (MW: 14 kDa, IEP: 4.3), and bovine serum albumin (BSA MW: 67 kDa, IEP: 4.9) were used as model acidic peptide/protein drugs. The in vitro release profiles of these acidic peptide/protein drugs from NGMS and CGMS were compared and different periods of cross-linking were obtained. The slower release of these acidic peptide/protein drugs from CGMS compared with those from NGMS with cross-linking for 48 hr. was caused by the suppression of burst release during the initial phase. The degree of suppression of burst release of the three peptide/protein drugs during the initial phase by CGMS was in the following order: (rh)-insulin > BMLA > BSA. The release of insulin with a lower molecular weight from CGMS was particularly suppressed compared with the other two drugs with higher molecular weights in the initial phase. The control of the release rate of acidic peptide/protein drugs from gelatin microsphere can be achieved by amination of gelatin. Therefore, CGMS is useful for the controlled release of acidic peptide/ protein drugs.

  18. Tuning the Protein Corona of Hydrogel Nanoparticles: The Synthesis of Abiotic Protein and Peptide Affinity Reagents.

    Science.gov (United States)

    O'Brien, Jeffrey; Shea, Kenneth J

    2016-06-21

    Nanomaterials, when introduced into a complex, protein-rich environment, rapidly acquire a protein corona. The type and amount of proteins that constitute the corona depend significantly on the synthetic identity of the nanomaterial. For example, hydrogel nanoparticles (NPs) such as poly(N-isopropylacrylamide) (NIPAm) have little affinity for plasma proteins; in contrast, carboxylated poly(styrene) NPs acquire a dense protein corona. This range of protein adsorption suggests that the protein corona might be "tuned" by controlling the chemical composition of the NP. In this Account, we demonstrate that small libraries of synthetic polymer NPs incorporating a diverse pool of functional monomers can be screened for candidates with high affinity and selectivity to targeted biomacromolecules. Through directed synthetic evolution of NP compositions, one can tailor the protein corona to create synthetic organic hydrogel polymer NPs with high affinity and specificity to peptide toxins, enzymes, and other functional proteins, as well as to specific domains of large proteins. In addition, many NIPAm NPs undergo a change in morphology as a function of temperature. This transformation often correlates with a significant change in NP-biomacromolecule affinity, resulting in a temperature-dependent protein corona. This temperature dependence has been used to develop NP hydrogels with autonomous affinity switching for the protection of proteins from thermal stress and as a method of biomacromolecule purification through a selective thermally induced catch and release. In addition to temperature, changes in pH or buffer can also alter a NP protein corona composition, a property that has been exploited for protein purification. Finally, synthetic polymer nanoparticles with low nanomolar affinity for a peptide toxin were shown to capture and neutralize the toxin in the bloodstream of living mice. While the development of synthetic polymer alternatives to protein affinity reagents is

  19. Tuning the Protein Corona of Hydrogel Nanoparticles: The Synthesis of Abiotic Protein and Peptide Affinity Reagents.

    Science.gov (United States)

    O'Brien, Jeffrey; Shea, Kenneth J

    2016-06-21

    Nanomaterials, when introduced into a complex, protein-rich environment, rapidly acquire a protein corona. The type and amount of proteins that constitute the corona depend significantly on the synthetic identity of the nanomaterial. For example, hydrogel nanoparticles (NPs) such as poly(N-isopropylacrylamide) (NIPAm) have little affinity for plasma proteins; in contrast, carboxylated poly(styrene) NPs acquire a dense protein corona. This range of protein adsorption suggests that the protein corona might be "tuned" by controlling the chemical composition of the NP. In this Account, we demonstrate that small libraries of synthetic polymer NPs incorporating a diverse pool of functional monomers can be screened for candidates with high affinity and selectivity to targeted biomacromolecules. Through directed synthetic evolution of NP compositions, one can tailor the protein corona to create synthetic organic hydrogel polymer NPs with high affinity and specificity to peptide toxins, enzymes, and other functional proteins, as well as to specific domains of large proteins. In addition, many NIPAm NPs undergo a change in morphology as a function of temperature. This transformation often correlates with a significant change in NP-biomacromolecule affinity, resulting in a temperature-dependent protein corona. This temperature dependence has been used to develop NP hydrogels with autonomous affinity switching for the protection of proteins from thermal stress and as a method of biomacromolecule purification through a selective thermally induced catch and release. In addition to temperature, changes in pH or buffer can also alter a NP protein corona composition, a property that has been exploited for protein purification. Finally, synthetic polymer nanoparticles with low nanomolar affinity for a peptide toxin were shown to capture and neutralize the toxin in the bloodstream of living mice. While the development of synthetic polymer alternatives to protein affinity reagents is

  20. Major Peptides from Amaranth (Amaranthus cruentus Protein Inhibit HMG-CoA Reductase Activity

    Directory of Open Access Journals (Sweden)

    Rosana Aparecida Manólio Soares

    2015-02-01

    Full Text Available The objective of this study was to identify the major peptides generated by the in vitro hydrolysis of Amaranthus cruentus protein and to verify the effect of these peptides on the activity of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase, a key enzyme in cholesterol biosynthesis. A protein isolate was prepared, and an enzymatic hydrolysis that simulated the in vivo digestion of the protein was performed. After hydrolysis, the peptide mixture was filtered through a 3 kDa membrane. The peptide profile of this mixture was determined by reversed phase high performance chromatography (RP-HPLC, and the peptide identification was performed by LC-ESI MS/MS. Three major peptides under 3 kDa were detected, corresponding to more than 90% of the peptides of similar size produced by enzymatic hydrolysis. The sequences identified were GGV, IVG or LVG and VGVI or VGVL. These peptides had not yet been described for amaranth protein nor are they present in known sequences of amaranth grain protein, except LVG, which can be found in amaranth α‑amylase. Their ability to inhibit the activity of HMG-CoA reductase was determined, and we found that the sequences GGV, IVG, and VGVL, significantly inhibited this enzyme, suggesting a possible hypocholesterolemic effect.

  1. New Milk Protein-Derived Peptides with Potential Antimicrobial Activity: An Approach Based on Bioinformatic Studies

    Science.gov (United States)

    Dziuba, Bartłomiej; Dziuba, Marta

    2014-01-01

    New peptides with potential antimicrobial activity, encrypted in milk protein sequences, were searched for with the use of bioinformatic tools. The major milk proteins were hydrolyzed in silico by 28 enzymes. The obtained peptides were characterized by the following parameters: molecular weight, isoelectric point, composition and number of amino acid residues, net charge at pH 7.0, aliphatic index, instability index, Boman index, and GRAVY index, and compared with those calculated for known 416 antimicrobial peptides including 59 antimicrobial peptides (AMPs) from milk proteins listed in the BIOPEP database. A simple analysis of physico-chemical properties and the values of biological activity indicators were insufficient to select potentially antimicrobial peptides released in silico from milk proteins by proteolytic enzymes. The final selection was made based on the results of multidimensional statistical analysis such as support vector machines (SVM), random forest (RF), artificial neural networks (ANN) and discriminant analysis (DA) available in the Collection of Anti-Microbial Peptides (CAMP database). Eleven new peptides with potential antimicrobial activity were selected from all peptides released during in silico proteolysis of milk proteins. PMID:25141106

  2. New Milk Protein-Derived Peptides with Potential Antimicrobial Activity: An Approach Based on Bioinformatic Studies

    Directory of Open Access Journals (Sweden)

    Bartłomiej Dziuba

    2014-08-01

    Full Text Available New peptides with potential antimicrobial activity, encrypted in milk protein sequences, were searched for with the use of bioinformatic tools. The major milk proteins were hydrolyzed in silico by 28 enzymes. The obtained peptides were characterized by the following parameters: molecular weight, isoelectric point, composition and number of amino acid residues, net charge at pH 7.0, aliphatic index, instability index, Boman index, and GRAVY index, and compared with those calculated for known 416 antimicrobial peptides including 59 antimicrobial peptides (AMPs from milk proteins listed in the BIOPEP database. A simple analysis of physico-chemical properties and the values of biological activity indicators were insufficient to select potentially antimicrobial peptides released in silico from milk proteins by proteolytic enzymes. The final selection was made based on the results of multidimensional statistical analysis such as support vector machines (SVM, random forest (RF, artificial neural networks (ANN and discriminant analysis (DA available in the Collection of Anti-Microbial Peptides (CAMP database. Eleven new peptides with potential antimicrobial activity were selected from all peptides released during in silico proteolysis of milk proteins.

  3. Major peptides from amaranth (Amaranthus cruentus) protein inhibit HMG-CoA reductase activity.

    Science.gov (United States)

    Soares, Rosana Aparecida Manólio; Mendonça, Simone; de Castro, Luíla Ívini Andrade; Menezes, Amanda Caroline Cardoso Corrêa Carlos; Arêas, José Alfredo Gomes

    2015-01-01

    The objective of this study was to identify the major peptides generated by the in vitro hydrolysis of Amaranthus cruentus protein and to verify the effect of these peptides on the activity of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase), a key enzyme in cholesterol biosynthesis. A protein isolate was prepared, and an enzymatic hydrolysis that simulated the in vivo digestion of the protein was performed. After hydrolysis, the peptide mixture was filtered through a 3 kDa membrane. The peptide profile of this mixture was determined by reversed phase high performance chromatography (RP-HPLC), and the peptide identification was performed by LC-ESI MS/MS. Three major peptides under 3 kDa were detected, corresponding to more than 90% of the peptides of similar size produced by enzymatic hydrolysis. The sequences identified were GGV, IVG or LVG and VGVI or VGVL. These peptides had not yet been described for amaranth protein nor are they present in known sequences of amaranth grain protein, except LVG, which can be found in amaranth α‑amylase. Their ability to inhibit the activity of HMG-CoA reductase was determined, and we found that the sequences GGV, IVG, and VGVL, significantly inhibited this enzyme, suggesting a possible hypocholesterolemic effect. PMID:25690031

  4. Normalization of nomenclature for peptide motifs as ligands of modular protein domains

    DEFF Research Database (Denmark)

    Aasland, Rein; Abrams, Charles; Ampe, Christophe;

    2002-01-01

    We propose a normalization of symbols and terms used to describe, accurately and succinctly, the detailed interactions between amino acid residues of pairs of interacting proteins at protein:protein (or protein:peptide) interfaces. Our aim is to unify several diverse descriptions currently in use...

  5. Unusual Fragmentation of Peptide and Protein in Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Mitsuo Takayama

    2001-01-01

    Unusual amine - bond fragmentation on the peptide/protein backbone has been reported using matrix - assisted laser desorption/ionization time - of- flight mass spectrometry (MALDI - TOFMS)The amine - bond cleavage occurred without metastable decay, while the peptide - bond cleavage occurred with metastable decay of peptide ions in a drift region of TOF mass analyzer. It was presumed that the amine - bond cleavage occurred as a non - ergodic process independent of the ionization under MALDI conditions.

  6. Milk protein-derived peptide inhibitors of angiotensin-I-converting enzyme

    OpenAIRE

    FitzGerald, Richard J.; Meisel, Hans

    2000-01-01

    peer-reviewed Numerous casein and whey protein-derived angiotensin-I-converting enzyme (ACE) inhibitory peptides/hydrolysates have been identified. Clinical trials in hypertensive animals and humans show that these peptides/hydrolysates can bring about a significant reduction in hypertension. These peptides/hydrolysates may be classified as functional food ingredients and nutraceuticals due to their ability to provide health benefits i.e. as functional food ingredients in reduc...

  7. Protein and lipid interactions of mammalian antibacterial peptides

    OpenAIRE

    Wang, Yuqin

    2001-01-01

    Gene-encoded antibacterial peptides are multifunctional effector molecules and play an important role in host innate immunity. Upon stimulation, the mature active peptides are released from inactive precursors. Cathelicidins constitute a family of antibacterial peptides, which share a conserved N-terminal cathelin-like region followed by a variable C-terminal antibacterial domain. In addition to its antibacterial activity, LL-37, the only cathelicidin found in human, is ...

  8. Functional interactions between polypyrimidine tract binding protein and PRI peptide ligand containing proteins.

    Science.gov (United States)

    Coelho, Miguel B; Ascher, David B; Gooding, Clare; Lang, Emma; Maude, Hannah; Turner, David; Llorian, Miriam; Pires, Douglas E V; Attig, Jan; Smith, Christopher W J

    2016-08-15

    Polypyrimidine tract binding protein (PTBP1) is a heterogeneous nuclear ribonucleoprotein (hnRNP) that plays roles in most stages of the life-cycle of pre-mRNA and mRNAs in the nucleus and cytoplasm. PTBP1 has four RNA binding domains of the RNA recognition motif (RRM) family, each of which can bind to pyrimidine motifs. In addition, RRM2 can interact via its dorsal surface with proteins containing short peptide ligands known as PTB RRM2 interacting (PRI) motifs, originally found in the protein Raver1. Here we review our recent progress in understanding the interactions of PTB with RNA and with various proteins containing PRI ligands. PMID:27528752

  9. A robust method of determination of high concentrations of peptides and proteins

    DEFF Research Database (Denmark)

    Levashov, Pavel A; Sutherland, Duncan S; Besenbacher, Flemming;

    2009-01-01

    In this paper, we pioneer application of a unique method of protein determination by coloring peptide bonds for analysis of a variety of biomolecules with different grades of purity (e.g., oligopeptides, membrane, and glycol proteins). We demonstrated that the calibration curve for all studied...... molecules is universal and linear within 0.1 to 1.2mg protein content range. The assay thus can be used to analyze peptides without preliminary dilutions and calibration in up to 1g/ml solutions of peptides, which is crucial for many biotechnological processes, such as development of coatings, scaffolds......, and biocompatible materials....

  10. Rapid Identification of Protein Kinase Phosphorylation Site Motifs Using Combinatorial Peptide Libraries.

    Science.gov (United States)

    Miller, Chad J; Turk, Benjamin E

    2016-01-01

    Eukaryotic protein kinases phosphorylate substrates at serine, threonine, and tyrosine residues that fall within the context of short sequence motifs. Knowing the phosphorylation site motif for a protein kinase facilitates designing substrates for kinase assays and mapping phosphorylation sites in protein substrates. Here, we describe an arrayed peptide library protocol for rapidly determining kinase phosphorylation consensus sequences. This method uses a set of peptide mixtures in which each of the 20 amino acid residues is systematically substituted at nine positions surrounding a central site of phosphorylation. Peptide mixtures are arrayed in multiwell plates and analyzed by radiolabel assay with the kinase of interest. The preferred sequence is determined from the relative rate of phosphorylation of each peptide in the array. Consensus peptides based on these sequences typically serve as efficient and specific kinase substrates for high-throughput screening or incorporation into biosensors.

  11. Spinal activity of interleukin 6 mediates myelin basic protein-induced allodynia.

    Science.gov (United States)

    Ko, Justin S; Eddinger, Kelly A; Angert, Mila; Chernov, Andrei V; Dolkas, Jennifer; Strongin, Alex Y; Yaksh, Tony L; Shubayev, Veronica I

    2016-08-01

    Mechanosensory fibers are enveloped by myelin, a unique multilamellar membrane permitting saltatory neuronal conduction. Damage to myelin is thought to contribute to severe pain evoked by innocuous tactile stimulation (i.e., mechanical allodynia). Our earlier (Liu et al., 2012) and present data demonstrate that a single injection of a myelin basic protein-derived peptide (MBP84-104) into an intact sciatic nerve produces a robust and long-lasting (>30days) mechanical allodynia in female rats. The MBP84-104 peptide represents the immunodominant epitope and requires T cells to maintain allodynia. Surprisingly, only systemic gabapentin (a ligand of voltage-gated calcium channel α2δ1), but not ketorolac (COX inhibitor), lidocaine (sodium channel blocker) or MK801 (NMDA antagonist) reverse allodynia induced by the intrasciatic MBP84-104. The genome-wide transcriptional profiling of the sciatic nerve followed by the bioinformatics analyses of the expression changes identified interleukin (IL)-6 as the major cytokine induced by MBP84-104 in both the control and athymic T cell-deficient nude rats. The intrasciatic MBP84-104 injection resulted in both unilateral allodynia and unilateral IL-6 increase the segmental spinal cord (neurons and astrocytes). An intrathecal delivery of a function-blocking IL-6 antibody reduced the allodynia in part by the transcriptional effects in large-diameter primary afferents in DRG. Our data suggest that MBP regulates IL-6 expression in the nervous system and that the spinal IL-6 activity mediates nociceptive processing stimulated by the MBP epitopes released after damage or disease of the somatosensory nervous system. PMID:26970355

  12. Multifunctional antimicrobial proteins and peptides: natural activators of immune systems.

    Science.gov (United States)

    Niyonsaba, François; Nagaoka, Isao; Ogawa, Hideoki; Okumura, Ko

    2009-01-01

    In addition to the physical barrier of the stratum corneum, cutaneous innate immunity also includes the release of various humoral mediators, such as cytokines and chemokines, recruitment and activation of phagocytes, and the production of antimicrobial proteins/peptides (AMPs). AMPs form an innate epithelial chemical shield, which provides a front-line component in innate immunity to inhibit microbial invasion; however, this might be an oversimplification of the diverse functions of these molecules. In fact, apart from exhibiting a broad spectrum of microbicidal properties, it is increasingly evident that AMPs display additional activities that are related to the stimulation and modulation of the cutaneous immune system. These diverse functions include chemoattraction and activation of immune and/or inflammatory cells, the production and release of cytokines and chemokines, acceleration of angiogenesis, promotion of wound healing, neutralization of harmful microbial products, and bridging of both innate and adaptive immunity. Thus, better understanding of the functions of AMPs in skin and identification of their signaling mechanisms may offer new strategies for the development of potential therapeutics for the treatment of infection- and/or inflammation-related skin diseases. Here, we briefly outline the structure, regulation of expression, and multifunctional roles of principal skin-derived AMPs.

  13. Bioavailability of milk protein-derived bioactive peptides: a glycaemic management perspective.

    Science.gov (United States)

    Horner, Katy; Drummond, Elaine; Brennan, Lorraine

    2016-06-01

    Milk protein-derived peptides have been reported to have potential benefits for reducing the risk of type 2 diabetes. However, what the active components are and whether intact peptides exert this bioactivity has received little investigation in human subjects. Furthermore, potentially useful bioactive peptides can be limited by low bioavailability. Various peptides have been identified in the gastrointestinal tract and bloodstream after milk-protein ingestion, providing valuable insights into their potential bioavailability. However, these studies are currently limited and the structure and sequence of milk peptides exerting bioactivity for glycaemic management has received little investigation in human subjects. The present article reviews the bioavailability of milk protein-derived peptides in human studies to date, and examines the evidence on milk proteins and glycaemic management, including potential mechanisms of action. Areas in need of advancement are identified. Only by establishing the bioavailability of milk protein-derived peptides, the active components and the mechanistic pathways involved can the benefits of milk proteins for the prevention or management of type 2 diabetes be fully realised in future.

  14. Boc SPPS of two hydrophobic peptides using a ''solubilising tail'' strategy : Dodecaalanine and chemotactic protein 10(42-55)

    NARCIS (Netherlands)

    Englebretsen, DR; Alewood, PF

    1996-01-01

    The solid phase syntheses of the hydrophobic peptides dodecaalanine and chemotactic protein-10(42-55) were achieved using a ''solubilising tail'' strategy. Peptide constructs of the form H-hydrophobic peptide-glycolamide ester-(Gly-Arg)(4)-Gly-OH were synthesised by Boc SPPS. The peptide-constructs

  15. Identification of peptide and protein doping related drug compounds confiscated in Denmark between 2007-2013

    DEFF Research Database (Denmark)

    Hartvig, Rune Andersen; Holm, Niels Bjerre; Dalsgaard, Petur Weihe;

    2014-01-01

    We present an overview of protein and peptide compounds confiscated in Denmark from late 2007 till late 2013 together with a description of a newly developed HRAM-LC-MS method used for identification. As examples of identification, we present data for the peptides AOD-9604, [D-Ala2, Gln8, Ala15, ...

  16. Hydrolysis of Whey Protein Isolate with Bacillus licheniformis Protease: Fractionation and Identification of Aggregating Peptides

    NARCIS (Netherlands)

    Creusot, N.P.; Gruppen, H.

    2007-01-01

    The objective of this work was to identify the dominant aggregating peptides from a whey protein hydrolysate (degree of hydrolysis of 6.8%) obtained with Bacillus licheniformis protease. The aggregating peptides were fractionated with preparative reversed-phase chromatography and identified with liq

  17. Activities of Venom Proteins and Peptides with Possible Therapeutic Applications from Bees and WASPS.

    Science.gov (United States)

    Ye, Xiujuan; Guan, Suzhen; Liu, Jiwen; Ng, Charlene C W; Chan, Gabriel H H; Sze, Stephen C W; Zhang, Kalin Y; Naude, Ryno; Rolka, Krzysztof; Wong, Jack Ho; Ng, Tzi Bun

    2016-01-01

    The variety of proteins and peptides isolated from honey bee venom and wasp venom includes melittin, adiapin, apamine, bradykinin, cardiopep, mast cell degranulating peptide, mastoparan, phospholipase A2 and secapin. Some of the activities they demonstrate may find therapeutic applications. PMID:27323949

  18. Targeting diverse protein-protein interaction interfaces with α/β-peptides derived from the Z-domain scaffold.

    Science.gov (United States)

    Checco, James W; Kreitler, Dale F; Thomas, Nicole C; Belair, David G; Rettko, Nicholas J; Murphy, William L; Forest, Katrina T; Gellman, Samuel H

    2015-04-14

    Peptide-based agents derived from well-defined scaffolds offer an alternative to antibodies for selective and high-affinity recognition of large and topologically complex protein surfaces. Here, we describe a strategy for designing oligomers containing both α- and β-amino acid residues ("α/β-peptides") that mimic several peptides derived from the three-helix bundle "Z-domain" scaffold. We show that α/β-peptides derived from a Z-domain peptide targeting vascular endothelial growth factor (VEGF) can structurally and functionally mimic the binding surface of the parent peptide while exhibiting significantly decreased susceptibility to proteolysis. The tightest VEGF-binding α/β-peptide inhibits the VEGF165-induced proliferation of human umbilical vein endothelial cells. We demonstrate the versatility of this strategy by showing how principles underlying VEGF signaling inhibitors can be rapidly extended to produce Z-domain-mimetic α/β-peptides that bind to two other protein partners, IgG and tumor necrosis factor-α. Because well-established selection techniques can identify high-affinity Z-domain derivatives from large DNA-encoded libraries, our findings should enable the design of biostable α/β-peptides that bind tightly and specifically to diverse targets of biomedical interest. Such reagents would be useful for diagnostic and therapeutic applications.

  19. Study of Myelin Basic Protein Associated with Pediatric Systematic Epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yang Sida; He Xin; Yang Yiyu; Zhu Huihua; He Dansha; Deng Weiyi

    2000-01-01

    Objective: To investigate the quantitative myelin basic protein (MBP) in cerebrospinal fluid (CSF) and serum in pediatric systematic epilepsy (SEP), study the relation between SEP and MBP, and the possibility predicating'the injury of myelin and blood-brain barrier (BBB) from pediatric SEP. Background: While tactors induced destroy of cerebral and Myelin, MBP was released out into CSF to increase its concentration. On the other hand, the BBB was involved to make serum MBP increased. The related studies had confirmed these viewpoints above. The test for quantitative MBP was recognized as the specific biochemical index, which diagnose if there is or not organic injury of cerebral and myelin. There was few reports about the studies of quantitative MBP in CSF and serum of EP, not mention to those published in domestic pediatric academia. Methods: 47 cases were studied during one month after the SEP attack, whose MBP in serum were quantitatively and 31 inside in CSF were also tested by easy MBP-ELISA method; the quantitative MBP in serum of 30 control cases and 10 in CSF were tested, too. Results: MBP values in CSF and serum of SEP pediatric patients were 2.95±0.61 ng/ml and 3.17±0.53 ng/ml; whereas 1.41 ±0.19 ng/ml and 1.30±0.04 ng/ml in control group. Both mean valves of MBP in CSF and serum in study group were significantly higher than control group (either P< 0.01). Discussion: In general, electrophysiological evidences supported the issue that epileptic episode was originated from abnormal electrical activities of nervous cells. Pathological studies revealed degeneration and necrosis of nerve existed in temporal epileptic focus, where there was morphological change of myelin. This study showed MBP values in CSF and serum of SEEP, during one month after attack, increased significantly; suggested there was changed component of MBP, while SEP could not be controled. Those above indicated the destroy of myelin, increasing of BBB permeability that induced its

  20. Screening of soy protein-derived hypotriglyceridemic di-peptides in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Matsui Toshiro

    2011-05-01

    Full Text Available Abstract Background Soy protein and soy peptides have attracted considerable attention because of their potentially beneficial biological properties, including antihypertensive, anticarcinogenic, and hypolipidemic effects. Although soy protein isolate contains several bioactive peptides that have distinct physiological activities in lipid metabolism, it is not clear which peptide sequences are responsible for the triglyceride (TG-lowering effects. In the present study, we investigated the effects of soy protein-derived peptides on lipid metabolism, especially TG metabolism, in HepG2 cells and obese Otsuka Long-Evans Tokushima fatty (OLETF rats. Results In the first experiment, we found that soy crude peptide (SCP-LD3, which was prepared by hydrolyze of soy protein isolate with endo-type protease, showed hypolipidemic effects in HepG2 cells and OLETF rats. In the second experiment, we found that hydrophilic fraction, separated from SCP-LD3 with hydrophobic synthetic absorbent, revealed lipid-lowering effects in HepG2 cells and OLETF rats. In the third experiment, we found that Fraction-C (Frc-C peptides, fractionated from hydrophilic peptides by gel permeation chromatography-high performance liquid chromatography, significantly reduced TG synthesis and apolipoprotein B (apoB secretion in HepG2 cells. In the fourth experiment, we found that the fraction with 0.1% trifluoroacetic acid, isolated from Frc-C peptides by octadecylsilyl column chromatography, showed hypolipidemic effects in HepG2 cells. In the final experiment, we found that 3 di-peptides, Lys-Ala, Val-Lys, and Ser-Tyr, reduced TG synthesis, and Ser-Tyr additionally reduced apoB secretion in HepG2 cells. Conclusion Novel active peptides with TG-lowering effects from soy protein have been isolated.

  1. Peptide nanofibers modified with a protein by using designed anchor molecules bearing hydrophobic and functional moieties.

    Science.gov (United States)

    Miyachi, Ayaka; Takahashi, Tsuyoshi; Matsumura, Sachiko; Mihara, Hisakazu

    2010-06-11

    Self-assembly of peptides and proteins is a key feature of biological functions. Short amphiphilic peptides designed with a beta-sheet structure can form sophisticated nanofiber structures, and the fibers are available as nanomaterials for arranging biomolecules. Peptide FI (H-PKFKIIEFEP-OH) self-assembles into nanofibers with a coiled fine structure, as reported in our previous work. We have constructed anchor molecules that have both a binding moiety for the fiber structure and a functional unit capable of capturing target molecules, with the purpose of arranging proteins on the designed peptide nanofibers. Designed anchors containing an alkyl chain as a binding unit and biotin as a functional moiety were found to bind to peptide fibers FI and F2i (H-ALEAKFAAFEAKLA-NH(2)). The surface-exposed biotin moiety on the fibers could capture an anti-biotin antibody. Moreover, hydrophobic dipeptide anchor units composed of iminodiacetate connected to Phe-Phe or Ile-Ile and a peptide composed of six histidine residues connected to biotin could also connect FI peptide fibers to the anti-biotin antibody through the chelation of Ni(2+) ions. This strategy of using designed anchors opens a novel approach to constructing nanoscale protein arrays on peptide nanomaterials. PMID:20419712

  2. CPAD, Curated Protein Aggregation Database: A Repository of Manually Curated Experimental Data on Protein and Peptide Aggregation.

    Science.gov (United States)

    Thangakani, A Mary; Nagarajan, R; Kumar, Sandeep; Sakthivel, R; Velmurugan, D; Gromiha, M Michael

    2016-01-01

    Accurate distinction between peptide sequences that can form amyloid-fibrils or amorphous β-aggregates, identification of potential aggregation prone regions in proteins, and prediction of change in aggregation rate of a protein upon mutation(s) are critical to research on protein misfolding diseases, such as Alzheimer's and Parkinson's, as well as biotechnological production of protein based therapeutics. We have developed a Curated Protein Aggregation Database (CPAD), which has collected results from experimental studies performed by scientific community aimed at understanding protein/peptide aggregation. CPAD contains more than 2300 experimentally observed aggregation rates upon mutations in known amyloidogenic proteins. Each entry includes numerical values for the following parameters: change in rate of aggregation as measured by fluorescence intensity or turbidity, name and source of the protein, Uniprot and Protein Data Bank codes, single point as well as multiple mutations, and literature citation. The data in CPAD has been supplemented with five different types of additional information: (i) Amyloid fibril forming hexa-peptides, (ii) Amorphous β-aggregating hexa-peptides, (iii) Amyloid fibril forming peptides of different lengths, (iv) Amyloid fibril forming hexa-peptides whose crystal structures are available in the Protein Data Bank (PDB) and (v) Experimentally validated aggregation prone regions found in amyloidogenic proteins. Furthermore, CPAD is linked to other related databases and resources, such as Uniprot, Protein Data Bank, PUBMED, GAP, TANGO, WALTZ etc. We have set up a web interface with different search and display options so that users have the ability to get the data in multiple ways. CPAD is freely available at http://www.iitm.ac.in/bioinfo/CPAD/. The potential applications of CPAD have also been discussed. PMID:27043825

  3. CPAD, Curated Protein Aggregation Database: A Repository of Manually Curated Experimental Data on Protein and Peptide Aggregation.

    Directory of Open Access Journals (Sweden)

    A Mary Thangakani

    Full Text Available Accurate distinction between peptide sequences that can form amyloid-fibrils or amorphous β-aggregates, identification of potential aggregation prone regions in proteins, and prediction of change in aggregation rate of a protein upon mutation(s are critical to research on protein misfolding diseases, such as Alzheimer's and Parkinson's, as well as biotechnological production of protein based therapeutics. We have developed a Curated Protein Aggregation Database (CPAD, which has collected results from experimental studies performed by scientific community aimed at understanding protein/peptide aggregation. CPAD contains more than 2300 experimentally observed aggregation rates upon mutations in known amyloidogenic proteins. Each entry includes numerical values for the following parameters: change in rate of aggregation as measured by fluorescence intensity or turbidity, name and source of the protein, Uniprot and Protein Data Bank codes, single point as well as multiple mutations, and literature citation. The data in CPAD has been supplemented with five different types of additional information: (i Amyloid fibril forming hexa-peptides, (ii Amorphous β-aggregating hexa-peptides, (iii Amyloid fibril forming peptides of different lengths, (iv Amyloid fibril forming hexa-peptides whose crystal structures are available in the Protein Data Bank (PDB and (v Experimentally validated aggregation prone regions found in amyloidogenic proteins. Furthermore, CPAD is linked to other related databases and resources, such as Uniprot, Protein Data Bank, PUBMED, GAP, TANGO, WALTZ etc. We have set up a web interface with different search and display options so that users have the ability to get the data in multiple ways. CPAD is freely available at http://www.iitm.ac.in/bioinfo/CPAD/. The potential applications of CPAD have also been discussed.

  4. Antimicrobial peptides and proteins in host-microbe interaction and immediate defense

    OpenAIRE

    Kai-Larsen, Ylva

    2009-01-01

    Antimicrobial peptides and proteins (AMPs) are effector molecules of innate immunity and are capable to kill a broad spectrum of microbes, i.e. bacteria, fungi and viruses. They are widespread in nature and have been found in almost all species of the animal kingdom, as well as in plants. The mammalian repertoire of antimicrobial peptides includes the defensins and the cathelicidins. Furthermore, several of the antimicrobial proteins are members of the S100 family. AMPs are ...

  5. The Peptide Network between Tetanus Toxin and Human Proteins Associated with Epilepsy

    OpenAIRE

    Guglielmo Lucchese; Jean Pierre Spinosa; Darja Kanduc

    2014-01-01

    Sequence matching analyses show that Clostridium tetani neurotoxin shares numerous pentapeptides (68, including multiple occurrences) with 42 human proteins that, when altered, have been associated with epilepsy. Such a peptide sharing is higher than expected, nonstochastic, and involves tetanus toxin-derived epitopes that have been validated as immunopositive in the human host. Of note, an unexpected high level of peptide matching is found in mitogen-activated protein kinase 10 (MK10), a pro...

  6. Comparison of Functional Protein Transduction Domains Using the NEMO Binding Domain Peptide

    OpenAIRE

    Paul Robbins; Khaleel Khaja

    2010-01-01

    Protein transduction domains (PTDs), both naturally occurring and synthetic, have been extensively utilized for intracellular delivery of biologically active molecules both in vitro and in vivo. However, most comparisons of transduction efficiency have been performed using fluorescent markers. To compare efficiency of functional protein transduction, a peptide derived from IkB kinase ß (IKKß) that prevents formation of an active IKK complex was used as a biologically active cargo. This peptid...

  7. Nanotechnology enabled drug delivery of proteins and peptides to the lung

    OpenAIRE

    Barthold, Sarah

    2016-01-01

    In addition to the so-called small molecule drugs, proteins and peptides are of increasing interest for pharmacotherapy, due to several advantageous properties. In general, those compounds are administered parenterally. However, non-invasive routes of administration represent a great part of research. Amongst others is the pulmonary application of proteins and peptides for local delivery in the case of pulmonary diseases, such as idiopathic pulmonary fibrosis, where the alveolar epithelium is...

  8. Structural location determines functional roles of the basic amino acids of KR-12, the smallest antimicrobial peptide from human cathelicidin LL-37.

    Science.gov (United States)

    Mishra, Biswajit; Epand, Raquel F; Epand, Richard M; Wang, Guangshun

    2013-11-14

    Cationic antimicrobial peptides are recognized templates for developing a new generation of antimicrobials to combat superbugs. Human cathelicidin LL-37 is an essential host defense molecule in human innate immunity. Previously, we identified KR-12 as the smallest antibacterial peptide of LL-37. KR-12 has a narrow activity spectrum since it is active against Gram-negative Escherichia coli but not Gram-positive Staphylococcus aureus. The functional roles of the basic amino acids of KR-12, however, have not yet been elucidated. An alanine scan of cationic amino acids of KR-12 provided evidence for their distinct roles in the activities of the peptides. Bacterial killing and membrane permeation experiments indicate that the R23A and K25A mutants, as well as the lysine-to-arginine mutant, were more potent than KR-12. Another three cationic residues (K18, R19, and R29) of KR-12, which are located in the hydrophilic face of the amphiphathic helix, appeared to be more important in clustering anionic lipids or hemolysis than R23 and K25 in the interfacial region. While the loss of interfacial R23 or K25 reduced peptide helicity, underscoring its important role in membrane binding, the overall increase in peptide activity of KR-12 could be ascribed to the increased peptide hydrophobicity that outweighed the role of basic charge in this case. In contrast, the mutations of interfacial R23 or K25 reduced peptide bactericidal activity of GF-17, an overlapping, more hydrophobic and potent peptide also derived from LL-37. Thus, the hydrophobic context of the peptide determines whether an alanine substitution of an interfacial basic residue increases or decreases membrane permeation and peptide activity.

  9. Rational Design of a Carrier Protein for the Production of Recombinant Toxic Peptides in Escherichia coli

    Science.gov (United States)

    Pizzo, Elio; Varcamonti, Mario; Zanfardino, Anna; Sgambati, Valeria; Di Maro, Antimo; Carpentieri, Andrea; Izzo, Viviana; Di Donato, Alberto; Cafaro, Valeria; Notomista, Eugenio

    2016-01-01

    Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids), which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200–250 mg/L). After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in diluted acetic acid of an acid labile Asp-Pro sequence with more than 95% efficiency. To improve peptide purification, Onconase was mutated to eliminate all acid labile sequences thus reducing the release of unwanted peptides during the acid cleavage. Mutations were chosen to preserve the differential solubility of Onconase as function of pH, which allows its selective precipitation at neutral pH after the cleavage. The improved carrier allowed the production of 15–18 mg of recombinant peptide per liter of culture with 96–98% purity without the need of further chromatographic steps after the acid cleavage. The antimicrobial activity of the recombinant peptide, with an additional proline at the N-terminus, was tested on Gram-negative and Gram-positive strains and was found to be identical to that measured for synthetic GKY20. This finding suggests that N-terminal proline residue does not change the antimicrobial properties of recombinant (P)GKY20. The improved carrier, which does not contain cysteine and methionine residues, Asp-Pro and Asn-Gly sequences, is well suited for the production of peptides using any of the most popular chemical cleavage methods. PMID:26808536

  10. Rational Design of a Carrier Protein for the Production of Recombinant Toxic Peptides in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Katia Pane

    Full Text Available Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids, which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200-250 mg/L. After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in diluted acetic acid of an acid labile Asp-Pro sequence with more than 95% efficiency. To improve peptide purification, Onconase was mutated to eliminate all acid labile sequences thus reducing the release of unwanted peptides during the acid cleavage. Mutations were chosen to preserve the differential solubility of Onconase as function of pH, which allows its selective precipitation at neutral pH after the cleavage. The improved carrier allowed the production of 15-18 mg of recombinant peptide per liter of culture with 96-98% purity without the need of further chromatographic steps after the acid cleavage. The antimicrobial activity of the recombinant peptide, with an additional proline at the N-terminus, was tested on Gram-negative and Gram-positive strains and was found to be identical to that measured for synthetic GKY20. This finding suggests that N-terminal proline residue does not change the antimicrobial properties of recombinant (PGKY20. The improved carrier, which does not contain cysteine and methionine residues, Asp-Pro and Asn-Gly sequences, is well suited for the production of peptides using any of the most popular chemical cleavage methods.

  11. Rational Design of a Carrier Protein for the Production of Recombinant Toxic Peptides in Escherichia coli.

    Science.gov (United States)

    Pane, Katia; Durante, Lorenzo; Pizzo, Elio; Varcamonti, Mario; Zanfardino, Anna; Sgambati, Valeria; Di Maro, Antimo; Carpentieri, Andrea; Izzo, Viviana; Di Donato, Alberto; Cafaro, Valeria; Notomista, Eugenio

    2016-01-01

    Commercial uses of bioactive peptides require low cost, effective methods for their production. We developed a new carrier protein for high yield production of recombinant peptides in Escherichia coli very well suited for the production of toxic peptides like antimicrobial peptides. GKY20, a short antimicrobial peptide derived from the C-terminus of human thrombin, was fused to the C-terminus of Onconase, a small ribonuclease (104 amino acids), which efficiently drove the peptide into inclusion bodies with very high expression levels (about 200-250 mg/L). After purification of the fusion protein by immobilized metal ion affinity chromatography, peptide was obtained by chemical cleavage in diluted acetic acid of an acid labile Asp-Pro sequence with more than 95% efficiency. To improve peptide purification, Onconase was mutated to eliminate all acid labile sequences thus reducing the release of unwanted peptides during the acid cleavage. Mutations were chosen to preserve the differential solubility of Onconase as function of pH, which allows its selective precipitation at neutral pH after the cleavage. The improved carrier allowed the production of 15-18 mg of recombinant peptide per liter of culture with 96-98% purity without the need of further chromatographic steps after the acid cleavage. The antimicrobial activity of the recombinant peptide, with an additional proline at the N-terminus, was tested on Gram-negative and Gram-positive strains and was found to be identical to that measured for synthetic GKY20. This finding suggests that N-terminal proline residue does not change the antimicrobial properties of recombinant (P)GKY20. The improved carrier, which does not contain cysteine and methionine residues, Asp-Pro and Asn-Gly sequences, is well suited for the production of peptides using any of the most popular chemical cleavage methods. PMID:26808536

  12. Milk-derived proteins and peptides in clinical trials

    Directory of Open Access Journals (Sweden)

    Jolanta Artym

    2013-08-01

    Full Text Available Clinical trials are reviewed, involving proteins and peptides derived from milk (predominantly bovine, with the exception of lactoferrin, which will be the subject of another article. The most explored milk fraction is α-lactalbumin (LA, which is often applied with glycomacropeptide (GMP – a casein degradation product. These milk constituents are used in health-promoting infant and adult formulae as well as in a modified form (HAMLET to treat cancer. Lactoperoxidase (LCP is used as an additive to mouth hygiene products and as a salivary substitute. Casein derivatives are applied, in addition, in the dry mouth syndrome. On the other hand, casein hydrolysates, containing active tripeptides, found application in hypertension and in type 2 diabetes. Lysozyme is routinely used for food conservation and in pharmaceutical products. It was successfully used in premature infants with concomitant diseases to improve health parameters. When used as prophylaxis in patients with scheduled surgery, it significantly reduced the incidence of hepatitis resulting from blood transfusion. Lysozyme was also used in infected children as an antimicrobial agent showing synergistic effects in combination with different antibiotics. Proline-rich polypeptide (PRP was introduced to therapy of Alzheimer’s disease patients. The therapeutic value of PRP was proved in several clinical trials and supported by studies on its mechanism of action. Concentrated immunoglobulin preparations from colostrum and milk of hyperimmunized cows showed efficacy in prevention of infections by bacteria, viruses and protozoa. A nutrition formula with milk-derived TGF-β2 (Modulen IBD® found application in treatment of pediatric Crohn’s disease. In conclusion, the preparations containing milk-derived products are safe and effective measures in prevention and treatment of infections as well as autoimmune and neoplastic diseases.

  13. Protein and peptide alkoxyl radicals can give rise to C-terminal decarboxylation and backbone cleavage

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan

    1996-01-01

    with larger peptides, amino acid homopolymers, and proteins. These observations suggest that alpha-carbon alkoxyl radicals may be key intermediates in the fragmentation of proteins in the presence of oxygen. The radicals released in these processes may react further to form O2.-, or redox cycle metal ions....... These reactions may be propagating processes during protein chain oxidation....

  14. Structure and Energetic Contributions of a Designed Modular Peptide-Binding Protein with Picomolar Affinity.

    Science.gov (United States)

    Hansen, Simon; Tremmel, Dirk; Madhurantakam, Chaithanya; Reichen, Christian; Mittl, Peer R E; Plückthun, Andreas

    2016-03-16

    Natural armadillo repeat proteins (nArmRP) like importin-α or β-catenin bind their target peptides such that each repeat interacts with a dipeptide unit within the stretched target peptide. However, this modularity is imperfect and also restricted to short peptide stretches of usually four to six consecutive amino acids. Here we report the development and characterization of a regularized and truly modular peptide-specific binding protein, based on designed armadillo repeat proteins (dArmRP), binding to peptides of alternating lysine and arginine residues (KR)n. dArmRP were obtained from nArmRP through cycles of extensive protein engineering, which rendered them more uniform. This regularity is reflected in the consistent binding of dArmRP to (KR)-peptides, where affinities depend on the lengths of target peptides and the number of internal repeats in a very systematic manner, thus confirming the modularity of the interaction. This exponential dependency between affinity and recognition length suggests that each module adds a constant increment of binding energy to sequence-specific recognition. This relationship was confirmed by comprehensive mutagenesis studies that also reveal the importance of individual peptide side chains. The 1.83 Å resolution crystal structure of a dArmRP with five identical internal repeats in complex with the cognate (KR)5 peptide proves a modular binding mode, where each dipeptide is recognized by one internal repeat. The confirmation of this true modularity over longer peptide stretches lays the ground for the design of binders with different specificities and tailored affinities by the assembly of dipeptide-specific modules based on armadillo repeats. PMID:26878586

  15. Group 3 LEA protein model peptides protect enzymes against desiccation stress.

    Science.gov (United States)

    Furuki, Takao; Sakurai, Minoru

    2016-09-01

    We tested whether model peptides for group 3 late embryogenesis abundant (G3LEA) proteins, which we developed previously, are capable of maintaining the catalytic activities of enzymes dried in their presence. Three different peptides were compared: 1) PvLEA-22, which consists of two tandem repeats of the 11-mer motif found in G3LEA proteins from an African sleeping chironomid; 2) PvLEA-44, which is made of four tandem repeats of the same 11-mer motif; and 3) a peptide whose amino acid composition is the same as that of PvLEA-22, but whose sequence is scrambled. We selected two enzymes, lactate dehydrogenase (LDH) and β-d-galactosidase (BDG), as targets because they have different isoelectric point (pI) values, in the alkaline and acidic range, respectively. While these enzymes were almost inactivated when dried alone, their catalytic activity was preserved at ≥70% of native levels in the presence of any of the above three peptides. This degree of protection is comparable to that conferred by several full-length G3LEA proteins, as reported previously for LDH. Interestingly, the protective activity of the peptides was enhanced slightly when they were mixed with trehalose, especially when the molar content of the peptides was low. On the basis of these results, the G3LEA model peptides show promise as protectants for the dry preservation of enzymes/proteins with a wide range of pI values. PMID:27131872

  16. Antioxidant properties of a new antioxidative peptide from algae protein waste hydrolysate in different oxidation systems.

    Science.gov (United States)

    Sheih, I-Chuan; Wu, Tung-Kung; Fang, Tony J

    2009-07-01

    Microalgae have been a popular edible food, but there are no known reports on the antioxidative peptides derived from microalgae. The algae protein waste, which is normally discarded as animal feed, is a by-product during production of algae essence from microalgae, Chlorella vulgaris. Algae protein waste was hydrolyzed using pepsin, and a potent antioxidative peptide of VECYGPNRPQF was separated and isolated. The peptide could efficiently quench a variety of free radicals, including hydroxyl radical, superoxide radical, peroxyl radical, DPPH radical and ABTS radicals, and performed more efficiently than that observed for BHT, Trolox and peptides from marine protein sources in most cases. The purified peptide also has significant protective effects on DNA and prevents cellular damage caused by hydroxyl radicals. In addition, the peptide has gastrointestinal enzyme-resistance and no cytotoxicity observed in human lung fibroblasts cell lines (WI-38) in vitro. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce antioxidative peptides. PMID:19299123

  17. Analysis of Protein-RNA and Protein-Peptide Interactions in Equine Infectious Anemia

    Energy Technology Data Exchange (ETDEWEB)

    Jae-Hyung Lee

    2007-12-01

    Macromolecular interactions are essential for virtually all cellular functions including signal transduction processes, metabolic processes, regulation of gene expression and immune responses. This dissertation focuses on the characterization of two important macromolecular interactions involved in the relationship between Equine Infectious Anemia Virus (EIAV) and its host cell in horse: (1) the interaction between the EIAV Rev protein and its binding site, the Rev-responsive element (RRE) and (2) interactions between equine MHC class I molecules and epitope peptides derived from EIAV proteins. EIAV, one of the most divergent members of the lentivirus family, has a single-stranded RNA genome and carries several regulatory and structural proteins within its viral particle. Rev is an essential EIAV regulatory encoded protein that interacts with the viral RRE, a specific binding site in the viral mRNA. Using a combination of experimental and computational methods, the interactions between EIAV Rev and RRE were characterized in detail. EIAV Rev was shown to have a bipartite RNA binding domain contain two arginine rich motifs (ARMs). The RRE secondary structure was determined and specific structural motifs that act as cis-regulatory elements for EIAV Rev-RRE interaction were identified. Interestingly, a structural motif located in the high affinity Rev binding site is well conserved in several diverse lentiviral genoes, including HIV-1. Macromolecular interactions involved in the immune response of the horse to EIAV infection were investigated by analyzing complexes between MHC class I proteins and epitope peptides derived from EIAV Rev, Env and Gag proteins. Computational modeling results provided a mechanistic explanation for the experimental finding that a single amino acid change in the peptide binding domain of the quine MHC class I molecule differentially affectes the recognitino of specific epitopes by EIAV-specific CTL. Together, the findings in this

  18. Analysis of Protein-RNA and Protein-Peptide Interactions in Equine Infectious Anemia

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Hyung [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Macromolecular interactions are essential for virtually all cellular functions including signal transduction processes, metabolic processes, regulation of gene expression and immune responses. This dissertation focuses on the characterization of two important macromolecular interactions involved in the relationship between Equine Infectious Anemia Virus (EIAV) and its host cell in horse: (1) the interaction between the EIAV Rev protein and its binding site, the Rev-responsive element (RRE) and (2) interactions between equine MHC class I molecules and epitope peptides derived from EIAV proteins. EIAV, one of the most divergent members of the lentivirus family, has a single-stranded RNA genome and carries several regulatory and structural proteins within its viral particle. Rev is an essential EIAV regulatory encoded protein that interacts with the viral RRE, a specific binding site in the viral mRNA. Using a combination of experimental and computational methods, the interactions between EIAV Rev and RRE were characterized in detail. EIAV Rev was shown to have a bipartite RNA binding domain contain two arginine rich motifs (ARMs). The RRE secondary structure was determined and specific structural motifs that act as cis-regulatory elements for EIAV Rev-RRE interaction were identified. Interestingly, a structural motif located in the high affinity Rev binding site is well conserved in several diverse lentiviral genoes, including HIV-1. Macromolecular interactions involved in the immune response of the horse to EIAV infection were investigated by analyzing complexes between MHC class I proteins and epitope peptides derived from EIAV Rev, Env and Gag proteins. Computational modeling results provided a mechanistic explanation for the experimental finding that a single amino acid change in the peptide binding domain of the quine MHC class I molecule differentially affectes the recognitino of specific epitopes by EIAV-specific CTL. Together, the findings in this

  19. Identification of novel dipeptidyl peptidase-IV and angiotensin-I-converting enzyme inhibitory peptides from meat proteins using in silico analysis.

    Science.gov (United States)

    Lafarga, Tomas; O'Connor, Paula; Hayes, Maria

    2014-09-01

    Angiotensin-I-converting enzyme (ACE-I, EC 3.4.15.1), renin (EC 3.4.23.15), and dipeptidyl peptidase-IV (DPP-IV, EC 3.4.14.5) play key roles in the control of hypertension and the development of type-2 diabetes and other diseases associated with metabolic syndrome. The aim of this work was to utilize known in silico methodologies, peptide databases and software including ProtParam (http://web.expasy.org/protparam/), Basic Local Alignment Tool (BLAST), ExPASy PeptideCutter (http://web.expasy.org/peptide_cutter/) and BIOPEP (http://www.uwm.edu.pl/biochemia/index.php/pl/biopep) to assess the release of potentially bioactive DPP-IV, renin and ACE-I inhibitory peptides from bovine and porcine meat proteins including hemoglobin, collagen and serum albumin. These proteins were chosen as they are found commonly in meat by-products such as bone, blood and low-value meat cuts. In addition, the bioactivities of identified peptides were confirmed using chemical synthesis and in vitro bioassays. The concentration of peptide required to inhibit the activity of ACE-I and DPP-IV by 50% was determined for selected, active peptides. Novel ACE-I and DPP-IV inhibitory peptides were identified in this study using both in silico analysis and a literature search to streamline enzyme selection for peptide production. These novel peptides included the ACE-I inhibitory tri-peptide Ile-Ile-Tyr and the DPP-IV inhibitory tri-peptide Pro-Pro-Leu corresponding to sequences f (182-184) and f (326-328) of both porcine and bovine serum albumin which can be released following hydrolysis with the enzymes papain and pepsin, respectively. This work demonstrates that meat proteins are a suitable resource for the generation of bioactive peptides and further demonstrates the usefulness of in silico methodologies to streamline identification and generation of bioactive peptides. PMID:25020248

  20. Production and properties of health-promoting proteins and peptides from bovine colostrum and milk.

    Science.gov (United States)

    Korhonen, H J

    2013-01-01

    The high nutritive value and diverse functional properties of milk proteins are well known. Beyond these qualities, milk proteins have attracted growing scientific and commercial interest as a source of biologically active molecules. Such proteins are found in abundance in colostrum which is the initial milk secreted by mammalian species during late pregnancy and the first few days after birth of the offspring. The best characterized colostrum-based bioactive proteins include alpha-lactalbumin, beta-lactoglobulin, immunoglobulins, lactoferrin, lactoperoxidase and growth factors. All of them can nowadays be enriched and purified on an industrial scale from bovine colostral whey or cheese whey. These native proteins exhibit a wide range of biological activities that are known to affect the digestive function, metabolic responses to absorbed nutrients, growth and development of organs and disease resistance. Also, some of these proteins may prove beneficial in reduction of the risks of chronic human diseases reflected by the metabolic syndrome. It is speculated that such potentially beneficial effects are partially attributed to bioactive peptides derived from intact proteins. These peptides can be liberated during gastrointestinal digestion or fermentation of milk by starter cultures. The efficacy of a few peptides has been established in animal and human studies and the number of commercial products supplemented with specific milk peptides is envisaged to increase on global markets. Bovine colostrum appears as a highly potential source of biologically active native proteins and peptide fractions for inclusion as health-promoting ingredients in various food applications. PMID:24200017

  1. Improved recovery of proteome-informative, protein N-terminal peptides by combined fractional diagonal chromatography (COFRADIC).

    Science.gov (United States)

    Staes, An; Van Damme, Petra; Helsens, Kenny; Demol, Hans; Vandekerckhove, Joël; Gevaert, Kris

    2008-04-01

    We previously described a proteome-wide, peptide-centric procedure for sorting protein N-terminal peptides and used these peptides as readouts for protease degradome and xenoproteome studies. This procedure is part of a repertoire of gel-free techniques known as COmbined FRActional DIagonal Chromatography (COFRADIC) and highly enriches for alpha-amino-blocked peptides, including alpha-amino-acetylated protein N-terminal peptides. Here, we introduce two additional steps that significantly increase the fraction of such proteome-informative, N-terminal peptides: strong cation exchange (SCX) segregation of alpha-amino-blocked and alpha-amino-free peptides and an enzymatic step liberating pyroglutamyl peptides for 2,4,6-trinitrobenzenesulphonic acid (TNBS) modification and thus COFRADIC sorting. The SCX step reduces the complexity of the analyte mixture by enriching N-terminal peptides and depleting alpha-amino-free internal peptides as well as proline-starting peptides prior to COFRADIC. The action of pyroglutamyl aminopeptidases prior to the first COFRADIC peptide separation results in greatly diminishing numbers of contaminating pyroglutamyl peptides in peptide maps. We further show that now close to 95% of all COFRADIC-sorted peptides are alpha-amino-acetylated and, using the same amount of starting material, our novel procedure leads to an increased number of protein identifications.

  2. Proteins, peptides, polysaccharides, and nucleotides with inhibitory activity on human immunodeficiency virus and its enzymes.

    Science.gov (United States)

    Ng, Tzi Bun; Cheung, Randy Chi Fai; Wong, Jack Ho; Chan, Wai Yee

    2015-12-01

    Human immunodeficiency virus (HIV), the causative agent of acquired immune deficiency syndrome, has claimed innumerable lives in the past. Many biomolecules which suppress HIV replication and also other biomolecules that inhibit enzymes essential to HIV replication have been reported. Proteins including a variety of milk proteins, ribosome-inactivating proteins, ribonucleases, antifungal proteins, and trypsin inhibitors; peptides comprising cathelicidins, defensins, synthetic peptides, and others; polysaccharides and polysaccharopeptides; nucleosides, nucleotides, and ribozymes, demonstrated anti-HIV activity. In many cases, the mechanism of anti-HIV action has been elucidated. Strategies have been devised to augment the anti-HIV potency of these compounds.

  3. Peptide aptamer identified by molecular docking targeting translationally controlled tumor protein in leukemia cells.

    Science.gov (United States)

    Kadioglu, Onat; Efferth, Thomas

    2016-08-01

    Bioinformatics screening and molecular docking analyses were utilized to select high affinity peptides targeting translationally controlled tumor protein (TCTP). Selected peptide aptamers were tested towards cancer cell lines with different levels of TCTP expression. One peptide (WGQWPYHC) revealed specific cytotoxicity according to the TCTP expression in tumor cells without affecting normal cells. Western blot analysis showed peptide-induced down-regulation of TCTP as primary target as well as of cell-cycle related downstream proteins (CDK2, CDK6, Cyclin D3) in MOLT-4 leukemia cells. "WGQWPYHC" deserves further analysis for targeted therapy of TCTP-expressing tumor cells. Graphical abstract Molecular docking on TCTP, cytotoxicity toward MOLT-4 leukemia cell line and downregulation of CDK2, CDK6, CyclinD3 and TCTP proteins. PMID:26972431

  4. Purification and identification of antioxidant peptides from walnut (Juglans regia L.) protein hydrolysates.

    Science.gov (United States)

    Chen, Ning; Yang, Hongmei; Sun, Yi; Niu, Jun; Liu, Shuying

    2012-12-01

    Walnut proteins were hydrolyzed separately using three different proteases to obtain antioxidant peptides. The antioxidant activities of the hydrolysates were measured using 1,1-diphenyl-2-picryl hydrazyl (DPPH) assay. Among hydrolysates, pepsin hydrolysate obtained by 3h exhibited the highest antioxidant activities, which could also quench the hydroxyl radical, chelate ferrous ion, exhibit reducing power and inhibit the lipid peroxidation. Then, 3-h pepsin hydrolysates were purified sequentially by ultrafiltration, gel filtration and RP-HPLC. The sequence of the peptide with the highest antioxidative activity was identified to be Ala-Asp-Ala-Phe (423.23 Da) using RP-HPLC-ESI-MS, which was identified for the first time from walnut protein hydrolysates. Last, the inhibition of the peptide on lipid peroxidation was similar with that of reduced glutathione (GSH). These results indicate that the protein hydrolysates and/or its isolated peptides may be effectively used as food additives.

  5. Recent advances in proteolysis and peptide/protein separation by chromatographic strategies

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This review gives a broad glance on the progress of recent advances on proteolysis and peptide/protein separation by chroma-tographic strategies in the past ten years, covering the main research in these areas especially in China. The reviewed research focused on enzymatic micro-reactors and peptide separation in bottom-up approaches, and protein and peptide separation in top-down approaches. The new enzymatic micro-reactor is able to accelerate proteolytic reaction rate from conventionally a couple of hours to a few seconds, and the multiple dimensional chromatographic-separation with various models or arrays could sufficiently separate the proteomic mixture. These advances have significantly promoted the research of protein/peptide separation and identification in proteomics.

  6. Specific RNA binding by amino-terminal peptides of alfalfa mosaic virus coat protein.

    Science.gov (United States)

    Baer, M L; Houser, F; Loesch-Fries, L S; Gehrke, L

    1994-01-01

    Specific RNA-protein interactions and ribonucleoprotein complexes are essential for many biological processes, but our understanding of how ribonucleoprotein particles form and accomplish their biological functions is rudimentary. This paper describes the interaction of alfalfa mosaic virus (A1MV) coat protein or peptides with viral RNA. A1MV coat protein is necessary both for virus particle formation and for the initiation of replication of the three genomic RNAs. We have examined protein determinants required for specific RNA binding and analyzed potential structural changes elicited by complex formation. The results indicate that the amino-terminus of the viral coat protein, which lacks primary sequence homology with recognized RNA binding motifs, is both necessary and sufficient for binding to RNA. Circular dichroism spectra and electrophoretic mobility shift experiments suggest that the RNA conformation is altered when amino-terminal coat protein peptides bind to the viral RNA. The peptide--RNA interaction is functionally significant because the peptides will substitute for A1MV coat protein in initiating RNA replication. The apparent conformational change that accompanies RNA--peptide complex formation may generate a structure which, unlike the viral RNA alone, can be recognized by the viral replicase. Images PMID:8313916

  7. Milk proteins-derived bioactive peptides in dairy products: molecular, biological and methodological aspects

    Directory of Open Access Journals (Sweden)

    Bartłomiej Dziuba

    2014-03-01

    Full Text Available Proteins are one of the primary components of the food, both in terms of nutrition and function. They are main source of amino acids, essential for synthesis of proteins, and also source of energy. Additionally, many proteins exhibit specifi c biological activities, which may have effect on functional or pro-health properties of food products. These proteins and their hydrolysis products, peptides, may infl uence the properties of food and human organism. The number of commercially available food products containing bioactive peptides is very low, apart from that milk proteins are their rich source. It could be supposed that number of available products with declared activity will rise in near future because of observed strong uptrend on interest in such products. Molecular and biological properties of milk proteins, as precursors of bioactive peptides was characterised in the work. Therefore, the strategy of research and obtaining of such peptides both in laboratory and industrial scale, as well as the range of their commercial application, was presented. Several examples of research efforts presenting high potential to develop new products containing bioactive peptides from milk proteins and predetermined as nutraceuticals was described.

  8. Milk proteins-derived bioactive peptides in dairy products: molecular, biological and methodological aspects.

    Science.gov (United States)

    Dziuba, Bartłomiej; Dziuba, Marta

    2014-01-01

    Proteins are one of the primary components of the food, both in terms of nutrition and function. They are main source of amino acids, essential for synthesis of proteins, and also source of energy. Additionally, many proteins exhibit specific biological activities, which may have effect on functional or pro-health properties of food products. These proteins and their hydrolysis products, peptides, may influence the properties of food and human organism. The number of commercially available food products containing bioactive peptides is very low, apart from that milk proteins are their rich source. It could be supposed that number of available products with declared activity will rise in near future because of observed strong uptrend on interest in such products. Molecular and biological properties of milk proteins, as precursors of bioactive peptides was characterised in the work. Therefore, the strategy of research and obtaining of such peptides both in laboratory and industrial scale, as well as the range of their commercial application, was presented. Several examples of research efforts presenting high potential to develop new products containing bioactive peptides from milk proteins and predetermined as nutraceuticals was described.

  9. International Union of Basic and Clinical Pharmacology. XCV. Recent Advances in the Understanding of the Pharmacology and Biological Roles of Relaxin Family Peptide Receptors 1–4, the Receptors for Relaxin Family Peptides

    OpenAIRE

    Halls, Michelle L.; Bathgate, Ross A. D.; Sutton, Steve W.; Dschietzig, Thomas B.; Roger J Summers

    2015-01-01

    Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1–4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gαs, Gαi, and Gαo proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP...

  10. Peptide aptamers: The versatile role of specific protein function inhibitors in plant biotechnology.

    Science.gov (United States)

    Colombo, Monica; Mizzotti, Chiara; Masiero, Simona; Kater, Martin M; Pesaresi, Paolo

    2015-11-01

    In recent years, peptide aptamers have emerged as novel molecular tools that have attracted the attention of researchers in various fields of basic and applied science, ranging from medicine to analytical chemistry. These artificial short peptides are able to specifically bind, track, and inhibit a given target molecule with high affinity, even molecules with poor immunogenicity or high toxicity, and represent a remarkable alternative to antibodies in many different applications. Their use is on the rise, driven mainly by the medical and pharmaceutical sector. Here we discuss the enormous potential of peptide aptamers in both basic and applied aspects of plant biotechnology and food safety. The different peptide aptamer selection methods available both in vivo and in vitro are introduced, and the most important possible applications in plant biotechnology are illustrated. In particular, we discuss the generation of broad-based virus resistance in crops, "reverse genetics" and aptasensors in bioassays for detecting contaminations in food and feed. Furthermore, we suggest an alternative to the transfer of peptide aptamers into plant cells via genetic transformation, based on the use of cell-penetrating peptides that overcome the limits imposed by both crop transformation and Genetically Modified Organism commercialization.

  11. Purification and identification of novel antioxidant peptides from egg white protein and their antioxidant activities.

    Science.gov (United States)

    Liu, Jingbo; Jin, Yan; Lin, Songyi; Jones, Gregory S; Chen, Feng

    2015-05-15

    The aim of this study was to isolate antioxidant peptides from egg white protein hydrolysates (EWPH) and identify novel antioxidant peptides by LC tandem mass spectrometric and mid-infrared spectroscopy (MIR). The amino acid composition of peptides was also analyzed by amino acid analyzer on the basis of ninhydrin reaction. Three novel peptides with molecular weights of 628.64 Da, 630.71 Da, and 684.1 Da were identified as Asp-His-Thr-Lys-Glu (DHTKE), Phe-Phe-Glu-Phe-His (FFGFN) and Met-Pro-Asp-Ala-His-Leu (MPDAHL), respectively. DHTKE exhibited the best oxygen radical absorbance capacity (P<0.05). The concentration of FFGFN and MPDAHL to scavenge 50% of DPPH radicals was 80 mM and 60mM, respectively. Thus, the three peptides may have potential applications as a functional food, which could also be used as nutraceutical compounds. PMID:25577078

  12. Bio-inspired Silicification of Silica-binding Peptide-Silk Protein Chimeras: Comparison of Chemically and Genetically Produced Proteins

    OpenAIRE

    Canabady-Rochelle, Laetitia L.S.; Belton, David J.; Deschaume, Olivier; Currie, Heather A.; Kaplan, David L; Perry, Carole C.

    2012-01-01

    Novel protein chimeras constituted of ‘silk’ and a silica-binding peptide (KSLSRHDHIHHH) were synthesized by genetic or chemical approaches and their influence on silica-silk based chimera composite formation evaluated. Genetic chimeras were constructed from 6 or 15 repeats of the 32 amino acid consensus sequence of Nephila clavipes spider silk ([SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQG]n) to which one silica binding peptide was fused at the N terminus. For the chemical chimera, 25 equivalents of t...

  13. PPINGUIN: Peptide Profiling Guided Identification of Proteins improves quantitation of iTRAQ ratios

    Directory of Open Access Journals (Sweden)

    Bauer Chris

    2012-02-01

    Full Text Available Abstract Background Recent development of novel technologies paved the way for quantitative proteomics. One of the most important among them is iTRAQ, employing isobaric tags for relative or absolute quantitation. Despite large progress in technology development, still many challenges remain for derivation and interpretation of quantitative results. One of these challenges is the consistent assignment of peptides to proteins. Results We have developed Peptide Profiling Guided Identification of Proteins (PPINGUIN, a statistical analysis workflow for iTRAQ data addressing the problem of ambiguous peptide quantitations. Motivated by the assumption that peptides uniquely derived from the same protein are correlated, our method employs clustering as a very early step in data processing prior to protein inference. Our method increases experimental reproducibility and decreases variability of quantitations of peptides assigned to the same protein. Giving further support to our method, application to a type 2 diabetes dataset identifies a list of protein candidates that is in very good agreement with previously performed transcriptomics meta analysis. Making use of quantitative properties of signal patterns identified, PPINGUIN can reveal new isoform candidates. Conclusions Regarding the increasing importance of quantitative proteomics we think that this method will be useful in practical applications like model fitting or functional enrichment analysis. We recommend to use this method if quantitation is a major objective of research.

  14. [Peptide mapping of the major proteins in 2 strains of influenza virus].

    Science.gov (United States)

    Savich, I M; Gerasimova, L M; Mertvetsov, N P

    1985-01-01

    The protein composition of two influenza A virus strains from different serological groups was studied. For preliminary separation of envelope and core proteins the virus was treated with nonionic detergent Triton X-100 solution followed by chromatography in ultragel AcA 34. After their separation by disk electrophoresis and treatment with trypsin they were labeled with tritium and peptide analysis was carried out. Differences in peptide maps between the appropriate light and heavy chains of hemagglutinins of the strains under study were demonstrated. Differences in the composition of nucleoprotein and matrix protein were insignificant. PMID:3922120

  15. Bioluminescent Ligand-Receptor Binding Assays for Protein or Peptide Hormones.

    Science.gov (United States)

    Liu, Ya-Li; Guo, Zhan-Yun

    2016-01-01

    Bioluminescence has been widely used in biomedical research due to its high sensitivity, low background, and broad linear range. In recent studies, we applied bioluminescence to ligand-receptor binding assays for some protein or peptide hormones based on a newly developed small monomeric Nanoluciferase (NanoLuc) reporter that has the so far brightest bioluminescence. The conventional ligand-receptor binding assays rely on radioligands that have drawbacks, such as radioactive hazards and short shelf lives. In contrast, the novel bioluminescent binding assays use the NanoLuc-based protein or peptide tracers that are safe, stable, and ultrasensitive. Thus, the novel bioluminescent ligand-receptor binding assay would be applied to more and more protein or peptide hormones for ligand-receptor interaction studies in future. In the present article, we provided detailed protocols for setting up the novel bioluminescent ligand-receptor binding assays using two representative protein hormones as examples. PMID:27424896

  16. Incorporation of noncanonical amino acids into Rosetta and use in computational protein-peptide interface design.

    Directory of Open Access Journals (Sweden)

    P Douglas Renfrew

    Full Text Available Noncanonical amino acids (NCAAs can be used in a variety of protein design contexts. For example, they can be used in place of the canonical amino acids (CAAs to improve the biophysical properties of peptides that target protein interfaces. We describe the incorporation of 114 NCAAs into the protein-modeling suite Rosetta. We describe our methods for building backbone dependent rotamer libraries and the parameterization and construction of a scoring function that can be used to score NCAA containing peptides and proteins. We validate these additions to Rosetta and our NCAA-rotamer libraries by showing that we can improve the binding of a calpastatin derived peptides to calpain-1 by substituting NCAAs for native amino acids using Rosetta. Rosetta (executables and source, auxiliary scripts and code, and documentation can be found at (http://www.rosettacommons.org/.

  17. Discovery and application of peptides that bind to proteins and solid state inorganic materials

    Science.gov (United States)

    Stearns, Linda A.

    A series of three projects was undertaken on the theme of peptide-based molecular recognition. In the first project, a messenger RNA (mRNA) display selection was carried out against the II-VI semiconductors zinc sulfide (ZnS), zinc selenide (ZnSe), and cadmium sulfide (CdS). Sequence analysis of 18-mer semiconductor-binding peptides (SBPs) following four rounds of selection indicated that the amino acid sequences were enriched in polar residues compared to the naive library, suggesting that hydrogen-bonding interactions are a dominant mode of interaction between the SBPs and their cognate inorganic surfaces. Select peptides were expressed as fusions of the green fluorescent protein (GFP) to visualize their recognition of semiconductor crystals. Interpretation of the results was complicated by a high fluorescence background that was observed with certain control GFP fusions. Additional experiments, including cross-specificity binding assays, are needed to characterize the peptides that were isolated in this selection. A second project described the practical application of a known inorganic-binding and nucleating peptide. Peptide A3, which was previously isolated by phage display, was chemically conjugated to a short DNA strand using the heterobifunctional linker succinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate (SMCC). The resulting peptide-DNA conjugate was hybridized to ten complementary single-stranded capture probes extending outward from the surface of an origami DNA nanotube. A gold precursor solution was added to initiate nucleation and growth of gold nanoparticles at the site of the peptide. Transmission electron microscopy (TEM) was used to visualize the gold nanoparticle-decorated nanostructures. This approach holds immense promise for organizing compositionally-diverse materials at the nanoscale. In a third project, a novel non-iterative approach to mRNA display called covalent capture was demonstrated. Using human transferrin as a target

  18. Protective mechanisms against peptide and protein peroxides generated by singlet oxygen

    DEFF Research Database (Denmark)

    Morgan, Philip E; Dean, Roger T; Davies, Michael Jonathan

    2004-01-01

    or detoxify such peroxides. It is shown that catalase, horseradish peroxidase, and Cu/Zn superoxide dismutase do not react rapidly with these peroxides. Oxymyoglobin and oxyhemoglobin, but not the met (Fe3+) forms of these proteins, react with peptide but not protein, peroxides with oxidation of the heme iron...

  19. One-pot peptide and protein conjugation: a combination of enzymatic transamidation and click chemistry.

    Science.gov (United States)

    Rachel, N M; Pelletier, J N

    2016-02-11

    Enzymatic transamidation and copper-catalyzed azide-alkyne cycloaddition (CuAAC) were combined to yield covalently conjugated peptides and proteins. The addition of glutathione preserved enzymatic activity in the presence of copper. Tuning the reaction kinetics was key to success, providing up to 95% conversion. This one-pot reaction allowed for targeted fluorescent protein labeling. PMID:26741126

  20. Proteomic allergen-peptide/protein interaction assay for the identification of human skin sensitizers

    NARCIS (Netherlands)

    Dietz, L.; Kinzebach, S.; Ohnesorge, S.; Franke, B.; Goette, I.; Koenig-Gressel, D.; Thierse, H.J.

    2013-01-01

    Modification of proteins by skin sensitizers is a pivotal step in T cell mediated allergic contact dermatitis (ACD). In this process small reactive chemicals interact covalently or non-covalently with cellular or extracellular skin self-proteins or self-peptides to become recognized by the human imm

  1. Contribution to the study of proteins and peptides structure by hydrogen isotopic exchange

    International Nuclear Information System (INIS)

    Development of hydrogen exchange measurement methods to study the structure and the molecular interaction of globular protein molecules in aqueous solution (ribonuclease A, cytochrome c, coupling factors of chloroplasts), in peptide hormones in trifluoroethanol solution (angiotensin II, corticotropin) and in proteins of membranes (rhodopsin)

  2. Protein quantification by MALDI-selected reaction monitoring mass spectrometry using sulfonate derivatized peptides.

    Science.gov (United States)

    Lesur, Antoine; Varesio, Emmanuel; Hopfgartner, Gérard

    2010-06-15

    The feasibility of protein absolute quantification with matrix-assisted laser desorption/ionization (MALDI) using the selected reaction monitoring (SRM) acquisition mode on a triple quadrupole linear ion trap mass spectrometer (QqQ(LIT)) equipped with a high-frequency laser is demonstrated. A therapeutic human monoclonal antibody (mAb) was used as a model protein, and four tryptic peptides generated by fast tryptic digestion were selected as quantification surrogates. MALDI produces mostly singly charged peptides which hardly fragment under low-energy collision-induced dissociation (CID), and therefore the benefits of using 4-sulfophenyl isothiocyanate (SPITC) as a fragmentation enhancer derivatization agent were evaluated. Despite a moderate impact on the sensitivity, the N-terminus sulfonated peptides generate nearly complete y-ion ladders when native peptides produce few fragments. This aspect provides an alternative SRM transition set for each peptide. As a consequence, SRM transitions selectivity can be tuned more easily for peptide quantitation in complex matrices when monitoring several SRM transitions. From a quantitative point of view, the signal response depending on mAb concentration was found to be linear over 2.5 orders of magnitude for the most sensitive peptide, allowing precise and accurate measurement by MALDI-SRM/MS. PMID:20481516

  3. Cancer therapeutic approach based on conformational stabilization of mutant p53 protein by small peptides

    Science.gov (United States)

    Tal, Perry; Eizenberger, Shay; Cohen, Elad; Goldfinger, Naomi; Pietrokovski, Shmuel; Oren, Moshe; Rotter, Varda

    2016-01-01

    The p53 tumor suppressor serves as a major barrier against malignant transformation. Over 50% of tumors inactivate p53 by point mutations in its DNA binding domain. Most mutations destabilize p53 protein folding, causing its partial denaturation at physiological temperature. Thus a high proportion of human tumors overexpress a potential potent tumor suppressor in a non-functional, misfolded form. The equilibrium between the properly folded and misfolded states of p53 may be affected by molecules that interact with p53, stabilizing its native folding and restoring wild type p53 activity to cancer cells. To select for mutant p53 (mutp53) reactivating peptides, we adopted the phage display technology, allowing interactions between mutp53 and random peptide libraries presented on phages and enriching for phage that favor the correctly folded p53 conformation. We obtained a large database of potential reactivating peptides. Lead peptides were synthesized and analyzed for their ability to restore proper p53 folding and activity. Remarkably, many enriched peptides corresponded to known p53-binding proteins, including RAD9. Importantly, lead peptides elicited dramatic regression of aggressive tumors in mouse xenograft models. Such peptides might serve as novel agents for human cancer therapy. PMID:26943582

  4. PPINGUIN: Peptide Profiling Guided Identification of Proteins improves quantitation of iTRAQ ratios

    OpenAIRE

    Bauer, Chris; Kleinjung, Frank; Rutishauser, Dorothea; Panse, Christian; Chadt, Alexandra; Dreja, Tanja; Al-Hasani, Hadi; Reinert, Knut; Schlapbach, Ralph; Schuchhardt, Johannes

    2012-01-01

    BACKGROUND: Recent development of novel technologies paved the way for quantitative proteomics. One of the most important among them is iTRAQ, employing isobaric tags for relative or absolute quantitation. Despite large progress in technology development, still many challenges remain for derivation and interpretation of quantitative results. One of these challenges is the consistent assignment of peptides to proteins. RESULTS: We have developed Peptide Profiling Guided Identification of Pr...

  5. A Novel Lactic Acid Bacteria Growth-stimulating Peptide from Broad Bean (Vicia faba .) Protein Hydrolysates

    OpenAIRE

    Ping Xiao; Yuan Liu; Rizwan-ur-Rehman; Ran Kang; Yanping Wang

    2015-01-01

    In this study, broad bean protein hydrolysates (BPH) produced by alcalase with strong-stimulating activity for lactic acid bacteria (LAB) was first time reported. In order to obtain the key peptide that have growth-stimulating activity for lactic acid bacteria (LAB), gel filtration chromatography and Reverse Phase High Performance Liquid Chromatography (RP-HPLC) were applied to isolate and purify the peptides from BPH. Finally, F4-2 elicited the highest activity for LAB, corresponding to amin...

  6. Protein-membrane interaction: effect of myelin basic protein on the dynamics of oriented lipids

    Energy Technology Data Exchange (ETDEWEB)

    Natali, F.; Relini, A.; Gliozzi, A.; Rolandi, R.; Cavatorta, P.; Deriu, A.; Fasano, A.; Riccio, P

    2003-08-01

    We have studied the effect of physiological amounts of myelin basic protein (MBP) on pure dimyristoyl L-{alpha}-phosphatidic acid (DMPA) oriented membranes. The investigation has been carried out using several complementary experimental methods to provide a detailed characterization of the proteo-lipid complexes. In particular, taking advantage of the power of the quasi-elastic neutron scattering (QENS) technique as optimal probe in biology, a significant effect is suggested to be induced by MBP on the anisotropy of lipid dynamics across the liquid-gel phase transition. Thus, the enhancement of the spatially restricted, vertical translation motion of DMPA is suggested to be the main responsible for the increased contribution of the out of plane lipid dynamics observed at 340 K.

  7. Protein membrane interaction: effect of myelin basic protein on the dynamics of oriented lipids

    Science.gov (United States)

    Natali, F.; Relini, A.; Gliozzi, A.; Rolandi, R.; Cavatorta, P.; Deriu, A.; Fasano, A.; Riccio, P.

    2003-08-01

    We have studied the effect of physiological amounts of myelin basic protein (MBP) on pure dimyristoyl L-α-phosphatidic acid (DMPA) oriented membranes. The investigation has been carried out using several complementary experimental methods to provide a detailed characterization of the proteo-lipid complexes. In particular, taking advantage of the power of the quasi-elastic neutron scattering (QENS) technique as optimal probe in biology, a significant effect is suggested to be induced by MBP on the anisotropy of lipid dynamics across the liquid-gel phase transition. Thus, the enhancement of the spatially restricted, vertical translation motion of DMPA is suggested to be the main responsible for the increased contribution of the out of plane lipid dynamics observed at 340 K.

  8. Versatile modes of peptide recognition by the AAA+ adaptor protein SspB

    Energy Technology Data Exchange (ETDEWEB)

    Levchenko, Igor; Grant, Robert A.; Flynn, Julia M.; Sauer, Robert T.; Baker, Tania A. (MIT)

    2010-07-19

    Energy-dependent proteases often rely on adaptor proteins to modulate substrate recognition. The SspB adaptor binds peptide sequences in the stress-response regulator RseA and in ssrA-tagged proteins and delivers these molecules to the AAA+ ClpXP protease for degradation. The structure of SspB bound to an ssrA peptide is known. Here, we report the crystal structure of a complex between SspB and its recognition peptide in RseA. Notably, the RseA sequence is positioned in the peptide-binding groove of SspB in a direction opposite to the ssrA peptide, the two peptides share only one common interaction with the adaptor, and the RseA interaction site is substantially larger than the overlapping ssrA site. This marked diversity in SspB recognition of different target proteins indicates that it is capable of highly flexible and dynamic substrate delivery.

  9. Isolation, purification and characterization of antioxidative peptide of pearl millet (Pennisetum glaucum) protein hydrolysate.

    Science.gov (United States)

    Agrawal, Himani; Joshi, Robin; Gupta, Mahesh

    2016-08-01

    Pearl millet (Pennisetum glaucum) is a rich source of protein, used for present study to hydrolyze protein, peptide separation and its functional activity. Antioxidative bioactive peptide was successfully identified from pearl millet using trypsin enzyme. Different antioxidative potential of isolated peptide were assessed based on activity of DPPH radical, ABTS radical, hydroxyl radical, Fe(2+) chelating ability and reducing power. Bioactive peptide separated by gel-filtration chromatography, showed the higher antioxidant activity as tested by different free radicals. The activity of pearl millet protein hydrolysate fraction was found for DPPH assay (67.66%), ABTS assay (78.81%), Fe(2+) chelating ability (51.20%), hydroxyl assay (60.95%) and reducing power (0.375nm) was further purified using reversed-phase UFLC and subjected to matrix assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) for sequential identification of the peptide. The sequence SDRDLLGPNNQYLPK was identified as antioxidant peptide. PMID:26988514

  10. DNA display selection of peptide ligands for a full-length human G protein-coupled receptor on CHO-K1 cells.

    Directory of Open Access Journals (Sweden)

    Nobuhide Doi

    Full Text Available The G protein-coupled receptors (GPCRs, which form the largest group of transmembrane proteins involved in signal transduction, are major targets of currently available drugs. Thus, the search for cognate and surrogate peptide ligands for GPCRs is of both basic and therapeutic interest. Here we describe the application of an in vitro DNA display technology to screening libraries of peptide ligands for full-length GPCRs expressed on whole cells. We used human angiotensin II (Ang II type-1 receptor (hAT1R as a model GPCR. Under improved selection conditions using hAT1R-expressing Chinese hamster ovary (CHO-K1 cells as bait, we confirmed that Ang II gene could be enriched more than 10,000-fold after four rounds of selection. Further, we successfully selected diverse Ang II-like peptides from randomized peptide libraries. The results provide more precise information on the sequence-function relationships of hAT1R ligands than can be obtained by conventional alanine-scanning mutagenesis. Completely in vitro DNA display can overcome the limitations of current display technologies and is expected to prove widely useful for screening diverse libraries of mutant peptide and protein ligands for receptors that can be expressed functionally on the surface of CHO-K1 cells.

  11. Protein mimics by attachment of cyclic peptides to molecular scaffolds

    NARCIS (Netherlands)

    van de Langemheen, W.

    2014-01-01

    The interaction between proteins is important in all biological functions. In practically every cellular process protein complexes have been identified as essential components. Defects or disturbance in the regulation of protein-protein interactions are responsible for many diseases. Therefore, the

  12. Identification of MHC class I H-2 Kb/Db-restricted immunogenic peptides derived from retinal proteins

    DEFF Research Database (Denmark)

    Wang, Mingjun; Bai, Fang; Pries, Mette;

    2006-01-01

    PURPOSE: To identify H-2 Kb/Db-binding immunogenic peptides derived from retinal proteins. METHODS: Computer-based prediction was used to identify potentially H-2 Kb/Db-binding peptides derived from the interphotoreceptor retinol-binding protein (IRBP), soluble retinal antigen (S-antigen), recove......PURPOSE: To identify H-2 Kb/Db-binding immunogenic peptides derived from retinal proteins. METHODS: Computer-based prediction was used to identify potentially H-2 Kb/Db-binding peptides derived from the interphotoreceptor retinol-binding protein (IRBP), soluble retinal antigen (S...

  13. Radio-peptides targeting g-protein coupled receptors in cancer: from bench to bed

    International Nuclear Information System (INIS)

    Full text of publication follows. In the development of targeted imaging and therapy agents the most important challenge and prerequisite is to identify and validate the molecular targets of any disease. The targets should be specific, relevant, easily accessible and highly expressed. In addition they should have no or at least very low expression in normal tissue. Among the many drug targets is the large family of G-protein coupled receptors (GPCRs). It is the most important family of marketed drugs and the basic accomplishments in the field were recognised by the award of the recent Nobel price in chemistry. GPCRs also play a role in cancer. Several of these receptors are massively over-expressed in different human tumors such as neuroendocrine tumors (over-expression of the somatostatin receptor family), prostate and breast tumors (bombesin receptor family), brain tumors (NK1 receptor) etc.. This allows to develop (nuclear, MRI, optical) probes for imaging and potentially targeted therapy (theragnostics). Natural ligands targeting GPCRs are often peptides. They need to be modified for metabolic stability, modified for labeling with radio-metals (conjugation of bifunctional chelators) or radio-halogens (prosthetic groups). Preserved biological integrity after modification and labeling needs to be assured, long retention times in the tumor is important, conferred by internalisation. Radio-metal labeling in particular needs to be reasonably fast and the radio metal complexes have to show high stability with regard to radio-metal release. These prerequisites will be discussed for somatostatin receptor based radio-peptides in particular. For a successful clinical application preclinical imaging and biodistribution in adequate animal models are mandatory. New tracers for positron emission tomography (PET) and single photon emission computed tomography (SPECT) will be presented for neuroendocrine tumors and prostate cancer. In particular radiolabeled antagonists will

  14. A review on the strategies for oral delivery of proteins and peptides and their clinical perspectives.

    Science.gov (United States)

    Muheem, Abdul; Shakeel, Faiyaz; Jahangir, Mohammad Asadullah; Anwar, Mohammed; Mallick, Neha; Jain, Gaurav Kumar; Warsi, Musarrat Husain; Ahmad, Farhan Jalees

    2016-07-01

    In the modern world, a number of therapeutic proteins such as vaccines, antigens, and hormones are being developed utilizing different sophisticated biotechnological techniques like recombinant DNA technology and protein purification. However, the major glitches in the optimal utilization of therapeutic proteins and peptides by the oral route are their extensive hepatic first-pass metabolism, degradation in the gastrointestinal tract (presence of enzymes and pH-dependent factors), large molecular size and poor permeation. These problems can be overcome by adopting techniques such as chemical transformation of protein structures, enzyme inhibitors, mucoadhesive polymers and permeation enhancers. Being invasive, parenteral route is inconvenient for the administration of protein and peptides, several research endeavors have been undertaken to formulate a better delivery system for proteins and peptides with major emphasis on non-invasive routes such as oral, transdermal, vaginal, rectal, pulmonary and intrauterine. This review article emphasizes on the recent advancements made in the delivery of protein and peptides by a non-invasive (peroral) route into the body. PMID:27330372

  15. Efficient Synthesis of Peptide and Protein Functionalized Pyrrole-Imidazole Polyamides Using Native Chemical Ligation.

    Science.gov (United States)

    Janssen, Brian M G; van Ommeren, Sven P F I; Merkx, Maarten

    2015-06-04

    The advancement of DNA-based bionanotechnology requires efficient strategies to functionalize DNA nanostructures in a specific manner with other biomolecules, most importantly peptides and proteins. Common DNA-functionalization methods rely on laborious and covalent conjugation between DNA and proteins or peptides. Pyrrole-imidazole (Py-Im) polyamides, based on natural minor groove DNA-binding small molecules, can bind to DNA in a sequence specific fashion. In this study, we explore the use of Py-Im polyamides for addressing proteins and peptides to DNA in a sequence specific and non-covalent manner. A generic synthetic approach based on native chemical ligation was established that allows efficient conjugation of both peptides and recombinant proteins to Py-Im polyamides. The effect of Py-Im polyamide conjugation on DNA binding was investigated by Surface Plasmon Resonance (SPR). Although the synthesis of different protein-Py-Im-polyamide conjugates was successful, attenuation of DNA affinity was observed, in particular for the protein-Py-Im-polyamide conjugates. The practical use of protein-Py-Im-polyamide conjugates for addressing DNA structures in an orthogonal but non-covalent manner, therefore, remains to be established.

  16. Efficient Synthesis of Peptide and Protein Functionalized Pyrrole-Imidazole Polyamides Using Native Chemical Ligation

    Directory of Open Access Journals (Sweden)

    Brian M. G. Janssen

    2015-06-01

    Full Text Available The advancement of DNA-based bionanotechnology requires efficient strategies to functionalize DNA nanostructures in a specific manner with other biomolecules, most importantly peptides and proteins. Common DNA-functionalization methods rely on laborious and covalent conjugation between DNA and proteins or peptides. Pyrrole-imidazole (Py–Im polyamides, based on natural minor groove DNA-binding small molecules, can bind to DNA in a sequence specific fashion. In this study, we explore the use of Py–Im polyamides for addressing proteins and peptides to DNA in a sequence specific and non-covalent manner. A generic synthetic approach based on native chemical ligation was established that allows efficient conjugation of both peptides and recombinant proteins to Py–Im polyamides. The effect of Py–Im polyamide conjugation on DNA binding was investigated by Surface Plasmon Resonance (SPR. Although the synthesis of different protein-Py–Im-polyamide conjugates was successful, attenuation of DNA affinity was observed, in particular for the protein-Py–Im-polyamide conjugates. The practical use of protein-Py–Im-polyamide conjugates for addressing DNA structures in an orthogonal but non-covalent manner, therefore, remains to be established.

  17. Production and characterization of polyclonal antibody against a synthetic peptide from β-actin protein

    Directory of Open Access Journals (Sweden)

    Nazila Amini

    2014-06-01

    Full Text Available Objective(s:Antibodies against actin, as one of the most widely studied structural and multifunctional housekeeping proteins in eukaryotic cells, are used as internal loading controls in western blot analyses. The aim of this study was to produce polyclonal antibody against a synthetic peptide derived from N-terminal region of β-actin protein to be used as a protein loading control in western blot and other assay systems. Materials and Methods: A synthetic peptide derived from β-actin protein was designed and conjugated to Keyhole limpet hemocyanin (KLH (and used to immunize a white New Zealand rabbit. The antibody was purified from serum by affinity chromatography column. The purity of the antibody was determined by SDS-PAGE and its ability to recognize the immunizing peptide was measured by ELISA. The reactivity of the antibody with β-actin protein in a panel of different cell lysates was then evaluated by western blot. In addition, the reactivity of the antibody with the corresponding protein was also evaluated by Immunocytochemistry and Immunohistochemistry in different samples. Results: The antibody could recognize the immunizing peptide in ELISA. It could also recognize            β-actin protein in western blot as well as in immunocytochemistry and immunohistochemistry. Conclusion: Our data suggest that this antibody may be used as an internal control in western blot analyses as well as in other immunological applications such as ELISA,immunocytochemistry and immunohistochemistry.

  18. Antifungal peptides, a heat shock protein-like peptide, and a serine-threonine kinase-like protein from Ceylon spinach seeds.

    Science.gov (United States)

    Wang, Hexiang; Ng, Tzi Bun

    2004-07-01

    Two antifungal peptides (designated alpha- and beta-basrubrins) with molecular masses of 4-5 kDa and distinct N-terminal sequences, and a peptide and a protein with N-terminal sequences resembling heat shock protein (hsp) and serine-threonine kinase, respectively, were isolated from seeds of the Ceylon spinach Basella rubra. The purification procedure entailed saline extraction, (NH4)2SO4 precipitation, ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose, and FPLC-gel filtration on a Superdex peptide column. alpha- and beta-basrubrins inhibited mycelial growth in Botrytis cirerea with an IC50 value of 7.5 and 14.7 microM, respectively, Mycosphaerella arachidicola with an IC50 of 12.4 and 6.9 microM, and Fusarium oxysporum with an IC50 of 5.8 and 6.2 microM. Neither alpha-basrubrin nor beta-basrubin exhibited DNase, RNase, lectin or protease activity, indicating that their antifungal action is not due to these activities. HIV-1 reverse transcriptase was inhibited by alpha- and beta-basrubrins with an IC50 of 246 and 370 microM, respectively. Translation in rabbit reticulocyte lysate was inhibited by alpha- and beta-basrubrins with an IC50 of 400 and 100 nM. The heat shock protein-like peptide and serine-threonine kinase-like protein exhibited a molecular mass of 3 and 30 kDa, respectively. They inhibited neither translation in a rabbit reticulocyte system at concentrations up to 50 microM nor HIV-1 reverse transcriptase activity at concentrations up to 400 microM. They did not exert antifungal activity toward B. cinerea, M. arachidicola, and F. oxysporum when tested up to 16 microg. None of the aforementioned proteins demonstrated DNase, RNase, protease or lectin activity. PMID:15245882

  19. Active protein aggregates induced by terminally attached self-assembling peptide ELK16 in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Zhou Bihong

    2011-02-01

    Full Text Available Abstract Background In recent years, it has been gradually realized that bacterial inclusion bodies (IBs could be biologically active. In particular, several proteins including green fluorescent protein, β-galactosidase, β-lactamase, alkaline phosphatase, D-amino acid oxidase, polyphosphate kinase 3, maltodextrin phosphorylase, and sialic acid aldolase have been successfully produced as active IBs when fused to an appropriate partner such as the foot-and-mouth disease virus capsid protein VP1, or the human β-amyloid peptide Aβ42(F19D. As active IBs may have many attractive advantages in enzyme production and industrial applications, it is of considerable interest to explore them further. Results In this paper, we report that an ionic self-assembling peptide ELK16 (LELELKLK2 was able to effectively induce the formation of cytoplasmic inclusion bodies in Escherichia coli (E. coli when attached to the carboxyl termini of four model proteins including lipase A, amadoriase II, β-xylosidase, and green fluorescent protein. These aggregates had a general appearance similar to the usually reported cytoplasmic inclusion bodies (IBs under transmission electron microscopy or fluorescence confocal microscopy. Except for lipase A-ELK16 fusion, the three other fusion protein aggregates retained comparable specific activities with the native counterparts. Conformational analyses by Fourier transform infrared spectroscopy revealed the existence of newly formed antiparallel beta-sheet structures in these ELK16 peptide-induced inclusion bodies, which is consistent with the reported assembly of the ELK16 peptide. Conclusions This has been the first report where a terminally attached self-assembling β peptide ELK16 can promote the formation of active inclusion bodies or active protein aggregates in E. coli. It has the potential to render E. coli and other recombinant hosts more efficient as microbial cell factories for protein production. Our observation might

  20. Characterization of particulate drug delivery systems for oral delivery of Peptide and protein drugs

    DEFF Research Database (Denmark)

    Christophersen, Philip Carsten; Fano, Mathias; Saaby, Lasse;

    2015-01-01

    are summarized. Additionally, the paper provides an overview of recent studies on characterization of solid drug carriers for peptide/protein drugs, drug distribution in particles, drug release and stability in simulated GI fluids, as well as the absorption of peptide/protein drugs in cell-based models. The use......Oral drug delivery is a preferred route because of good patient compliance. However, most peptide/ protein drugs are delivered via parenteral routes because of the absorption barriers in the gastrointestinal (GI) tract such as enzymatic degradation by proteases and low permeability acrossthe...... biological membranes. To overcome these barriers, different formulation strategies for oral delivery of biomacromolecules have been proposed, including lipid based formulations and polymer-based particulate drug delivery systems (DDS). The aim of this review is to summarize the existing knowledge about oral...

  1. Recent advances in topical delivery of proteins and peptides mediated by soft matter nanocarriers.

    Science.gov (United States)

    Witting, Madeleine; Obst, Katja; Friess, Wolfgang; Hedtrich, Sarah

    2015-11-01

    Proteins and peptides are increasingly important therapeutics for the treatment of severe and complex diseases like cancer or autoimmune diseases due to their high specificity and potency. Their unique structure and labile physicochemical properties, however, require special attention in the production and formulation process as well as during administration. Aside from conventional systemic injections, the topical application of proteins and peptides is an appealing alternative due to its non-invasive nature and thus high acceptance by patients. For this approach, soft matter nanocarriers are interesting delivery systems which offer beneficial properties such as high biocompatibility, easiness of modifications, as well as targeted drug delivery and release. This review aims to highlight and discuss technological developments in the field of soft matter nanocarriers for the delivery of proteins and peptides via the skin, the eye, the nose, and the lung, and to provide insights in advantages, limitations, and practicability of recent advances.

  2. Antimicrobial activity of peptides derived from olive flounder lipopolysaccharide binding protein/bactericidal permeability-increasing protein (LBP/BPI).

    Science.gov (United States)

    Nam, Bo-Hye; Moon, Ji-Young; Park, Eun-Hee; Kim, Young-Ok; Kim, Dong-Gyun; Kong, Hee Jeong; Kim, Woo-Jin; Jee, Young Ju; An, Cheul Min; Park, Nam Gyu; Seo, Jung-Kil

    2014-10-17

    We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase.

  3. Antimicrobial Activity of Peptides Derived from Olive Flounder Lipopolysaccharide Binding Protein/Bactericidal Permeability-Increasing Protein (LBP/BPI

    Directory of Open Access Journals (Sweden)

    Bo-Hye Nam

    2014-10-01

    Full Text Available We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase.

  4. Analysis of Protein Interactions with Immobilized Peptide Arrays Synthesized on Membrane Supports

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Ronald Frank and Stefan Dübel This protocol was adapted from “Analysis of Protein Interactions with Immobilized Peptide Arrays Synthesized on Membrane Supports,” contributed by Ronald Frank and Stefan Dübel, Chapter 31, in [*Protein-Protein Interactions*, ](http://www.cshlpress.com/link/protpro2p.htm)2nd edition (eds. Golemis and Adams). Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA, 2005. ### INTRODUCTION The following protocol describes the synt...

  5. Improved serodiagnosis of hepatitis C virus infection with synthetic peptide antigen from capsid protein.

    OpenAIRE

    Hosein, B; Fang, C T; Popovsky, M A; J. Ye; Zhang, M; WANG, C. Y.

    1991-01-01

    Cloning and expression of hepatitis C virus have allowed the development of immunoassays to detect hepatitis C virus infection. However, currently available recombinant fusion protein C100-3 assays, based on a nonstructural protein of the virus, are limited in sensitivity, particularly for detecting acute infection. In this report seroconversion panels showed that an assay based on synthetic peptides, derived from immunodominant regions of both capsid and nonstructural proteins, accelerated h...

  6. Biophysical characterization of G-protein coupled receptor-peptide ligand binding

    OpenAIRE

    Langelaan, David N.; Ngweniform, Pascaline; Rainey, Jan K.

    2011-01-01

    G-protein coupled receptors (GPCRs) are ubiquitous membrane proteins allowing intracellular response to extracellular factors that range from photons of light to small molecules to proteins. Despite extensive exploitation of GRCRs as therapeutic targets, biophysical characterization of GPCR-ligand interactions remains challenging. In this minireview, we focus on techniques which have been successfully employed for structural and biophysical characterization of peptide ligands binding to their...

  7. Activation of multiple mitogen-activated protein kinases by recombinant calcitonin gene-related peptide receptor.

    Science.gov (United States)

    Parameswaran, N; Disa, J; Spielman, W S; Brooks, D P; Nambi, P; Aiyar, N

    2000-02-18

    Calcitonin gene-related peptide is a 37-amino-acid neuropeptide and a potent vasodilator. Although calcitonin gene-related peptide has been shown to have a number of effects in a variety of systems, the mechanisms of action and the intracellular signaling pathways, especially the regulation of mitogen-activated protien kinase (MAPK) pathway, is not known. In the present study we investigated the role of calcitonin gene-related peptide in the regulation of MAPKs in human embryonic kidney (HEK) 293 cells stably transfected with a recombinant porcine calcitonin gene-related peptide-1 receptor. Calcitonin gene-related peptide caused a significant dose-dependent increase in cAMP response and the effect was inhibited by calcitonin gene-related peptide(8-37), the calcitonin gene-related peptide-receptor antagonist. Calcitonin gene-related peptide also caused a time- and concentration-dependent increase in extracellular signal-regulated kinase (ERK) and P38 mitogen-activated protein kinase (P38 MAPK) activities, with apparently no significant change in cjun-N-terminal kinase (JNK) activity. Forskolin, a direct activator of adenylyl cyclase also stimulated ERK and P38 activities in these cells suggesting the invovement of cAMP in this process. Calcitonin gene-related peptide-stimulated ERK and P38 MAPK activities were inhibited significantly by calcitonin gene-related peptide receptor antagonist, calcitonin gene-related peptide-(8-37) suggesting the involvement of calcitonin gene-related peptide-1 receptor. Preincubation of the cells with the cAMP-dependent protein kinase inhibitor, H89 [¿N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide, hydrochloride¿] inhibited calcitonin gene-related peptide-mediated activation of ERK and p38 kinases. On the other hand, preincubation of the cells with wortmannin ¿[1S-(1alpha,6balpha,9abeta,11alpha, 11bbeta)]-11-(acetyloxy)-1,6b,7,8,9a,10,11, 11b-octahydro-1-(methoxymethyl)-9a,11b-dimethyl-3H-furo[4,3, 2-de]indeno[4,5-h]-2

  8. Peptide Synthesis through Cell-Free Expression of Fusion Proteins Incorporating Modified Amino Acids as Latent Cleavage Sites for Peptide Release.

    Science.gov (United States)

    Liutkus, Mantas; Fraser, Samuel A; Caron, Karine; Stigers, Dannon J; Easton, Christopher J

    2016-05-17

    Chlorinated analogues of Leu and Ile are incorporated during cell-free expression of peptides fused to protein, by exploiting the promiscuity of the natural biosynthetic machinery. They then act as sites for clean and efficient release of the peptides simply by brief heat treatment. Dehydro analogues of Leu and Ile are similarly incorporated as latent sites for peptide release through treatment with iodine under cold conditions. These protocols complement enzyme-catalyzed methods and have been used to prepare calcitonin, gastrin-releasing peptide, cholecystokinin-7, and prolactin-releasing peptide prohormones, as well as analogues substituted with unusual amino acids, thus illustrating their practical utility as alternatives to more traditional chemical peptide synthesis. PMID:26918308

  9. Imidate-Based Cross-Linkers for Structural Proteomics: Increased Charge of Protein and Peptide Ions and CID and ECD Fragmentation Studies

    Science.gov (United States)

    Koolen, Hector H. F.; Gomes, Alexandre F.; Schwab, Nicolas V.; Eberlin, Marcos N.; Gozzo, Fabio C.

    2014-07-01

    Chemical cross-linking is an attractive low-resolution technique for structural studies of protein complexes. Distance constraints obtained from cross-linked peptides identified by mass spectrometry (MS) are used to construct and validate protein models. Amidinating cross-linkers such as diethyl suberthioimidate (DEST) have been used successfully in chemical cross-linking experiments. In this work, the application of a commercial diimidate cross-linking reagent, dimethyl suberimidate (DMS), was evaluated with model peptides and proteins. The peptides were designed with acetylated N-termini followed by random sequences containing two Lys residues separated by an Arg residue. After cross-linking reactions, intra- and intermolecular cross-linked species were submitted to CID and ECD dissociations to study their fragmentation features in the gas phase. Fragmentation of intramolecular peptides by collision induced dissociation (CID) demonstrates a unique two-step fragmentation pathway involving formation of a ketimine as intermediate. Electron capture and electron transfer dissociation (ECD and ETD) experiments demonstrated that the cyclic moiety is not dissociated. Intermolecular species demonstrated previously described fragmentation behavior in both CID and ECD experiments. The charge state distributions (CSD) obtained after reaction with DMS were compared with those obtained with disuccinimidyl suberate (DSS). CSDs for peptides and proteins were increased after their reaction with DMS, owing to the higher basicity of DMS modified species. These features were also observed in LC-MS experiments with bovine carbonic anhydrase II (BCA) after cross-linking with DMS and tryptic proteolysis. Cross-linked peptides derived from this protein were identified at high confidence and those species were in agreement with the crystal structure of BCA.

  10. Analysis of the Resveratrol-binding Protein using Phage-displayed Random Peptide Library

    Institute of Scientific and Technical Information of China (English)

    Lei FENG; Jian JIN; Lian-Feng ZHANG; Ting YAN; Wen-Yi TAO

    2006-01-01

    Resveratrol, a plant polyphenol, is found in significant amounts in the skin of grapes and in some traditional herbs. It is reported to exert different biological activities, such as inhibiting lipid peroxidation,scavenging free radicals, inhibiting platelet aggregation, and anticancer activity. In order to screen the resveratrol-binding proteins, we synthesized biotinylated resveratrol, purified by liquid chromatography and immobilized it into streptavidin-coated microplate wells. 3-(4,5-Demethylthiazol-)-2,5-diphenyl tetrazolium bromide assay showed little change in the anticancer activity of biotinylated resveratrol in vitro. A random library of phage-displayed peptides was screened for binding to immobilized resveratrol to isolate resveratrolbinding proteins. Several peptides were found to bind to resveratrol specifically, which was proven by enzyme-linked immunosorbent assay. Through amino acid sequence analysis of the selected peptides and human proteins using the BLAST program, the results showed that resveratrol has an affinity for various proteins such as breast cancer-associated antigen, breast cancer resistance protein, death-associated transcription factor, and human cyclin-dependent kinase. These results demonstrate that our study provides a feasible method for the study of binding proteins of natural compounds using a phage-displayed random peptide library.

  11. Interaction of 18-residue peptides derived from amphipathic helical segments of globular proteins with model membranes

    Indian Academy of Sciences (India)

    Chandrasekaran Sivakamasundari; Ramakrishnan Nagaraj

    2009-06-01

    We investigated the interaction of six 18-residue peptides derived from amphipathic helical segments of globular proteins with model membranes. The net charge of the peptides at neutral pH varies from –1 to +6. Circular dichroism spectra indicate that peptides with a high net positive charge tend to fold into a helical conformation in the presence of negatively charged lipid vesicles. In helical conformation, their average hydrophobic moment and hydrophobicity would render them surface-active. The composition of amino acids on the polar face of the helix in the peptides is considerably different. The peptides show variations in their ability to permeabilise zwitterionic and anionic lipid vesicles. Whereas increased net positive charge favours greater permeabilisation, the distribution of charged residues in the polar face also plays a role in determining membrane activity. The distribution of amino acids in the polar face of the helix in the peptides that were investigated do not fall into the canonical classes described. Amphipathic helices, which are part of proteins, with a pattern of amino acid distribution different from those observed in class L, A and others, could help in providing newer insights into peptide–membrane interactions.

  12. Hypochlorite-induced oxidation of amino acids, peptides and proteins

    DEFF Research Database (Denmark)

    Hawkins, C L; Pattison, D I; Davies, Michael Jonathan

    2003-01-01

    Activated phagocytes generate the potent oxidant hypochlorite (HOCl) via the release of the enzyme myeloperoxidase and hydrogen peroxide. HOCl is known to react with a number of biological targets including proteins, DNA, lipids and cholesterol. Proteins are likely to be major targets for reaction...... with HOCl within a cell due to their abundance and high reactivity with HOCl. This review summarizes information on the rate of reaction of HOCl with proteins, the nature of the intermediates formed, the mechanisms involved in protein oxidation and the products of these reactions. The predicted targets...... for reaction with HOCl from kinetic modeling studies and the consequences of HOCl-induced protein oxidation are also discussed....

  13. The use of redox polymers in labelling procedures of proteins and peptides with 99mTc. I. Properties of redox polymers and technique of labelling

    International Nuclear Information System (INIS)

    Background: Using a polymer-analogue reaction, redox polymers with a dextran matrix to anchor the end a(b)-alanine-N,N'-diacetate group converted into the Sn2+ cycle have been developed for the labelling of proteins, peptides, and labile compounds with 99mTc. The reaction kinetics and the labelling efficiency of 99mTc depend primarily on the degree of dextran matrix cross-linking and the qualitative nature of the redox polymer end groups. METHODS: Preparation for labelling takes place directly in basic protein and peptide solutions without adjusting pH or adding other adjuvants. Prior to the final modification into kit form, the redox polymers are removed by ultrafiltration. RESULTS: The results of labelling of model compounds (aspartic acid, cysteine) with 99mTc at various solution pH values clearly show that, at pH values over 6.0, it will be primarily the free end SH groups that will serve as binding sites for the proteins and peptides. To label proteins and peptides, we selected a redox polymer with G-25 cross-linking, which allows the achievement of a radiochemical purity over 95% and high stability of the labelled compounds. CONCLUSION: The method of radiolabelling compounds with 99mTc based on redox polymers was developed mainly to overcome the problems faced when using other conventional methods in the labelling of sensitive compounds. (author)

  14. Isolation of cross-linked peptides by diagonal strong cation exchange chromatography for protein complex topology studies by peptide fragment fingerprinting from large sequence databases.

    Science.gov (United States)

    Buncherd, Hansuk; Roseboom, Winfried; Ghavim, Behrad; Du, Weina; de Koning, Leo J; de Koster, Chris G; de Jong, Luitzen

    2014-06-27

    Knowledge of spatial proximity of amino acid residues obtained by chemical cross-linking and mass spectrometric analysis provides information about protein folding, protein-protein interactions and topology of macromolecular assemblies. We show that the use of bis(succinimidyl)-3-azidomethyl glutarate as a cross-linker provides a solution for two major analytical problems of cross-link mapping by peptide fragment fingerprinting (PFF) from complex sequence databases, i.e., low abundance of protease-generated target peptides and lack of knowledge of the masses of linked peptides. Tris(carboxyethyl)phosphine (TCEP) reduces the azido group in cross-linked peptides to an amine group in competition with cleavage of an amide bond formed in the cross-link reaction. TCEP-induced reaction products were separated by diagonal strong cation exchange (SCX) from unmodified peptides. The relation between the sum of the masses of the cleavage products and the mass of the parent cross-linked peptide enables determination of the masses of candidate linked peptides. By reversed phase LC-MS/MS analysis of secondary SCX fractions, we identified several intraprotein and interprotein cross-links in a HeLa cell nuclear extract, aided by software tools supporting PFF from the entire human sequence database. The data provide new information about interacting protein domains, among others from assemblies involved in splicing.

  15. Inhibition of glyceraldehyde-3-phosphate dehydrogenase by peptide and protein peroxides generated by singlet oxygen attack

    DEFF Research Database (Denmark)

    Morgan, Philip E; Dean, Roger T; Davies, Michael Jonathan

    2002-01-01

    inhibited by these peroxides in the absence of added Fe2+-EDTA. The presence of this metal-ion complex enhanced the inhibition observed with these enzymes consistent with the occurrence of radical-mediated reactions. Overall, these studies demonstrate that singlet oxygen-mediated damage to an initial target...... protein can result in selective subsequent damage to other proteins, as evidenced by loss of enzymatic activity, via the formation and subsequent reactions of protein peroxides. These reactions may be important in the development of cellular dysfunction as a result of photo-oxidation.......Reaction of certain peptides and proteins with singlet oxygen (generated by visible light in the presence of rose bengal dye) yields long-lived peptide and protein peroxides. Incubation of these peroxides with glyceraldehyde-3-phosphate dehydrogenase, in the absence of added metal ions, results...

  16. Current trends in mass spectrometry of peptides and proteins: Application to veterinary and sports-doping control.

    Science.gov (United States)

    van den Broek, Irene; Blokland, Marco; Nessen, Merel A; Sterk, Saskia

    2015-01-01

    Detection of misuse of peptides and proteins as growth promoters is a major issue for sport and food regulatory agencies. The limitations of current analytical detection strategies for this class of compounds, in combination with their efficacy in growth-promoting effects, make peptide and protein drugs highly susceptible to abuse by either athletes or farmers who seek for products to illicitly enhance muscle growth. Mass spectrometry (MS) for qualitative analysis of peptides and proteins is well-established, particularly due to tremendous efforts in the proteomics community. Similarly, due to advancements in targeted proteomic strategies and the rapid growth of protein-based biopharmaceuticals, MS for quantitative analysis of peptides and proteins is becoming more widely accepted. These continuous advances in MS instrumentation and MS-based methodologies offer enormous opportunities for detection and confirmation of peptides and proteins. Therefore, MS seems to be the method of choice to improve the qualitative and quantitative analysis of peptide and proteins with growth-promoting properties. This review aims to address the opportunities of MS for peptide and protein analysis in veterinary control and sports-doping control with a particular focus on detection of illicit growth promotion. An overview of potential peptide and protein targets, including their amino acid sequence characteristics and current MS-based detection strategies is, therefore, provided. Furthermore, improvements of current and new detection strategies with state-of-the-art MS instrumentation are discussed for qualitative and quantitative approaches.

  17. A Novel Peptide from Soybean Protein Isolate Significantly Enhances Resistance of the Organism under Oxidative Stress.

    Directory of Open Access Journals (Sweden)

    Heran Ma

    Full Text Available Recent studies have indicated that protein hydrolysates have broad biological effects. In the current study we describe a novel antioxidative peptide, FDPAL, from soybean protein isolate (SPI. The aim of this study was to purify and characterize an antioxidative peptide from SPI and determine its antioxidative mechanism. LC-MS/MS was used to isolate and identify the peptide from SPI. The sequence of the peptide was determined to be Phe-Asp-Pro-Ala-Leu (FDPAL, 561 Da. FDPAL can cause significant enhancement of resistance to oxidative stress both in cells as well as simple organisms. In Caenorhabditis elegans (C. elegans, FDPAL can up-regulate the expression of certain genes associated with resistance. The antioxidant activity of this peptide can be attributed to the presence of a specific amino acid sequence. Results from our work suggest that FDPAL can facilitate potential applications of proteins carrying this sequence in the nutraceutical, bioactive material and clinical medicine areas, as well as in cosmetics and health care products.

  18. Isolation and characterization of anti-inflammatory peptides derived from whey protein.

    Science.gov (United States)

    Ma, Ye; Liu, Jie; Shi, Haiming; Yu, Liangli Lucy

    2016-09-01

    The present study was conducted to isolate and characterize anti-inflammatory peptides from whey protein hydrolysates using alcalase. Nine subfractions were obtained after sequential purification by ultrafiltration, Sephadex G-25 gel (GE Healthcare, Uppsala, Sweden) filtration chromatography, and preparative HPLC. Among them, subfraction F4e showed the strongest inhibitory activity on interleukin-1β (IL-1β), cyclooxygenase-2, and tumor necrosis factor-α (TNF-α) mRNA expression in lipopolysaccharide-induced RAW 264.7 mouse macrophages. Eight peptides, including 2 new peptides-Asp-Tyr-Lys-Lys-Tyr (DYKKY) and Asp-Gln-Trp-Leu (DQWL)-were identified from subfractions F4c and F4e, respectively, using ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. Peptide DQWL showed the strongest inhibitory ability on IL-1β, cyclooxygenase-2, and TNF-α mRNA expression and production of IL-1β and TNF-α proteins at concentrations of 10 and 100μg/mL, respectively. Additionally, DQWL treatment significantly inhibited nuclear factor-κB activation by suppressing nuclear translocation of nuclear factor-κB p65 and blocking inhibitor κB kinase phosphorylation and inhibitor κB degradation together with p38 mitogen-activated protein kinase activation. Our study suggests that peptide DQWL has anti-inflammatory potential; further confirmation using an in vivo model is needed. PMID:27394940

  19. Interaction of amyloid inhibitor proteins with amyloid beta peptides: insight from molecular dynamics simulations.

    Directory of Open Access Journals (Sweden)

    Payel Das

    Full Text Available Knowledge of the detailed mechanism by which proteins such as human αB- crystallin and human lysozyme inhibit amyloid beta (Aβ peptide aggregation is crucial for designing treatment for Alzheimer's disease. Thus, unconstrained, atomistic molecular dynamics simulations in explicit solvent have been performed to characterize the Aβ17-42 assembly in presence of the αB-crystallin core domain and of lysozyme. Simulations reveal that both inhibitor proteins compete with inter-peptide interaction by binding to the peptides during the early stage of aggregation, which is consistent with their inhibitory action reported in experiments. However, the Aβ binding dynamics appear different for each inhibitor. The binding between crystallin and the peptide monomer, dominated by electrostatics, is relatively weak and transient due to the heterogeneous amino acid distribution of the inhibitor surface. The crystallin-bound Aβ oligomers are relatively long-lived, as they form more extensive contact surface with the inhibitor protein. In contrast, a high local density of arginines from lysozyme allows strong binding with Aβ peptide monomers, resulting in stable complexes. Our findings not only illustrate, in atomic detail, how the amyloid inhibitory mechanism of human αB-crystallin, a natural chaperone, is different from that of human lysozyme, but also may aid de novo design of amyloid inhibitors.

  20. A Novel Peptide from Soybean Protein Isolate Significantly Enhances Resistance of the Organism under Oxidative Stress.

    Science.gov (United States)

    Ma, Heran; Liu, Rui; Zhao, Ziyuan; Zhang, Zhixian; Cao, Yue; Ma, Yudan; Guo, Yi; Xu, Li

    2016-01-01

    Recent studies have indicated that protein hydrolysates have broad biological effects. In the current study we describe a novel antioxidative peptide, FDPAL, from soybean protein isolate (SPI). The aim of this study was to purify and characterize an antioxidative peptide from SPI and determine its antioxidative mechanism. LC-MS/MS was used to isolate and identify the peptide from SPI. The sequence of the peptide was determined to be Phe-Asp-Pro-Ala-Leu (FDPAL, 561 Da). FDPAL can cause significant enhancement of resistance to oxidative stress both in cells as well as simple organisms. In Caenorhabditis elegans (C. elegans), FDPAL can up-regulate the expression of certain genes associated with resistance. The antioxidant activity of this peptide can be attributed to the presence of a specific amino acid sequence. Results from our work suggest that FDPAL can facilitate potential applications of proteins carrying this sequence in the nutraceutical, bioactive material and clinical medicine areas, as well as in cosmetics and health care products. PMID:27455060

  1. Selecting protein N-terminal peptides by combined fractional diagonal chromatography.

    Science.gov (United States)

    Staes, An; Impens, Francis; Van Damme, Petra; Ruttens, Bart; Goethals, Marc; Demol, Hans; Timmerman, Evy; Vandekerckhove, Joël; Gevaert, Kris

    2011-07-14

    In recent years, procedures for selecting the N-terminal peptides of proteins with analysis by mass spectrometry have been established to characterize protease-mediated cleavage and protein α-N-acetylation on a proteomic level. As a pioneering technology, N-terminal combined fractional diagonal chromatography (COFRADIC) has been used in numerous studies in which these protein modifications were investigated. Derivatization of primary amines--which can include stable isotope labeling--occurs before trypsin digestion so that cleavage occurs after arginine residues. Strong cation exchange (SCX) chromatography results in the removal of most of the internal peptides. Diagonal, reversed-phase peptide chromatography, in which the two runs are separated by reaction with 2,4,6-trinitrobenzenesulfonic acid, results in the removal of the C-terminal peptides and remaining internal peptides and the fractionation of the sample. We describe here the fully matured N-terminal COFRADIC protocol as it is currently routinely used, including the most substantial improvements (including treatment with glutamine cyclotransferase and pyroglutamyl aminopeptidase to remove pyroglutamate before SCX, and a sample pooling scheme to reduce the overall number of liquid chromatography-tandem mass spectrometry analyses) that were made since its original publication. Completion of the N-terminal COFRADIC procedure takes ~5 d.

  2. beta-Scission of C-3 (beta-carbon) alkoxyl radicals on peptides and proteins

    DEFF Research Database (Denmark)

    Headlam, H A; Mortimer, A; Easton, C J;

    2000-01-01

    of methanal (formaldehyde). This product has been quantified with a number of oxidized peptides and proteins, and can account for up to 64% of the initial attacking radicals with some Ala peptides. When quantified together with the hydroperoxide precursors, these species account for up to 80% of the initial...... radicals, confirming that this is a major process. Methanal causes cell toxicity and DNA damage and is an animal carcinogen and a genotoxic agent in human cells. Thus, the formation and subsequent reaction of alkoxyl radicals formed at the C-3 position on aliphatic amino acid side chains on peptides......Exposure of proteins to radicals in the presence of O(2) brings about multiple changes in the target molecules. These alterations include oxidation of side chains, fragmentation, cross-linking, changes in hydrophobicity and conformation, altered susceptibility to proteolytic enzymes, and formation...

  3. Absolute rate constants for the reaction of hypochlorous acid with protein side chains and peptide bonds

    DEFF Research Database (Denmark)

    Pattison, D I; Davies, Michael Jonathan

    2001-01-01

    , absolute second-order rate constants for the reactions of HOCl with protein side chains, model compounds, and backbone amide (peptide) bonds have been determined at physiological pH values. The reactivity of HOCl with potential reactive sites in proteins is summarized by the series: Met (3.8 x 10(7) M(-1......) x s(-1)) > backbone amides (10-10(-3) M(-1) x s(-1)) > Gln(0.03 M(-1) x s(-1)) approximately Asn (0.03 M(-1) x s(-1)). The rate constants for reaction of HOCl with backbone amides (peptide bonds) vary by 4 orders of magnitude with uncharged peptide bonds reacting more readily with HOCl than those...

  4. Current trends in mass spectrometry of peptides and proteins: application to veterinary and sports-doping control

    NARCIS (Netherlands)

    Broek, I.; Blokland, M.H.; Nessen, M.A.; Sterk, S.S.

    2015-01-01

    Detection of misuse of peptides and proteins as growth promoters is a major issue for sport and food regulatory agencies. The limitations of current analytical detection strategies for this class of compounds, in combination with their efficacy in growth-promoting effects, make peptide and protein d

  5. Processing and functionality of rice bran protein and peptides

    Science.gov (United States)

    Rice bran comprises approximately 10% of the rough rice kernel. Its germ is a rich source of oil; while defatted bran consists of proteins, minerals, vitamins and fibers, or the indigestible carbohydrates. About 61% of the minerals are located in the bran. The rice bran proteins have shown great pot...

  6. Cyanine-based probe\\tag-peptide pair fluorescence protein imaging and fluorescence protein imaging methods

    Science.gov (United States)

    Mayer-Cumblidge, M. Uljana; Cao, Haishi

    2013-01-15

    A molecular probe comprises two arsenic atoms and at least one cyanine based moiety. A method of producing a molecular probe includes providing a molecule having a first formula, treating the molecule with HgOAc, and subsequently transmetallizing with AsCl.sub.3. The As is liganded to ethanedithiol to produce a probe having a second formula. A method of labeling a peptide includes providing a peptide comprising a tag sequence and contacting the peptide with a biarsenical molecular probe. A complex is formed comprising the tag sequence and the molecular probe. A method of studying a peptide includes providing a mixture containing a peptide comprising a peptide tag sequence, adding a biarsenical probe to the mixture, and monitoring the fluorescence of the mixture.

  7. Display of Peptides and Proteins on the Surface of Bacteriophage λ

    Science.gov (United States)

    Sternberg, Nat; Hoess, Ronald H.

    1995-02-01

    The display of peptides or proteins on the surface of viruses is an important technology for studying peptides or proteins and their interaction with other molecules. Here we describe a display vehicle based on bacteriophage λ that incorporates a number of features distinct from other currently used display systems. Fusions of peptides or protein domains have been made to the amino terminus of the 11-kDa D protein of the λ capsid. These fusions assemble onto the viral capsid and appear to be accessible to ligand interactions, based on the ability of a monoclonal antibody to recognize an epitope fused to the D protein on phage heads. To produce large D fusion display libraries and yet avoid the cumbersome task of cloning many fragments into λ DNA, we have used the Cre-loxP site-specific recombination system in vivo to incorporate plasmids encoding the D fusions into the phage genome. Finally, we show that D fusion proteins can be added in vitro to phage lacking D protein and be assembled onto the viral capsid.

  8. Enzymatic generation of peptides from potato proteins by selected proteases and characterization of their structural properties.

    Science.gov (United States)

    Waglay, Amanda; Karboune, Salwa

    2016-03-01

    The use of low grade starting material for the generation of peptides with bioactivity properties is of interest. The proteins from the potato starch industry byproduct is a promising source, as several health benefits may be associated with their hydrolysates. The efficiency of selected proteases (Novo Pro-D, Alcalase, Flavourzyme, and Papain), exhibiting different substrate specificities and cleavage action modes, to hydrolyze potato protein isolate (patatin and protease inhibitors) was investigated. Novo Pro-D resulted in the lowest degree of hydrolysis, whereas Alcalase, Flavourzyme, and Papain exhibited a high catalytic efficiency for the hydrolysis of potato proteins. The degree of hydrolysis behaved in a concentration dependent manner. However, the end-product profile (peptides and free amino acids) was dependent not only on the protease specificity, its cleavage action mode (endo/exo) and the availability of the intermediate substrates but also on the contribution of the protease inhibitors to the reaction kinetics through their inhibitory effects. Indeed, the dependence of the exo-activity on the catalytic efficiency of the endo-action of protease was shown to be significant. Papain generated more unique peptide sequences with homology assessment matching several potato proteins when compared with Flavourzyme. This can be attributed to the high exo-peptidase activity of Flavourzyme resulting in the generation of shorter peptides which were difficult to match. Flavourzyme produced more peptides originated from patatin fraction, whereas Papain resulted in the release of more peptides corresponding to the protease inhibitor fractions. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:420-429, 2016. PMID:26871415

  9. Proteins, Peptides and Amino Acids: Role in Infant Nutrition.

    Science.gov (United States)

    Nutten, Sophie

    2016-01-01

    Proteins are polymers composed of 30 or more amino acids; some of them are essential dietary components, since they are not synthetized by human metabolic processes. They are crucial for healthy growth and development and influence major functions of the body. The infant's first year is a critical time of rapid growth and development, which must be supported by a high rate of protein synthesis. Breast milk, as a single specific food source in the first months of life, is providing the total protein and essential amino acids required. Infant formulas have been designed for infants who cannot be breastfed. They should be similar to breast milk in their composition and their functional outcomes, insuring appropriate growth, optimal development, maturation of the immune system, easy digestion and healthy metabolic programming. By modifying their protein components, specific infant formulas have also been developed for specific needs. For example, partially hydrolyzed (prevention of atopic dermatitis) and extensively hydrolyzed or amino-acid-based infant formulas (reduction in allergy symptoms) have been designed for the management of cow's milk protein allergy. In conclusion, proteins provided via breast milk or infant formula are essential components of the infant's diet; therefore, the specific quality, quantity and conformation of proteins are of utmost importance for healthy growth and development.

  10. Proteins, Peptides and Amino Acids: Role in Infant Nutrition.

    Science.gov (United States)

    Nutten, Sophie

    2016-01-01

    Proteins are polymers composed of 30 or more amino acids; some of them are essential dietary components, since they are not synthetized by human metabolic processes. They are crucial for healthy growth and development and influence major functions of the body. The infant's first year is a critical time of rapid growth and development, which must be supported by a high rate of protein synthesis. Breast milk, as a single specific food source in the first months of life, is providing the total protein and essential amino acids required. Infant formulas have been designed for infants who cannot be breastfed. They should be similar to breast milk in their composition and their functional outcomes, insuring appropriate growth, optimal development, maturation of the immune system, easy digestion and healthy metabolic programming. By modifying their protein components, specific infant formulas have also been developed for specific needs. For example, partially hydrolyzed (prevention of atopic dermatitis) and extensively hydrolyzed or amino-acid-based infant formulas (reduction in allergy symptoms) have been designed for the management of cow's milk protein allergy. In conclusion, proteins provided via breast milk or infant formula are essential components of the infant's diet; therefore, the specific quality, quantity and conformation of proteins are of utmost importance for healthy growth and development. PMID:27336588

  11. Peptide phosphorylation by calcium-dependent protein kinase from maize seedlings.

    Science.gov (United States)

    Loog, M; Toomik, R; Sak, K; Muszynska, G; Järv, J; Ek, P

    2000-01-01

    Ca2+-dependent protein kinase (CDPK-1) was purified from maize seedlings, and its substrate specificity studied using a set of synthetic peptides derived from the phosphorylatable sequence RVLSRLHS15VRER of maize sucrose synthase 2. The decapeptide LARLHSVRER was found to be efficiently phosphorylated as a minimal substrate. The same set of peptides were found to be phosphorylated by mammalian protein kinase Cbeta (PKC), but showed low reactivity with protein kinase A (PKA). Proceeding from the sequence LARLHSVRER, a series of cellulose-membrane-attached peptides of systematically modified structure was synthesised. These peptides had hydrophobic (Ala, Leu) and ionic (Arg, Glu) amino acids substituted in each position. The phosphorylation of these substrates by CDPK-1 was measured and the substrate specificity of the maize protein kinase characterised by the consensus sequence motif A/L-5X-4R-3X-2X-1SX+1R+2Z+3R+4, where X denotes a position with no strict amino acid requirements and Z a position strictly not tolerating arginine compared with the other three varied amino acids. This motif had a characteristic sequence element RZR at positions +2 to +4 and closely resembled the primary structure of the sucrose synthase phosphorylation site. The sequence surrounding the phosphorylatable serine in this consensus motif was similar to the analogous sequence K/RXXS/TXK/R proposed for mammalian PKC, but different from the consensus motif RRXS/TX for PKA. PMID:10632703

  12. The specificity of protection against cationic antimicrobial peptides by lactoferrin binding protein B.

    Science.gov (United States)

    Morgenthau, Ari; Partha, Sarathy K; Adamiak, Paul; Schryvers, Anthony B

    2014-10-01

    A variety of Gram-negative pathogens possess host-specific lactoferrin (Lf) receptors that mediate the acquisition of iron from host Lf. The integral membrane protein component of the receptor, lactoferrin binding protein A specifically binds host Lf and is required for acquisition of iron from Lf. In contrast, the role of the bi-lobed surface lipoprotein, lactoferrin binding protein B (LbpB), in Lf binding and iron acquisition is uncertain. A common feature of LbpBs from most species is the presence of clusters of negatively charged amino acids in the protein's C-terminal lobe. Recently it has been shown that the negatively charged regions from the Neisseria meningitidis LbpB are responsible for protecting against an 11 amino acid cationic antimicrobial peptide (CAP), lactoferricin (Lfcin), derived from human Lf. In this study we investigated whether the LbpB confers resistance to other CAPs since N. meningitidis is likely to encounter other CAPs from the host. LbpB provided protection against the cathelicidin derived peptide, cathelicidin related antimicrobial peptide (mCRAMP), but did not confer protection against Tritrp 1 or LL37 under our experimental conditions. When tested against a range of rationally designed synthetic peptides, LbpB was shown to protect against IDR-1002 and IDR-0018 but not against HH-2 or HHC10. PMID:25038734

  13. Characterization of particulate drug delivery systems for oral delivery of Peptide and protein drugs

    DEFF Research Database (Denmark)

    Christophersen, Philip Carsten; Fano, Mathias; Saaby, Lasse;

    2015-01-01

    Oral drug delivery is a preferred route because of good patient compliance. However, most peptide/ protein drugs are delivered via parenteral routes because of the absorption barriers in the gastrointestinal (GI) tract such as enzymatic degradation by proteases and low permeability acrossthe biol...

  14. Liposomes : Vehicles for the targeted and controlled delivery of peptides and proteins

    NARCIS (Netherlands)

    Crommelin, DJA; Daemen, T; Scherphof, GL; Vingerhoeds, MH; Heeremans, JLM; Kluft, C; Storm, G

    1997-01-01

    Several approaches are presented that have been developed for the liposomal delivery of peptides and proteins. For a rational design of targeted liposomes, the anatomical and physiological constraints with respect to the distribution of liposomes in the body have to be taken into account. Target sit

  15. Physicochemical Changes of Antioxidant Peptides Hydrolyzed From Porcine Plasma Protein Subject to Free Hydroxyl Radical System

    Directory of Open Access Journals (Sweden)

    Hehong Yang

    2013-01-01

    Full Text Available Antioxidant peptides have attracted much attention for potential application as natural food ingredients but the fate of them, as well as oxidized proteins in foods during processing, is still poorly understood. Physicochemical changes in antioxidant peptides hydrolysated from porcine plasma protein were discussed in a free hydroxyl radical-mediated oxidation system. Porcine Plasma Protein Hydrolysates (PPH was prepared by hydrolyzing porcine plasma protein with Alcalase for 5 h at pH 8.0, 55°C. The content of carbonyl groups increased significantly at various degrees when PPH exposed to free radical-mediated oxidation for different time and different concentrations of H2O2, while total sulfhydryls, reactive sulfhydryls and free amines contents decreased. It was concluded that PPH played an antioxidant role in the radical-mediated oxidation system. This provides a potential way for antioxidation in food production.

  16. Mathematical aspects of the kinetics of formation and degradation of linear peptide or protein aggregates.

    Science.gov (United States)

    Zhdanov, Vladimir P

    2016-08-01

    In cells, peptides and proteins are sometimes prone to aggregation. In neurons, for example, amyloid β peptides form plaques related to Alzheimer's disease (AD). The corresponding kinetic models either ignore or do not pay attention to degradation of these species. Here, the author proposes a generic kinetic model describing formation and degradation of linear aggregates. The process is assumed to occur via reversible association of monomers and attachment of monomers to or detachment from terminal parts of aggregates. Degradation of monomers is described as a first-order process. Degradation of aggregates is considered to occur at their terminal and internal parts with different rates and these steps are described by first-order equations as well. Irrespective of the choice of the values of the rate constants, the model predicts that eventually the system reaches a stable steady state with the aggregate populations rapidly decreasing with increasing size at large sizes. The corresponding steady-state size distributions of aggregates are illustrated in detail. The transient kinetics are also shown. The observation of AD appears, however, to indicate that the peptide production becomes eventually unstable, i.e., the growth of the peptide population is not properly limited. This is expected to be related to the specifics of the genetic networks controlling the peptide production. Following this line, two likely general networks with, respectively, global negative and positive feedbacks in the peptide production are briefly discussed. PMID:27132946

  17. Protein C-terminal labeling and biotinylation using synthetic peptide and split-intein.

    Directory of Open Access Journals (Sweden)

    Gerrit Volkmann

    Full Text Available BACKGROUND: Site-specific protein labeling or modification can facilitate the characterization of proteins with respect to their structure, folding, and interaction with other proteins. However, current methods of site-specific protein labeling are few and with limitations, therefore new methods are needed to satisfy the increasing need and sophistications of protein labeling. METHODOLOGY: A method of protein C-terminal labeling was developed using a non-canonical split-intein, through an intein-catalyzed trans-splicing reaction between a protein and a small synthetic peptide carrying the desired labeling groups. As demonstrations of this method, three different proteins were efficiently labeled at their C-termini with two different labels (fluorescein and biotin either in solution or on a solid surface, and a transferrin receptor protein was labeled on the membrane surface of live mammalian cells. Protein biotinylation and immobilization on a streptavidin-coated surface were also achieved in a cell lysate without prior purification of the target protein. CONCLUSIONS: We have produced a method of site-specific labeling or modification at the C-termini of recombinant proteins. This method compares favorably with previous protein labeling methods and has several unique advantages. It is expected to have many potential applications in protein engineering and research, which include fluorescent labeling for monitoring protein folding, location, and trafficking in cells, and biotinylation for protein immobilization on streptavidin-coated surfaces including protein microchips. The types of chemical labeling may be limited only by the ability of chemical synthesis to produce the small C-intein peptide containing the desired chemical groups.

  18. Heparin-binding peptide as a novel affinity tag for purification of recombinant proteins.

    Science.gov (United States)

    Morris, Jacqueline; Jayanthi, Srinivas; Langston, Rebekah; Daily, Anna; Kight, Alicia; McNabb, David S; Henry, Ralph; Kumar, Thallapuranam Krishnaswamy Suresh

    2016-10-01

    Purification of recombinant proteins constitutes a significant part of the downstream processing in biopharmaceutical industries. Major costs involved in the production of bio-therapeutics mainly depend on the number of purification steps used during the downstream process. Affinity chromatography is a widely used method for the purification of recombinant proteins expressed in different expression host platforms. Recombinant protein purification is achieved by fusing appropriate affinity tags to either N- or C- terminus of the target recombinant proteins. Currently available protein/peptide affinity tags have proved quite useful in the purification of recombinant proteins. However, these affinity tags suffer from specific limitations in their use under different conditions of purification. In this study, we have designed a novel 34-amino acid heparin-binding affinity tag (HB-tag) for the purification of recombinant proteins expressed in Escherichia coli (E. coli) cells. HB-tag fused recombinant proteins were overexpressed in E. coli in high yields. A one-step heparin-Sepharose-based affinity chromatography protocol was developed to purify HB-fused recombinant proteins to homogeneity using a simple sodium chloride step gradient elution. The HB-tag has also been shown to facilitate the purification of target recombinant proteins from their 8 M urea denatured state(s). The HB-tag has been demonstrated to be successfully released from the fusion protein by an appropriate protease treatment to obtain the recombinant target protein(s) in high yields. Results of the two-dimensional NMR spectroscopy experiments indicate that the purified recombinant target protein(s) exist in the native conformation. Polyclonal antibodies raised against the HB-peptide sequence, exhibited high binding specificity and sensitivity to the HB-fused recombinant proteins (∼10 ng) in different crude cell extracts obtained from diverse expression hosts. In our opinion, the HB-tag provides a

  19. Purification of noncoding RNA and bound proteins using FLAG peptide-conjugated antisense-oligonucleotides.

    Science.gov (United States)

    Adachi, Shungo; Natsume, Tohru

    2015-01-01

    To understand the function of certain RNAs, including noncoding RNAs, it is important to identify the proteins that interact with the RNAs. Here we describe the method for purification of ribonucleoprotein (RNP) complexes composed of specific cellular RNAs by pull-down with FLAG peptide-conjugated antisense oligonucleotide (ASO). Using this method, we identified a novel protein component of U7 snRNP complex.

  20. Probing Protein Interactions with Stapled Peptides: Myc Family and Insulin Receptor

    OpenAIRE

    Liang, Rebecca Yue

    2013-01-01

    One of the most exciting frontiers of expanding pharmacopeia to combat currently untreatable diseases is achieving specifically and potently disruption of unwanted protein-protein interactions where traditional small molecule drugs tend to fall short. Our laboratory has developed the methodology of peptide stapling and pioneered successful applications in multiple disease models since its induction over a decade ago. One common feature of past applications is the use of a single stapled pepti...

  1. Electrical protein detection in cell lysates using high-density peptide-aptamer microarrays

    Directory of Open Access Journals (Sweden)

    Evans David

    2008-01-01

    Full Text Available Abstract Background The dissection of biological pathways and of the molecular basis of disease requires devices to analyze simultaneously a staggering number of protein isoforms in a given cell under given conditions. Such devices face significant challenges, including the identification of probe molecules specific for each protein isoform, protein immobilization techniques with micrometer or submicrometer resolution, and the development of a sensing mechanism capable of very high-density, highly multiplexed detection. Results We present a novel strategy that offers practical solutions to these challenges, featuring peptide aptamers as artificial protein detectors arrayed on gold electrodes with feature sizes one order of magnitude smaller than existing formats. We describe a method to immobilize specific peptide aptamers on individual electrodes at the micrometer scale, together with a robust and label-free electronic sensing system. As a proving proof of principle experiment, we demonstrate the specific recognition of cyclin-dependent protein kinases in whole-cell lysates using arrays of ten electrodes functionalized with individual peptide aptamers, with no measurable cross-talk between electrodes. The sensitivity is within the clinically relevant range and can detect proteins against the high, whole-cell lysate background. Conclusion The use of peptide aptamers selected in vivo to recognize specific protein isoforms, the ability to functionalize each microelectrode individually, the electronic nature and scalability of the label-free detection and the scalability of the array fabrication combine to yield the potential for highly multiplexed devices with increasingly small detection areas and higher sensitivities that may ultimately allow the simultaneous monitoring of tens or hundreds of thousands of protein isoforms.

  2. Production and Purification of Antioxidant Peptides from Flatfish Skin Protein Hydrolysates

    Institute of Scientific and Technical Information of China (English)

    朱宏吉; 王世鹏; 田丽; 张华

    2015-01-01

    Antioxidant peptides of flatfish skin protein hydrolyzed by four enzymes(Papain, Pepsin, Trypsin and Neutrase, respectively)were investigated. The Trypsin hydrolysate obtained by hydrolysis exhibited the highest 1,1-dipheny-l-2-picrylhydrazyl(DPPH)radical scavenging activity(DRSA)compared with other hydrolysates. Re-sponse surface method ology(RSM), based on Box-Behnken design, was used to study the influence of hydrolysis conditions on the DRSA. The optimal hydrolysis conditions were as follows:pH 7.38, temperature 48.2℃and en-zyme/substrate(E/S)ratio 2 840 U/g. Under these conditions, the maximum DRSA was(22.85 ± 0.57)%,. The experimental values agreed with the value (23.09%,)predicted by the model within a 95%, confidence interval. By using gel filtration chromatography and reversed-phase high performance liquid chromatography(RP-HPLC), anti-oxidant peptide(D2-P)was isolated from flatfish skin protein hydrolysates(FSPH)and could exhibit a(54.28 ± 1.37)%, scavenging activity on DPPH radical at the concentration of 5 mg/mL. This is the first report of a scientific basis for the preparation of antioxidant peptides from flatfish skin. The results suggested that the antioxidant pep-tides can be exploited into functional foods or used as a novel source of nutraceuticals.

  3. Recognition of signal peptide by protein translocation machinery in middle silk gland of silkworm Bombyx mori

    Institute of Scientific and Technical Information of China (English)

    Xiuyang Guo; Yi Zhang; Xue Zhang; Shengpeng Wang; Changde Lu

    2008-01-01

    To investigate the functions of signal peptide in protein secretion in the middle silk gland of silkworm Bombyx mori,a series of recombinant Autographa californica multiple nucleopolyhedroviruses containing enhanced green fluorescent protein (egfp) gene,led by sericin-1 promoter and mutated signal peptide coding sequences,were constructed by region-deletions or single amino acid residue deletions.The recombinant Autographa californica multiple nucleopolyhedroviruses were injected into the hemocoele of newly ecdysed fifth-instar silkworm larvae.The expression and secretion of EGFP in the middle silk gland were examined by fluorescence microscopy and Western blot analysis.Results showed that even with a large part (up to 14 amino acid residues) of the ser-1 signal peptide deleted,the expressed EGFP could still be secreted into the cavity of the silk gland.Western blot analysis showed that shortening of the signal peptide from the C-terminal suppressed the maturation of pro-EGFP to EGFP.When 8 amino acid residues were deleted from the C-terminal of the signal peptide (mutant 13 aa),the secretion of EGFP was incomplete,implicating the importance of proper coupling of the h-region and c-region.The deletion of amino acid residue(s) in the h-region did not affect the secretion of EGFP,indicating that the recognition of signal peptide by translocation machinery was mainly by a structural domain,but not by special amino acid residue(s).Furthermore,the deletion of Arg2 or replacement with Asp in the n-region of the signal peptide did not influence secretion of EGFP,suggesting that a positive charge is not crucial.

  4. Interactions of calmodulin with death-associated protein kinase peptides: experimental and modeling studies.

    Science.gov (United States)

    Kuczera, Krzysztof; Kursula, Petri

    2012-01-01

    We have studied the interactions between calmodulin (CaM) and three target peptides from the death-associated protein kinase (DAPK) protein family using both experimental and modeling methods, aimed at determining the details of the underlying biological regulation mechanisms. Experimentally, calorimetric binding free energies were determined for the complexes of CaM with peptides representing the DAPK2 wild-type and S308D mutant, as well as DAPK1. The observed affinity of CaM was very similar for all three studied peptides. The DAPK2 and DAPK1 peptides differ significantly in sequence and total charge, while the DAPK2 S308D mutant is designed to model the effects of DAPK2 Ser308 phosphorylation. The crystal structure of the CaM-DAPK2 S308D mutant peptide is also reported. The structures of CaM-DAPK peptide complexes present a mode of CaM-kinase interaction, in which bulky hydrophobic residues at positions 10 and 14 are both bound to the same hydrophobic cleft. To explain the microscopic effects underlying these interactions, we performed free energy calculations based on the approximate MM-PBSA approach. For these highly charged systems, standard MM-PBSA calculations did not yield satisfactory results. We proposed a rational modification of the approach which led to reasonable predictions of binding free energies. All three complexes are strongly stabilized by two effects: electrostatic interactions and buried surface area. The strong favorable interactions are to a large part compensated by unfavorable entropic terms, in which vibrational entropy is the largest contributor. The electrostatic component of the binding free energy followed the trend of the overall peptide charge, with strongest interactions for DAPK1 and weakest for the DAPK2 mutant. The electrostatics was dominated by interactions of the positively charged residues of the peptide with the negatively charged residues of CaM. The nonpolar binding free energy was comparable for all three peptides, the

  5. Therapeutic effects of cell-permeant peptides that activate G proteins downstream of growth factors

    Science.gov (United States)

    Ma, Gary S.; Aznar, Nicolas; Kalogriopoulos, Nicholas; Midde, Krishna K.; Lopez-Sanchez, Inmaculada; Sato, Emi; Dunkel, Ying; Gallo, Richard L.; Ghosh, Pradipta

    2015-01-01

    In eukaryotes, receptor tyrosine kinases (RTKs) and trimeric G proteins are two major signaling hubs. Signal transduction via trimeric G proteins has long been believed to be triggered exclusively by G protein-coupled receptors (GPCRs). This paradigm has recently been challenged by several studies on a multimodular signal transducer, Gα-Interacting Vesicle associated protein (GIV/Girdin). We recently demonstrated that GIV’s C terminus (CT) serves as a platform for dynamic association of ligand-activated RTKs with Gαi, and for noncanonical transactivation of G proteins. However, exogenous manipulation of this platform has remained beyond reach. Here we developed cell-permeable GIV-CT peptides by fusing a TAT-peptide transduction domain (TAT-PTD) to the minimal modular elements of GIV that are necessary and sufficient for activation of Gi downstream of RTKs, and used them to engineer signaling networks and alter cell behavior. In the presence of an intact GEF motif, TAT-GIV-CT peptides enhanced diverse processes in which GIV’s GEF function has previously been implicated, e.g., 2D cell migration after scratch-wounding, invasion of cancer cells, and finally, myofibroblast activation and collagen production. Furthermore, topical application of TAT-GIV-CT peptides enhanced the complex, multireceptor-driven process of wound repair in mice in a GEF-dependent manner. Thus, TAT-GIV peptides provide a novel and versatile tool to manipulate Gαi activation downstream of growth factors in a diverse array of pathophysiologic conditions. PMID:25926659

  6. Rgg protein structure-function and inhibition by cyclic peptide compounds.

    Science.gov (United States)

    Parashar, Vijay; Aggarwal, Chaitanya; Federle, Michael J; Neiditch, Matthew B

    2015-04-21

    Peptide pheromone cell-cell signaling (quorum sensing) regulates the expression of diverse developmental phenotypes (including virulence) in Firmicutes, which includes common human pathogens, e.g., Streptococcus pyogenes and Streptococcus pneumoniae. Cytoplasmic transcription factors known as "Rgg proteins" are peptide pheromone receptors ubiquitous in Firmicutes. Here we present X-ray crystal structures of a Streptococcus Rgg protein alone and in complex with a tight-binding signaling antagonist, the cyclic undecapeptide cyclosporin A. To our knowledge, these represent the first Rgg protein X-ray crystal structures. Based on the results of extensive structure-function analysis, we reveal the peptide pheromone-binding site and the mechanism by which cyclosporin A inhibits activation of the peptide pheromone receptor. Guided by the Rgg-cyclosporin A complex structure, we predicted that the nonimmunosuppressive cyclosporin A analog valspodar would inhibit Rgg activation. Indeed, we found that, like cyclosporin A, valspodar inhibits peptide pheromone activation of conserved Rgg proteins in medically relevant Streptococcus species. Finally, the crystal structures presented here revealed that the Rgg protein DNA-binding domains are covalently linked across their dimerization interface by a disulfide bond formed by a highly conserved cysteine. The DNA-binding domain dimerization interface observed in our structures is essentially identical to the interfaces previously described for other members of the XRE DNA-binding domain family, but the presence of an intermolecular disulfide bond buried in this interface appears to be unique. We hypothesize that this disulfide bond may, under the right conditions, affect Rgg monomer-dimer equilibrium, stabilize Rgg conformation, or serve as a redox-sensitive switch.

  7. Longitudinal changes in C-reactive protein, proform of eosinophil major basic protein, and pregnancy-associated plasma protein-A during weight changes in obese children

    DEFF Research Database (Denmark)

    Lausten-Thomsen, Ulrik; Gamborg, Michael; Bøjsøe, Christine;

    2015-01-01

    BACKGROUND: Childhood obesity is associated with several complications, including cardiovascular comorbidity. Several biomarkers, such as high-sensitive C-reactive protein (hs-CRP), proform of eosinophil major basic protein (Pro-MBP) and pregnancy associated plasma protein-A (PAPP-A), have equall...

  8. Trends in the Design and Development of Specific Aptamers Against Peptides and Proteins.

    Science.gov (United States)

    Tabarzad, Maryam; Jafari, Marzieh

    2016-04-01

    Aptamers are single stranded oligonucleotides, comparable to monoclonal antibodies (mAbs) in selectivity and affinity and have significant strategic properties in design, development and applications more than mAbs. Ease of design and development, simple chemical modification and the attachment of functional groups, easily handling and more adaptability with analytical methods, small size and adaptation with nanostructures are the valuable characteristics of aptamers in comparison to large protein based ligands. Among a broad range of targets that their specific aptamers developed, proteins and peptides have significant position according to the number of related studies performed so far. Since proteins control many of important physiological and pathological incidents in the living organisms, particularly human beings and because of the benefits of aptamers in clinical and analytical applications, aptamer related technologies in the field of proteins and peptides are under progress, exclusively. Currently, there is only one FDA approved therapeutic aptamer in the pharmaceutical market, which is specific to vascular endothelial growth factor and is prescribed for age related macular degenerative disease. Additionally, there are several aptamers in the different phases of clinical trials. Almost all of these aptamers are specific to clinically important peptide or protein targets. In addition, the application of protein specific aptamers in the design and development of targeted drug delivery systems and diagnostic biosensors is another intersting field of aptamer technology. In this review, significant efforts related to development and applications of aptamer technologies in proteins and peptides sciences were considered to emphasis on the importance of aptamers in medicinal and clinical applications. PMID:26984473

  9. Effect of electrostatics on aggregation of prion protein Sup35 peptide

    International Nuclear Information System (INIS)

    Self-assembly of misfolded proteins into ordered fibrillar structures is a fundamental property of a wide range of proteins and peptides. This property is also linked with the development of various neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Environmental conditions modulate the misfolding and aggregation processes. We used a peptide, CGNNQQNY, from yeast prion protein Sup35, as a model system to address effects of environmental conditions on aggregate formation. The GNNQQNY peptide self-assembles in fibrils with structural features that are similar to amyloidogenic proteins. Atomic force microscopy (AFM) and thioflavin T (ThT) fluorescence assay were employed to follow the aggregation process at various pHs and ionic strengths. We also used single molecule AFM force spectroscopy to probe interactions between the peptides under various conditions. The ThT fluorescence data showed that the peptide aggregates fast at pH values approaching the peptide isoelectric point (pI = 5.3) and the kinetics is 10 times slower at acidic pH (pH 2.0), suggesting that electrostatic interactions contribute to the peptide self-assembly into aggregates. This hypothesis was tested by experiments performed at low (11 mM) and high (150 mM) ionic strengths. Indeed, the aggregation lag time measured at pH 2 at low ionic strength (11 mM) is 195 h, whereas the lag time decreases ∼5 times when the ionic strength is increased to 150 mM. At conditions close to the pI value, pH 5.6, the aggregation lag time is 12 ± 6 h under low ionic strength, and there is minimal change to the lag time at 150 mM NaCl. The ionic strength also influences the morphology of aggregates visualized with AFM. In pH 2.0 and at high ionic strength, the aggregates are twofold taller than those formed at low ionic strength. In parallel, AFM force spectroscopy studies revealed minimal contribution of electrostatics to dissociation of transient peptide dimers. (paper)

  10. Antioxidative, DPP-IV and ACE inhibiting peptides from fish protein hydrolysed with intestinal proteases

    OpenAIRE

    Falkenberg, Susan Skanderup; Stagsted, Jan; Nielsen, Henrik Hauch

    2012-01-01

    Proteins from fish tissue could be a promising source of peptides with a nutritional and pharmaceutical value, e.g. as treatment of type 2 diabetes with dipeptidyl peptidase IV (DPP-IV) inhibiting peptides, and could be used in health and functional foods and thereby increasing the value of secondary marine products.The approach in this study is to hydrolyse skin and belly flap tissue from Salmon with the use of mammalian digestive proteases from pancreas and intestinal mucosa and test hydrol...

  11. Effect of electrostatics on aggregation of prion protein Sup35 peptide

    Science.gov (United States)

    Portillo, Alexander M.; Krasnoslobodtsev, Alexey V.; Lyubchenko, Yuri L.

    2012-04-01

    Self-assembly of misfolded proteins into ordered fibrillar structures is a fundamental property of a wide range of proteins and peptides. This property is also linked with the development of various neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Environmental conditions modulate the misfolding and aggregation processes. We used a peptide, CGNNQQNY, from yeast prion protein Sup35, as a model system to address effects of environmental conditions on aggregate formation. The GNNQQNY peptide self-assembles in fibrils with structural features that are similar to amyloidogenic proteins. Atomic force microscopy (AFM) and thioflavin T (ThT) fluorescence assay were employed to follow the aggregation process at various pHs and ionic strengths. We also used single molecule AFM force spectroscopy to probe interactions between the peptides under various conditions. The ThT fluorescence data showed that the peptide aggregates fast at pH values approaching the peptide isoelectric point (pI = 5.3) and the kinetics is 10 times slower at acidic pH (pH 2.0), suggesting that electrostatic interactions contribute to the peptide self-assembly into aggregates. This hypothesis was tested by experiments performed at low (11 mM) and high (150 mM) ionic strengths. Indeed, the aggregation lag time measured at pH 2 at low ionic strength (11 mM) is 195 h, whereas the lag time decreases ˜5 times when the ionic strength is increased to 150 mM. At conditions close to the pI value, pH 5.6, the aggregation lag time is 12 ± 6 h under low ionic strength, and there is minimal change to the lag time at 150 mM NaCl. The ionic strength also influences the morphology of aggregates visualized with AFM. In pH 2.0 and at high ionic strength, the aggregates are twofold taller than those formed at low ionic strength. In parallel, AFM force spectroscopy studies revealed minimal contribution of electrostatics to dissociation of transient peptide dimers.

  12. Determination of aromatic and sulfur-containing amino acids, peptides, and proteins using high-performance liquid chromatography with photolytic electrochemical detection

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Lin; Krull, I.S. (Northeastern Univ., Boston, MA (USA))

    1990-12-01

    Aromatic amino acids, sulfur-containing amino acids, peptides containing such constituents, and proteins can now be detected in high-performance liquid chromatography by the use of on-line, postcolumn, continuous photolytic derivatization with electrochemical (HPLC-h{nu}-EC) detection. The overall approach is a very simple, reproducible, rapid, and fully automatable approach for the determination of certain amino acids, peptides, and proteins with excellent selectivity, sensitivity, and linearities of response. Dual-electrode response ratios, lamp-on/lamp-off behavior, and chromatographic capacity factors all contribute to the enhanced selectivity of the overall HPLC-h{nu}-EC determination for these particular classes of bioorganics and biopolymers. The analytical figures of merit, chromatography detection, and method validation approaches have all be optimally derived and demonstrated reproducible. Applications of the basic methodology to real-world samples are demonstrated and validated.

  13. Identification of a novel Plasmopara halstedii elicitor protein combining de novo peptide sequencing algorithms and RACE-PCR

    Directory of Open Access Journals (Sweden)

    Madlung Johannes

    2010-05-01

    Full Text Available Abstract Background Often high-quality MS/MS spectra of tryptic peptides do not match to any database entry because of only partially sequenced genomes and therefore, protein identification requires de novo peptide sequencing. To achieve protein identification of the economically important but still unsequenced plant pathogenic oomycete Plasmopara halstedii, we first evaluated the performance of three different de novo peptide sequencing algorithms applied to a protein digests of standard proteins using a quadrupole TOF (QStar Pulsar i. Results The performance order of the algorithms was PEAKS online > PepNovo > CompNovo. In summary, PEAKS online correctly predicted 45% of measured peptides for a protein test data set. All three de novo peptide sequencing algorithms were used to identify MS/MS spectra of tryptic peptides of an unknown 57 kDa protein of P. halstedii. We found ten de novo sequenced peptides that showed homology to a Phytophthora infestans protein, a closely related organism of P. halstedii. Employing a second complementary approach, verification of peptide prediction and protein identification was performed by creation of degenerate primers for RACE-PCR and led to an ORF of 1,589 bp for a hypothetical phosphoenolpyruvate carboxykinase. Conclusions Our study demonstrated that identification of proteins within minute amounts of sample material improved significantly by combining sensitive LC-MS methods with different de novo peptide sequencing algorithms. In addition, this is the first study that verified protein prediction from MS data by also employing a second complementary approach, in which RACE-PCR led to identification of a novel elicitor protein in P. halstedii.

  14. Bioinspired silicification of silica-binding peptide-silk protein chimeras: comparison of chemically and genetically produced proteins.

    Science.gov (United States)

    Canabady-Rochelle, Laetitia L S; Belton, David J; Deschaume, Olivier; Currie, Heather A; Kaplan, David L; Perry, Carole C

    2012-03-12

    Novel protein chimeras constituted of "silk" and a silica-binding peptide (KSLSRHDHIHHH) were synthesized by genetic or chemical approaches and their influence on silica-silk based chimera composite formation evaluated. Genetic chimeras were constructed from 6 or 15 repeats of the 32 amino acid consensus sequence of Nephila clavipes spider silk ([SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQG](n)) to which one silica binding peptide was fused at the N terminus. For the chemical chimera, 28 equiv of the silica binding peptide were chemically coupled to natural Bombyx mori silk after modification of tyrosine groups by diazonium coupling and EDC/NHS activation of all acid groups. After silica formation under mild, biomaterial-compatible conditions, the effect of peptide addition on the properties of the silk and chimeric silk-silica composite materials was explored. The composite biomaterial properties could be related to the extent of silica condensation and to the higher number of silica binding sites in the chemical chimera as compared with the genetically derived variants. In all cases, the structure of the protein/chimera in solution dictated the type of composite structure that formed with the silica deposition process having little effect on the secondary structural composition of the silk-based materials. Similarly to our study of genetic silk based chimeras containing the R5 peptide (SSKKSGSYSGSKGSKRRIL), the role of the chimeras (genetic and chemical) used in the present study resided more in aggregation and scaffolding than in the catalysis of condensation. The variables of peptide identity, silk construct (number of consensus repeats or silk source), and approach to synthesis (genetic or chemical) can be used to "tune" the properties of the composite materials formed and is a general approach that can be used to prepare a range of materials for biomedical and sensor-based applications. PMID:22229696

  15. Characterization of Protein and Peptide Binding to Nanogels Formed by Differently Charged Chitosan Derivatives

    Directory of Open Access Journals (Sweden)

    Anastasia Zubareva

    2013-07-01

    Full Text Available Chitosan (Chi is a natural biodegradable cationic polymer with remarkable potency as a vehicle for drug or vaccine delivery. Chi possesses multiple groups, which can be used both for Chi derivatization and for particle formation. The aim of this work was to produce stable nanosized range Chi gels (nanogels, NGs with different charge and to study the driving forces of complex formation between Chi NGs and proteins or peptides. Positively charged NGs of 150 nm in diameter were prepared from hexanoyl chitosan (HC by the ionotropic gelation method while negatively charged NGs of 190 nm were obtained from succinoyl Chi (SC by a Ca2+ coacervation approach. NGs were loaded with a panel of proteins or peptides with different weights and charges. We show that NGs preferentially formed complexes with oppositely charged molecules, especially peptides, as was demonstrated by gel-electrophoresis, confocal microscopy and HPLC. Complex formation was accompanied by a change in zeta-potential and decrease in size. We concluded that complex formation between Chi NGs and peptide/proteins is mediated mostly by electrostatic interactions.

  16. Design of cyclic peptides that bind protein surfaces with antibody-like affinity.

    Science.gov (United States)

    Millward, Steven W; Fiacco, Stephen; Austin, Ryan J; Roberts, Richard W

    2007-09-21

    There is a pressing need for new molecular tools to target protein surfaces with high affinity and specificity. Here, we describe cyclic messenger RNA display with a trillion-member covalent peptide macrocycle library. Using this library, we have designed a number of high-affinity, redox-insensitive, cyclic peptides that target the signaling protein G alpha i1. In addition to cyclization, our library construction took advantage of an expanded genetic code, utilizing nonsense suppression to insert N-methylphenylalanine as a 21st amino acid. The designed macrocycles exhibit several intriguing features. First, the core motif seen in all of the selected variants is the same and shares an identical context with respect to the macrocyclic scaffold, consistent with the idea that selection simultaneously optimizes both the cyclization chemistry and the structural placement of the binding epitope. Second, detailed characterization of one molecule, cyclic G alpha i binding peptide (cycGiBP), demonstrates substantially enhanced proteolytic stability relative to that of the parent linear molecule. Third and perhaps most important, the cycGiBP peptide binds the target with very high affinity ( K i approximately 2.1 nM), similar to those of many of the best monoclonal antibodies and higher than that of the betagamma heterodimer, an endogenous G alpha i1 ligand. Overall the work provides a general route to design novel, low-molecular-weight, high-affinity ligands that target protein surfaces.

  17. A peptide fusion protein in hibits angiogenesis and tumorgrowth by blocking VEGF binding to KDR

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Vascular endothelial growth factor (VEGF) binding to its tyrosine kinase receptors (KDR/FLK1, Flt-1) induces angiogenesis. In search of the peptides blocking VEGF binding to its receptor KDR/FLK1 to inhibit tumor- angiogenesis and growth, we screened a phage display peptide library with KDR as target protein, and some candidate peptides were isolated. In this study, we cloned the DNA fragment coding the peptide K237 from the library, into a vector pQE42 to express fusion protein DHFR-K237 in E. coli M15. The affection of fusion protein DHFR-K237 on endothelial cell proliferation and angiogenesis was investigated. In vitro, DHFR-K237 could completely block VEGF binding to KDR and significantly inhibit the VEGF-medi- ated proliferation of the human vascular endothelial cells. In vivo, DHFR-K237 inhibited angiogenesis in chick embryo chorioa- llantoric membrane and tumor growth in nude mice. These results suggest that K237 is an effective antagonist of VEGF binding to KDR, and could be a potential agent for cancer biotherapy.

  18. Catalytic Peptide Dendrimers as Artificial Proteins: Functional Selection and Optimization from Combinatorial Libraries

    Institute of Scientific and Technical Information of China (English)

    Jean-Louis Reymond

    2005-01-01

    @@ 1Introduction In de novo protein design one attempts to create artificial proteins with defined structure and function from first principles, usually with the help of trial-and-error procedures that scan a large number of possible amino acid sequences. Our approach to de novo protein design is based on peptide dendrimers. Dendrimers are tree-like structures that adopt a globular or disk-shaped structure as a consequence of topology rather than folding. Our peptide dendrimers are obtained by alternating alpha-aminoacids with branching diaminoacids[1].Dendrimers containing combinations of histidine, serine and aspartate display enzyme-like catalytic properties for the hydrolysis of esters, including enantiomeric discrimination[1d]. The catalytic effect involves cooperative substrate binding and catalysis by a positive dendritic effect[1d].

  19. Bioactive vegetable proteins and peptides in lipid-lowering: nutraceutical potential

    Directory of Open Access Journals (Sweden)

    Jorge Carlos Ruiz Ruiz

    2014-04-01

    Full Text Available As the last century saw a decline in the burden of nutritional deficiency and infectious disease, the global burden of chronic disease, cardiovascular disease (CVD in particular, is increasing. CVD is the leading cause of death in the developed countries. Significant research efforts on the prevention and treatment of this disease have identified elevated plasma cholesterol as a primary risk factor for CVD. Although CVD progresses with hypercholesterolemia, it seems possibility to delay and prevent its development through improvement of diet. Recent findings demonstrate that protein concentrates, protein hydrolysates, and peptides derived from vegetables may promote a significant decrease in blood cholesterol concentration. This reduction in cholesterol and lipid levels by protein, protein hydrolysates, and peptides can be the result of dietary changes, reduced cholesterol biosynthesis, changes in bile acid synthesis, and reduced absorption of lipid cholesterol and bile acid. Combination drug/diet therapies may reduce the number of drug prescriptions, the progressive rise in "optimal" drug dosage and costs associated with pharmaceutical management of disease. These bioactive vegetable proteins, hydrolysates and peptides may be used in formulation of functional foods, nutraceuticals, and natural drugs because of their health benefit effects suggesting their use as an alternative in treatment of various dyslipidemias, and a potential agent for reducing cardiovascular diseases risk factors.

  20. A Novel MALDI Matrix for Analyzing Peptides and Proteins: Paraffin Wax Immobilized Matrix

    Institute of Scientific and Technical Information of China (English)

    WEI Yuanlong; MEI Yuan; XU Zhe; WANG Cuihong; GUO Yinlong; DU Yiping; ZHANG Weibing

    2009-01-01

    A new kind of MALDI matrix, termed paraffin wax immobilized matrix, was used to study peptide mixtures and proteins. During the preparation process, the paraffin wax was heated and coated on the stainless-steel target plate, and then 2,5-dihydrobenzoic acid (DHB) was deposited on the paraffin layer and stainless-steel target plate to obtain different kinds of matrix spots. The morphology of matrices on different supports and peptide-matrix co-crystallization were observed by a high resolution digital-video microscopy system. Peptide mixtures and bovine serum albumin (BSA) digests were used to investigate the performance of the immobilized matrices on the paraffin target. The MALDI-FTMS analysis results also showed that the detection sensitivity of matrices immobilized in the paraffin sample support was better than that on other sample supports.

  1. Antioxidant activity of cod (Gadus morhua) protein hydrolysates: Fractionation and characterisation of peptide fractions

    DEFF Research Database (Denmark)

    Farvin Habebullah, Sabeena; Andersen, Lisa Lystbæk; Otte, Jeanette;

    2016-01-01

    This study aimed to characterise peptide fractions (>5 kDa, 3–5 kDa and antioxidative activity obtained from a cod protein hydrolysate. The free amino acids in all fractions were dominated by Ala, Gly, Glu and Ser. The total amino acid composition had high proportions of Lys, Ala...... to the antioxidative activity of the peptide fractions, and Tyr seemed to play a major role in the antioxidant activity....... and Glu. The 3–5 kDa and activity. The DPPH radical-scavenging activity of the 3–5 kDa fraction was exerted mainly by one sub-fraction dominated by peptides with masses below 600 Da...

  2. A Novel Lactic Acid Bacteria Growth-stimulating Peptide from Broad Bean (Vicia faba . Protein Hydrolysates

    Directory of Open Access Journals (Sweden)

    Ping Xiao

    2015-03-01

    Full Text Available In this study, broad bean protein hydrolysates (BPH produced by alcalase with strong-stimulating activity for lactic acid bacteria (LAB was first time reported. In order to obtain the key peptide that have growth-stimulating activity for lactic acid bacteria (LAB, gel filtration chromatography and Reverse Phase High Performance Liquid Chromatography (RP-HPLC were applied to isolate and purify the peptides from BPH. Finally, F4-2 elicited the highest activity for LAB, corresponding to amino acid sequence Ser-Ala-Gln (304.10Da was identified by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF/TOF MS/MS. Thus, this study shows that broad bean peptide is a good source to promote the LAB growth and this function is reported for the first time.

  3. Neurotoxicity of prion peptides mimicking the central domain of the cellular prion protein.

    Directory of Open Access Journals (Sweden)

    Silvia Vilches

    Full Text Available The physiological functions of PrP(C remain enigmatic, but the central domain, comprising highly conserved regions of the protein may play an important role. Indeed, a large number of studies indicate that synthetic peptides containing residues 106-126 (CR located in the central domain (CD, 95-133 of PrP(C are neurotoxic. The central domain comprises two chemically distinct subdomains, the charge cluster (CC, 95-110 and a hydrophobic region (HR, 112-133. The aim of the present study was to establish the individual cytotoxicity of CC, HR and CD. Our results show that only the CD peptide is neurotoxic. Biochemical, Transmission Electron Microscopy and Atomic Force Microscopy experiments demonstrated that the CD peptide is able to activate caspase-3 and disrupt the cell membrane, leading to cell death.

  4. A vocabulary of ancient peptides at the origin of folded proteins.

    Science.gov (United States)

    Alva, Vikram; Söding, Johannes; Lupas, Andrei N

    2015-12-14

    The seemingly limitless diversity of proteins in nature arose from only a few thousand domain prototypes, but the origin of these themselves has remained unclear. We are pursuing the hypothesis that they arose by fusion and accretion from an ancestral set of peptides active as co-factors in RNA-dependent replication and catalysis. Should this be true, contemporary domains may still contain vestiges of such peptides, which could be reconstructed by a comparative approach in the same way in which ancient vocabularies have been reconstructed by the comparative study of modern languages. To test this, we compared domains representative of known folds and identified 40 fragments whose similarity is indicative of common descent, yet which occur in domains currently not thought to be homologous. These fragments are widespread in the most ancient folds and enriched for iron-sulfur- and nucleic acid-binding. We propose that they represent the observable remnants of a primordial RNA-peptide world.

  5. Enzymatic Release and Characterization of Novel Bioactive Peptides from Milk Proteins

    DEFF Research Database (Denmark)

    De Gobba, Cristian

    a positive impact on body functions or conditions and may ultimately influence health. Bioactivities such as ACE-inhibitory, antioxidant, opioid, antimicrobial and anti-inflammatory have been identified in milk derived peptides. The purpose of this project is to identify novel bioactive peptides (ACE......Milk is considered the most complete food, providing most of the nutrients needed. Milk proteins are not only important for their function as a source of amino acids, but they are also a source of bioactive peptides. These are short amino acid sequences with different activities that have...... commercial enzymes. The bovine casein was hydrolysed using the supernatant of a Greenlandic bacterium (Arsukibacterium ikkense), produced in the NOVENIA project, which contains cold-active proteolytic enzymes. The hydrolysates were tested for the relevant bioactivities and active fractions were fractionated...

  6. A vocabulary of ancient peptides at the origin of folded proteins.

    Science.gov (United States)

    Alva, Vikram; Söding, Johannes; Lupas, Andrei N

    2015-01-01

    The seemingly limitless diversity of proteins in nature arose from only a few thousand domain prototypes, but the origin of these themselves has remained unclear. We are pursuing the hypothesis that they arose by fusion and accretion from an ancestral set of peptides active as co-factors in RNA-dependent replication and catalysis. Should this be true, contemporary domains may still contain vestiges of such peptides, which could be reconstructed by a comparative approach in the same way in which ancient vocabularies have been reconstructed by the comparative study of modern languages. To test this, we compared domains representative of known folds and identified 40 fragments whose similarity is indicative of common descent, yet which occur in domains currently not thought to be homologous. These fragments are widespread in the most ancient folds and enriched for iron-sulfur- and nucleic acid-binding. We propose that they represent the observable remnants of a primordial RNA-peptide world. PMID:26653858

  7. Cell wall trapping of autocrine peptides for human G-protein-coupled receptors on the yeast cell surface.

    Directory of Open Access Journals (Sweden)

    Jun Ishii

    Full Text Available G-protein-coupled receptors (GPCRs regulate a wide variety of physiological processes and are important pharmaceutical targets for drug discovery. Here, we describe a unique concept based on yeast cell-surface display technology to selectively track eligible peptides with agonistic activity for human GPCRs (Cell Wall Trapping of Autocrine Peptides (CWTrAP strategy. In our strategy, individual recombinant yeast cells are able to report autocrine-positive activity for human GPCRs by expressing a candidate peptide fused to an anchoring motif. Following expression and activation, yeast cells trap autocrine peptides onto their cell walls. Because captured peptides are incapable of diffusion, they have no impact on surrounding yeast cells that express the target human GPCR and non-signaling peptides. Therefore, individual yeast cells can assemble the autonomous signaling complex and allow single-cell screening of a yeast population. Our strategy may be applied to identify eligible peptides with agonistic activity for target human GPCRs.

  8. Affecting proton mobility in activated peptide and whole protein ions via lysine guanidination.

    Science.gov (United States)

    Pitteri, Sharon J; Reid, Gavin E; McLuckey, Scott A

    2004-01-01

    We have evaluated the effect of lysine guanidination in peptides and proteins on the dissociation of protonated ions in the gas phase. The dissociation of guanidinated model peptide ions compared to their unmodified forms showed behavior consistent with concepts of proton mobility as a major factor in determining favored fragmentation channels. Reduction of proton mobility associated with lysine guanidination was reflected by a relative increase in cleavages occurring C-terminal to aspartic acid residues as well as increases in small molecule losses. To evaluate the effect of guanidination on the dissociation behavior of whole protein ions, bovine ubiquitin was selected as a model. Essentially, all of the amide bond cleavages associated with the +10 charge state of fully guanidinated ubiquitin were observed to occur C-terminal to aspartic acid residues, unlike the dissociation behavior of the +10 ion of the unmodified protein, where competing cleavage N-terminal to proline and nonspecific amide bond cleavages were also observed. The +8 and lower charge states of the guanidinated protein showed prominent losses of small neutral molecules. This overall fragmentation behavior is consistent with current hypotheses regarding whole protein dissociation that consider proton mobility and intramolecular charge solvation as important factors in determining favored dissociation channels, and are also consistent with the fragmentation behaviors observed for the guanidinated model peptide ions. Further evaluation of the utility of condensed phase guanidination of whole proteins is necessary but the results described here confirm that guanidination can be an effective strategy for enhancing C-terminal aspartic acid cleavages. Gas phase dissociation exclusively at aspartic acid residues, especially for whole protein ions, could be useful in identifying and characterizing proteins via tandem mass spectrometry of whole protein ions.

  9. Microfluidic electrocapture technology in protein and peptide analysis

    OpenAIRE

    Astorga-Wells, Juan

    2004-01-01

    After sequencing the genomes of several organisms, science in the postgenomic era now aims at a thorough study of the proteins present in a given tissue or organism. Since this task requires an enormous analytical effort, integrated microfluidic systems are envisioned as the solution to automated high throughput analysis of biomolecules. This thesis is focused on a microfluidic methodology and device that present several advantages over present technologies. The microfluidic...

  10. The role of basic residues in the adsorption of blood proteins onto the graphene surface

    Science.gov (United States)

    Gu, Zonglin; Yang, Zaixing; Wang, Lingle; Zhou, Hong; Jimenez-Cruz, Camilo A.; Zhou, Ruhong

    2015-06-01

    With its many unique properties, graphene has shown great potential in various biomedical applications, while its biocompatibility has also attracted growing concerns. Previous studies have shown that the formation of protein-graphene corona could effectively reduce its cytotoxicity; however, the underlying molecular mechanism remains not well-understood. Herein, we use extensive molecular dynamics simulations to demonstrate that blood proteins such as bovine fibrinogen (BFG) can absorb onto the graphene surface quickly and tightly to form a corona complex. Aromatic residues contributed significantly during this adsorption process due to the strong π-π stacking interactions between their aromatic rings and the graphene sp2-carbons. Somewhat surprisingly, basic residues like arginine, also played an equally or even stronger role during this process. The strong dispersion interactions between the sidechains of these solvent-exposed basic residues and the graphene surface provide the driving force for a tight binding of these basic residues. To the best of our knowledge, this is the first study with blood proteins to show that, in addition to the aromatic residues, the basic residues also play an important role in the formation of protein-graphene corona complexes.

  11. Changes in the anisotropy of oriented membrane dynamics induced by myelin basic protein

    Science.gov (United States)

    Natali, F.; Gliozzi, A.; Rolandi, R.; Relini, A.; Cavatorta, P.; Deriu, A.; Fasano, A.; Riccio, P.

    We report recent results showing the evidence of the effect induced by physiological amounts of myelin basic protein (MBP) on the dynamics of dimyristoyl L-a-phosphatidic acid (DMPA) membranes. Incoherent elastic neutron scattering scans, performed over a wide temperature range, have shown that the anisotropy of motions in oriented membranes is significantly enhanced by the presence of MBP.

  12. Changes in the anisotropy of oriented membrane dynamics induced by myelin basic protein

    Energy Technology Data Exchange (ETDEWEB)

    Natali, F. [OGG-INFM, Grenoble (France); Gliozzi, A.; Rolandi, R.; Relini, A. [Dipartimento di Fisica and Istituto Nazionale per la Fisica della Materia, Universita di Genova (Italy); Cavatorta, P.; Deriu, A. [Dipartimento di Fisica and Istituto Nazionale per la Fisica della Materia, Universita di Parma (Italy); Fasano, A. [Dipartimento di Biochimica e Biologia Molecolare, Universita di Bari (Italy); Riccio, P. [Dipartimento di Biologia D.B.A.F., Universita della Basilicata, Potenza (Italy)

    2002-07-01

    We report recent results showing the evidence of the effect induced by physiological amounts of myelin basic protein (MBP) on the dynamics of dimyristoyl L-a-phosphatidic acid (DMPA) membranes. Incoherent elastic neutron scattering scans, performed over a wide temperature range, have shown that the anisotropy of motions in oriented membranes is significantly enhanced by the presence of MBP. (orig.)

  13. Ox peripheral nerve myelin membrane. Purification and partial characterization of two basic proteins

    NARCIS (Netherlands)

    London, Y.

    1971-01-01

    Two basic proteins were purified from the peripheral nervous system. The isolation was achieved by (1) delipidation with chloroform-butanol mixtures, dry acetone, and dry ether, (2) acid extraction at pH 2 and then (3) dialysis against distilled water, lyophilization, and solubilization in pH-10.7 b

  14. Immune Response of Multiparous Hyper-Immunized Sows against Peptides from Non-Structural and Structural Proteins of PRRSV

    Directory of Open Access Journals (Sweden)

    Edgar Rascón-Castelo

    2015-11-01

    Full Text Available The purpose of this study was to evaluate the humoral and cellular responses of commercial multiparous and hyper-immunized sows against peptides from non-structural (nsp and structural proteins of porcine reproductive and respiratory syndrome virus (PRRSV. We selected sows with different numbers of parities from a commercial farm. Management practices on this farm include the use of the MLV commercial vaccine four times per year, plus two vaccinations during the acclimation period. The humoral response was evaluated via the antibody recognition of peptides from nsp and structural proteins, and the cellular response was assessed by measuring the frequency of peptide and PRRSV-specific IFN-gamma-secreting cells (IFNγ-SC. Our results show that sows with six parities have more antibodies against peptides from structural proteins than against peptides from nsp. The analysis of the cellular response revealed that the number of immunizations did not affect the frequency of IFNγ-SC and that the response was stronger against peptides from structural proteins (M protein than against nsp (nsp2. In summary, these results demonstrate that multiparous, hyper-immunized sows have a stronger immune humoral response to PRRSV structural peptides than nsp, but no differences in IFNγ-SC against the same peptides were observed.

  15. Isolation and partial purification of antimicrobial peptides/proteins from dung beetle, Onthophagus taurus immune hemolymph

    International Nuclear Information System (INIS)

    Antimicrobial peptides are important in the first line of the host defense system of all insect species. In the present study antimicrobial peptide(s) were isolated from the hemolymph of the dung beetle Onthophagus taurus. Both non induced and immune induced hemolymphs were tested for their antimicrobial activity against different bacterial strains and C. albicans. Induction was done by injecting E. coli into the abdominal cavity of the O. taurus. The non induced hemolymph did not show activity against any of the tested fungal and bacterial strains where as induced hemolymph showed activity against all tested bacterial strains but no activity against C. albicans. The induced hemolymph was subjected to non reducing SDS-PAGE and UV wavelength scan was performed to detect the presence of peptides. The immune induced hemolymph was purified by gel filtration chromatography to separate the proteins responsible for the antibacterial activity. The fractions within the peak were tested against those bacteria which previously showed sensitivity to the crude immune induced hemolymph. All fractions were found to be active against all tested bacteria with difference in zone of inhibition. The peptides are active against prokaryotes and not against eukaryotes. These properties reveal its unique characteristics and therapeutic application. (author)

  16. Self-assembling peptide inspired by a barnacle underwater adhesive protein.

    Science.gov (United States)

    Nakano, Masahiro; Shen, Jian-Ren; Kamino, Kei

    2007-06-01

    An underwater bioadhesive generally comprises a multiprotein complex that provides a molecular basis for self-assembly. We report here a new class of self-assembling peptide inspired by a 20 kDa barnacle cement protein. Studies on the chemically synthesized 24-residue peptide have revealed that (1) it underwent irreversible self-assembly upon the addition of salt, (2) the self-assembly was started at a salt concentration close to that of seawater with noncovalent intermolecular interactions, (3) the self-assembled material resembled a macroscopic membrane of interwoven nanofilaments, (4) incubation in an alkaline pH range formed the intramolecular disulfide bond of a peptide molecule, thus triggering a conformation change of the molecule, and (5) conformational change of the building block promoted the formation of a nanofiber, resulting in the display of a three-dimensional meshlike mesoscopic structure with defined pores having a diameter of approximately 200 nm. The peptide is likely to provide a suitable basis for further development of peptide-based materials.

  17. ISOLATION AND PARTIAL PURIFICATION OF ANTIMICROBIAL PEPTIDES/PROTEINS FROM DUNG BEETLE, ONTHOPHAGUS TAURUS IMMUNE HEMOLYMPH

    Directory of Open Access Journals (Sweden)

    Vasanth Patil H.B

    2013-06-01

    Full Text Available Antimicrobial peptides are important in the first line of the host defense system of all insect species. In the present study antimicrobial peptide(s were isolated from the hemolymph of the dung beetle Onthophagus taurus. Both non induced and immune induced hemolymphs were tested for their antimicrobial activity against different bacterial strains and C. albicans. Induction was done by injecting E. coli into the abdominal cavity of the O. taurus. The non induced hemolymph did not show activity against any of the tested fungal and bacterial strains where as induced hemolymph showed activity against all tested bacterial strains but no activity against C. albicans. The induced hemolymph was subjected to non reducing SDS-PAGE and UV wavelength scan was performed to detect the presence of peptides. The immune induced hemolymph was purified by gel filtration chromatography to separate the proteins responsible for the antibacterial activity. The fractions within the peak were tested against those bacteria which previously showed sensitivity to the crude immune induced hemolymph. All fractions were found to be active against all tested bacteria with difference in zone of inhibition. The peptides are active against prokaryotes & not against eukaryotes. These properties reveal its unique characteristics and therapeutic application.

  18. β-Propeller Blades as Ancestral Peptides in Protein Evolution

    OpenAIRE

    Kopec, Klaus O.; Lupas, Andrei N.

    2013-01-01

    Proteins of the β-propeller fold are ubiquitous in nature and widely used as structural scaffolds for ligand binding and enzymatic activity. This fold comprises between four and twelve four-stranded β-meanders, the so called blades that are arranged circularly around a central funnel-shaped pore. Despite the large size range of β-propellers, their blades frequently show sequence similarity indicative of a common ancestry and it has been proposed that the majority of β-propellers arose diverge...

  19. Characterization of new outer membrane proteins of Pseudomonas aeruginosa using a combinatorial peptide ligand library.

    Science.gov (United States)

    Ben Mlouka, Mohamed Amine; Khemiri, Arbia; Seyer, Damien; Hardouin, Julie; Chan Tchi Song, Philippe; Dé, Emmanuelle; Jouenne, Thierry; Cosette, Pascal

    2015-02-01

    Most often, the use of ProteoMiner beads has been restricted to human serum proteins for the normalization of major proteins, such as albumin. However, there are other situations of interest in which the presence of major proteins would quench the signals of low abundance polypeptides. We propose the use of these beads for investigating the envelope of the gram-negative bacterium Pseudomonas aeruginosa. Initially, we performed comparative 2D electrophoresis to qualitatively evaluate the incidence of the normalization stage. This demonstrated a significant reduction of the major membrane proteins. Thereafter, using shotgun analysis, the same protein extract was targeted by using combinatorial peptide ligand library capture. This treatment yielded 154 additional outer membrane proteins (OMPs) uncovered by the study of the crude sample. PMID:25471289

  20. Blocking peptides against HBV: PreS1 protein selected from a phage display library

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Liu, Yang; Zu, Xiangyang; Jin, Rui [State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071 (China); Xiao, Gengfu, E-mail: xiaogf@wh.iov.cn [State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071 (China)

    2011-09-09

    Highlights: {yields} Successfully selected specific PreS1-interacting peptides by using phage displayed library. {yields} Alignment of the positive phage clones revealed a consensus PreS1 binding motif. {yields} A highly enriched peptide named P7 had a strong binding ability for PreS1. {yields} P7 could block PreS1 attachment. -- Abstract: The PreS1 protein is present on the outermost part of the hepatitis B virus (HBV) surface and has been shown to have a pivotal function in viral infectivity and assembly. The development of reagents with high affinity and specificity for PreS1 is of great significance for early diagnosis and treatment of HBV infection. A phage display library of dodecapeptide was screened for interactions with purified PreS1 protein. Alignment of the positive phage clones revealed a putative consensus PreS1 binding motif of HX{sub n}HX{sub m}HP/R. Moreover, a peptide named P7 (KHMHWHPPALNT) was highly enriched and occurred with a surprisingly high frequency of 72%. A thermodynamic study revealed that P7 has a higher binding affinity to PreS1 than the other peptides. Furthermore, P7 was able to abrogate the binding of HBV virions to the PreS1 antibody, suggesting that P7 covers key functional sites on the native PreS1 protein. This newly isolated peptide may, therefore, be a new therapeutic candidate for the treatment of HBV. The consensus motif could be modified to deliver imaging, diagnostic, and therapeutic agents to tissues affected by HBV.

  1. Differential Properties of Venom Peptides and Proteins in Solitary vs. Social Hunting Wasps

    Directory of Open Access Journals (Sweden)

    Si Hyeock Lee

    2016-01-01

    Full Text Available The primary functions of venoms from solitary and social wasps are different. Whereas most solitary wasps sting their prey to paralyze and preserve it, without killing, as the provisions for their progeny, social wasps usually sting to defend their colonies from vertebrate predators. Such distinctive venom properties of solitary and social wasps suggest that the main venom components are likely to be different depending on the wasps’ sociality. The present paper reviews venom components and properties of the Aculeata hunting wasps, with a particular emphasis on the comparative aspects of venom compositions and properties between solitary and social wasps. Common components in both solitary and social wasp venoms include hyaluronidase, phospholipase A2, metalloendopeptidase, etc. Although it has been expected that more diverse bioactive components with the functions of prey inactivation and physiology manipulation are present in solitary wasps, available studies on venom compositions of solitary wasps are simply too scarce to generalize this notion. Nevertheless, some neurotoxic peptides (e.g., pompilidotoxin and dendrotoxin-like peptide and proteins (e.g., insulin-like peptide binding protein appear to be specific to solitary wasp venom. In contrast, several proteins, such as venom allergen 5 protein, venom acid phosphatase, and various phospholipases, appear to be relatively more specific to social wasp venom. Finally, putative functions of main venom components and their application are also discussed.

  2. Selective separation and concentration of antihypertensive peptides from rapeseed protein hydrolysate by electrodialysis with ultrafiltration membranes.

    Science.gov (United States)

    He, Rong; Girgih, Abraham T; Rozoy, Elodie; Bazinet, Laurent; Ju, Xing-Rong; Aluko, Rotimi E

    2016-04-15

    Rapeseed protein isolate was subjected to alcalase digestion to obtain a protein hydrolysate that was separated into peptide fractions using electrodialysis with ultrafiltration membrane (EDUF) technology. The EDUF process (6h duration) led to isolation of three peptide fractions: anionic (recovered in KCl-1 compartment), cationic (recovered in KCl-2 compartment), and those that remained in the feed compartment, which was labeled final rapeseed protein hydrolysate (FRPH). As expected the KCl-1 peptides were enriched in negatively-charged (43.57%) while KCl-2 contained high contents of positively-charged (28.35%) amino acids. All the samples inhibited angiotensin converting enzyme (ACE) and renin activities in dose-dependent manner with original rapeseed protein hydrolysate having the least ACE-inhibitory IC50 value of 0.0932±0.0037 mg/mL while FRPH and KCl-2 had least renin-inhibitory IC50 values of 0.47±0.05 and 0.55±0.06 mg/mL, respectively. Six hours after oral administration (100 mg/kg body weight) to spontaneously hypertensive rats, the FRPH produced the maximum systolic blood pressure reduction of -51 mmHg. PMID:26617047

  3. Identification and characterization of antioxidant peptides obtained by gastrointestinal digestion of amaranth proteins.

    Science.gov (United States)

    Orsini Delgado, María C; Nardo, Agustina; Pavlovic, Marija; Rogniaux, Hélène; Añón, María C; Tironi, Valeria A

    2016-04-15

    The objective of the present work was to separate and identify antioxidant peptides from a simulated gastrointestinal digest (Id) from Amaranthus mantegazzianus proteins (I), which has previously been demonstrated to have this activity. I and Id were separated by preparative RP-HPLC. Fractions were evaluated by the ORAC method and the more active ones were analyzed by LC-MS/MS. Each fraction presented diverse peptides from different proteins, most of them from the 11S globulin. After grouping the peptides from 11S globulin according to their overlapping sequences, and based on previous information about structure-activity relationships, ten sequences were synthesized, in order to evaluate their antioxidant activity. Four peptides presented interesting activity: AWEEREQGSR>YLAGKPQQEH∼IYIEQGNGITGM∼TEVWDSNEQ. They exhibited some of the structural characteristics already known to demonstrate this activity, all of them containing at least one bulky aromatic residue. All belonged to little structured, internal or exposed regions of the acid subunit of the 11S globulin. PMID:26675853

  4. A cell penetrating peptide-integrated and enediyne-energized fusion protein shows potent antitumor activity.

    Science.gov (United States)

    Ru, Qin; Shang, Bo-Yang; Miao, Qing-Fang; Li, Liang; Wu, Shu-Ying; Gao, Rui-Juan; Zhen, Yong-Su

    2012-11-20

    Arginine-rich peptides belong to a subclass of cell penetrating peptides that are taken up by living cells and can be detected freely diffusing inside the cytoplasm and nucleoplasm. This phenomenon has been attributed to either an endocytotic mode of uptake and a subsequent release from vesicles or a direct membrane penetration. Lidamycin is an antitumor antibiotic, which consists of an active enediyne chromophore (AE) and a noncovalently bound apoprotein (LDP). In the present study, a fusion protein (Arg)(9)-LDP composed of cell penetrating peptide (Arg)(9) and LDP was prepared by DNA recombination, and the enediyne-energized fusion protein (Arg)(9)-LDP-AE was prepared by molecular reconstitution. The data in fixed cells demonstrated that (Arg)(9)-LDP could rapidly enter cells, and the results based on fluorescence activated cell sorting indicated that the major route for (Arg)(9)-mediated cellular uptake of protein molecules was endocytosis. (Arg)(9)-LDP-AE demonstrated more potent cytotoxicity against different carcinoma cell lines than lidamycin in vitro. In the mouse hepatoma 22 model, (Arg)(9)-LDP-AE (0.3mg/kg) suppressed the tumor growth by 89.2%, whereas lidamycin (0.05 mg/kg) by 74.6%. Furthermore, in the glioma U87 xenograft model in nude mice, (Arg)(9)-LDP-AE at 0.2mg/kg suppressed tumor growth by 88.8%, compared with that of lidamycin by 62.9% at 0.05 mg/kg. No obvious toxic effects were observed in all groups during treatments. The results showed that energized fusion protein (Arg)(9)-LDP-AE was more effective than lidamycin and would be a promising candidate for glioma therapy. In addition, this approach to manufacturing fusion proteins might serve as a technology platform for the development of new cell penetrating peptides-based drugs. PMID:22982402

  5. Kinetics of the interaction of myelin basic protein with phospholipid layers

    Science.gov (United States)

    Facci, Paolo; Cavatorta, Paolo; Cristofolini, Luigi; Fontana, M. P.; Riccio, Paolo

    1999-04-01

    The time dependence of the adsorption of myelin basic protein onto dipalmitoyl phosphatidyl glycerol multilayers has been followed directly, using a novel application of a microgravimetric gauge. Our results, supplemented by other data obtained by FTIR, show the ease and versatility of the quartz microbalance for investigating the interaction processes between proteins and phospholipid layers and show that the protein adsorption is accompanied by structural changes in the proteolipid ensemble and adsorbed liquid water; it is furthermore dependent on the mesoscopic defect morphology of the ensemble.

  6. Peptide tag/probe pairs based on the coordination chemistry for protein labeling.

    Science.gov (United States)

    Uchinomiya, Shohei; Ojida, Akio; Hamachi, Itaru

    2014-02-17

    Protein-labeling methods serve as essential tools for analyzing functions of proteins of interest under complicated biological conditions such as in live cells. These labeling methods are useful not only to fluorescently visualize proteins of interest in biological systems but also to conduct protein and cell analyses by harnessing the unique functions of molecular probes. Among the various labeling methods available, an appropriate binding pair consisting of a short peptide and a de novo designed small molecular probe has attracted attention because of its wide utility and versatility. Interestingly, most peptide tag/probe pairs exploit metal-ligand coordination interactions as the main binding force responsible for their association. Herein, we provide an overview of the recent progress of these coordination-chemistry-based protein-labeling methods and their applications for fluorescence imaging and functional analysis of cellular proteins, while highlighting our originally developed labeling methods. These successful examples clearly exemplify the utility and versatility of metal coordination chemistry in protein functional analysis.

  7. Lactobacillus gasseri requires peptides, not proteins or free amino acids, for growth in milk.

    Science.gov (United States)

    Arakawa, K; Matsunaga, K; Takihiro, S; Moritoki, A; Ryuto, S; Kawai, Y; Masuda, T; Miyamoto, T

    2015-03-01

    Lactobacillus gasseri is a widespread commensal lactic acid bacterium inhabiting human mucosal niches and has many beneficial effects as a probiotic. However, L. gasseri is difficult to grow in milk, which hurts usability for the food industry. It had been previously reported that supplementation with yeast extract or proteose peptone, including peptides, enables L. gasseri to grow well in milk. In this study, our objective was to confirm peptide requirement of L. gasseri and evaluate efficacy of peptide release by enzymatic proteolysis on growth of L. gassei in milk. Three strains of L. gasseri did not grow well in modified DeMan, Rogosa, Sharpe broth without any nitrogen sources (MRS-N), but addition of a casein-derived peptide mixture, tryptone, promoted growth. In contrast, little effect was observed after adding casein or a casein-derived amino acid mixture, casamino acids. These results indicate that L. gasseri requires peptides, not proteins or free amino acids, among milk-derived nitrogen sources for growth. Lactobacillus gasseri JCM 1131T hardly had growth capacity in 6 kinds of milk-based media: bovine milk, human milk, skim milk, cheese whey, modified MRS-N (MRSL-N) supplemented with acid whey, and MRSL-N supplemented with casein. Moreover, treatment with digestive proteases, particularly pepsin, to release peptides made it grow well in each milk-based medium. The pepsin treatment was the most effective for growth of strain JCM 1131T in skim milk among the tested food-grade proteases such as trypsin, α-chymotrypsin, calf rennet, ficin, bromelain, and papain. As well as strain JCM 1131T, pepsinolysis of milk improved growth of other L. gasseri strains and some strains of enteric lactobacilli such as Lactobacillus crispatus, Lactobacillus gallinarum, Lactobacillus johnsonii, and Lactobacillus reuteri. These results suggest that some relatives of L. gasseri also use peptides as desirable nitrogen sources, and that milk may be a good supplier of nutritious

  8. Lactobacillus gasseri requires peptides, not proteins or free amino acids, for growth in milk.

    Science.gov (United States)

    Arakawa, K; Matsunaga, K; Takihiro, S; Moritoki, A; Ryuto, S; Kawai, Y; Masuda, T; Miyamoto, T

    2015-03-01

    Lactobacillus gasseri is a widespread commensal lactic acid bacterium inhabiting human mucosal niches and has many beneficial effects as a probiotic. However, L. gasseri is difficult to grow in milk, which hurts usability for the food industry. It had been previously reported that supplementation with yeast extract or proteose peptone, including peptides, enables L. gasseri to grow well in milk. In this study, our objective was to confirm peptide requirement of L. gasseri and evaluate efficacy of peptide release by enzymatic proteolysis on growth of L. gassei in milk. Three strains of L. gasseri did not grow well in modified DeMan, Rogosa, Sharpe broth without any nitrogen sources (MRS-N), but addition of a casein-derived peptide mixture, tryptone, promoted growth. In contrast, little effect was observed after adding casein or a casein-derived amino acid mixture, casamino acids. These results indicate that L. gasseri requires peptides, not proteins or free amino acids, among milk-derived nitrogen sources for growth. Lactobacillus gasseri JCM 1131T hardly had growth capacity in 6 kinds of milk-based media: bovine milk, human milk, skim milk, cheese whey, modified MRS-N (MRSL-N) supplemented with acid whey, and MRSL-N supplemented with casein. Moreover, treatment with digestive proteases, particularly pepsin, to release peptides made it grow well in each milk-based medium. The pepsin treatment was the most effective for growth of strain JCM 1131T in skim milk among the tested food-grade proteases such as trypsin, α-chymotrypsin, calf rennet, ficin, bromelain, and papain. As well as strain JCM 1131T, pepsinolysis of milk improved growth of other L. gasseri strains and some strains of enteric lactobacilli such as Lactobacillus crispatus, Lactobacillus gallinarum, Lactobacillus johnsonii, and Lactobacillus reuteri. These results suggest that some relatives of L. gasseri also use peptides as desirable nitrogen sources, and that milk may be a good supplier of nutritious

  9. In silico and in vitro studies of cytotoxic activity of different peptides derived from vesicular stomatitis virus G protein

    Directory of Open Access Journals (Sweden)

    Fereshte Ghandehari

    2015-01-01

    Conclusion: The results confirmed that P26 and P7 peptides might induce membrane damage and initiate apoptosis. The present study suggested that P26 and P7 peptides could be appropriate candidates for further studies as cytotoxic agents and modifications in the residue at positions 70-280 might potentially produce a more efficient VSVG protein in gene therapy.

  10. Chloroacetamide-Linked Nucleotides and DNA for Cross-Linking with Peptides and Proteins.

    Science.gov (United States)

    Olszewska, Agata; Pohl, Radek; Brázdová, Marie; Fojta, Miroslav; Hocek, Michal

    2016-09-21

    Nucleotides, 2'-deoxyribonucleoside triphosphates (dNTPs), and DNA probes bearing reactive chloroacetamido group linked to nucleobase (cytosine or 7-deazadaenine) through a propargyl tether were prepared and tested in cross-linking with cysteine- or histidine-containing peptides and proteins. The chloroacetamide-modifed dNTPs proved to be good substrates for DNA polymerases in the enzymatic synthesis of modified DNA probes. Modified nucleotides and DNA reacted efficiently with cysteine and cysteine-containing peptides, whereas the reaction with histidine was sluggish and low yielding. The modified DNA efficiently cross-linked with p53 protein through alkylation of cysteine and showed potential for cross-linking with histidine (in C277H mutant of p53).

  11. Probing Peptide and Protein Insertion in a Biomimetic S-Layer Supported Lipid Membrane Platform

    Directory of Open Access Journals (Sweden)

    Samar Damiati

    2015-01-01

    Full Text Available The most important aspect of synthetic lipid membrane architectures is their ability to study functional membrane-active peptides and membrane proteins in an environment close to nature. Here, we report on the generation and performance of a biomimetic platform, the S-layer supported lipid membrane (SsLM, to investigate the structural and electrical characteristics of the membrane-active peptide gramicidin and the transmembrane protein α-hemolysin in real-time using a quartz crystal microbalance with dissipation monitoring in combination with electrochemical impedance spectroscopy. A shift in membrane resistance is caused by the interaction of α-hemolysin and gramicidin with SsLMs, even if only an attachment onto, or functional channels through the lipid membrane, respectively, are formed. Moreover, the obtained results did not indicate the formation of functional α-hemolysin pores, but evidence for functional incorporation of gramicidin into this biomimetic architecture is provided.

  12. Improved Identification and Relative Quantification of Sites of Peptide and Protein Oxidation for Hydroxyl Radical Footprinting

    Science.gov (United States)

    Li, Xiaoyan; Li, Zixuan; Xie, Boer; Sharp, Joshua S.

    2013-11-01

    Protein oxidation is typically associated with oxidative stress and aging and affects protein function in normal and pathological processes. Additionally, deliberate oxidative labeling is used to probe protein structure and protein-ligand interactions in hydroxyl radical protein footprinting (HRPF). Oxidation often occurs at multiple sites, leading to mixtures of oxidation isomers that differ only by the site of modification. We utilized sets of synthetic, isomeric "oxidized" peptides to test and compare the ability of electron-transfer dissociation (ETD) and collision-induced dissociation (CID), as well as nano-ultra high performance liquid chromatography (nanoUPLC) separation, to quantitate oxidation isomers with one oxidation at multiple adjacent sites in mixtures of peptides. Tandem mass spectrometry by ETD generates fragment ion ratios that accurately report on relative oxidative modification extent on specific sites, regardless of the charge state of the precursor ion. Conversely, CID was found to generate quantitative MS/MS product ions only at the higher precursor charge state. Oxidized isomers having multiple sites of oxidation in each of two peptide sequences in HRPF product of protein Robo-1 Ig1-2, a protein involved in nervous system axon guidance, were also identified and the oxidation extent at each residue was quantified by ETD without prior liquid chromatography (LC) separation. ETD has proven to be a reliable technique for simultaneous identification and relative quantification of a variety of functionally different oxidation isomers, and is a valuable tool for the study of oxidative stress, as well as for improving spatial resolution for HRPF studies.

  13. Anti-peptide aptamers recognize amino acid sequence and bind a protein epitope.

    OpenAIRE

    Xu, W; Ellington, A. D.

    1996-01-01

    In vitro selection of nucleic acid binding species (aptamers) is superficially similar to the immune response. Both processes produce biopolymers that can recognize targets with high affinity and specificity. While antibodies are known to recognize the sequence and conformation of protein surface features (epitopes), very little is known about the precise interactions between aptamers and their epitopes. Therefore, aptamers that could recognize a particular epitope, a peptide fragment of huma...

  14. Magnetic techniques for the isolation and purification of proteins and peptides

    OpenAIRE

    Safarik, Ivo; Safarikova, Mirka

    2004-01-01

    Isolation and separation of specific molecules is used in almost all areas of biosciences and biotechnology. Diverse procedures can be used to achieve this goal. Recently, increased attention has been paid to the development and application of magnetic separation techniques, which employ small magnetic particles. The purpose of this review paper is to summarize various methodologies, strategies and materials which can be used for the isolation and purification of target proteins and peptides ...

  15. Multiple antigen peptide dendrimer elicits antibodies for detecting rat and mouse growth hormone binding proteins

    OpenAIRE

    Aguilar, Roberto M.; Talamantes, Frank J.; Bustamante, Juan J.; Muñoz, Jesus; Treviño, Lisa R.; Martinez, Andrew O.; Haro, Luis S.

    2009-01-01

    The membrane-bound rat growth hormone receptor (GH-R) and an alternatively spliced isoform, the soluble rat GH binding protein (GH-BP), are comprised of identical N-terminal GH binding domains, however, their C-terminal sequences differ. Immunological reagents are needed to distinguish between the two isoforms in order to understand their respective roles in mediating the actions of GH. Accordingly, a tetravalent multiple antigen peptide (MAP) dendrimer with four identical branches of a C-ter...

  16. Distribution of glutamine and asparagine residues and their near neighbors in peptides and proteins.

    OpenAIRE

    Robinson, A. B.; Robinson, L. R.

    1991-01-01

    In a statistical study of neighboring residues in 1465 peptides and proteins comprising 450,431 residues, it was found that the preferences for residues neighboring to glutamine and asparagine residues are consistent with the hypothesis that the rates of deamidation of these residues are of biological significance. Some dipeptide and tripeptide structures have special usefulness and some are especially undesirable. More such structures exist for amide residues than for other residues, and the...

  17. Myelin membrane assembly is driven by a phase transition of myelin basic proteins into a cohesive protein meshwork.

    Science.gov (United States)

    Aggarwal, Shweta; Snaidero, Nicolas; Pähler, Gesa; Frey, Steffen; Sánchez, Paula; Zweckstetter, Markus; Janshoff, Andreas; Schneider, Anja; Weil, Marie-Theres; Schaap, Iwan A T; Görlich, Dirk; Simons, Mikael

    2013-01-01

    Rapid conduction of nerve impulses requires coating of axons by myelin. To function as an electrical insulator, myelin is generated as a tightly packed, lipid-rich multilayered membrane sheath. Knowledge about the mechanisms that govern myelin membrane biogenesis is required to understand myelin disassembly as it occurs in diseases such as multiple sclerosis. Here, we show that myelin basic protein drives myelin biogenesis using weak forces arising from its inherent capacity to phase separate. The association of myelin basic protein molecules to the inner leaflet of the membrane bilayer induces a phase transition into a cohesive mesh-like protein network. The formation of this protein network shares features with amyloid fibril formation. The process is driven by phenylalanine-mediated hydrophobic and amyloid-like interactions that provide the molecular basis for protein extrusion and myelin membrane zippering. These findings uncover a physicochemical mechanism of how a cytosolic protein regulates the morphology of a complex membrane architecture. These results provide a key mechanism in myelin membrane biogenesis with implications for disabling demyelinating diseases of the central nervous system.

  18. Myelin membrane assembly is driven by a phase transition of myelin basic proteins into a cohesive protein meshwork.

    Directory of Open Access Journals (Sweden)

    Shweta Aggarwal

    Full Text Available Rapid conduction of nerve impulses requires coating of axons by myelin. To function as an electrical insulator, myelin is generated as a tightly packed, lipid-rich multilayered membrane sheath. Knowledge about the mechanisms that govern myelin membrane biogenesis is required to understand myelin disassembly as it occurs in diseases such as multiple sclerosis. Here, we show that myelin basic protein drives myelin biogenesis using weak forces arising from its inherent capacity to phase separate. The association of myelin basic protein molecules to the inner leaflet of the membrane bilayer induces a phase transition into a cohesive mesh-like protein network. The formation of this protein network shares features with amyloid fibril formation. The process is driven by phenylalanine-mediated hydrophobic and amyloid-like interactions that provide the molecular basis for protein extrusion and myelin membrane zippering. These findings uncover a physicochemical mechanism of how a cytosolic protein regulates the morphology of a complex membrane architecture. These results provide a key mechanism in myelin membrane biogenesis with implications for disabling demyelinating diseases of the central nervous system.

  19. Comparative mechanisms of protein transduction mediated by cell-penetrating peptides in prokaryotes.

    Science.gov (United States)

    Liu, Betty Revon; Huang, Yue-Wern; Aronstam, Robert S; Lee, Han-Jung

    2015-04-01

    Bacterial and archaeal cell envelopes are complex multilayered barriers that serve to protect these microorganisms from their extremely harsh and often hostile environments. Import of exogenous proteins and nanoparticles into cells is important for biotechnological applications in prokaryotes. In this report, we demonstrate that cell-penetrating peptides (CPPs), both bacteria-expressed nona-arginine peptide (R9) and synthetic R9 (SR9), are able to deliver noncovalently associated proteins or quantum dots into four representative species of prokaryotes: cyanobacteria (Synechocystis sp. PCC 6803), bacteria (Escherichia coli DH5α and Arthrobacter ilicis D-50), and archaea (Thermus aquaticus). Although energy-dependent endocytosis is generally accepted as a hallmark that distinguishes eukaryotes from prokaryotes, cellular uptake of uncomplexed green fluorescent protein (GFP) by cyanobacteria was mediated by classical endocytosis. Mechanistic studies revealed that macropinocytosis plays a critical and major role in CPP-mediated protein transduction in all four prokaryotes. Membrane damage was not observed when cyanobacterial cells were treated with R9/GFP complexes, nor was cytotoxicity detected when bacteria or archaea were treated with SR9/QD complexes in the presence of macropinocytic inhibitors. These results indicate that the uptake of protein is not due to a compromise of membrane integrity in cyanobacteria, and that CPP can be an effective and safe carrier for membrane trafficking in prokaryotic cells. Our investigation provides important new insights into the transport of exogenous proteins and nanoparticles across the complex membrane systems of prokaryotes.

  20. Milk Proteins, Peptides, and Oligosaccharides: Effects against the 21st Century Disorders

    Directory of Open Access Journals (Sweden)

    Chia-Chien Hsieh

    2015-01-01

    Full Text Available Milk is the most complete food for mammals, as it supplies all the energy and nutrients needed for the proper growth and development of the neonate. Milk is a source of many bioactive components, which not only help meeting the nutritional requirements of the consumers, but also play a relevant role in preventing various disorders. Milk-derived proteins and peptides have the potential to act as coadjuvants in conventional therapies, addressing cardiovascular diseases, metabolic disorders, intestinal health, and chemopreventive properties. In addition to being a source of proteins and peptides, milk contains complex oligosaccharides that possess important functions related to the newborn’s development and health. Some of the health benefits attributed to milk oligosaccharides include prebiotic probifidogenic effects, antiadherence of pathogenic bacteria, and immunomodulation. This review focuses on recent findings demonstrating the biological activities of milk peptides, proteins, and oligosaccharides towards the prevention of diseases of the 21st century. Processing challenges hindering large-scale production and commercialization of those bioactive compounds have been also addressed.

  1. Effects of diethyldithiocarbamate on myelin basic protein expression in the rat lateral olfactory tract

    Institute of Scientific and Technical Information of China (English)

    Kun Xiong; He Huang; Hui Wang; Yan Cai; Jing Yang; Jufang Huang; Xuegang Luo

    2009-01-01

    BACKGROUND: Dithiocarbamates can cause demyelination of axons in the peripheral nervous system. Its derivate, diethyldithiocarbamate, is cytotoxic, and causes olfactory mucosal damage and atrophy of the olfactory bulb. However, it is still unclear whether the myelin sheath of the lateral olfactory tract is affected by diethyldithiocarbamate.OBJECTIVE: To investigate the effects of diethyldithiocarbamate on the myelin sheath of the rat lateral olfactory tract. This was done by examining changes in myelin basic protein expression after diethyldithiocarbamate treatment.DESIGN, TIME AND SETTING: A randomized, controlled, animal study was performed at the Laboratory of the Department of Human Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, China from July to November 2007.MATERIALS: A total of 72 Sprague Dawley rats were randomly assigned into a diethyldithiocarbamate group (n=32), a solvent control group (n=32), and a blank control group (n=8). The diethyldithiocarbamate and solvent control groups were separately divided into 3-d, 7-d, 14-d and 28-d survival subgroups, with eight rats in each. Diethyldithiocarbamate (Sigma, USA) and goat anti-myelin basic protein polyclonal antibody (Santa Cruz, USA) were used in this study.METHODS: Rats in the diethyldithiocarbamate and solvent control groups were subcutaneously injected with diethyldithiocarbamate (600 mg/kg) and 0.01 mol/L phosphate buffered saline (600 mg/kg) at the posterior neck, respectively. Rats in the blank control group received no treatment.MAIN OUTCOME MEASURES: Immunohistochemical staining and Western blot assay were used to measure myelin basic protein expression in the rat lateral olfactory tract.RESULTS: Following immunohistochemical staining, myelin basic protein was uniformly distributed in the rat lateral olfactory tract in the blank control and solvent control groups. Western blot assay showed 21.5, 18, 17 and 14 ku positive bands. No significant difference was found

  2. Reverse-phase HPLC separation of hemp seed (Cannabis sativa L.) protein hydrolysate produced peptide fractions with enhanced antioxidant capacity.

    Science.gov (United States)

    Girgih, Abraham T; Udenigwe, Chibuike C; Aluko, Rotimi E

    2013-03-01

    Hemp seed protein hydrolysate (HPH) was produced through simulated gastrointestinal tract (GIT) digestion of hemp seed protein isolate followed by partial purification and separation into eight peptide fractions by reverse-phase (RP)-HPLC. The peptide fractions exhibited higher oxygen radical absorbance capacity as well as scavenging of 2,2-diphenyl-1-picrylhydrazyl, superoxide and hydroxyl radicals when compared to HPH. Radical scavenging activities of the fractionated peptides increased as content of hydrophobic amino acids or elution time was increased, with the exception of hydroxyl radical scavenging that showed decreased trend. Glutathione (GSH), HPH and the RP-HPLC peptide fractions possessed low ferric ion reducing ability but all had strong (>60 %) metal chelating activities. Inhibition of linoleic acid oxidation by some of the HPH peptide fractions was higher at 1 mg/ml when compared to that observed at 0.1 mg/ml peptide concentration. Peptide separation resulted in higher concentration of some hydrophobic amino acids (especially proline, leucine and isoleucine) in the fractions (mainly F5 and F8) when compared to HPH. The elution time-dependent increased concentrations of the hydrophobic amino acids coupled with decreased levels of positively charged amino acids may have been responsible for the significantly higher (p < 0.05) antioxidant properties observed for some of the peptide fractions when compared to the unfractionated HPH. In conclusion, the antioxidant activity of HPH after simulated GIT digestion is mainly influenced by the amino acid composition of some of its peptides.

  3. Targeting diverse protein–protein interaction interfaces with α/β-peptides derived from the Z-domain scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Checco, James W.; Kreitler, Dale F.; Thomas, Nicole C.; Belair, David G.; Rettko, Nicholas J.; Murphy, William L.; Forest, Katrina T.; Gellman, Samuel H. (UW)

    2015-04-14

    Peptide-based agents derived from well-defined scaffolds offer an alternative to antibodies for selective and high-affinity recognition of large and topologically complex protein surfaces. Here, we describe a strategy for designing oligomers containing both α- and β-amino acid residues ("α/β-peptides") that mimic several peptides derived from the three-helix bundle "Z-domain" scaffold. We show that α/β-peptides derived from a Z-domain peptide targeting vascular endothelial growth factor (VEGF) can structurally and functionally mimic the binding surface of the parent peptide while exhibiting significantly decreased susceptibility to proteolysis. The tightest VEGF-binding α/β-peptide inhibits the VEGF₁₆₅-induced proliferation of human umbilical vein endothelial cells. We demonstrate the versatility of this strategy by showing how principles underlying VEGF signaling inhibitors can be rapidly extended to produce Z-domain–mimetic α/β-peptides that bind to two other protein partners, IgG and tumor necrosis factor-α. Because well-established selection techniques can identify high-affinity Z-domain derivatives from large DNA-encoded libraries, our findings should enable the design of biostable α/β-peptides that bind tightly and specifically to diverse targets of biomedical interest. Such reagents would be useful for diagnostic and therapeutic applications.

  4. Engineering and Characterization of Peptides and Proteins at Surfaces and Interfaces: A Case Study in Surface-Sensitive Vibrational Spectroscopy.

    Science.gov (United States)

    Ding, Bei; Jasensky, Joshua; Li, Yaoxin; Chen, Zhan

    2016-06-21

    Understanding molecular structures of interfacial peptides and proteins impacts many research fields by guiding the advancement of biocompatible materials, new and improved marine antifouling coatings, ultrasensitive and highly specific biosensors and biochips, therapies for diseases related to protein amyloid formation, and knowledge on mechanisms for various membrane proteins and their interactions with ligands. Developing methods for measuring such unique systems, as well as elucidating the structure and function relationship of such biomolecules, has been the goal of our lab at the University of Michigan. We have made substantial progress to develop sum frequency generation (SFG) vibrational spectroscopy into a powerful technique to study interfacial peptides and proteins, which lays a foundation to obtain unique and valuable insights when using SFG to probe various biologically relevant systems at the solid/liquid interface in situ in real time. One highlighting feature of this Account is the demonstration of the power of combining SFG with other techniques and methods such as ATR-FTIR, surface engineering, MD simulation, liquid crystal sensing, and isotope labeling in order to study peptides and proteins at interfaces. It is necessary to emphasize that SFG plays a major role in these studies, while other techniques and methods are supplemental. The central role of SFG is to provide critical information on interfacial peptide and protein structure (e.g., conformation and orientation) in order to elucidate how surface engineering (e.g., to vary the structure) can ultimately affect surface function (e.g., to optimize the activity). This Account focuses on the most significant recent progress in research on interfacial peptides and proteins carried out by our group including (1) the development of SFG analysis methods to determine orientations of regular as well as disrupted secondary structures, and the successful demonstration and application of an isotope

  5. Viral replication modulated by synthetic peptide derived from hepatitis B virus X protein

    Institute of Scientific and Technical Information of China (English)

    Chang-Zheng Song; Qing-Wei Wang; Chang-Cheng Song; Zeng-Liang Bai

    2004-01-01

    AIM: A strategy for viral vaccine design is the use of conserved peptides to overcome the problem of sequence diversity. At present it is still unclear whether conserved peptide is safe as a candidate vaccine. We reported it here for the first time not only to highlight the biohazard issue and safety importance for viral peptide vaccine, but also to explore the effect of a fully conserved peptide on HBV replication within the carboxyl terminus of HBx.METHODS: We synthesized the fully conserved peptide (CP)with nine residues, FVLGGCRHK. HBV-producing 2.2.15 cells were treated with or without 3.5 μM CP for 36 hours.Quantitative detection of viral DNA was performed by realtime PCR. HBV antigens were determined by enzyme-linked immunoadsorbent assay (ELISA). Quantitative analyses of p53 and Bax proteins were based on immunofluorescence.Flow cytometry was performed to detect cell cycle and apoptosis.RESULTS: Both extracellular and intracellular copies of HBV DNA per ml were significantly increased atter incubation with 3.5 μM of CP. HBsAg and HBeAg in the cultured medium of CP-treatment cells were as abundant as untreated control cells. CP infiuenced negatively the extracellular viral gene products, and 3.5 μM CP could significantly inhibit intracellular HBsAg expression. In response to CP, intracellular HBeAg displayed an opposite pattern to that of HBsAg, and 3.5 μM CP could efficiently increase the level of intracellular HBeAg.Flow cytometric analyses exhibited no significant changes on cell cycle, apoptosis, p53 and Bax proteins in 2.2.15 cells with or without CP.CONCLUSION: Together with the resulte generated from the synthetic peptide, we address that the conserved region,a domain of HBx, may be responsible for modulating HBV replication. As conserved peptides from infectious microbes are used as immunogens to elicit immune responses, their latent biological hazard for human beings should be evaluated.

  6. Viroporin potential of the lentivirus lytic peptide (LLP domains of the HIV-1 gp41 protein

    Directory of Open Access Journals (Sweden)

    Garry Robert F

    2007-11-01

    Full Text Available Abstract Background Mechanisms by which HIV-1 mediates reductions in CD4+ cell levels in infected persons are being intensely investigated, and have broad implications for AIDS drug and vaccine development. Virally induced changes in membrane ionic permeability induced by lytic viruses of many families contribute to cytopathogenesis. HIV-1 induces disturbances in plasma membrane ion transport. The carboxyl terminus of TM (gp41 contains potential amphipathic α-helical motifs identified through their structural similarities to naturally occurring cytolytic peptides. These sequences have been dubbed lentiviral lytic peptides (LLP -1, -2, and -3. Results Peptides corresponding to the LLP domains (from a clade B virus partition into lipid membranes, fold into α-helices and disrupt model membrane permeability. A peptide corresponding to the LLP-1 domain of a clade D HIV-1 virus, LLP-1D displayed similar activity to the LLP-1 domain of the clade B virus in all assays, despite a lack of amino acid sequence identity. Conclusion These results suggest that the C-terminal domains of HIV-1 Env proteins may form an ion channel, or viroporin. Increased understanding of the function of LLP domains and their role in the viral replication cycle could allow for the development of novel HIV drugs.

  7. Acidity-Mediated, Electrostatic Tuning of Asymmetrically Charged Peptides Interactions with Protein Nanopores.

    Science.gov (United States)

    Asandei, Alina; Chinappi, Mauro; Kang, Hee-Kyoung; Seo, Chang Ho; Mereuta, Loredana; Park, Yoonkyung; Luchian, Tudor

    2015-08-01

    Despite success in probing chemical reactions and dynamics of macromolecules on submillisecond time and nanometer length scales, a major impasse faced by nanopore technology is the need to cheaply and controllably modulate macromolecule capture and trafficking across the nanopore. We demonstrate herein that tunable charge separation engineered at the both ends of a macromolecule very efficiently modulates the dynamics of macromolecules capture and traffic through a nanometer-size pore. In the proof-of-principle approach, we employed a 36 amino acids long peptide containing at the N- and C-termini uniform patches of glutamic acids and arginines, flanking a central segment of asparagines, and we studied its capture by the α-hemolysin (α-HL) and the mean residence time inside the pore in the presence of a pH gradient across the protein. We propose a solution to effectively control the dynamics of peptide interaction with the nanopore, with both association and dissociation reaction rates of peptide-α-HL interactions spanning orders of magnitude depending upon solution acidity on the peptide addition side and the transmembrane electric potential, while preserving the amplitude of the blockade current signature. PMID:26144534

  8. Towards rice bran protein utilization: In silico insight on the role of oryzacystatins in biologically-active peptide production.

    Science.gov (United States)

    Udenigwe, Chibuike C

    2016-01-15

    Rice bran proteins (RBP) have been demonstrated to harbour biologically active peptides, which can be released by proteases and applied in human health promotion. In this study, the roles of rice bran cysteine protease inhibitors, oryzacystatins, were considered for efficient production of bioactive peptides from RBP. In silico evidence demonstrates that aspartate protease (pepsin at pH>2) and metalloproteinase (thermolysin) have strong prospects for use in simultaneously cleaving the QXVXGX motif of oryzacystatins, which can lead to their inactivation, and in releasing bioactive sequences from the protease inhibitors. The cleaved bioactive peptides are known to possess activities that can be applied in the management of hypertension, oxidative stress, type 2 diabetes mellitus and other aberrant cellular processes. Moreover, several potentially bioactive di- and tripeptides were identified in oryzacystatin peptide pools. This study provides an important consideration and a direction that can lead to efficient release of bioactive peptides from rice bran proteins for functional food applications. PMID:26258712

  9. Biotechnological Fluorescent Ligands of the Bradykinin B1 Receptor: Protein Ligands for a Peptide Receptor.

    Directory of Open Access Journals (Sweden)

    Xavier Charest-Morin

    Full Text Available The bradykinin (BK B1 receptor (B1R is a peculiar G protein coupled receptor that is strongly regulated to the point of being inducible in immunopathology. Limited clinical evidence suggests that its expression in peripheral blood mononuclear cells is a biomarker of active inflammatory states. In an effort to develop a novel imaging/diagnostic tool, we report the rational design and testing of a fusion protein that is a ligand of the human B1R but not likely to label peptidases. This ligand is composed of a fluorescent protein (FP (enhanced green FP [EGFP] or mCherry prolonged at its N-terminus by a spacer peptide and a classical peptide agonist or antagonist (des-Arg9-BK, [Leu8]des-Arg9-BK, respectively. The design of the spacer-ligand joint peptide was validated by a competition assay for [3H]Lys-des-Arg9-BK binding to the human B1R applied to 4 synthetic peptides of 18 or 19 residues. The labeling of B1R-expressing cells with EGFP or mCherry fused with 7 of such peptides was performed in parallel (microscopy. Both assays indicated that the best design was FP-(Asn-Glyn-Lys-des-Arg9-BK; n = 15 was superior to n = 5, suggesting benefits from minimizing steric hindrance between the FP and the receptor. Cell labeling concerned mostly plasma membranes and was inhibited by a B1R antagonist. EGFP-(Asn-Gly15-Lys-des-Arg9-BK competed for the binding of [3H]Lys-des-Arg9-BK to human recombinant B1R, being only 10-fold less potent than the unlabeled form of Lys-des-Arg9-BK to do so. The fusion protein did not label HEK 293a cells expressing recombinant human BK B2 receptors or angiotensin converting enzyme. This study identifies a modular C-terminal sequence that can be adapted to protein cargoes, conferring high affinity for the BK B1R, with possible applications in diagnostic cytofluorometry, histology and drug delivery (e.g., in oncology.

  10. Antioxidant and ACE Inhibitory Bioactive Peptides Purified from Egg Yolk Proteins

    Directory of Open Access Journals (Sweden)

    Marwa Yousr

    2015-12-01

    Full Text Available Protein by-products from the extraction of lecithin from egg yolk can be converted into value-added products, such as bioactive hydrolysates and peptides that have potential health enhancing antioxidant, and antihypertensive properties. In this study, the antioxidant and angiotensin converting enzyme (ACE inhibitory activities of peptides isolated and purified from egg yolk protein were investigated. Defatted egg yolk was hydrolyzed using pepsin and pancreatin and sequentially fractionated by ultrafiltration, followed by gel filtration to produce egg yolk gel filtration fractions (EYGF. Of these, two fractions, EYGF-23 and EYGF-33, effectively inhibited the peroxides and thiobarbituric acid reactive substance (TBARS in an oxidizing linoleic acid model system. The antioxidant mechanism involved superoxide anion and hydroxyl radicals scavenging and ferrous chelation. The presence of hydrophobic amino acids such as tyrosine (Y and tryptophan (W, in sequences identified by LC-MS as WYGPD (EYGF-23 and KLSDW (EYGF-33, contributed to the antioxidant activity and were not significantly different from the synthetic BHA antioxidant. A third fraction (EYGF-56 was also purified from egg yolk protein by gel filtration and exhibited high ACE inhibitory activity (69% and IC50 value (3.35 mg/mL. The SDNRNQGY peptide (10 mg/mL had ACE inhibitory activity, which was not significantly different from that of the positive control captopril (0.5 mg/mL. In addition, YPSPV in (EYGF-33 (10 mg/mL had higher ACE inhibitory activity compared with captopril. These findings indicated a substantial potential for producing valuable peptides with antioxidant and ACE inhibitory activity from egg yolk.

  11. Combinatorial peptide ligand libraries for the analysis of low-expression proteins: Validation for normal urine and definition of a first protein MAP.

    Science.gov (United States)

    Santucci, Laura; Candiano, Giovanni; Bruschi, Maurizio; D'Ambrosio, Chiara; Petretto, Andrea; Scaloni, Andrea; Urbani, Andrea; Righetti, Pier G; Ghiggeri, Gian M

    2012-02-01

    In this review, we report the evolution on experimental conditions for the analysis of normal urine based on combinatorial peptide ligand library (CPLL) treatment and successive 2-DE and 2-DE/MS analysis. The main topics are (i) definition of the urine sample requirements, (ii) optimization of the urine/ligand ratio, (iii) essay conditions, (iv) en bloc elution. Overall, normal urine protein composition as studied by 2-DE includes over 2600 spots. Relevant data on inter and intraessay reproducibility obtained by the analysis of different normal urines repeated several times are also here presented. We found a 73% reproducibility upon analysis of the same sample and 68% correspondence of protein composition among different normal urine samples. Based on the above results, we are completing the characterization with LC-MS of 249 spots. The composition of normal urine proteins after CPLLs is finally shown with the indication of those spots which are currently under identification. This map will be completed in a near future; in the meantime this would represent the basic reference sample for newly developed studies on human diseases. PMID:22246922

  12. Multiple sclerosis autoantigen myelin basic protein escapes control by ubiquitination during proteasomal degradation.

    Science.gov (United States)

    Belogurov, Alexey; Kudriaeva, Anna; Kuzina, Ekaterina; Smirnov, Ivan; Bobik, Tatyana; Ponomarenko, Natalia; Kravtsova-Ivantsiv, Yelena; Ciechanover, Aaron; Gabibov, Alexander

    2014-06-20

    The vast majority of cellular proteins are degraded by the 26S proteasome after their ubiquitination. Here, we report that the major component of the myelin multilayered membrane sheath, myelin basic protein (MBP), is hydrolyzed by the 26S proteasome in a ubiquitin-independent manner both in vitro and in mammalian cells. As a proteasomal substrate, MBP reveals a distinct and physiologically relevant concentration range for ubiquitin-independent proteolysis. Enzymatic deimination prevents hydrolysis of MBP by the proteasome, suggesting that an abnormally basic charge contributes to its susceptibility toward proteasome-mediated degradation. To our knowledge, our data reveal the first case of a pathophysiologically important autoantigen as a ubiquitin-independent substrate of the 26S proteasome.

  13. Peptide Vocabulary Analysis Reveals Ultra-Conservation and Homonymity in Protein Sequences

    Directory of Open Access Journals (Sweden)

    Derek Gatherer

    2007-01-01

    Full Text Available A new algorithm is presented for vocabulary analysis (word detection in texts of human origin. It performs at 60%–70% overall accuracy and greater than 80% accuracy for longer words, and approximately 85% sensitivity on Alice in Wonderland, a considerable improvement on previous methods. When applied to protein sequences, it detects short sequences analogous to words in human texts, i.e. intolerant to changes in spelling (mutation, and relatively contextindependent in their meaning (function. Some of these are homonyms of up to 7 amino acids, which can assume different structures in different proteins. Others are ultra-conserved stretches of up to 18 amino acids within proteins of less than 40% overall identity, reflecting extreme constraint or convergent evolution. Different species are found to have qualitatively different major peptide vocabularies, e.g. some are dominated by large gene families, while others are rich in simple repeats or dominated by internally repetitive proteins. This suggests the possibility of a peptide vocabulary signature, analogous to genome signatures in DNA. Homonyms may be useful in detecting convergent evolution and positive selection in protein evolution. Ultra-conserved words may be useful in identifying structures intolerant to substitution over long periods of evolutionary time.

  14. Electrospray-assisted laser desorption/ionization and tandem mass spectrometry of peptides and proteins.

    Science.gov (United States)

    Peng, Ivory X; Shiea, Jentaie; Ogorzalek Loo, Rachel R; Loo, Joseph A

    2007-01-01

    We have constructed an electrospray-assisted laser desorption/ionization (ELDI) source which utilizes a nitrogen laser pulse to desorb intact molecules from matrix-containing sample solution droplets, followed by electrospray ionization (ESI) post-ionization. The ELDI source is coupled to a quadrupole ion trap mass spectrometer and allows sampling under ambient conditions. Preliminary data showed that ELDI produces ESI-like multiply charged peptides and proteins up to 29 kDa carbonic anhydrase and 66 kDa bovine albumin from single-protein solutions, as well as from complex digest mixtures. The generated multiply charged polypeptides enable efficient tandem mass spectrometric (MS/MS)-based peptide sequencing. ELDI-MS/MS of protein digests and small intact proteins was performed both by collisionally activated dissociation (CAD) and by nozzle-skimmer dissociation (NSD). ELDI-MS/MS may be a useful tool for protein sequencing analysis and top-down proteomics study, and may complement matrix-assisted laser desorption/ionization (MALDI)-based measurements. PMID:17639579

  15. Adrenomedullin promotes differentiation of oligodendrocyte precursor cells into myelin-basic-protein expressing oligodendrocytes under pathological conditions in vitro.

    Science.gov (United States)

    Maki, Takakuni; Takahashi, Yoko; Miyamoto, Nobukazu; Liang, Anna C; Ihara, Masafumi; Lo, Eng H; Arai, Ken

    2015-07-01

    Oligodendrocytes, which are the main cell type in cerebral white matter, are generated from their precursor cells (oligodendrocyte precursor cells: OPCs). However, the differentiation from OPCs to oligodendrocytes is disturbed under stressed conditions. Therefore, drugs that can improve oligodendrocyte regeneration may be effective for white matter-related diseases. Here we show that a vasoactive peptide adrenomedullin (AM) promotes the in vitro differentiation of OPCs under pathological conditions. Primary OPCs were prepared from neonatal rat brains, and differentiated into myelin-basic-protein expressing oligodendrocytes over time. This in vitro OPC differentiation was inhibited by prolonged chemical hypoxic stress induced by non-lethal CoCl(2) treatment. However, AM promoted the OPC differentiation under the hypoxic stress conditions, and the AM receptor antagonist AM(22-52) canceled the AM-induced OPC differentiation. In addition, AM treatment increased the phosphorylation level of Akt in OPC cultures, and correspondingly, the PI3K/Akt inhibitor LY294002 blocked the AM-induced OPC differentiation. Taken together, AM treatment rescued OPC maturation under pathological conditions via an AM-receptor-PI3K/Akt pathway. Oligodendrocytes play critical roles in white matter by forming myelin sheath. Therefore, AM signaling may be a promising therapeutic target to boost oligodendrocyte regeneration in CNS disorders.

  16. Adrenomedullin promotes differentiation of oligodendrocyte precursor cells into myelin-basic-protein expressing oligodendrocytes under pathological conditions in vitro

    Directory of Open Access Journals (Sweden)

    Takakuni Maki

    2015-07-01

    Full Text Available Oligodendrocytes, which are the main cell type in cerebral white matter, are generated from their precursor cells (oligodendrocyte precursor cells: OPCs. However, the differentiation from OPCs to oligodendrocytes is disturbed under stressed conditions. Therefore, drugs that can improve oligodendrocyte regeneration may be effective for white matter-related diseases. Here we show that a vasoactive peptide adrenomedullin (AM promotes the in vitro differentiation of OPCs under pathological conditions. Primary OPCs were prepared from neonatal rat brains, and differentiated into myelin-basic-protein expressing oligodendrocytes over time. This in vitro OPC differentiation was inhibited by prolonged chemical hypoxic stress induced by non-lethal CoCl2 treatment. However, AM promoted the OPC differentiation under the hypoxic stress conditions, and the AM receptor antagonist AM22–52 canceled the AM-induced OPC differentiation. In addition, AM treatment increased the phosphorylation level of Akt in OPC cultures, and correspondingly, the PI3K/Akt inhibitor LY294002 blocked the AM-induced OPC differentiation. Taken together, AM treatment rescued OPC maturation under pathological conditions via an AM-receptor-PI3K/Akt pathway. Oligodendrocytes play critical roles in white matter by forming myelin sheath. Therefore, AM signaling may be a promising therapeutic target to boost oligodendrocyte regeneration in CNS disorders.

  17. Adrenomedullin promotes differentiation of oligodendrocyte precursor cells into myelin-basic-protein expressing oligodendrocytes under pathological conditions in vitro.

    Science.gov (United States)

    Maki, Takakuni; Takahashi, Yoko; Miyamoto, Nobukazu; Liang, Anna C; Ihara, Masafumi; Lo, Eng H; Arai, Ken

    2015-07-01

    Oligodendrocytes, which are the main cell type in cerebral white matter, are generated from their precursor cells (oligodendrocyte precursor cells: OPCs). However, the differentiation from OPCs to oligodendrocytes is disturbed under stressed conditions. Therefore, drugs that can improve oligodendrocyte regeneration may be effective for white matter-related diseases. Here we show that a vasoactive peptide adrenomedullin (AM) promotes the in vitro differentiation of OPCs under pathological conditions. Primary OPCs were prepared from neonatal rat brains, and differentiated into myelin-basic-protein expressing oligodendrocytes over time. This in vitro OPC differentiation was inhibited by prolonged chemical hypoxic stress induced by non-lethal CoCl(2) treatment. However, AM promoted the OPC differentiation under the hypoxic stress conditions, and the AM receptor antagonist AM(22-52) canceled the AM-induced OPC differentiation. In addition, AM treatment increased the phosphorylation level of Akt in OPC cultures, and correspondingly, the PI3K/Akt inhibitor LY294002 blocked the AM-induced OPC differentiation. Taken together, AM treatment rescued OPC maturation under pathological conditions via an AM-receptor-PI3K/Akt pathway. Oligodendrocytes play critical roles in white matter by forming myelin sheath. Therefore, AM signaling may be a promising therapeutic target to boost oligodendrocyte regeneration in CNS disorders. PMID:26002630

  18. Computational Methods for Protein Structure Prediction and Modeling Volume 1: Basic Characterization

    CERN Document Server

    Xu, Ying; Liang, Jie

    2007-01-01

    Volume one of this two volume sequence focuses on the basic characterization of known protein structures as well as structure prediction from protein sequence information. The 11 chapters provide an overview of the field, covering key topics in modeling, force fields, classification, computational methods, and struture prediction. Each chapter is a self contained review designed to cover (1) definition of the problem and an historical perspective, (2) mathematical or computational formulation of the problem, (3) computational methods and algorithms, (4) performance results, (5) existing software packages, and (6) strengths, pitfalls, challenges, and future research directions.

  19. Myelin basic protein reduces molecular motions in DMPA, an elastic neutron scattering study

    Science.gov (United States)

    Natali, F.; Gliozzi, A.; Rolandi, R.; Cavatorta, P.; Deriu, A.; Fasano, A.; Riccio, P.

    2001-07-01

    We have studied the effect of physiological amounts of myelin basic protein (MBP) on pure dimyristoyl L- α-phosphatidic acid (DMPA) vesicles using the elastic neutron scattering technique. Elastic scans have been performed in a wide temperature range (20-300 K). In the lower temperature region the behaviour of the integrated elastic intensity was the typical one of harmonic systems. The analysis of the Q and T dependence performed in terms of an asymmetric double well potential clearly showed that the effect of the protein consisted in a significant reduction of the conformational mobility of the DMPA bilayers and in the stabilisation of the membrane.

  20. Myelin basic protein synthesis is regulated by small non-coding RNA 715.

    Science.gov (United States)

    Bauer, Nina M; Moos, Christina; van Horssen, Jack; Witte, Maarten; van der Valk, Paul; Altenhein, Benjamin; Luhmann, Heiko J; White, Robin

    2012-09-01

    Oligodendroglial Myelin Basic Protein (MBP) synthesis is essential for myelin formation in the central nervous system. During oligodendrocyte differentiation, MBP mRNA is kept in a translationally silenced state while intracellularly transported, until neuron-derived signals initiate localized MBP translation. Here we identify the small non-coding RNA 715 (sncRNA715) as an inhibitor of MBP translation. SncRNA715 localizes to cytoplasmic granular structures and associates with MBP mRNA transport granule components. We also detect increased levels of sncRNA715 in demyelinated chronic human multiple sclerosis lesions, which contain MBP mRNA but lack MBP protein.

  1. Hematopoietic progenitors express myelin basic protein and ensheath axons in Shiverer brain.

    Science.gov (United States)

    Goolsby, James; Makar, Tapas; Dhib-Jalbut, Suhayl; Bever, Christopher T; Pessac, Bernard; Trisler, David

    2013-04-15

    Oligodendroglia are cells of the central nervous system (CNS) that form myelin sheath, which insulates neuronal axons. Neuropathologies of the CNS include dysmyelination of axons in multiple sclerosis and CNS trauma. Cell replacement is a promising but largely untested therapy for dysmyelination. Shiverer mouse, a genetic mutant that does not synthesize full-length myelin basic protein (MBP), a critical prerequisite protein in CNS myelin sheath formation, provides an unequivocal model for determining the potential of stem cells to become oligodendroglia. We demonstrate that adult wild-type mouse bone marrow stem cells can express MBP and ensheath axons when transplanted into Shiverer brain.

  2. Circulating antibody to myelin basic protein in relapsing-remitting multiple sclerosis

    International Nuclear Information System (INIS)

    Sera from multiple sclerosis patients with relapsing-remitting disease and normal subjects were tested for antibody to myelin basic protein by a sensitive radioimmunoassay. The results showed a marginally decreased titre in multiple sclerosis superimposed on a seasonal variation. There was no correlation with the clinical state of the patients. Results are discussed briefly in relation to humoral antibody function in multiple sclerosis and experimental autoimmune encephalitis. (author)

  3. Designed armadillo repeat proteins as general peptide-binding scaffolds: consensus design and computational optimization of the hydrophobic core

    DEFF Research Database (Denmark)

    Parmeggiani, Fabio; Pellarin, Riccardo; Larsen, Anders Peter;

    2007-01-01

    Armadillo repeat proteins are abundant eukaryotic proteins involved in several cellular processes, including signaling, transport, and cytoskeletal regulation. They are characterized by an armadillo domain, composed of tandem armadillo repeats of approximately 42 amino acids, which mediates...... interactions with peptides or parts of proteins in extended conformation. The conserved binding mode of the peptide in extended form, observed for different targets, makes armadillo repeat proteins attractive candidates for the generation of modular peptide-binding scaffolds. Taking advantage of the large...... number of repeat sequences available, a consensus-based approach combined with a force field-based optimization of the hydrophobic core was used to derive soluble, highly expressed, stable, monomeric designed proteins with improved characteristics compared to natural armadillo proteins. These sequences...

  4. Myelin basic protein induces neuron-specific toxicity by directly damaging the neuronal plasma membrane.

    Directory of Open Access Journals (Sweden)

    Jie Zhang

    Full Text Available The central nervous system (CNS insults may cause massive demyelination and lead to the release of myelin-associated proteins including its major component myelin basic protein (MBP. MBP is reported to induce glial activation but its effect on neurons is still little known. Here we found that MBP specifically bound to the extracellular surface of the neuronal plasma membrane and induced neurotoxicity in vitro. This effect of MBP on neurons was basicity-dependent because the binding was blocked by acidic lipids and competed by other basic proteins. Further studies revealed that MBP induced damage to neuronal membrane integrity and function by depolarizing the resting membrane potential, increasing the permeability to cations and other molecules, and decreasing the membrane fluidity. At last, artificial liposome vesicle assay showed that MBP directly disturbed acidic lipid bilayer and resulted in increased membrane permeability. These results revealed that MBP induces neurotoxicity through its direct interaction with acidic components on the extracellular surface of neuronal membrane, which may suggest a possible contribution of MBP to the pathogenesis in the CNS disorders with myelin damage.

  5. Peptide-based Biopolymers in Biomedicine and Biotechnology

    Science.gov (United States)

    Chow, Dominic; Nunalee, Michelle L.; Lim, Dong Woo; Simnick, Andrew J.; Chilkoti, Ashutosh

    2008-01-01

    Peptides are emerging as a new class of biomaterials due to their unique chemical, physical, and biological properties. The development of peptide-based biomaterials is driven by the convergence of protein engineering and macromolecular self-assembly. This review covers the basic principles, applications, and prospects of peptide-based biomaterials. We focus on both chemically synthesized and genetically encoded peptides, including poly-amino acids, elastin-like polypeptides, silk-like polymers and other biopolymers based on repetitive peptide motifs. Applications of these engineered biomolecules in protein purification, controlled drug delivery, tissue engineering, and biosurface engineering are discussed. PMID:19122836

  6. Recent Research in Antihypertensive Activity of Food Protein-derived Hydrolyzates and Peptides.

    Science.gov (United States)

    Saleh, Ahmed S M; Zhang, Qing; Shen, Qun

    2016-04-01

    Year to year obesity prevalence, reduced physical activities, bad habits/or stressful lifestyle, and other environmental and physiological impacts lead to increase in diseases such as coronary heart disease, stroke, cancer, diabetes, and hypertension worldwide. Hypertension is considered as one of the most common serious chronic diseases; however, discovery of medications with high efficacy and without side effects for treatment of patients remains a challenge for scientists. Recent trends in functional foods have evidenced that food bioactive proteins play a major role in the concepts of illness and curing; therefore, nutritionists, biomedical scientists, and food scientists are working together to develop improved systems for the discovery of peptides with increased potency and therapeutic benefits. This review presents a recent research carried out to date for the purpose of isolation and identification of bioactive hydrolyzates and peptides with angiotensin I converting enzyme inhibitory activity and antihypertensive effect from animal, marine, microbial, and plant food proteins. Effects of food processing and hydrolyzation conditions as well as some other impacts on formation, activity, and stability of these hydrolyzates and peptides are also presented. PMID:25036695

  7. Comparison of Functional Protein Transduction Domains Using the NEMO Binding Domain Peptide

    Directory of Open Access Journals (Sweden)

    Paul Robbins

    2010-01-01

    Full Text Available Protein transduction domains (PTDs, both naturally occurring and synthetic, have been extensively utilized for intracellular delivery of biologically active molecules both in vitro and in vivo. However, most comparisons of transduction efficiency have been performed using fluorescent markers. To compare efficiency of functional protein transduction, a peptide derived from IkB kinase ß (IKKß that prevents formation of an active IKK complex was used as a biologically active cargo. This peptide, termed NEMO Binding Domain (NBD, is able to block activation of the transcriptional factor NF-κB by IKK, but not basal NF-κB activity. Our results demonstrate that Antp and Tat PTDs were most effective for delivery of NBD for inhibition of NF-kB activation compared to other PTD-NBD in both Hela and 293 cells, however, at higher concentrations (100 µM, the Antp-NBD as well as the FGF-NBD peptide caused significant cellular toxicity. In contrast to the cell culture results, delivery of NBD using 8K (octalysine and 6R (six arginine were the most effect in blocking inflammation following local, footpad delivery in a KLH-induced DTH murine model of inflammatory arthritis. These results demonstrate differences between PTDs for delivery of a functional cargo between cell types.

  8. Isolation and identification of antioxidant peptides from enzymatically hydrolyzed rice bran protein.

    Science.gov (United States)

    Wattanasiritham, Ladda; Theerakulkait, Chockchai; Wickramasekara, Samanthi; Maier, Claudia S; Stevens, Jan F

    2016-02-01

    Khao Dawk Mali 105 rice bran protein (RBP) was fractionated into albumin (12.5%), globulin (13.9%), glutelin (70.8%) and prolamine (2.9%). The native and denatured RBP fractions were hydrolyzed with papain and trypsin for 3h at optimum conditions. The RBP fractions and their hydrolysates were evaluated for their antioxidant activity by the Oxygen Radical Absorbance Capacity (ORAC) assay. The trypsin-hydrolyzed denatured albumin exhibited the highest antioxidant activity with an ORAC value of 4.07 μmol of Trolox equivalent (TE)/mg protein. This hydrolysate was separated by using RP-HPLC and three fractions with high antioxidant activity were examined by LTQ-FTICR ESI mass spectrometry. The MW of the peptides from these fractions were 800-2100 Da. and consisted of 6-21 amino acid residues. Most of the peptides from the fractions demonstrated typical characteristics of well-known antioxidant peptides. The results suggest that trypsin-hydrolyzed denatured rice bran albumin might be useful as a natural food antioxidant. PMID:26304333

  9. Identification of the bioactive and consensus peptide motif from Momordica charantia insulin receptor-binding protein.

    Science.gov (United States)

    Lo, Hsin-Yi; Li, Chia-Cheng; Ho, Tin-Yun; Hsiang, Chien-Yun

    2016-08-01

    Many food bioactive peptides with diverse functions have been discovered by studying plant proteins. We have previously identified a 68-residue insulin receptor (IR)-binding protein (mcIRBP) from Momordica charantia that exhibits hypoglycemic effects in mice via interaction with IR. By in vitro digestion, we found that mcIRBP-19, spanning residues 50-68 of mcIRBP, enhanced the binding of insulin to IR, stimulated the phosphorylation of PDK1 and Akt, induced the expression of glucose transporter 4, and stimulated both the uptake of glucose in cells and the clearance of glucose in diabetic mice. Furthermore, mcIRBP-19 homologs were present in various plants and shared similar β-hairpin structures and IR kinase-activating abilities to mcIRBP-19. In conclusion, our findings suggested that mcIRBP-19 is a blood glucose-lowering bioactive peptide that exhibits IR-binding potentials. Moreover, we newly identified novel IR-binding bioactive peptides in various plants which belonged to different taxonomic families. PMID:26988505

  10. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 1. Peptides to Proteins

    Science.gov (United States)

    Donohoe, Gregory C.; Khakinejad, Mahdiar; Valentine, Stephen J.

    2015-04-01

    Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection.

  11. Subproteomic analysis of basic proteins in aged skeletal muscle following offgel pre-fractionation.

    Science.gov (United States)

    Gannon, Joan; Ohlendieck, Kay

    2012-04-01

    The progressive loss of skeletal muscle mass is a serious pathophysiological problem in the elderly, which warrants detailed biochemical studies into the underlying mechanism of age-related fiber degeneration. Over the last few years, mass spectrometry (MS)-based proteomics has identified a considerable number of new biomarkers of muscle aging in humans and animal models of sarcopenia. However, interpretation of the proteomic findings is often complicated by technical and biological limitations. Although gel electrophoresis-based approaches represent a highly sensitive analytical way for the large-scale and high-throughput survey of global changes in skeletal muscle proteins during aging, often the presence of components with an isoelectric point in the basic range is underestimated. We, therefore, carried out a comparative subproteomic study of young versus aged rat muscle focusing on potential changes in muscle proteins with an alkaline isoelectric point, using a combination of offgel electrophoresis and two-dimensional (2D) slab gel electrophoresis. Offgel electrophoresis was successfully applied as a prefractionation step to enrich basic protein species from crude tissue extracts representing young adult versus senescent muscle specimens. Proteomics has demonstrated alterations in a small cohort of basic proteins during muscle aging. The mass spectrometric identification of altered proteins and immunoblotting revealed a decrease in the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and a concomitant increase in mitochondrial creatine kinase (CK) and ubiquinol cytochrome‑c reductase. This agrees with the idea of a glycolytic-to-oxidative shift during muscle aging, which is indicative of an overall fast-to-slow transition process in senescent rat muscle. Thus, alterations in the abundance of metabolic enzymes appear to play a central role in the molecular pathogenesis of age‑dependent muscle wasting. PMID:22267262

  12. Membrane binding of prion protein N-terminal peptides characterised by neutron reflectometry

    International Nuclear Information System (INIS)

    The prion protein (PrP) is widely recognised to mis-fold into the causative agent of the transmissible spongiform encephalopathies, known as Creutzfeldt–Jakob disease (CJD) in humans, scrappie in sheep or Bovine spongiform encephalopathy in cows (BSE, “mad cow disease”). PrP has previously been shown to bind to lipid membranes with binding influenced by both membrane composition and pH. Aside from the mis-folding events associated with prion pathogenesis, PrP can undergo various post-translational modifications, including internal cleavage events. Alpha and beta-cleavage of PrP produces two N-terminal fragments, N1 and N2 respectively, which interact specifically with negatively charged phospholipids at low pH. Previous work probing N1 and N2 interactions with supported bilayers raised the possibility that the peptides could insert deeply with minimal disruption [1]. This work aimed to refine the binding parameters of these peptides with lipid bilayers. To this end, neutron reflectometry was used to define the structural details of the interactions in combination with quartz crystal microbalance interrogation and calcein release assays. Neutron reflectometry confirmed that peptides equivalent to N1 and N2 insert into the interstitial space between the phospholipid headgroups but do not penetrate into the acyl tail region. In accord with previous studies, interactions were stronger for the N1 fragment than for the N2, with more peptide bound per lipid. Neutron reflectometry analysis also detected lengthening of the lipid acyl tails, with a concurrent decrease in lipid area. Overall, the data shows that the N1 and N2 peptides interact with the anionic phospholipid headgroups of supported lipid bilayers, inducing lipid ordering in the absence of significant penetration into the acyl tails or permeation of the membrane.

  13. ZOT-derived peptide and chitosan functionalized nanocarrier for oral delivery of protein drug.

    Science.gov (United States)

    Lee, Jong Hyun; Sahu, Abhishek; Choi, Won Il; Lee, Jae Young; Tae, Giyoong

    2016-10-01

    In this study, we developed a dual ligand functionalized pluronic-based nanocarrier (NC) for oral delivery of insulin. Chitosan and zonula occludins toxin (ZOT)-derived, tight junction opening peptide were conjugated to NC to increase the permeability of loaded insulin across the small intestine through the paracellular pathway. Surface functionalized NC, either by chitosan or peptide, could modulate the tight junction (TJ) integrity in contrast to no effect of unmodified NC, as evidenced by the change in transepithelial electrical resistance (TEER) and immunostaining of Claudin-4, a tight junction marker, in Caco-2 cell monolayer. On the other hand, dual ligand (chitosan and peptide) functionalized NC significantly further increased the permeation of insulin across Caco-2 cell monolayer. More importantly, insulin loaded, dual ligand functionalized NC could increase the plasma insulin level and efficiently regulate the glycemic response for a prolonged period of time (∼1 day) upon oral administration to diabetic rats, whereas delivery of insulin by single ligand functionalized NCs, either by chitosan or peptide, as well as by unmodified NC and free insulin, could not induce the effective regulation of the blood glucose level. The use of fluorescence dye labeled insulin (FITC-insulin) and Cy5.5 labeled NC revealed that both insulin and dual ligand functionalized NC were adequately penetrated across the whole intestine villi in contrast to limited adsorption of insulin and NC mainly onto the epithelial surface of the intestine for single ligand functionalized NCs. These results suggest that dual conjugation of ZOT-derived peptide and chitosan is a promising approach to functionalize the surface of nanocarrier for oral delivery of protein drugs. PMID:27380442

  14. Molecular identification of a Drosophila G protein-coupled receptor specific for crustacean cardioactive peptide

    DEFF Research Database (Denmark)

    Cazzamali, Giuseppe; Hauser, Frank; Kobberup, Sune;

    2003-01-01

    part of the receptor gene. DNA corresponding to the corrected gene CG6111 was expressed in Chinese hamster ovary cells, where it was found to code for a receptor that could be activated by low concentrations of crustacean cardioactive peptide, which is a neuropeptide also known to occur in Drosophila......The Drosophila Genome Project website (www.flybase.org) contains the sequence of an annotated gene (CG6111) expected to code for a G protein-coupled receptor. We have cloned this receptor and found that its gene was not correctly predicted, because an annotated neighbouring gene (CG14547) was also....... Furthermore, we identified a gene sequence in the genomic database from the malaria mosquito Anopheles gambiae that very likely codes for a crustacean cardioactive peptide receptor....

  15. Temperature-Dependence of the Amide-I Frequency Map for Peptides and Proteins

    Institute of Scientific and Technical Information of China (English)

    Chen Han; Jian-ping Wang

    2011-01-01

    In our recent work [Phys.Chem.Chem.Phys.11,9149 (2009)],a molecular-mechanics force field-based amide-I vibration frequency map (MM-map) for peptides and proteins was constructed.In this work,the temperature dependence of the MM-map is examined based on high-temperature molecular dynamics simulations and infrared (IR) experiments.It is shown that the 298-K map works for up to 500-K molecular dynamics trajectories,which reasonably reproduces the 88 ℃ experimental IR results.Linear IR spectra are also simulated for two tripeptides containing natural and unnatural amino acid residues,and the results are in reasonable agreement with experiment.The results suggest the MM-map can be used to obtain the temperature-dependent amide-I local mode frequencies and their distributions for peptide oligomers,which is useful in particular for understanding the IR signatures of the thermally unfolded species.

  16. Mutational analysis of residues implicated in the interaction between protein kinase CK2 and peptide substrates

    DEFF Research Database (Denmark)

    Sarno, S; Vaglio, P; Marin, O;

    1997-01-01

    Sixteen derivatives of the optimal peptide substrate RRRA-DDSDDDDD in which aspartic acids were singly or multiply substituted by alanine have been assayed for their phosphorylation efficiency by either wild type protein kinase CK2 or CK2 alpha mutants defective in substrate recognition. With wild...... substitutions tend to have a more than additive effect even if they affect individually dispensable aspartic acids; thus, double, triple, and quintuple substitutions at positions n - 2 and -1, and n + 2, +4, and +5 had detrimental consequences comparable to those observed with substitutions at n + 1 and n + 3....... However, if the suboptimal substrate RRRA-AASDDDDD was used, the single mutants K49A, K71A, K77A, R80A, and H160A also exhibited Km values significantly higher than those of wild type CK2. Kinetic analysis with singly substituted derivatives of peptide RRRA-DDSDDDDD revealed that K49 is implicated in the...

  17. A bicomponent Plasmodium falciparum investigational vaccine composed of protein-peptide conjugates.

    Science.gov (United States)

    Kubler-Kielb, Joanna; Majadly, Fathy; Biesova, Zuzana; Mocca, Christopher P; Guo, Chunyan; Nussenzweig, Ruth; Nussenzweig, Victor; Mishra, Satish; Wu, Yimin; Miller, Louis H; Keith, Jerry M; Liu, Teh-Yung; Robbins, John B; Schneerson, Rachel

    2010-01-19

    There is yet no licensed vaccine against malaria, a serious human disease affecting mostly children, with an annual death rate of about one million. Plasmodia, the malaria-causing parasites, have two obligatory hosts: mammals or birds, in which they multiply asexually, and mosquitoes with sexual multiplication. The most common and serious type of malaria is caused by Plasmodium falciparum. The circumsporozoite protein (CSP), a major surface antigen of sporozoites, is a protective antigen. A unique feature of P. falciparum CSP is its large central domain composed of over 30 tetrapeptide repeats of Asn-Ala-Asn-Pro (NANP). Several NANP peptide-protein conjugates were tested clinically but elicited a low level of CSP antibodies for a short duration. To provide a CSP-based candidate vaccine, we investigated recombinant CSP and NANP conjugates of various peptide lengths, with different N-terminal amino acids, bound at different ratios to various carrier proteins. Injected into mice, CSP alone and CSP or NANP conjugates induced antibodies with booster responses and were positive by the sporozoite immunofluorescent assay. The use of the mosquito stage P. falciparum ookinete surface protein, Pfs25, cross-linked onto itself as a carrier for NANP, induced in mice high levels of uniquely long-lasting antibodies to both vaccine components with secondary biological activities, that will provide immunity to liver infection by sporozoites and block transmission by mosquitoes.

  18. In vitro affinity screening of protein and peptide binders by megavalent bead surface display.

    Science.gov (United States)

    Diamante, Letizia; Gatti-Lafranconi, Pietro; Schaerli, Yolanda; Hollfelder, Florian

    2013-10-01

    The advent of protein display systems has provided access to tailor-made protein binders by directed evolution. We introduce a new in vitro display system, bead surface display (BeSD), in which a gene is mounted on a bead via strong non-covalent (streptavidin/biotin) interactions and the corresponding protein is displayed via a covalent thioether bond on the DNA. In contrast to previous monovalent or low-copy bead display systems, multiple copies of the DNA and the protein or peptide of interest are displayed in defined quantities (up to 10(6) of each), so that flow cytometry can be used to obtain a measure of binding affinity. The utility of the BeSD in directed evolution is validated by library selections of randomized peptide sequences for binding to the anti-hemagglutinin (HA) antibody that proceed with enrichments in excess of 10(3) and lead to the isolation of high-affinity HA-tags within one round of flow cytometric screening. On-bead K(d) measurements suggest that the selected tags have affinities in the low nanomolar range. In contrast to other display systems (such as ribosome, mRNA and phage display) that are limited to affinity panning selections, BeSD possesses the ability to screen and rank binders by their affinity in vitro, a feature that hitherto has been exclusive to in vivo multivalent cell display systems (such as yeast display).

  19. Advancement and applications of peptide phage display technology in biomedical science.

    Science.gov (United States)

    Wu, Chien-Hsun; Liu, I-Ju; Lu, Ruei-Min; Wu, Han-Chung

    2016-01-01

    Combinatorial phage library is a powerful research tool for high-throughput screening of protein interactions. Of all available molecular display techniques, phage display has proven to be the most popular approach. Screening phage-displayed random peptide libraries is an effective means of identifying peptides that can bind target molecules and regulate their function. Phage-displayed peptide libraries can be used for (i) B-cell and T-cell epitope mapping, (ii) selection of bioactive peptides bound to receptors or proteins, disease-specific antigen mimics, peptides bound to non-protein targets, cell-specific peptides, or organ-specific peptides, and (iii) development of peptide-mediated drug delivery systems and other applications. Targeting peptides identified using phage display technology may be useful for basic research and translational medicine. In this review article, we summarize the latest technological advancements in the application of phage-displayed peptide libraries to applied biomedical sciences.

  20. Effects of Amyloid Precursor Protein 17 Peptide on the Protection of Diabetic Encephalopathy and Improvement of Glycol Metabolism in the Diabetic Rat

    OpenAIRE

    Heng Meng; Duo Zhang; Haishan Yang

    2013-01-01

    Researchers have proposed that amyloid precursor protein 17 peptide (APP17 peptide), an active fragment of amyloid precursor protein (APP) in the nervous system, has therapeutic effects on neurodegeneration. Diabetic encephalopathy (DE) is a neurological disease caused by diabetes. Here we use multiple experimental approaches to investigate the effect of APP17 peptide on changes in learning behavior and glycol metabolism in rats. It was found that rats with DE treated by APP17 peptide showed ...

  1. Contribution of Long Fibrils and Peptides to Surface and Foaming Behavior of Soy Protein Fibril System.

    Science.gov (United States)

    Wan, Zhili; Yang, Xiaoquan; Sagis, Leonard M C

    2016-08-16

    When soy glycinin (11S) is heated for a prolonged time at pH 2 (20 h at 85 °C), a mixture is formed consisting of long semiflexible 11S fibrils and small peptides. The surface and foaming properties of this mixture were investigated at different pHs, and compared to the behavior of pure fibrils and pure peptides, to determine the individual contributions of these two factions to the behavior of the mixture. The adsorption of these three systems at air-water interfaces and the resulting surface rheological properties were studied by combining drop shape analysis tensiometry, ellipsometry, and surface large amplitude oscillatory dilatational (LAOD) rheology. Lissajous plots of surface pressure versus deformation were used to analyze the surface rheological response in terms of interfacial microstructure. Our results show that the adsorption kinetics, dilatational rheological properties, and the foaming behavior of the mixture were mainly dominated by the small peptides in the fibril system. Compared to pH 2, the fibril mixture at pH 5 and 7 provides much better foam stability and appears to be a very promising protein material to make stable foams, even at low protein concentration (0.1 wt %). The presence of fibril clusters and peptide aggregates at pH 5 and 7 contributed to foam stability of the mixture. In contrast, pure fibril formed an interface with a highly pH-responsive adsorption and rheological behavior, and the foamability and foam stability of the pure fibrils were very poor. PMID:27452662

  2. Gastrointestinal Endogenous Protein-Derived Bioactive Peptides: An in Vitro Study of Their Gut Modulatory Potential

    Science.gov (United States)

    Dave, Lakshmi A.; Hayes, Maria; Mora, Leticia; Montoya, Carlos A.; Moughan, Paul J.; Rutherfurd, Shane M.

    2016-01-01

    A recently proposed paradigm suggests that, like their dietary counterparts, digestion of gastrointestinal endogenous proteins (GEP) may also produce bioactive peptides. With an aim to test this hypothesis, in vitro digests of four GEP namely; trypsin (TRYP), lysozyme (LYS), mucin (MUC), serum albumin (SA) and a dietary protein chicken albumin (CA) were screened for their angiotensin-I converting (ACE-I), renin, platelet-activating factor-acetylhydrolase (PAF-AH) and dipeptidyl peptidase-IV inhibitory (DPP-IV) and antioxidant potential following simulated in vitro gastrointestinal digestion. Further, the resultant small intestinal digests were enriched to obtain peptides between 3–10 kDa in size. All in vitro digests of the four GEP were found to inhibit ACE-I compared to the positive control captopril when assayed at a concentration of 1 mg/mL, while the LYS < 3-kDa permeate fraction inhibited renin by 40% (±1.79%). The LYS < 10-kDa fraction inhibited PAF-AH by 39% (±4.34%), and the SA < 3-kDa fraction inhibited DPP-IV by 45% (±1.24%). The MUC < 3-kDa fraction had an ABTS-inhibition antioxidant activity of 150 (±24.79) µM trolox equivalent and the LYS < 10-kDa fraction inhibited 2,2-Diphenyl-1-picrylhydrazyl (DPPH) by 54% (±1.62%). Moreover, over 190 peptide-sequences were identified from the bioactive GEP fractions. The findings of the present study indicate that GEP are a significant source of bioactive peptides which may influence gut function. PMID:27043546

  3. Isoaspartic acid is present at specific sites in myelin basic protein from multiple sclerosis patients: could this represent a trigger for disease onset?

    Science.gov (United States)

    Friedrich, Michael G; Hancock, Sarah E; Raftery, Mark J; Truscott, Roger J W

    2016-08-12

    Multiple sclerosis (MS) is associated with breakdown of the myelin sheath that coats neurons in the central nervous system. The cause of MS is not known, although the pathogenesis involves destruction of myelin by the immune system. It was the aim of this study to examine the abundant myelin protein, myelin basic protein (MBP), to determine if there are sites of modification that may be characteristic for MS. MBP from the cerebellum was examined from controls and MS patients across the age range using mass spectrometry and amino acid analysis. Amino acid racemization data indicated that myelin basic protein is long-lived and proteomic analysis of MBP showed it to be highly modified. A common modification of MBP was racemization of Asp and this was significantly greater in MS patients. In long-lived proteins, L-Asp and L-Asn can racemize to three other isomers, D-isoAsp, L-isoAsp and D-Asp and this is significant because isoAsp formation in peptides renders them immunogenic.Proteomic analysis revealed widespread modifications of MBP with two surface regions that are altered in MS. In particular, isoAsp was significantly elevated at these sites in MS patients. The generation of isoAsp could be responsible for eliciting an immune response to modified MBP and therefore be implicated in the etiology of MS.

  4. Application of stable isotopes to the NMR conformational study of peptides and membrane proteins; Application des isotopes stables a l`etude conformationnelle par RMN de peptides et proteines membranaires

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, J.M.; Macquaire, F.; Cordier, F.; Musat, G.; Baleux, F. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Biologie Cellulaire et Moleculaire; Huynh-Dinh, T.; Roux, M.; Sanson, A. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France)

    1994-12-31

    The nuclear magnetic resonance spectral analysis of the lipid-peptide complexes generally necessitates isotopic enrichment, specifically or not, of the lipidic or peptidic partner. The isotope labelling depends on the membrane model and the associated NMR techniques: high resolution {sup 1}H NMR of peptides or proteins in the presence of per-deuterated phospholipidic micells, high resolution (micells) or ``solid`` type {sup 2}H NMR of the lipid partner, ``solid`` type NMR ({sup 15}N, {sup 13}C) of the peptide partner in a bi-layer. Application examples are given: utilization of stable isotopes for NMR study of lipopeptide structure and dynamic, of folding-up and functional linking at the annexines membrane interface, and of phospholipid conformation and dynamics in the lipids-ions-peptides interactions. 3 figs.

  5. Radiation chemistry of amino acids, peptides and proteins in relation to the radiation sterilization of high-protein foods

    International Nuclear Information System (INIS)

    An important source of information on the question of whether or not toxic or other deleterious substances are formed in the radiation sterilization of foods is the chemical study of reaction products and reaction mechanisms in the radiolysis of individual food components. The present evaluation of the radiation chemistry of amino acids, peptides and proteins outlines the various radiation-induced processes which lead to amino acid degradation and to the synthesis of amino acid derivatives of higher molecular weight. Among the latter are the α,α'-diamino dicarboxylic acids which are formed as major products in the radiolysis of peptides both in aqueous solution and in the solid state. The α,α'-diamino acids are of particular interest as irradiation products because they represent a class of compounds not normally encountered in plant and animal protein sources. Such compounds have, however, been isolated from certain types of bacteria and pathogenic toxins. All of the available data strongly suggest that the α,α'-diamino acids are produced in significant yield in the radiation sterilization of high protein foods. The importance of initiating extensive chemical and biological studies of initiating extensive chemical and biological studies of these and of other high molecular weight products in irradiated food is emphasized

  6. Radiation chemistry of amino acids, peptides and proteins in relation to the radiation sterilization of high-protein foods

    International Nuclear Information System (INIS)

    An important source of information on the question of whether or not toxic or other deleterious substances are formed in the radiation sterilization of foods is the chemical study of reaction products and reaction mechanisms in the radiolysis of individual food components. The present evaluation of the radiation chemistry of amino acids, peptides, and proteins outlines the various radiation-induced processes which lead to amino acid degradation and to the synthesis of amino acid derivatives of higher molecular weight. Among the latter are the α,α'-diamino dicarboxylic acids which are formed as major products in the radiolysis of peptides both in aqueous solution and in the solid state. The α,α'-diamino acids are of particular interest as irradiation products because they represent a class of compounds not normally encountered in plant and animal protein sources. Such compounds have, however, been isolated from certain types of bacteria and bacterial products. All of the available data strongly suggest that the α,α'-diamino acids are produced in significant yield in the radiation sterilization of high protein foods. The importance of initiating extensive chemical and biological studies of these and of other high molecular weight products in irradiated food is emphasized

  7. The radiation chemistry of amino acids, peptides and proteins in relation to the radiation sterilization of high-protein foods

    International Nuclear Information System (INIS)

    An important source of information on the question of whether or not toxic or other deleterious substances are formed in the radiation sterilization of foods is the chemical study of reaction products and reaction mechanisms in the radiolysis of individual food components. The present evaluation of the radiation chemistry of amino acids, peptides and proteins outlines the various radiation-induced processes which lead to amino acid degradation and to the synthesis of amino acid derivatives of higher molecular weight. Among the latter are the α,α'-diamino dicarboxylic acids which are formed as major products in the radiolysis of peptides both in aqueous solution and in the solid state. The α,α'-diamino acids are of particular interest as irradiation products because they represent a class of compounds not normally encountered in plant and animal protein sources. Such compounds have, however, been isolated from certain types of bacteria and bacterial products. All of the available data strongly suggest that the α,α'-diamino acids are produced in significant yield in the radiation sterilization of high protein foods. The importance of initiating extensive chemical and biological studies of these and of other high molecular weight products in irradiated food is emphasised. (author)

  8. Radiation chemistry of amino acids, peptides and proteins in relation to the radiation sterilization of high-protein foods

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, W. M.

    1981-12-01

    An important source of information on the question of whether or not toxic or other deleterious substances are formed in the radiation sterilization of foods is the chemical study of reaction products and reaction mechanisms in the radiolysis of individual food components. The present evaluation of the radiation chemistry of amino acids, peptides, and proteins outlines the various radiation-induced processes which lead to amino acid degradation and to the synthesis of amino acid derivatives of higher molecular weight. Among the latter are the ..cap alpha..,..cap alpha..'-diamino dicarboxylic acids which are formed as major products in the radiolysis of peptides both in aqueous solution and in the solid state. The ..cap alpha..,..cap alpha..'-diamino acids are of particular interest as irradiation products because they represent a class of compounds not normally encountered in plant and animal protein sources. Such compounds have, however, been isolated from certain types of bacteria and bacterial products. All of the available data strongly suggest that the ..cap alpha..,..cap alpha..'-diamino acids are produced in significant yield in the radiation sterilization of high protein foods. The importance of initiating extensive chemical and biological studies of these and of other high molecular weight products in irradiated food is emphasized.

  9. PEP-SiteFinder: a tool for the blind identification of peptide binding sites on protein surfaces.

    Science.gov (United States)

    Saladin, Adrien; Rey, Julien; Thévenet, Pierre; Zacharias, Martin; Moroy, Gautier; Tufféry, Pierre

    2014-07-01

    Peptide-protein interactions are important to many processes of life, particularly for signal transmission or regulatory mechanisms. When no information is known about the interaction between a protein and a peptide, it is of interest to propose candidate sites of interaction at the protein surface, to assist the design of biological experiments to probe the interaction, or to serve as a starting point for more focused in silico approaches. PEP-SiteFinder is a tool that will, given the structure of a protein and the sequence of a peptide, identify protein residues predicted to be at peptide-protein interface. PEP-SiteFinder relies on the 3D de novo generation of peptide conformations given its sequence. These conformations then undergo a fast blind rigid docking on the complete protein surface, and we have found, as the result of a benchmark over 41 complexes, that the best poses overlap to some extent the experimental patch of interaction for close to 90% complexes. In addition, PEP-SiteFinder also returns a propensity index we have found informative about the confidence of the prediction. The PEP-SiteFinder web server is available at http://bioserv.rpbs.univ-paris-diderot.fr/PEP-SiteFinder.

  10. Design and evaluation of antimalarial peptides derived from prediction of short linear motifs in proteins related to erythrocyte invasion.

    Directory of Open Access Journals (Sweden)

    Alessandra Bianchin

    Full Text Available The purpose of this study was to investigate the blood stage of the malaria causing parasite, Plasmodium falciparum, to predict potential protein interactions between the parasite merozoite and the host erythrocyte and design peptides that could interrupt these predicted interactions. We screened the P. falciparum and human proteomes for computationally predicted short linear motifs (SLiMs in cytoplasmic portions of transmembrane proteins that could play roles in the invasion of the erythrocyte by the merozoite, an essential step in malarial pathogenesis. We tested thirteen peptides predicted to contain SLiMs, twelve of them palmitoylated to enhance membrane targeting, and found three that blocked parasite growth in culture by inhibiting the initiation of new infections in erythrocytes. Scrambled peptides for two of the most promising peptides suggested that their activity may be reflective of amino acid properties, in particular, positive charge. However, one peptide showed effects which were stronger than those of scrambled peptides. This was derived from human red blood cell glycophorin-B. We concluded that proteome-wide computational screening of the intracellular regions of both host and pathogen adhesion proteins provides potential lead peptides for the development of anti-malarial compounds.

  11. Colorimetric assay for protein detection based on "nano-pumpkin" induced aggregation of peptide-decorated gold nanoparticles.

    Science.gov (United States)

    Wei, Luming; Wang, Xiaoying; Li, Chao; Li, Xiaoxi; Yin, Yongmei; Li, Genxi

    2015-09-15

    Small peptide can be used as an effective biological recognition element and provide an alternative tool for protein detection. However, the development of peptide-based detecting strategy still remains elusive due to the difficulty of signal transduction. Herein, we report a peptide-based colorimetric strategy for the detection of disease biomarker by using vascular endothelial growth factor receptor 1 (Flt-1) as an example. In this strategy, N-terminal aromatic residue-containing peptide modified gold nanoparticles (GNPs) can form bulky aggregate by the introduction of cucurbit[8]uril (CB[8]) that can selectively accommodate two N-terminal aromatic residue of peptides simultaneously regardless of their sequences. However, in the presence of Flt-1, the peptide can specifically bind to the protein molecule and the N-terminal aromatic residue will be occupied, resulting in little aggregation of GNPs. By taking advantage of the highly affinitive peptide and efficiency cross-linking effect of CB[8] to GNPs, colorimetric assay for protein detection can be achieved with a detection limit of 0.2 nM, which is comparable with traditional methods. The feasibility of our method has also been demonstrated in spiked serum sample, indicating potential application in the future. PMID:25932793

  12. NUTRALYS® pea protein: characterization of in vitro gastric digestion and in vivo gastrointestinal peptide responses relevant to satiety

    Directory of Open Access Journals (Sweden)

    Joost Overduin

    2015-04-01

    Design: Under in vitro simulated gastric conditions, the digestion of NUTRALYS® pea protein was compared to that of two dairy proteins, slow-digestible casein and fast-digestible whey. In vivo, blood glucose and gastrointestinal hormonal (insulin, ghrelin, cholecystokinin [CCK], glucagon-like peptide 1 [GLP-1], and peptide YY [PYY] responses were monitored in nine male Wistar rats following isocaloric (11 kcal meals containing 35 energy% of either NUTRALYS® pea protein, whey protein, or carbohydrate (non-protein. Results: In vitro, pea protein transiently aggregated into particles, whereas casein formed a more enduring protein network and whey protein remained dissolved. Pea-protein particle size ranged from 50 to 500 µm, well below the 2 mm threshold for gastric retention in humans. In vivo, pea-protein and whey-protein meals induced comparable responses for CCK, GLP-1, and PYY, that is, the anorexigenic hormones. Pea protein induced weaker initial, but equal 3-h integrated ghrelin and insulin responses than whey protein, possibly due to the slower gastric breakdown of pea protein observed in vitro. Two hours after meals, CCK levels were more elevated in the case of protein meals compared to that of non-protein meals. Conclusions: These results indicate that 1 pea protein transiently aggregates in the stomach and has an intermediately fast intestinal bioavailability in between that of whey and casein; 2 pea-protein- and dairy-protein-containing meals were comparably efficacious in triggering gastrointestinal satiety signals.

  13. Cell-mediated reduction of protein and peptide hydroperoxides to reactive free radicals

    DEFF Research Database (Denmark)

    Headlam, Henrietta A; Davies, Michael Jonathan

    2003-01-01

    Radical attack on proteins in the presence of O(2) gives protein hydroperoxides in high yields. These peroxides are decomposed by transition metal ions, reducing agents, UV light and heat, with the formation of a range of reactive radicals that are capable of initiating further damage. Evidence has....... In this study we have investigated the reduction of peptide and protein hydroperoxides by THP-1 (human monocyte-like) cells and it is shown that this process is accompanied by radical formation as detected by EPR spin trapping. The radicals detected, which are similar to those detected from metal-ion catalyzed...... transport system (TPMET) either directly, or indirectly via redox cycling of trace transition metal ions....

  14. Rapid expansion of the protein disulfide isomerase gene family facilitates the folding of venom peptides.

    Science.gov (United States)

    Safavi-Hemami, Helena; Li, Qing; Jackson, Ronneshia L; Song, Albert S; Boomsma, Wouter; Bandyopadhyay, Pradip K; Gruber, Christian W; Purcell, Anthony W; Yandell, Mark; Olivera, Baldomero M; Ellgaard, Lars

    2016-03-22

    Formation of correct disulfide bonds in the endoplasmic reticulum is a crucial step for folding proteins destined for secretion. Protein disulfide isomerases (PDIs) play a central role in this process. We report a previously unidentified, hypervariable family of PDIs that represents the most diverse gene family of oxidoreductases described in a single genus to date. These enzymes are highly expressed specifically in the venom glands of predatory cone snails, animals that synthesize a remarkably diverse set of cysteine-rich peptide toxins (conotoxins). Enzymes in this PDI family, termed conotoxin-specific PDIs, significantly and differentially accelerate the kinetics of disulfide-bond formation of several conotoxins. Our results are consistent with a unique biological scenario associated with protein folding: The diversification of a family of foldases can be correlated with the rapid evolution of an unprecedented diversity of disulfide-rich structural domains expressed by venomous marine snails in the superfamily Conoidea. PMID:26957604

  15. Identification of avocado (Persea americana) pulp proteins by nano-LC-MS/MS via combinatorial peptide ligand libraries.

    Science.gov (United States)

    Esteve, Clara; D'Amato, Alfonsina; Marina, María Luisa; García, María Concepción; Righetti, Pier Giorgio

    2012-09-01

    Avocado (Persea americana) proteins have been scarcely studied despite their importance, especially in food related allergies. The proteome of avocado pulp was explored in depth by extracting proteins with capture by combinatorial peptide ligand libraries at pH 7.4 and under conditions mimicking reverse-phase capture at pH 2.2. The total number of unique gene products identified amounts to 1012 proteins, of which 174 are in common with the control, untreated sample, 190 are present only in the control and 648 represent the new species detected via combinatorial peptide ligand libraries of all combined eluates and likely represent low-abundance proteins. Among the 1012 proteins, it was possible to identify the already known avocado allergen Pers a 1 and different proteins susceptible to be allergens such as a profilin, a polygalacturonase, a thaumatin-like protein, a glucanase, and an isoflavone reductase like protein.

  16. Identification of avocado (Persea americana) pulp proteins by nano-LC-MS/MS via combinatorial peptide ligand libraries.

    Science.gov (United States)

    Esteve, Clara; D'Amato, Alfonsina; Marina, María Luisa; García, María Concepción; Righetti, Pier Giorgio

    2012-09-01

    Avocado (Persea americana) proteins have been scarcely studied despite their importance, especially in food related allergies. The proteome of avocado pulp was explored in depth by extracting proteins with capture by combinatorial peptide ligand libraries at pH 7.4 and under conditions mimicking reverse-phase capture at pH 2.2. The total number of unique gene products identified amounts to 1012 proteins, of which 174 are in common with the control, untreated sample, 190 are present only in the control and 648 represent the new species detected via combinatorial peptide ligand libraries of all combined eluates and likely represent low-abundance proteins. Among the 1012 proteins, it was possible to identify the already known avocado allergen Pers a 1 and different proteins susceptible to be allergens such as a profilin, a polygalacturonase, a thaumatin-like protein, a glucanase, and an isoflavone reductase like protein. PMID:23019098

  17. Mapping a Noncovalent Protein-Peptide Interface by Top-Down FTICR Mass Spectrometry Using Electron Capture Dissociation

    Science.gov (United States)

    Clarke, David J.; Murray, Euan; Hupp, Ted; Mackay, C. Logan; Langridge-Smith, Pat R. R.

    2011-08-01

    Noncovalent protein-ligand and protein-protein complexes are readily detected using electrospray ionization mass spectrometry (ESI MS). Furthermore, recent reports have demonstrated that careful use of electron capture dissociation (ECD) fragmentation allows covalent backbone bonds of protein complexes to be dissociated without disruption of noncovalent protein-ligand interactions. In this way the site of protein-ligand interfaces can be identified. To date, protein-ligand complexes, which have proven tractable to this technique, have been mediated by ionic electrostatic interactions, i.e., ion pair interactions or salt bridging. Here we extend this methodology by applying ECD to study a protein-peptide complex that contains no electrostatics interactions. We analyzed the complex between the 21 kDa p53-inhibitor protein anterior gradient-2 and its hexapeptide binding ligand (PTTIYY). ECD fragmentation of the 1:1 complex occurs with retention of protein-peptide binding and analysis of the resulting fragments allows the binding interface to be localized to a C-terminal region between residues 109 and 175. These finding are supported by a solution-phase competition assay, which implicates the region between residues 108 and 122 within AGR2 as the PTTIYY binding interface. Our study expands previous findings by demonstrating that top-down ECD mass spectrometry can be used to determine directly the sites of peptide-protein interfaces. This highlights the growing potential of using ECD and related top-down fragmentation techniques for interrogation of protein-protein interfaces.

  18. Conformational Changes and Association of Membrane-Interacting Peptides in Myelin Membrane Models: A Case of the C-Terminal Peptide of Proteolipid Protein and the Antimicrobial Peptide Melittin.

    Science.gov (United States)

    Appadu, Ashtina; Jelokhani-Niaraki, Masoud; DeBruin, Lillian

    2015-11-25

    Model membranes composed of various lipid mixtures can segregate into liquid-ordered (Lo) and liquid-disordered (Ld) phases. In this study, lipid vesicles composed of mainly Lo or Ld phases as well as complex lipid systems representing the cytosolic leaflet of the myelin membrane were characterized by fluorescence resonance energy transfer with a donor/acceptor pair that preferentially partitioned into Lo or Ld phases, respectively. The fluidity of the lipid systems containing >30% cholesterol was modulated in the presence of the amphipathic peptide melittin. With all the studied lipid systems, melittin attained an α-helical conformation as determined by CD spectroscopy and attained varying degrees of membrane association and penetration as determined by intrinsic Trp fluorescence. The other protein domain utilized was a putative amphipathic helical peptide derived from the cytosolic C-terminal sequence of proteolipid protein (PLP) which is the most abundant protein in the myelin membrane. The C-terminal PLP peptide transitioned from a random coil to an α-helix in the presence of trifluoroethanol. Upon interacting with each of lipid vesicle system, the PLP peptide also folded into a helix; however, at high concentrations of the peptide with fluid lipid systems, associated helices transmuted into a β-sheet conformer. The membrane-associated aggregation of the cytosolic C-termini could be a mechanism by which the transmembrane PLP multimerizes in the myelin membrane. PMID:26561987

  19. On the mechanism of targeting of phage fusion protein-modified nanocarriers: only the binding peptide sequence matters

    Science.gov (United States)

    Wang, Tao; Kulkarni, Nikita; D’Souza, Gerard G.M.; Petrenko, Valery A.; Torchilin, Vladimir P.

    2011-01-01

    The integration of pharmaceutical nanocarriers with phage display techniques is emerging as a new paradigm for targeted cancer nanomedicines. We explored the direct use of landscape phage fusion proteins for the self-assembly of phage-derived binding peptides to liposomes for cancer cell targeting. The primary purpose of this study was to elucidate the targeting mechanism with a particular emphasis on the relative contributions of the two motifs that make up the landscape phage fusion protein (a binding peptide and the phage pVIII coat protein) to the targeting efficiency. Using transmission electron microscopy and dynamic light scattering, we confirmed the formation of phage-liposomes. Using FACS analysis, fluorescence microscopy, and fluorescence photospectrometry, we found that liposomes modified with MCF-7-specific phage fusion proteins (MCF-7 binding peptide, DMPGTVLP, fused to the phage PVIII coat protein) provided a strong and specific association with target MCF-7 cancer cells but not with co-cultured, non-target cells including C166-GFP and NIH3T3. The substitution for the binding peptide fused to phage pVIII coat protein abolished the targeting specificity. The addition of free binding peptide, DMPGTVLP, competitively inhibited the interaction of MCF-7-specific phage-liposomes with target MCF-7 cells but showed no reduction of MCF-7-associated plain liposomes. The proteolysis of the binding peptide reduced MCF-7 cell-associated phage-liposomes in a proteinase K (PK) concentration-dependent manner with no effect on the binding of plain liposomes to MCF-7 cells. Overall, only the binding peptide motif was involved in the targeting specificity of phage-liposomes. The presence of phage pVIII coat protein did not interfere with the targeting efficiency. PMID:21675738

  20. On the mechanism of targeting of phage fusion protein-modified nanocarriers: only the binding peptide sequence matters.

    Science.gov (United States)

    Wang, Tao; Kulkarni, Nikita; D'Souza, Gerard G M; Petrenko, Valery A; Torchilin, Vladimir P

    2011-10-01

    The integration of pharmaceutical nanocarriers with phage display techniques is emerging as a new paradigm for targeted cancer nanomedicines. We explored the direct use of landscape phage fusion proteins for the self-assembly of phage-derived binding peptides to liposomes for cancer cell targeting. The primary purpose of this study was to elucidate the targeting mechanism with a particular emphasis on the relative contributions of the two motifs that make up the landscape phage fusion protein (a binding peptide and the phage pVIII coat protein) to the targeting efficiency. Using transmission electron microscopy and dynamic light scattering, we confirmed the formation of phage-liposomes. Using FACS analysis, fluorescence microscopy, and fluorescence photospectrometry, we found that liposomes modified with MCF-7-specific phage fusion proteins (MCF-7 binding peptide, DMPGTVLP, fused to the phage PVIII coat protein) provided a strong and specific association with target MCF-7 cancer cells but not with cocultured, nontarget cells including C166-GFP and NIH3T3. The substitution for the binding peptide fused to phage pVIII coat protein abolished the targeting specificity. The addition of free binding peptide, DMPGTVLP, competitively inhibited the interaction of MCF-7-specific phage-liposomes with target MCF-7 cells but showed no reduction of MCF-7-associated plain liposomes. The proteolysis of the binding peptide reduced MCF-7 cell-associated phage-liposomes in a proteinase K (PK) concentration-dependent manner with no effect on the binding of plain liposomes to MCF-7 cells. Overall, only the binding peptide motif was involved in the targeting specificity of phage-liposomes. The presence of phage pVIII coat protein did not interfere with the targeting efficiency. PMID:21675738

  1. Mapping functional prion-prion protein interaction sites using prion protein based peptide-arrays

    NARCIS (Netherlands)

    Rigter, A.; Priem, J.; Timmers-Parohi, D.; Langeveld, J.; Bossers, A.

    2009-01-01

    Protein-protein interactions are at the basis of most if not all biological processes in living cells. Therefore, adapting existing techniques or developing new techniques to study interactions between proteins are of importance in elucidating which amino acid sequences contribute to these interacti

  2. dMM-PBSA: A New HADDOCK Scoring Function for Protein-Peptide Docking.

    Science.gov (United States)

    Spiliotopoulos, Dimitrios; Kastritis, Panagiotis L; Melquiond, Adrien S J; Bonvin, Alexandre M J J; Musco, Giovanna; Rocchia, Walter; Spitaleri, Andrea

    2016-01-01

    Molecular-docking programs coupled with suitable scoring functions are now established and very useful tools enabling computational chemists to rapidly screen large chemical databases and thereby to identify promising candidate compounds for further experimental processing. In a broader scenario, predicting binding affinity is one of the most critical and challenging components of computer-aided structure-based drug design. The development of a molecular docking scoring function which in principle could combine both features, namely ranking putative poses and predicting complex affinity, would be of paramount importance. Here, we systematically investigated the performance of the MM-PBSA approach, using two different Poisson-Boltzmann solvers (APBS and DelPhi), in the currently rising field of protein-peptide interactions (PPIs), identifying the correct binding conformations of 19 different protein-peptide complexes and predicting their binding free energies. First, we scored the decoy structures from HADDOCK calculation via the MM-PBSA approach in order to assess the capability of retrieving near-native poses in the best-scoring clusters and of evaluating the corresponding free energies of binding. MM-PBSA behaves well in finding the poses corresponding to the lowest binding free energy, however the built-in HADDOCK score shows a better performance. In order to improve the MM-PBSA-based scoring function, we dampened the MM-PBSA solvation and coulombic terms by 0.2, as proposed in the HADDOCK score and LIE approaches. The new dampened MM-PBSA (dMM-PBSA) outperforms the original MM-PBSA and ranks the decoys structures as the HADDOCK score does. Second, we found a good correlation between the dMM-PBSA and HADDOCK scores for the near-native clusters of each system and the experimental binding energies, respectively. Therefore, we propose a new scoring function, dMM-PBSA, to be used together with the built-in HADDOCK score in the context of protein-peptide docking

  3. Dendritic-tumor fusion cells derived heat shock protein70-peptide complex has enhanced immunogenicity.

    Science.gov (United States)

    Zhang, Yunfei; Zhang, Yong; Chen, Jun; Liu, Yunyan; Luo, Wen

    2015-01-01

    Tumor-derived heat shock protein70-peptide complexes (HSP70.PC-Tu) have shown great promise in tumor immunotherapy due to numerous advantages. However, large-scale phase III clinical trials showed that the limited immunogenicity remained to be enhanced. In previous research, we demonstrated that heat shock protein 70-peptide complexes (HSP70.PC-Fc) derived from dendritic cell (DC)-tumor fusions exhibit enhanced immunogenicity compared with HSP70.PCs from tumor cells. However, the DCs used in our previous research were obtained from healthy donors and not from the patient population. In order to promote the clinical application of these complexes, HSP70.PC-Fc was prepared from patient-derived DC fused directly with patient-derived tumor cells in the current study. Our results showed that compared with HSP70.PC-Tu, HSP70.PC-Fc elicited much more powerful immune responses against the tumor from which the HSP70 was derived, including enhanced T cell activation, and CTL responses that were shown to be antigen specific and HLA restricted. Our results further indicated that the enhanced immunogenicity is related to the activation of CD4+ T cells and increased association with other heat shock proteins, such as HSP90. Therefore, the current study confirms the enhanced immunogenicity of HSP70.PC derived from DC-tumor fusions and may provide direct evidence promoting their future clinical use.

  4. Bioactive Peptides from Angelica sinensis Protein Hydrolyzate Delay Senescence in Caenorhabditis elegans through Antioxidant Activities

    Directory of Open Access Journals (Sweden)

    Qiangqiang Wang

    2016-01-01

    Full Text Available Since excessive reactive oxygen species (ROS is known to be associated with aging and age-related diseases, strategies modulating ROS level and antioxidant defense systems may contribute to the delay of senescence. Here we show that the protein hydrolyzate from Angelica sinensis was capable of increasing oxidative survival of the model animal Caenorhabditis elegans intoxicated by paraquat. The hydrolyzate was then fractionated by ultrafiltration, and the antioxidant fraction (<3 kDa was purified by gel filtration to obtain the antioxidant A. sinensis peptides (AsiPeps, which were mostly composed of peptides with <20 amino acid residues. Further studies demonstrate that AsiPeps were able to reduce the endogenous ROS level, increase the activities of the antioxidant enzymes superoxide dismutase and catalase, and decrease the content of the lipid peroxidation product malondialdehyde in nematodes treated with paraquat or undergoing senescence. AsiPeps were also shown to reduce age pigments accumulation and extend lifespan but did not affect the food-intake behavior of the nematodes. Taken together, our results demonstrate that A. sinensis peptides (AsiPeps are able to delay aging process in C. elegans through antioxidant activities independent of dietary restriction.

  5. [Comparison of histone-like proteins from blue-green algae with ribosomal basic proteins of alga and wheat germ histones].

    Science.gov (United States)

    Gofshteĭn, L V; Iurina, N P; Romashkin, V I; Oparin, A I

    1975-01-01

    Histone-like proteins was found in blue-green alga Anacystis nidulans, which has no nucleus. F2b2, F2a2, F2a1 fractions were found in histone-like algae proteins and no fraction F1. Content of basic amino acids (arginine being prevailing in algae protein) is quite identical in histone-like algae proteins and in wheat germs histones, while the content of acid amino acids is considerably higher in algae. The presence in procaryotic cells of basic proteins similar in a number of properties to histones of higher organisms suggests that these proteins are evolutionary precursors of eucaryotic histones. PMID:813782

  6. Dengue virus M protein C-terminal peptide (DVM-C) forms ion channels.

    Science.gov (United States)

    Premkumar, A; Horan, C R; Gage, P W

    2005-03-01

    A chemically synthesized peptide consisting of the C-terminus of the M protein of the Dengue virus type 1 strain Singapore S275/90 (DVM-C) produced ion channel activity in artificial lipid bilayers. The channels had a variable conductance and were more permeable to sodium and potassium ions than to chloride ions and more permeable to chloride ions than to calcium ions. Hexamethylene amiloride (100 microM) and amantadine (10 microM), blocked channels formed by DVM-C. Ion channels may play an important role in the life cycle of many viruses and drugs that block these channels may prove to be useful antiviral agents.

  7. [Preparation and detection of anti-influenza A virus polymerase basic protein 1 polyclonal antibody].

    Science.gov (United States)

    Qin, Yujie; Zhang, Tinghong; Ye, Xin

    2016-01-01

    Influenza A virus is an enveloped virus that belongs to the Orthomyxoviridae family. It has 8 negative RNA segments that encode 16 viral proteins. The viral polymerase consists of 3 proteins (PB 1, PB2 and PA) which plays an important role in the transcription and replication of the influenza A virus. Polymerase basic protein 1 (PB 1) is a critical member of viral polymerase complex. In order to further study the function of PB1, we need to prepare the PB1 antibody with good quality. Therefore, we amplified PB1 conserved region (nt1648-2265) by PCR and cloned it into pET-30a vector, and transformed into Escherichia coli BL2 1. The expression of His tagged PB 1 protein was induced by IPTG, and His-PB 1 proteins were purified by Ni-NTA resin. For preparation of PB 1 protein antiserum, rabbits were immunized with His-PB 1 fusion protein 3 times. Then the titer of PB 1 polyclonal antibody was measured by indirect ELISA. The antibody was purified by membrane affinity purification and subjected to immunoblotting analysis. Data showed that PB1 antibody can recognize PB 1 protein from WSN virus infected or pCMV FLAG-PB 1 transfected cells. Meanwhile, PB 1 antibody can also recognize specifically other subtype strains of influenza A virus such as H9N2 and H3N2. PB 1 polyclonal antibody we generated will be a useful tool to study the biological function of PB1. PMID:27363203

  8. Different methylation characteristics of protein arginine methyltransferase 1 and 3 toward the Ewing Sarcoma protein and a peptide.

    Science.gov (United States)

    Pahlich, Steffen; Bschir, Karim; Chiavi, Claudio; Belyanskaya, Larisa; Gehring, Heinz

    2005-10-01

    The multifunctional Ewing Sarcoma (EWS) protein, a member of a large family of RNA-binding proteins, is extensively asymmetrically dimethylated at arginine residues within RGG consensus sequences. Using recombinant proteins we examined whether type I protein arginine methyltransferase (PRMT)1 or 3 is responsible for asymmetric dimethylations of the EWS protein. After in vitro methylation of the EWS protein by GST-PRMT1, we identified 27 dimethylated arginine residues out of 30 potential methylation sites by mass spectrometry-based techniques (MALDI-TOF MS and MS/MS). Thus, PRMT1 recognizes most if not all methylation sites of the EWS protein. With GST-PRMT3, however, only nine dimethylated arginines, located mainly in the C-terminal region of EWS protein, could be assigned, indicating that structural determinants prevent complete methylation. In contrary to previous reports this study also revealed that trypsin is able to cleave after methylated arginines. Pull-down experiments showed that endogenous EWS protein binds efficiently to GST-PRMT1 but less to GST-PRMT3, which is in accordance to the in vitro methylation results. Furthermore, methylation of a peptide containing different methylation sites revealed differences in the site selectivity as well as in the kinetic properties of GST-PRMT1 and GST-PRMT3. Kinetic differences due to an inhibition effect of the methylation inhibitor S-adenosyl-L-homocysteine could be excluded by determining the corresponding K(i) values of the two enzymes and the K(d) values for the methyl donor S-adenosyl-L-methionine. The study demonstrates the strength of MS-based methods for a qualitative and quantitative analysis of enzymic arginine methylation, a posttranslational modification that becomes more and more the object of investigations.

  9. Peptide-oligonucleotide conjugates as nanoscale building blocks for assembly of an artificial three-helix protein mimic

    DEFF Research Database (Denmark)

    Lou, Chenguang; Martos-Maldonado, Manuel C; Madsen, Charlotte S;

    2016-01-01

    Peptide-based structures can be designed to yield artificial proteins with specific folding patterns and functions. Template-based assembly of peptide units is one design option, but the use of two orthogonal self-assembly principles, oligonucleotide triple helix and a coiled coil protein domain...... formation have never been realized for de novo protein design. Here, we show the applicability of peptide-oligonucleotide conjugates for self-assembly of higher-ordered protein-like structures. The resulting nano-assemblies were characterized by ultraviolet-melting, gel electrophoresis, circular dichroism...... (CD) spectroscopy, small-angle X-ray scattering and transmission electron microscopy. These studies revealed the formation of the desired triple helix and coiled coil domains at low concentrations, while a dimer of trimers was dominating at high concentration. CD spectroscopy showed an extraordinarily...

  10. International Union of Basic and Clinical Pharmacology. XCV. Recent Advances in the Understanding of the Pharmacology and Biological Roles of Relaxin Family Peptide Receptors 1–4, the Receptors for Relaxin Family Peptides

    Science.gov (United States)

    Halls, Michelle L.; Bathgate, Ross A. D.; Sutton, Steve W.; Dschietzig, Thomas B.

    2015-01-01

    Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1–4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gαs, Gαi, and Gαo proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP1 is activated by Clq-tumor necrosis factor-related protein 8 and by small-molecular-weight agonists, such as ML290 [2-isopropoxy-N-(2-(3-(trifluoromethylsulfonyl)phenylcarbamoyl)phenyl)benzamide], that act allosterically. RXFP2 activates only the Gαs- and Gαo-coupled pathways. Relaxin-3 is primarily a neuropeptide, and its cognate receptor RXFP3 is a target for the treatment of depression, anxiety, and autism. A variety of peptide agonists, antagonists, biased agonists, and an allosteric modulator target RXFP3. Both RXFP3 and the related RXFP4 couple to Gαi/Gαo proteins. INSL5 has the properties of an incretin; it is secreted from the gut and is orexigenic. The expression of RXFP4 in gut, adipose tissue, and β-islets together with compromised glucose tolerance in INSL5 or RXFP4 knockout mice suggests a metabolic role. This review focuses on the many advances in our understanding of RXFP receptors in the last 5 years, their signal transduction mechanisms, the development of novel compounds that target RXFP1–4, the challenges facing the field, and current prospects for new therapeutics. PMID:25761609

  11. International Union of Basic and Clinical Pharmacology. XCV. Recent advances in the understanding of the pharmacology and biological roles of relaxin family peptide receptors 1-4, the receptors for relaxin family peptides.

    Science.gov (United States)

    Halls, Michelle L; Bathgate, Ross A D; Sutton, Steve W; Dschietzig, Thomas B; Summers, Roger J

    2015-01-01

    Relaxin, insulin-like peptide 3 (INSL3), relaxin-3, and INSL5 are the cognate ligands for the relaxin family peptide (RXFP) receptors 1-4, respectively. RXFP1 activates pleiotropic signaling pathways including the signalosome protein complex that facilitates high-sensitivity signaling; coupling to Gα(s), Gα(i), and Gα(o) proteins; interaction with glucocorticoid receptors; and the formation of hetero-oligomers with distinctive pharmacological properties. In addition to relaxin-related ligands, RXFP1 is activated by Clq-tumor necrosis factor-related protein 8 and by small-molecular-weight agonists, such as ML290 [2-isopropoxy-N-(2-(3-(trifluoromethylsulfonyl)phenylcarbamoyl)phenyl)benzamide], that act allosterically. RXFP2 activates only the Gα(s)- and Gα(o)-coupled pathways. Relaxin-3 is primarily a neuropeptide, and its cognate receptor RXFP3 is a target for the treatment of depression, anxiety, and autism. A variety of peptide agonists, antagonists, biased agonists, and an allosteric modulator target RXFP3. Both RXFP3 and the related RXFP4 couple to Gα(i)/Gα(o) proteins. INSL5 has the properties of an incretin; it is secreted from the gut and is orexigenic. The expression of RXFP4 in gut, adipose tissue, and β-islets together with compromised glucose tolerance in INSL5 or RXFP4 knockout mice suggests a metabolic role. This review focuses on the many advances in our understanding of RXFP receptors in the last 5 years, their signal transduction mechanisms, the development of novel compounds that target RXFP1-4, the challenges facing the field, and current prospects for new therapeutics. PMID:25761609

  12. High-throughput peptide mass fingerprinting and protein macroarray analysis using chemical printing strategies

    International Nuclear Information System (INIS)

    We describe a 'chemical printer' that uses piezoelectric pulsing for rapid and accurate microdispensing of picolitre volumes of fluid for proteomic analysis of 'protein macroarrays'. Unlike positive transfer and pin transfer systems, our printer dispenses fluid in a non-contact process that ensures that the fluid source cannot be contaminated by substrate during a printing event. We demonstrate automated delivery of enzyme and matrix solutions for on-membrane protein digestion and subsequent peptide mass fingerprinting (pmf) analysis directly from the membrane surface using matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). This approach bypasses the more commonly used multi-step procedures, thereby permitting a more rapid procedure for protein identification. We also highlight the advantage of printing different chemistries onto an individual protein spot for multiple microscale analyses. This ability is particularly useful when detailed characterisation of rare and valuable sample is required. Using a combination of PNGase F and trypsin we have mapped sites of N-glycosylation using on-membrane digestion strategies. We also demonstrate the ability to print multiple serum samples in a micro-ELISA format and rapidly screen a protein macroarray of human blood plasma for pathogen-derived antigens. We anticipate that the 'chemical printer' will be a major component of proteomic platforms for high-throughput protein identification and characterisation with widespread applications in biomedical and diagnostic discovery

  13. Combining peptide and DNA for protein assay: CRIP1 detection for breast cancer staging.

    Science.gov (United States)

    Xie, Haona; Li, Hao; Huang, Yue; Wang, Xiaoying; Yin, Yongmei; Li, Genxi

    2014-01-01

    In this work, a novel method for a protein assay is proposed which uses the specific protein-binding peptide of the target protein and sequence-specific DNA to interact with the target as the capture and detection probe, respectively. Meanwhile, since the DNA sequence can be coupled with gold nanoparticles to amplify the signal readout, a sensitive and easily operated method for protein assay is developed. We have also employed a transcription factor named as cysteine-rich intestinal protein 1 (CRIP1), which has been identified as an ideal biomarker for staging of breast cancer, as the model protein for this study. With the proposed method, CRIP1 can be determined in a linear range from 1.25 to 10.13 ng/mL, with a detection limit of 1.25 ng/mL. Furthermore, the proposed method can be directly used to assay CRIP1 in tissue samples. Owing to its desirable sensitivity, excellent reproducibility, and high selectivity, the proposed method may hold great potential in clinical practice in the future.

  14. Enrichment of Extracellular Matrix Proteins from Tissues and Digestion into Peptides for Mass Spectrometry Analysis.

    Science.gov (United States)

    Naba, Alexandra; Clauser, Karl R; Hynes, Richard O

    2015-07-23

    The extracellular matrix (ECM) is a complex meshwork of cross-linked proteins that provides biophysical and biochemical cues that are major regulators of cell proliferation, survival, migration, etc. The ECM plays important roles in development and in diverse pathologies including cardio-vascular and musculo-skeletal diseases, fibrosis, and cancer. Thus, characterizing the composition of ECMs of normal and diseased tissues could lead to the identification of novel prognostic and diagnostic biomarkers and potential novel therapeutic targets. However, the very nature of ECM proteins (large in size, cross-linked and covalently bound, heavily glycosylated) has rendered biochemical analyses of ECMs challenging. To overcome this challenge, we developed a method to enrich ECMs from fresh or frozen tissues and tumors that takes advantage of the insolubility of ECM proteins. We describe here in detail the decellularization procedure that consists of sequential incubations in buffers of different pH and salt and detergent concentrations and that results in 1) the extraction of intracellular (cytosolic, nuclear, membrane and cytoskeletal) proteins and 2) the enrichment of ECM proteins. We then describe how to deglycosylate and digest ECM-enriched protein preparations into peptides for subsequent analysis by mass spectrometry.

  15. Comprehensive analysis of protein glycosylation by solid-phase extraction of N-linked glycans and glycosite-containing peptides

    OpenAIRE

    Sun, Shisheng; Shah, Punit; Eshghi, Shadi Toghi; Yang, Weiming; Trikannad, Namita; Yang, Shuang; Chen, Lijun; Aiyetan, Paul; Höti, Naseruddin; Zhang, Zhen; Chan, Daniel W.; Hui ZHANG

    2015-01-01

    Comprehensive characterization of protein glycosylation is critical for understanding the structure and function of glycoproteins. However, due to the complexity and heterogeneity of glycoprotein conformations, current glycoprotein analyses focus mainly on either the de-glycosylated glycosylation site (glycosite)-containing peptides or the released glycans. Here, we describe a chemoenzymatic method called solid phase extraction of N-linked glycans and glycosite-containing peptides (NGAG) for ...

  16. Solution structures, dynamics, and ice growth inhibitory activity of peptide fragments derived from an antarctic yeast protein.

    Directory of Open Access Journals (Sweden)

    Syed Hussinien H Shah

    Full Text Available Exotic functions of antifreeze proteins (AFP and antifreeze glycopeptides (AFGP have recently been attracted with much interest to develop them as commercial products. AFPs and AFGPs inhibit ice crystal growth by lowering the water freezing point without changing the water melting point. Our group isolated the Antarctic yeast Glaciozyma antarctica that expresses antifreeze protein to assist it in its survival mechanism at sub-zero temperatures. The protein is unique and novel, indicated by its low sequence homology compared to those of other AFPs. We explore the structure-function relationship of G. antarctica AFP using various approaches ranging from protein structure prediction, peptide design and antifreeze activity assays, nuclear magnetic resonance (NMR studies and molecular dynamics simulation. The predicted secondary structure of G. antarctica AFP shows several α-helices, assumed to be responsible for its antifreeze activity. We designed several peptide fragments derived from the amino acid sequences of α-helical regions of the parent AFP and they also showed substantial antifreeze activities, below that of the original AFP. The relationship between peptide structure and activity was explored by NMR spectroscopy and molecular dynamics simulation. NMR results show that the antifreeze activity of the peptides correlates with their helicity and geometrical straightforwardness. Furthermore, molecular dynamics simulation also suggests that the activity of the designed peptides can be explained in terms of the structural rigidity/flexibility, i.e., the most active peptide demonstrates higher structural stability, lower flexibility than that of the other peptides with lower activities, and of lower rigidity. This report represents the first detailed report of downsizing a yeast AFP into its peptide fragments with measurable antifreeze activities.

  17. Low molecular weight peptides derived from sarcoplasmic proteins produced by an autochthonous starter culture in a beaker sausage model

    Directory of Open Access Journals (Sweden)

    Constanza M. López

    2015-06-01

    Significance: The selection of a specific autochthonous starter culture guarantees the hygiene and typicity of fermented sausages. The identification of new peptides as well as new target proteins by means of peptidomics represents a significant step toward the elucidation of the role of microorganisms in meat proteolysis. Moreover, these peptides may be further used as biomarkers capable to certify the use of the applied autochthonous starter culture described here.

  18. Effect of peptides derived from food proteins on blood pressure – a meta-analysis of randomised controlled trials

    OpenAIRE

    Pripp, Are Hugo

    2008-01-01

    Background: Peptides derived from food proteins have in clinical trials shown an effect on blood pressure. Their biological mechanism is mainly due to inhibition of angiotensin-I-converting enzyme (ACE) and thereby regulation of blood pressure through the renin-angiotensin system. A meta-analysis of these trials is needed to better quantify their effect, sources of variation and possible publication bias. Objective: To perform a meta-analysis of placebo-controlled clinical trials on peptides ...

  19. Interplay between Structure and Charge as a Key to Allosteric Modulation of Human 20S Proteasome by the Basic Fragment of HIV-1 Tat Protein.

    Directory of Open Access Journals (Sweden)

    Przemysław Karpowicz

    Full Text Available The proteasome is a giant protease responsible for degradation of the majority of cytosolic proteins. Competitive inhibitors of the proteasome are used against aggressive blood cancers. However, broadening the use of proteasome-targeting drugs requires new mechanistic approaches to the enzyme's inhibition. In our previous studies we described Tat1 peptide, an allosteric inhibitor of the proteasome derived from a fragment of the basic domain of HIV-Tat1 protein. Here, we attempted to dissect the structural determinants of the proteasome inhibition by Tat1. Single- and multiple- alanine walking scans were performed. Tat1 analogs with stabilized beta-turn conformation at positions 4-5 and 8-9, pointed out by the molecular dynamics modeling and the alanine scan, were synthesized. Structure of Tat1 analogs were analyzed by circular dichroism, Fourier transform infrared and nuclear magnetic resonance spectroscopy studies, supplemented by molecular dynamics simulations. Biological activity tests and structural studies revealed that high flexibility and exposed positive charge are hallmarks of Tat1 peptide. Interestingly, stabilization of a beta-turn at the 8-9 position was necessary to significantly improve the inhibitory potency.

  20. Rational design of a photo-responsive UVR8-derived protein and a self-assembling peptide-protein conjugate for responsive hydrogel formation

    Science.gov (United States)

    Zhang, Xiaoli; Dong, Chunming; Huang, Weiyun; Wang, Huaimin; Wang, Ling; Ding, Dan; Zhou, Hao; Long, Jiafu; Wang, Tingliang; Yang, Zhimou

    2015-10-01

    Responsive hydrogels hold great potential in controllable drug delivery, regenerative medicine, sensing, etc. We introduced in this study the first example of a photo-responsive protein for hydrogel formation. Based on the first example of the crystal structure of a photo-responsive protein, Arabidopsis thaliana protein UVR8, we designed and expressed its derived protein UVR8-1 with a hexa-peptide WRESAI. We also prepared supramolecular nanofibers with a TIP-1 protein at their surface. The simple mixing of these two components resulted in rapid hydrogel formation through the specific interactions between the protein TIP-1 and the peptide WRESAI. Since the protein could show a reversible dimer-monomer transformation, the resulting gels also showed a reversible gel-sol phase transition which was controlled by photo-irradiation. The photo-controllable gel-sol phase transition could be applied for protein delivery and cell separation.Responsive hydrogels hold great potential in controllable drug delivery, regenerative medicine, sensing, etc. We introduced in this study the first example of a photo-responsive protein for hydrogel formation. Based on the first example of the crystal structure of a photo-responsive protein, Arabidopsis thaliana protein UVR8, we designed and expressed its derived protein UVR8-1 with a hexa-peptide WRESAI. We also prepared supramolecular nanofibers with a TIP-1 protein at their surface. The simple mixing of these two components resulted in rapid hydrogel formation through the specific interactions between the protein TIP-1 and the peptide WRESAI. Since the protein could show a reversible dimer-monomer transformation, the resulting gels also showed a reversible gel-sol phase transition which was controlled by photo-irradiation. The photo-controllable gel-sol phase transition could be applied for protein delivery and cell separation. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05213k

  1. MOLS 2.0: software package for peptide modeling and protein-ligand docking.

    Science.gov (United States)

    Paul, D Sam; Gautham, N

    2016-10-01

    We previously developed an algorithm to perform conformational searches of proteins and peptides, and to perform the docking of ligands to protein receptors. In order to identify optimal conformations and docked poses, this algorithm uses mutually orthogonal Latin squares (MOLS) to rationally sample the vast conformational (or docking) space, and then analyzes this relatively small sample using a variant of mean field theory. The conformational search part of the algorithm was denoted MOLS 1.0. The docking portion of the algorithm, which allows only "flexible ligand/rigid receptor" docking, was denoted MOLSDOCK. Both are FORTRAN-based command-line-only molecular docking computer programs, though a GUI was developed later for MOLS 1.0. Both the conformational search and the rigid receptor docking parts of the algorithm have been extensively validated. We have now further enhanced the capabilities of the program by incorporating "induced fit" side-chain receptor flexibility for docking peptide ligands. Benchmarking and extensive testing is now being carried out for the flexible receptor portion of the docking. Additionally, to make both the peptide conformational search and docking algorithms (the latter including both flexible ligand/rigid receptor and flexible ligand/flexible receptor techniques) more accessible to the research community, we have developed MOLS 2.0, which incorporates a new Java-based graphical user interface (GUI). Here, we give a detailed description of MOLS 2.0. The source code and binary for MOLS 2.0 are distributed free (under a GNU Lesser General Public License) to the scientific community. They are freely available for download at https://sourceforge.net/projects/mols2-0/files/ . PMID:27638416

  2. MOLS 2.0: software package for peptide modeling and protein-ligand docking.

    Science.gov (United States)

    Paul, D Sam; Gautham, N

    2016-10-01

    We previously developed an algorithm to perform conformational searches of proteins and peptides, and to perform the docking of ligands to protein receptors. In order to identify optimal conformations and docked poses, this algorithm uses mutually orthogonal Latin squares (MOLS) to rationally sample the vast conformational (or docking) space, and then analyzes this relatively small sample using a variant of mean field theory. The conformational search part of the algorithm was denoted MOLS 1.0. The docking portion of the algorithm, which allows only "flexible ligand/rigid receptor" docking, was denoted MOLSDOCK. Both are FORTRAN-based command-line-only molecular docking computer programs, though a GUI was developed later for MOLS 1.0. Both the conformational search and the rigid receptor docking parts of the algorithm have been extensively validated. We have now further enhanced the capabilities of the program by incorporating "induced fit" side-chain receptor flexibility for docking peptide ligands. Benchmarking and extensive testing is now being carried out for the flexible receptor portion of the docking. Additionally, to make both the peptide conformational search and docking algorithms (the latter including both flexible ligand/rigid receptor and flexible ligand/flexible receptor techniques) more accessible to the research community, we have developed MOLS 2.0, which incorporates a new Java-based graphical user interface (GUI). Here, we give a detailed description of MOLS 2.0. The source code and binary for MOLS 2.0 are distributed free (under a GNU Lesser General Public License) to the scientific community. They are freely available for download at https://sourceforge.net/projects/mols2-0/files/ .

  3. Signal Peptide-Binding Drug as a Selective Inhibitor of Co-Translational Protein Translocation

    Science.gov (United States)

    Vermeire, Kurt; Bell, Thomas W.; Van Puyenbroeck, Victor; Giraut, Anne; Noppen, Sam; Liekens, Sandra; Schols, Dominique; Hartmann, Enno

    2014-01-01

    In eukaryotic cells, surface expression of most type I transmembrane proteins requires translation and simultaneous insertion of the precursor protein into the endoplasmic reticulum (ER) membrane for subsequent routing to the cell surface. This co-translational translocation pathway is initiated when a hydrophobic N-terminal signal peptide (SP) on the nascent protein emerges from the ribosome, binds the cytosolic signal recognition particle (SRP), and targets the ribosome-nascent chain complex to the Sec61 translocon, a universally conserved protein-conducting channel in the ER-membrane. Despite their common function in Sec61 targeting and ER translocation, SPs have diverse but unique primary sequences. Thus, drugs that recognise SPs could be exploited to inhibit translocation of specific proteins into the ER. Here, through flow cytometric analysis the small-molecule macrocycle cyclotriazadisulfonamide (CADA) is identified as a highly selective human CD4 (hCD4) down-modulator. We show that CADA inhibits CD4 biogenesis and that this is due to its ability to inhibit co-translational translocation of CD4 into the lumen of the ER, both in cells as in a cell-free in vitro translation/translocation system. The activity of CADA maps to the cleavable N-terminal SP of hCD4. Moreover, through surface plasmon resonance analysis we were able to show direct binding of CADA to the SP of hCD4 and identify this SP as the target of our drug. Furthermore, CADA locks the SP in the translocon during a post-targeting step, possibly in a folded state, and prevents the translocation of the associated protein into the ER lumen. Instead, the precursor protein is routed to the cytosol for degradation. These findings demonstrate that a synthetic, cell-permeable small-molecule can be developed as a SP-binding drug to selectively inhibit protein translocation and to reversibly regulate the expression of specific target proteins. PMID:25460167

  4. Signal peptide-binding drug as a selective inhibitor of co-translational protein translocation.

    Directory of Open Access Journals (Sweden)

    Kurt Vermeire

    2014-12-01

    Full Text Available In eukaryotic cells, surface expression of most type I transmembrane proteins requires translation and simultaneous insertion of the precursor protein into the endoplasmic reticulum (ER membrane for subsequent routing to the cell surface. This co-translational translocation pathway is initiated when a hydrophobic N-terminal signal peptide (SP on the nascent protein emerges from the ribosome, binds the cytosolic signal recognition particle (SRP, and targets the ribosome-nascent chain complex to the Sec61 translocon, a universally conserved protein-conducting channel in the ER-membrane. Despite their common function in Sec61 targeting and ER translocation, SPs have diverse but unique primary sequences. Thus, drugs that recognise SPs could be exploited to inhibit translocation of specific proteins into the ER. Here, through flow cytometric analysis the small-molecule macrocycle cyclotriazadisulfonamide (CADA is identified as a highly selective human CD4 (hCD4 down-modulator. We show that CADA inhibits CD4 biogenesis and that this is due to its ability to inhibit co-translational translocation of CD4 into the lumen of the ER, both in cells as in a cell-free in vitro translation/translocation system. The activity of CADA maps to the cleavable N-terminal SP of hCD4. Moreover, through surface plasmon resonance analysis we were able to show direct binding of CADA to the SP of hCD4 and identify this SP as the target of our drug. Furthermore, CADA locks the SP in the translocon during a post-targeting step, possibly in a folded state, and prevents the translocation of the associated protein into the ER lumen. Instead, the precursor protein is routed to the cytosol for degradation. These findings demonstrate that a synthetic, cell-permeable small-molecule can be developed as a SP-binding drug to selectively inhibit protein translocation and to reversibly regulate the expression of specific target proteins.

  5. Ionic liquid-polyvinyl chloride ionomer for highly selective isolation of basic proteins.

    Science.gov (United States)

    Shu, Yang; Chen, Xu-Wei; Wang, Jian-Hua

    2010-04-15

    Hydrophilic ionic liquid-polyvinyl chloride (PVC) hybrids were prepared by immobilizing N-methylimidazole (N-mim) to PVC chains in toluene. The NmimCl-PVC hybrids were characterized by FT-IR, (1)H NMR, surface charge analysis and elemental analysis. The immobilization ratio, i.e., the percentage of chloride on PVC chain reacting with N-mim to form the hybrid, varies from 4.3% to 15.1% by increasing the N-mim/PVC molar ratio. The most distinct feature of the hybrid is its excellent selectivity for adsorbing basic proteins by effective suppression of the non-specific protein adsorption by pure PVC, and a higher immobilization ratio facilitates better selectivity. In Tris-HCl buffer, 100 microg mL(-1) of basic proteins, i.e., lysozyme (Lys), cytochrome c (cyt-c) and hemoglobin (Hb), were favorably adsorbed with efficiencies of 97%, 98% and 94% by the hybrid with an immobilization ratio of 15.1%, while the adsorption of acidic proteins, i.e., bovine albumin serum (BSA), transferring (Trf) and immunoglobulin G (IgG) were negligible. The retained Lys, cyt-c and Hb could be readily recovered by elution with phosphate buffer, carbonate buffer and SDS solution with efficiencies of 89%, 87% and 84%, respectively. Another feature of the hybrid is the significant improvement of the biocompatibility characterized by the maintenance of the activity of hemoglobin after adsorption and elution process. The practical usefulness of the hybrid was demonstrated by selective isolation of hemoglobin from human whole blood.

  6. Identifying immunogenic CD4+ T-cell epitopes of Myeloid cell leukemia 1 using overlapping 20-mer peptides spanning the whole protein

    DEFF Research Database (Denmark)

    Woodworth, Joshua S.; Agger, Else Marie; Hansen, Paul Robert

    2015-01-01

    ) small-molecule inhibitors [6] and (iii) peptide inhibitors [7]. In recent years, therapeutic vaccination with synthetic peptides derived from anti-apoptotic proteins such as Mcl-1 has emerged as a promising strategy against hematological cancers. In this study, 34 overlapping 20-mer peptides, spanning...

  7. Synthetic protein scaffolds based on peptide motifs and cognate adaptor domains for improving metabolic productivity

    Directory of Open Access Journals (Sweden)

    Anselm H.C. Horn

    2015-11-01

    Full Text Available The efficiency of many cellular processes relies on the defined interaction among different proteins within the same metabolic or signaling pathway. Consequently, a spatial colocalization of functionally interacting proteins has frequently emerged during evolution. This concept has been adapted within the synthetic biology community for the purpose of creating artificial scaffolds. A recent advancement of this concept is the use of peptide motifs and their cognate adaptor domains. SH2, SH3, GBD, and PDZ domains have been used most often in research studies to date. The approach has been successfully applied to the synthesis of a variety of target molecules including catechin, D-glucaric acid, H2, hydrochinone, resveratrol, butyrate, gamma-aminobutyric acid, and mevalonate. Increased production levels of up to 77-fold have been observed compared to non-scaffolded systems. A recent extension of this concept is the creation of a covalent linkage between peptide motifs and adaptor domains, which leads to a more stable association of the scaffolded systems and thus bears the potential to further enhance metabolic productivity.

  8. /sup 125/I-peptide mapping of protein III isolated from four strains of Neisseria gonorrhoeae

    Energy Technology Data Exchange (ETDEWEB)

    Judd, R.C.

    1982-08-01

    Gonococcal outer-membrane protein I (PI) and PIII were isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis from reduced and unreduced whole-cell and outer-membrane lysates of four strains of nonpiliated (P-), transparent (O-) Neisseria gonorrhoeae. These proteins were radioiodinated and digested with alpha-chymotrypsin. The resultant /sup 125/I-peptides were then resolved by high-voltage thin-layer electrophoresis, followed by ascending thin-layer chromatography, and visualized by autoradiography. Results corroborated previous observations regarding the structural relationships of PIs having different apparent subunit molecular weights. All PIIIs had very similar apparent primary structures, regardless of the strain from which they were isolated, the source (i.e., whole cells or outer membranes), or the reduction state of the sodium dodecyl sulfate lysates. By the techniques used, it appeared that PIII is structurally similar in all of the gonococcal strains studied, even though each strain had structurally unique PIs.

  9. Random Insertion of a TetR-Inducing Peptide Tag into Escherichia coli Proteins Allows Analysis of Protein Levels by Induction of Reporter Gene Expression

    OpenAIRE

    Schlicht, Maximilian; Berens, Christian; Daam, Janko; Hillen, Wolfgang

    2006-01-01

    The insertion element InsTipα was constructed to generate protein expression data. It randomly fuses the TetR-inducing peptide Tip to the affected reading frame. Fusion protein expression is quantified by Tet-regulated reporter gene expression. The expression patterns of tagged Escherichia coli genes fully agree with published data from transcriptional fusions or microarrays, validating the Tip tag approach.

  10. Peptides interfering with protein-protein interactions in the ethylene signaling pathway delay tomato fruit ripening.

    Science.gov (United States)

    Bisson, Melanie M A; Kessenbrock, Mareike; Müller, Lena; Hofmann, Alexander; Schmitz, Florian; Cristescu, Simona M; Groth, Georg

    2016-01-01

    The plant hormone ethylene is involved in the regulation of several processes with high importance for agricultural applications, e.g. ripening, aging and senescence. Previous work in our group has identified a small peptide (NOP-1) derived from the nuclear localization signal of the Arabidopsis ethylene regulator ETHYLENE INSENSITIVE-2 (EIN2) C-terminal part as efficient inhibitor of ethylene responses. Here, we show that NOP-1 is also able to efficiently disrupt EIN2-ETR1 complex formation in tomato, indicating that the NOP-1 inhibition mode is conserved across plant species. Surface application of NOP-1 on green tomato fruits delays ripening similar to known inhibitors of ethylene perception (MCP) and ethylene biosynthesis (AVG). Fruits treated with NOP-1 showed similar ethylene production as untreated controls underlining that NOP-1 blocks ethylene signaling by targeting an essential interaction in this pathway, while having no effect on ethylene biosynthesis. PMID:27477591

  11. Phosphate cycling on the basic protein of Plodia interpunctella granulosis virus

    Science.gov (United States)

    Funk, C. J.; Consigli, R. A.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    The presence of infected cell-specific phosphoproteins was investigated in Plodia interpunctella granulosis virus (PiGV)-infected fat body using [32P]orthophosphoric acid labeling. One infected cell-specific phosphoprotein had a mobility similar to that of the basic protein (VP12) of PiGV. Further analysis, using immunoblotting and acid-urea gel analysis of infected fat body, confirmed that this phosphoprotein was VP12. However we did not detect phosphorylated VP12 in 32P-labeled nucleocapsids. Phosphoamino acid analysis of 32P-labeled VP12 revealed that phosphoserine was present in the basic protein. Since VP12 is phosphorylated in the infected cell, but not in the nucleocapsid, it appears that dephosphorylation of VP12 is a critical event in the life cycle of the virus. We therefore assayed virus nucleocapsids and infected fat body for the presence of phosphatase activity. Phosphatase activity was not detected in the virus, but the infected fat body had more activity than uninfected fat body. A model for nucleocapsid assembly and uncoating is presented which takes into account the phosphorylation state of VP12, the role of Zn2+ in the nucleocapsid, and the role of the capsid-associated kinase.

  12. CONTENTS OF SERUM MYELIN BASIC PROTEIN-IGG ANTIBODIES COMPLEXES IN NORMAL PREGNANCY AND GESTOSIS

    Directory of Open Access Journals (Sweden)

    V. G. Levchenko

    2010-01-01

    Full Text Available Serum levels of myelin basic protein (MBP-bound immune complexes were studied in blood sera from women with gestosis, as compared with those in normal pregnancy and non-pregnant woman. The amounts of IgG-MBP complex in blood serum were determined by enzyme immunoassay using isolated anti-МBP-antibodies. The study has shown that about 0.05 mcg of IgG ml of blood serum are associated with myelin basic protein in unpregnant women or in normal pregnancy. Mild gestosis is accompanied by a 2-3-fold increase in MBP immunocomplex concentrations in blood serum. More severe stages of gestosis are characterized by its further rise, thus achieving maximal values of such MBP immune complexes (0.8 mcg/ml in patients with pre-eclampsia and eclampsia. Their amounts were reduced twice after the periods of eclampsia. Serum levels of MBP-bound IgGs may be used to determine severity of gestosis and to predict a risk of eclampsia in pregnant women.

  13. Making Myelin Basic Protein -from mRNA transport to localized translation

    Directory of Open Access Journals (Sweden)

    Christina eMüller

    2013-09-01

    Full Text Available In the central nervous system (CNS of most vertebrates, oligodendrocytes enwrap neuronal axons with extensions of their plasma membrane to form the myelin sheath. Several proteins are characteristically found in myelin of which Myelin Basic Protein (MBP is the second most abundant one after Proteolipid Protein (PLP. The lack of functional MBP in rodents results in a severe hypomyelinated phenotype in the CNS demonstrating its importance for myelin synthesis. Mbp mRNA is transported from the nucleus to the plasma membrane and is translated locally at the axon-glial contact site. Axonal properties such as diameter or electrical activity influence the degree of myelination. As oligodendrocytes can myelinate many axonal segments with varying properties, localized MBP translation represents an important part of a rapid and axon-tailored synthesis machinery. MBP’s ability to compact cellular membranes may be problematic for the integrity of intracellular membranous organelles and can also explain why MBP is transported in oligodendrocytes in the form of an mRNA rather than as a protein. Here we review the recent findings regarding intracellular transport and signalling mechanisms leading to localized translation of Mbp mRNA in oligodendrocytes. More detailed insights into the MBP synthesis pathway are important for a better understanding of the myelination process and may foster the development of remyelination therapies for demyelinating diseases.

  14. Making myelin basic protein -from mRNA transport to localized translation.

    Science.gov (United States)

    Müller, Christina; Bauer, Nina M; Schäfer, Isabelle; White, Robin

    2013-09-27

    In the central nervous system (CNS) of most vertebrates, oligodendrocytes enwrap neuronal axons with extensions of their plasma membrane to form the myelin sheath. Several proteins are characteristically found in myelin of which myelin basic protein (MBP) is the second most abundant one after proteolipid protein. The lack of functional MBP in rodents results in a severe hypomyelinated phenotype in the CNS demonstrating its importance for myelin synthesis. Mbp mRNA is transported from the nucleus to the plasma membrane and is translated locally at the axon-glial contact site. Axonal properties such as diameter or electrical activity influence the degree of myelination. As oligodendrocytes can myelinate many axonal segments with varying properties, localized MBP translation represents an important part of a rapid and axon-tailored synthesis machinery. MBP's ability to compact cellular membranes may be problematic for the integrity of intracellular membranous organelles and can also explain why MBP is transported in oligodendrocytes in the form of an mRNA rather than as a protein. Here we review the recent findings regarding intracellular transport and signaling mechanisms leading to localized translation of Mbp mRNA in oligodendrocytes. More detailed insights into the MBP synthesis pathway are important for a better understanding of the myelination process and may foster the development of remyelination therapies for demyelinating diseases.

  15. Adsorption and protonation of peptides and proteins in pH responsive gels

    Science.gov (United States)

    Longo, Gabriel S.; Szleifer, Igal

    2016-08-01

    To describe the non-trivial features of the equilibrium protonation and physical adsorption of peptides/proteins in pH-responsive hydrogels, we summarize our recent theoretical work on the subject. In these systems, molecular confinement in nanometer-sized environments modifies the balance between chemical state, physical interactions and molecular organization, which results in a behavior that is qualitatively different from what is expected from assuming the bulk solution protonation. To enhance adsorption, the pH-dependent deprotonation curves of all amino acids of adsorbed proteins are adequately shifted and deformed, which depends, in a complex fashion, on the specific amino acid. This possibility of modifying different acid–base equilibriums gives the adsorbed protein degrees of freedom to regulate charge and enhance electrostatic attractions under a wide range of experimental conditions. Protein adsorption modifies the microenvironment inside the hydrogel, particularly the gel pH. As a result, the state of protonation of the network is different before and after adsorption. The physicochemical considerations described in this review can be useful in the design of functional materials involving protein adsorption.

  16. Gastric emptying, gastric secretion and enterogastrone response after administration of milk proteins or their peptide hydrolysates in humans

    DEFF Research Database (Denmark)

    Calbet, Jose A L; Holst, Jens Juul

    2004-01-01

    -times of (mean +/- SEM) 21.4 +/- 1.3, 19.3 +/- 2.2, 18.0 +/- 2.5 and 19.4 +/- 2.8 min, for the WHY, CAHY, C and W, respectively. The rates of intestinal absorption of water and amino acids were similar with the exception of the casein protein solution, for which the speed of intestinal amino acid absorption...... absorption and enterogastrone response, after the intragastric administration of complete cow milk proteins or their respective peptide hydrolysates in man. METHODS: Six healthy males were randomized to receive one of the following four solutions: whey whole protein (W), casein whole protein (C), whey...... by small differences in the amino acid composition or protein solubility. In contrast, the GIP response is accentuated when milk proteins are delivered as peptide hydrolysates....

  17. Solution structure and peptide binding of the PTB domain from the AIDA1 postsynaptic signaling scaffolding protein.

    Directory of Open Access Journals (Sweden)

    Ekaterina Smirnova

    Full Text Available AIDA1 links persistent chemical signaling events occurring at the neuronal synapse with global changes in gene expression. Consistent with its role as a scaffolding protein, AIDA1 is composed of several protein-protein interaction domains. Here we report the NMR structure of the carboxy terminally located phosphotyrosine binding domain (PTB that is common to all AIDA1 splice variants. A comprehensive survey of peptides identified a consensus sequence around an NxxY motif that is shared by a number of related neuronal signaling proteins. Using peptide arrays and fluorescence based assays, we determined that the AIDA1 PTB domain binds amyloid protein precursor (APP in a similar manner to the X11/Mint PTB domain, albeit at reduced affinity (∼10 µM that may allow AIDA1 to effectively sample APP, as well as other protein partners in a variety of cellular contexts.

  18. Structure activity relationship modelling of milk protein-derived peptides with dipeptidyl peptidase IV (DPP-IV) inhibitory activity.

    Science.gov (United States)

    Nongonierma, Alice B; FitzGerald, Richard J

    2016-05-01

    Quantitative structure activity type models were developed in an attempt to predict the key features of peptide sequences having dipeptidyl peptidase IV (DPP-IV) inhibitory activity. The models were then employed to help predict the potential of peptides, which are currently reported in the literature to be present in the intestinal tract of humans following milk/dairy product ingestion, to act as inhibitors of DPP-IV. Two models (z- and v-scale) for short (2-5 amino acid residues) bovine milk peptides, behaving as competitive inhibitors of DPP-IV, were developed. The z- and the v-scale models (p<0.05, R(2) of 0.829 and 0.815, respectively) were then applied to 56 milk protein-derived peptides previously reported in the literature to be found in the intestinal tract of humans which possessed a structural feature of DPP-IV inhibitory peptides (P at the N2 position). Ten of these peptides were synthetized and tested for their in vitro DPP-IV inhibitory properties. There was no agreement between the predicted and experimentally determined DPP-IV half maximal inhibitory concentrations (IC50) for the competitive peptide inhibitors. However, the ranking for DPP-IV inhibitory potency of the competitive peptide inhibitors was conserved. Furthermore, potent in vitro DPP-IV inhibitory activity was observed with two peptides, LPVPQ (IC50=43.8±8.8μM) and IPM (IC50=69.5±8.7μM). Peptides present within the gastrointestinal tract of human may have promise for the development of natural DPP-IV inhibitors for the management of serum glucose.

  19. Study on search for antioxidant peptides in unused protein resources and their production; Miriyo tanpaku shigen kara no kosanka pepuchido no tansaku to seisan ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    For the development of antioxidants that are high in use value, peptides are produced in a bioreactor from so-far-unused or little-used protein resources originating in marine organisms collected along the Sanriku coast, and antioxidants that they may contain are searched for. Three kinds of red alga, eight kinds of brown alga, and internal organs of processed fish are treated in the bioreactor. The bioreactor is a rotary membrane type especially built for the effective decomposition of proteins in this study. Reaction solutions containing proteins and enzymes are let through an ultrafiltration membrane module in rotation at a high speed, and the products with their molecules reduced in weight are effectively taken out of the system (free of clogging). The specimens checked for antioxidant features are all found to be positive when subjected to the iron rhodanide method or carotene method, the two methods determining the change in the amount of oxygen in hydroperoxide and {beta}-carotene that are produced when the linolic acid is oxidized. Every one of the specimens prepared for this study exhibits antioxidant features in plural, different mechanisms. It is necessary to collect further basic findings about oxidation inhibiting mechanisms for the development of more active antioxidant peptides. 39 refs., 46 figs., 8 tabs.

  20. Combined effects of soy isoflavones and milk basic protein on bone mineral density in hind-limb unloaded mice.

    Science.gov (United States)

    Matsumoto, Yu; Tousen, Yuko; Nishide, Yoriko; Tadaishi, Miki; Kato, Ken; Ishimi, Yoshiko

    2016-03-01

    We examined whether the combination of isoflavone and milk basic protein both are reported to be effective for bone metabolism, prevents bone loss induced by skeletal hind-limb unloading in mice. Female ddY strain mice, aged 8 weeks, were divided into six groups (n = 6-8 each): (1) normally housed group, (2) loading group, (3) hind-limb unloading group fed a control diet, (4) hind-limb unloading group fed a 0.2% isoflavone conjugates diet, (5) hind-limb unloading group fed a 1.0% milk basic protein diet, and (6) hind-limb unloading group fed a 0.2% isoflavone conjugates and 1.0% milk basic protein diet. After 3 weeks, femoral bone mineral density was markedly reduced in unloading mice. The combination of isoflavone and milk basic protein showed cooperative effects in preventing bone loss and milk basic protein inhibited the increased expression of osteogenic genes in bone marrow cells in unloading mice. These results suggest that the combination of soy isoflavone and milk basic protein may be useful for bone health in subjects with disabling conditions as well as astronauts.

  1. Determination of nutritional and bioactive properties of peptides in enzymatic pea, chickpea, and mung bean protein hydrolysates.

    Science.gov (United States)

    Aluko, Rotimi E

    2008-01-01

    Within the primary structure of many pea and mung bean proteins are peptide sequences that can potentially be used in the formulation of therapeutic products for the treatment and prevention of human diseases. However, these peptide sequences need protease treatments before they can be released free of the parent proteins. Unlike chemical hydrolysis, enzymatic treatment enables more efficient tailoring of peptide products without formation of toxic by-products or destruction of amino acids. This review provides information on current methods that have been used to convert inactive pea and mung bean proteins into bioactive peptides. It focuses on 3 main bioactive properties, such as inhibitions of (1) angiotensin converting enzyme (ACE) activity; (2) calmodulin (CaM)-dependent enzymes; and (3) copper-chelating activity. ACE is an established marker for hypertension, high levels of some CaM-dependent enzymes are risk factors for various human diseases including cancer and Alzheimer's disease, and high vascular copper concentrations may potentiate atherosclerosis. Also reviewed are the production and evaluation of activity of hypoallergenic peptides that may offer protection against anaphylactic reactions. The 3 main proteins discussed are chickpea, mung bean, and field pea.

  2. Chemical synthesis of transmembrane peptide and its application for research on the transmembrane-juxtamembrane region of membrane protein.

    Science.gov (United States)

    Sato, Takeshi

    2016-11-01

    Membrane proteins possess one or more hydrophobic regions that span the membrane and interact with the lipids that constitute the membrane. The interactions between the transmembrane (TM) region and lipids affect the structure and function of these membrane proteins. Molecular characterization of synthetic TM peptides in lipid bilayers helps to understand how the TM region participates in the formation of the structure and in the function of membrane proteins. The use of synthetic peptides enables site-specific labeling and modification and allows for designing of an artificial TM sequence. Research involving such samples has resulted in significant increase in the knowledge of the mechanisms that govern membrane biology. In this review, the chemical synthesis of TM peptides has been discussed. The preparation of synthetic TM peptides is still not trivial; however, the accumulated knowledge summarized here should provide a basis for preparing samples for spectroscopic analyses. The application of synthetic TM peptides for gaining insights into the mechanism of signal transduction by receptor tyrosine kinase (RTK) has also been discussed. RTK is a single TM protein and is one of the difficult targets in structural biology as crystallization of the full-length receptor has not been successful. This review describes the structural characterization of the synthetic TM-juxtamembrane sequence and proposes a possible scheme for the structural changes in this region for the activation of ErbBs, the epidermal growth factor receptor family. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 613-621, 2016. PMID:26573237

  3. STUDY OF PROTEINS AND PEPTIDES FROM PLANT FOODS AND THEIR POSSIBLE EFFECTS ON HUMAN HEALTH

    OpenAIRE

    Giangrieco, Ivana

    2011-01-01

    Foods can affect human health beyond basic nutritional effects. In fact, foods are a source of different molecules, including nutraceuticals, i.e. health-promoting molecules, and proteins that can cause allergic reactions. The objectives of this thesis are in the framework of a research program focused on the study of allergens and nutraceuticals from plant foods and their possible effects on human health. Kiwifruit has been chosen as a model of food endowed with beneficial effects on human h...

  4. Proteolytic activity of prostate-specific antigen (PSA towards protein substrates and effect of peptides stimulating PSA activity.

    Directory of Open Access Journals (Sweden)

    Johanna M Mattsson

    Full Text Available Prostate-specific antigen (PSA or kallikrein-related peptidase-3, KLK3 exerts chymotrypsin-like proteolytic activity. The main biological function of PSA is the liquefaction of the clot formed after ejaculation by cleavage of semenogelins I and II in seminal fluid. PSA also cleaves several other substrates, which may explain its putative functions in prostate cancer and its antiangiogenic activity. We compared the proteolytic efficiency of PSA towards several protein and peptide substrates and studied the effect of peptides stimulating the activity of PSA with these substrates. An endothelial cell tube formation model was used to analyze the effect of PSA-degraded protein fragments on angiogenesis. We showed that PSA degrades semenogelins I and II much more efficiently than other previously identified protein substrates, e.g., fibronectin, galectin-3 and IGFBP-3. We identified nidogen-1 as a new substrate for PSA. Peptides B2 and C4 that stimulate the activity of PSA towards small peptide substrates also enhanced the proteolytic activity of PSA towards protein substrates. Nidogen-1, galectin-3 or their fragments produced by PSA did not have any effect on endothelial cell tube formation. Although PSA cleaves several other protein substrates, in addition to semenogelins, the physiological importance of this activity remains speculative. The PSA levels in prostate are very high, but several other highly active proteases, such as hK2 and trypsin, are also expressed in the prostate and may cleave protein substrates that are weakly cleaved by PSA.

  5. Optical spectroscopy investigation of peptides issued from the AML1-ETO–E-protein complex relevant to acute myeloid leukemia

    OpenAIRE

    Porumb, H.

    2008-01-01

    The expression of AML1-ETO, resulting from the t(8; 21) chromosomal translocation causes 15% of acute myeloid leukaemias. The NHR2 region of ETO, bearing the motif LxxLL, is involved in the oligomerisation of the AML1-ETO. “Peptide NHR2” is one of the objects of the present investigation. The TAFH region of ETO may recruit AML1-ETO to transcription activators, such as E-protein. “Peptide TAFH” is another object of the present investigation. TAFH interacts with E-protein through the AD1 domain...

  6. Reaction mechanisms in the radiolysis of peptides, polypeptides and proteins II reactions at side-chain loci in model systems

    International Nuclear Information System (INIS)

    The major emphasis in radiation biology at the molecular level has been on the nucleic acid component of the nucleic acid-protein complex because of its primary genetic importance. But there is increasing evidence that radiation damage to the protein component also has important biological implications. Damage to capsid protein now appears to be a major factor in the radiation inactivation of phage and other viruses. And, there is increasing evidence that radiation-chemical change in the protein component of chromation leads to changes in the stability of the repressor-operator complexes involved in gene expression. Knowledge of the radiation chemistry of protein is also of importance in other fields such as the application of radiation sterilization to foods and drugs. Recent findings that a class of compounds, the α,α'-diaminodicarboxylic acids, not normally present in food proteins, are formed in protein radiolysis is of particular significance since certain of their peptide derivatives have been showing to exhibit immunological activity. The purpose of this review is to bring together and to correlate our present knowledge of products and mechanisms in the radiolysis of peptides, polypeptides and proteins both aqueous and solid-state. In part 1 we presented a discussion of the radiation-induced reactions of the peptide main-chain in model peptide and polypeptide systems. Here in part 2 the emphasis is on the competing radiation chemistry at side-chain loci of peptide derivatives of aliphatic, aromatic-unsaturated and sulfur-containing amino acids in similar systems. Information obtained with the various experimental techniques of product analysis, competition kinetics, spin-trapping, pulse radiolysis, and ESR spectroscopy are included

  7. Nucleotide sequence and structural determinants of specific binding of coat protein or coat protein peptides to the 3' untranslated region of alfalfa mosaic virus RNA 4.

    Science.gov (United States)

    Houser-Scott, F; Baer, M L; Liem, K F; Cai, J M; Gehrke, L

    1994-01-01

    The specific binding of alfalfa mosaic virus coat protein to viral RNA requires determinants in the 3' untranslated region (UTR). Coat protein and peptide binding sites in the 3' UTR of alfalfa mosaic virus RNA 4 have been analyzed by hydroxyl radical footprinting, deletion mapping, and site-directed mutagenesis experiments. The 3' UTR has several stable hairpins that are flanked by single-stranded (A/U)UGC sequences. Hydroxyl radical footprinting data show that five sites in the 3' UTR of alfalfa mosaic virus RNA 4 are protected by coat protein, and four of the five protected regions contain AUGC or UUGC. Electrophoretic mobility band shift results suggest four coat protein binding sites in the 3' UTR. A 3'-terminal 39-nucleotide RNA fragment containing four AUGC repeats bound coat protein and coat protein peptides with high affinity; however, coat protein bound poorly to antisense 3' UTR transcripts and poly(AUGC)10. Site-directed mutagenesis of AUGC865-868 resulted in a loss of coat protein binding and peptide binding by the RNA fragment. Alignment of alfalfa mosaic RNA sequences with those from several closely related ilarviruses demonstrates that AUGC865-868 is perfectly conserved; moreover, the RNAs are predicted to form similar 3'-terminal secondary structures. The data strongly suggest that alfalfa mosaic virus coat protein and ilavirus coat proteins recognize invariant AUGC sequences in the context of conserved structural elements. Images PMID:8139004

  8. Effect of Basic Residue on the Kinetics of Peptide Fragmentation Examined Using Surface-Induced Dissociation Combined with Resonant Ejection

    Energy Technology Data Exchange (ETDEWEB)

    Laskin, Julia

    2015-11-30

    In this work, resonant ejection coupled with surface-induced dissociation (SID) in a Fourier transform ion cyclotron resonance mass spectrometer is used to examine fragmentation kinetics of two singly protonated hexapeptides, RYGGFL and KYGGFL, containing the basic arginine residue and less basic lysine residue at the N-terminus. The kinetics of individual reaction channels at different collision energies are probed by applying a short ejection pulse (1 ms) in resonance with the cyclotron frequency of a selected fragment ion and varying the delay time between ion-surface collision and resonant ejection while keeping total reaction delay time constant. Rice-Ramsperger-Kassel-Marcus (RRKM) modeling of the experimental data provides accurate threshold energies and activation entropies of individual reaction channels. Substitution of arginine with less basic lysine has a pronounced effect on the observed fragmentation kinetics of several pathways, including the b2 ion formation, but has little or no effect on formation of the b5+H2O fragment ion. The combination of resonant ejection SID, time- and collision energy-resolved SID, and RRKM modeling of both types of experimental data provides a detailed mechanistic understanding of the primary dissociation pathways of complex gaseous ions.

  9. Crystal structure of YrrB: a TPR protein with an unusual peptide-binding site.

    Science.gov (United States)

    Han, Dohyun; Oh, Jongkil; Kim, Kyunggon; Lim, Hyosun; Kim, Youngsoo

    2007-09-01

    YrrB is a hypothetical protein containing a tetratricopeptide repeat (TPR) domain from a Gram-positive bacterium, Bacillus subtilis. We determined YrrB structure in the C2 space group to 2.5A resolution, which is the first TPR structure of the Gram-positive bacterium B. subtilis. In contrast to other known TPR structures, the concave surface of the YrrB TPR domain is composed of the putative peptide-binding pocket lined with positively-charged residues. This unique charge distribution reveals that YrrB can interact with partner proteins via an unusual TPR-mediated interaction mode, compared to that of other TPR-containing structures. Functional annotation using genomics analysis suggested that YrrB may be an interacting mediator in the complex formation among RNA sulfuration components. No proteins containing a TPR domain have been identified in the biosynthesis of sulfur-containing biomolecules. Thus, YrrB could play a new role as a connecting module among those proteins in the conserved gene cluster for RNA sulfuration.

  10. Glucagon-like peptide-1 receptor agonists increase pancreatic mass by induction of protein synthesis.

    Science.gov (United States)

    Koehler, Jacqueline A; Baggio, Laurie L; Cao, Xiemin; Abdulla, Tahmid; Campbell, Jonathan E; Secher, Thomas; Jelsing, Jacob; Larsen, Brett; Drucker, Daniel J

    2015-03-01

    Glucagon-like peptide-1 (GLP-1) controls glucose homeostasis by regulating secretion of insulin and glucagon through a single GLP-1 receptor (GLP-1R). GLP-1R agonists also increase pancreatic weight in some preclinical studies through poorly understood mechanisms. Here we demonstrate that the increase in pancreatic weight following activation of GLP-1R signaling in mice reflects an increase in acinar cell mass, without changes in ductal compartments or β-cell mass. GLP-1R agonists did not increase pancreatic DNA content or the number of Ki67(+) cells in the exocrine compartment; however, pancreatic protein content was increased in mice treated with exendin-4 or liraglutide. The increased pancreatic mass and protein content was independent of cholecystokinin receptors, associated with a rapid increase in S6 phosphorylation, and mediated through the GLP-1R. Rapamycin abrogated the GLP-1R-dependent increase in pancreatic mass but had no effect on the robust induction of Reg3α and Reg3β gene expression. Mass spectrometry analysis identified GLP-1R-dependent upregulation of Reg family members, as well as proteins important for translation and export, including Fam129a, eIF4a1, Wars, and Dmbt1. Hence, pharmacological GLP-1R activation induces protein synthesis, leading to increased pancreatic mass, independent of changes in DNA content or cell proliferation in mice.

  11. Disrupting protein expression with Peptide Nucleic Acids reduces infection by obligate intracellular Rickettsia.

    Science.gov (United States)

    Pelc, Rebecca S; McClure, Jennifer C; Kaur, Simran J; Sears, Khandra T; Rahman, M Sayeedur; Ceraul, Shane M

    2015-01-01

    Peptide Nucleic Acids (PNAs) are single-stranded synthetic nucleic acids with a pseudopeptide backbone in lieu of the phosphodiester linked sugar and phosphate found in traditional oligos. PNA designed complementary to the bacterial Shine-Dalgarno or start codon regions of mRNA disrupts translation resulting in the transient reduction in protein expression. This study examines the use of PNA technology to interrupt protein expression in obligate intracellular Rickettsia sp. Their historically intractable genetic system limits characterization of protein function. We designed PNA targeting mRNA for rOmpB from Rickettsia typhi and rickA from Rickettsia montanensis, ubiquitous factors important for infection. Using an in vitro translation system and competitive binding assays, we determined that our PNAs bind target regions. Electroporation of R. typhi and R. montanensis with PNA specific to rOmpB and rickA, respectively, reduced the bacteria's ability to infect host cells. These studies open the possibility of using PNA to suppress protein synthesis in obligate intracellular bacteria.

  12. Plasmodium falciparum signal peptide peptidase cleaves malaria heat shock protein 101 (HSP101). Implications for gametocytogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Michael; Russo, Crystal; Li, Xuerong [Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111 (United States); Chishti, Athar H., E-mail: athar.chishti@tufts.edu [Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111 (United States); Sackler School of Graduate Biomedical Sciences, Programs in Physiology, Pharmacology, and Microbiology, Tufts University School of Medicine, Boston, MA 02111 (United States)

    2014-08-08

    Highlights: • PfSPP is an ER resident protease. • PfSPP is expressed both as a monomer and dimer. • The signal peptide of HSP101 is the first known substrate of PfSPP. • Reduced PfSPP activity may significantly affect ER homeostasis. - Abstract: Previously we described the identification of a Plasmodium falciparum signal peptide peptidase (PfSPP) functioning at the blood stage of malaria infection. Our studies also demonstrated that mammalian SPP inhibitors prevent malaria parasite growth at the late-ring/early trophozoite stage of intra-erythrocytic development. Consistent with its role in development, we tested the hypothesis that PfSPP functions at the endoplasmic reticulum of P.falciparum where it cleaves membrane-bound signal peptides generated following the enzyme activity of signal peptidase. The localization of PfSPP to the endoplasmic reticulum was confirmed by immunofluorescence microscopy and immunogold electron microscopy. Biochemical analysis indicated the existence of monomer and dimer forms of PfSPP in the parasite lysate. A comprehensive bioinformatics screen identified several candidate PfSPP substrates in the parasite genome. Using an established transfection based in vivo luminescence assay, malaria heat shock protein 101 (HSP101) was identified as a substrate of PfSPP, and partial inhibition of PfSPP correlated with the emergence of gametocytes. This finding unveils the first known substrate of PfSPP, and provides new perspectives for the function of intra-membrane proteolysis at the erythrocyte stage of malaria parasite life cycle.

  13. Myelin Basic Protein Citrullination in Multiple Sclerosis: A Potential Therapeutic Target for the Pathology.

    Science.gov (United States)

    Yang, Lei; Tan, Dewei; Piao, Hua

    2016-08-01

    Multiple sclerosis (MS) is a multifactorial demyelinating disease characterized by neurodegenerative events and autoimmune response against myelin component. Citrullination or deimination, a post-translational modification of protein-bound arginine into citrulline, catalyzed by Ca(2+) dependent peptidylarginine deiminase enzyme (PAD), plays an essential role in physiological processes include gene expression regulation, apoptosis and the plasticity of the central nervous system, while aberrant citrullination can generate new epitopes, thus involving in the initiation and/or progression of autoimmune disorder like MS. Myelin basic protein (MBP) is the major myelin protein and is generally considered to maintain the stability of the myelin sheath. This review describes the MBP citrullination and its consequence, as well as offering further support for the "inside-out" hypothesis that MS is primarily a neurodegenerative disease with secondary inflammatory demyelination. In addition, it discusses the role of MBP citrullination in the immune inflammation and explores the potential of inhibition of PAD enzymes as a therapeutic strategy for the disease.

  14. Golli myelin basic proteins stimulate oligodendrocyte progenitor cell proliferation and differentiation in remyelinating adult mouse brain.

    Science.gov (United States)

    Paez, Pablo M; Cheli, Veronica T; Ghiani, Cristina A; Spreuer, Vilma; Handley, Vance W; Campagnoni, Anthony T

    2012-07-01

    Golli myelin basic proteins are necessary for normal myelination, acting via voltage and store-dependent Ca(2+) entry at multiple steps during oligodendrocyte progenitor cell (OPC) development. To date nothing is known regarding the role of golli proteins in demyelination or remyelination events. Here the effects of golli ablation and overexpression in myelin loss and recovery were examined using the cuprizone (CPZ) model of demyelination/remyelination. We found severe demyelination in the corpus callosum (CC) of golli-overexpressing mice (JOE) during the CPZ treatment, which was accompanied by an increased number of reactive astrocytes and activation of microglia/macrophages. During demyelination of JOE brains, a significant increase in the number of proliferating OPCs was found in the CC as well as in the subventricular zone, and our data indicate that these progenitors matured and fully remyelinated the CC of JOE animals after CPZ withdrawal. In contrast, in the absence of golli (golli-KO mice) delayed myelin loss associated with a smaller immune response, and a lower number of OPCs was found in these mice during the CPZ treatment. Furthermore, incomplete remyelination was observed after CPZ removal in large areas of the CC of golli-KO mice, reflecting irregular recovery of the oligodendrocyte population and subsequent myelin sheath formation. Our findings demonstrate that golli proteins sensitize mature oligodendrocytes to CPZ-induced demyelination, while at the same time stimulate the proliferation/recruitment of OPCs during demyelination, resulting in accelerated remyelination.

  15. Transcriptional upregulation of myelin components in spontaneous myelin basic protein-deficient mice.

    Science.gov (United States)

    Staats, Kim A; Pombal, Diana; Schönefeldt, Susann; Van Helleputte, Lawrence; Maurin, Hervé; Dresselaers, Tom; Govaerts, Kristof; Himmelreich, Uwe; Van Leuven, Fred; Van Den Bosch, Ludo; Dooley, James; Humblet-Baron, Stephanie; Liston, Adrian

    2015-05-01

    Myelin is essential for efficient signal transduction in the nervous system comprising of multiple proteins. The intricacies of the regulation of the formation of myelin, and its components, are not fully understood. Here, we describe the characterization of a novel myelin basic protein (Mbp) mutant mouse, mbp(jive), which spontaneously occurred in our mouse colony. These mice displayed the onset of a shaking gait before 3 weeks of age and seizure onset before 2 months of age. Due to a progressive increase of seizure intensity, mbp(jive) mice experienced premature lethality at around 3 months of age. Mbp mRNA transcript or protein was undetectable and, accordingly, genetic analysis demonstrated a homozygous loss of exons 3 to 6 of Mbp. Peripheral nerve conductance was mostly unimpaired. Additionally, we observed grave structural changes in white matter predominant structures were detected by T1, T2 and diffusion weighted magnetic resonance imaging. We additionally observed that Mbp-deficiency results in an upregulation of Qkl, Mag and Cnp, suggestive of a regulatory feedback mechanism whereby compensatory increases in Qkl have downstream effects on Mag and Cnp. Further research will clarify the role and specifications of this myelin feedback loop, as well as determine its potential role in therapeutic strategies for demyelinating disorders.

  16. Fluorogenic Tagging of Peptide and Protein 3-Nitrotyrosine with 4-(Aminomethyl)-benzenesulfonic Acid for Quantitative Analysis of Protein Tyrosine Nitration

    OpenAIRE

    Sharov, Victor S.; Dremina, Elena S.; Galeva, Nadezhda A.; Gerstenecker, Gary S.; Li, Xiaobao; Dobrowsky, Rick T; Stobaugh, John F.; Schöneich, Christian

    2010-01-01

    Protein 3-nitrotyrosine (3-NT) has been recognized as an important biomarker of nitroxidative stress associated with inflammatory and degenerative diseases, and biological aging. Analysis of protein-bound 3-NT continues to represent a challenge since in vivo it frequently does not accumulate on proteins in amounts detectable by quantitative analytical methods. Here, we describe a novel approach of fluorescent tagging and quantitation of peptide-bound 3-NT residues based on the selective reduc...

  17. Dissecting the Binding Mode of Low Affinity Phage Display Peptide Ligands to Protein Targets by Hydrogen/Deuterium Exchange Coupled to Mass Spectrometry

    DEFF Research Database (Denmark)

    Leurs, Ulrike; Lohse, Brian; Ming, Shonoi A;

    2014-01-01

    of hydrogen/deuterium exchange mass spectrometry (HDX-MS) to characterize interactions of low affinity peptides with their cognate protein targets. The HDX-MS workflow was optimized to accurately detect low-affinity peptide-protein interactions by use of ion mobility, electron transfer dissociation, non...... of KDM4C, indicating distinct binding modes. In contrast, the perturbation site of another PD-selected peptide inhibiting the function of KDM1A maps to a GST-tag. Our results demonstrate that HDX-MS can validate and map weak peptide-protein interactions, and pave the way for understanding and optimizing...

  18. Anaplasma marginale major surface protein 1a directs cell surface display of tick BM95 immunogenic peptides on Escherichia coli.

    Science.gov (United States)

    Canales, Mario; Almazán, Consuelo; Pérez de la Lastra, José M; de la Fuente, José

    2008-07-31

    The surface display of heterologous proteins on live Escherichia coli using anchoring motifs from outer membranes proteins has impacted on many areas of biochemistry, molecular biology and biotechnology. The Anaplasma marginale major surface protein 1a (MSP1a) contains N-terminal surface-exposed repeated peptides (28-289 amino acids) that are involved in pathogen interaction with host cell receptors and is surface-displayed when the recombinant protein is expressed in E. coli. Therefore, it was predicted that MSP1a would surface display on E. coli peptides inserted in the N-terminal repeats region of the protein. The Rhipicephalus (Boophilus) microplus BM86 and BM95 glycoproteins are homologous proteins that protect cattle against tick infestations. In this study, we demonstrated that a recombinant protein comprising tick BM95 immunogenic peptides fused to the A. marginale MSP1a N-terminal region is displayed on the E. coli surface and is recognized by anti-BM86 and anti-MSP1a antibodies. This system provides a novel approach to the surface display of heterologous antigenic proteins on live E. coli and suggests the possibility to use the recombinant bacteria for immunization studies against cattle tick infestations. PMID:18582976

  19. Purification of heat shock protein 70-associated tumor peptides and their antitumor immunity to hepatoma in mice

    Institute of Scientific and Technical Information of China (English)

    Dai-Xiong Chen; Yan-Rong Su; Gen-Ze Shao; Zhen-Chao Qian

    2004-01-01

    AIM: To purify the heat shock protein (HSP) 70-associated tumor peptides and to observe its non-MHC-I molecule restrictive antitumor effect.METHODS: By ConA-sepharose affinity chromatography,ADP-agarose affinity chromatography, and DEAE anion exchange chromatography, we were able to purify HSP70-associated peptides from mouse hepatoma (HCaF) cells treated in heat shock at 42 ℃ . Specific active immunization and adoptive cellular immunization assay were adopted to observe the immunoprotective effect elicited by HSP70-associated peptide complexes isolated from HcaF.RESULTS: The finally purified HSP-associated peptides had a very high purity and specificity found by SDS-PAGE and Western blot. Mice immunized with HSP70-associated peptide complexes purified from HCaF cells were protected from HCaF living cell challenge. This effect was dose dependent.Adoptive immunization of immune spleen cells of mice immunized with HSP70-associated peptide complexes could elicit immunity against HCaF challenge, and the tumor-free mice could resist repeated challenges. This effect could be continuously enhanced by repeated challenge with HCaF living cells. The tumor-free mice could tolerate the challenge for as high as l×107 HCaF cells. The mice immunized once with spleen cells pulsed with HSP70-associated peptide complexes in vitro could also result in a certain adoptive immunity against HCaF.CONCLUSION: High purity and specificity of HSP70-associated peptides could be achieved from tumor cells by the low-pressure affinity chromatography method used in this study. HSP70-associated peptide complexes derived from the HCaF can elicit non-MHC-I molecule restrictive immunoprotective effect against HCaF. This effect can be transferred by adoptive immunization to mice and enhanced by repeated challenge with HCaF live cells.

  20. Peptide-oligonucleotide conjugates as nanoscale building blocks for assembly of an artificial three-helix protein mimic

    Science.gov (United States)

    Lou, Chenguang; Martos-Maldonado, Manuel C.; Madsen, Charlotte S.; Thomsen, Rasmus P.; Midtgaard, Søren Roi; Christensen, Niels Johan; Kjems, Jørgen; Thulstrup, Peter W.; Wengel, Jesper; Jensen, Knud J.

    2016-07-01

    Peptide-based structures can be designed to yield artificial proteins with specific folding patterns and functions. Template-based assembly of peptide units is one design option, but the use of two orthogonal self-assembly principles, oligonucleotide triple helix and a coiled coil protein domain formation have never been realized for de novo protein design. Here, we show the applicability of peptide-oligonucleotide conjugates for self-assembly of higher-ordered protein-like structures. The resulting nano-assemblies were characterized by ultraviolet-melting, gel electrophoresis, circular dichroism (CD) spectroscopy, small-angle X-ray scattering and transmission electron microscopy. These studies revealed the formation of the desired triple helix and coiled coil domains at low concentrations, while a dimer of trimers was dominating at high concentration. CD spectroscopy showed an extraordinarily high degree of α-helicity for the peptide moieties in the assemblies. The results validate the use of orthogonal self-assembly principles as a paradigm for de novo protein design.

  1. Downregulation of the microtubule associated protein tau impairs process outgrowth and myelin basic protein mRNA transport in oligodendrocytes.

    Science.gov (United States)

    Seiberlich, Veronika; Bauer, Nina G; Schwarz, Lisa; Ffrench-Constant, Charles; Goldbaum, Olaf; Richter-Landsberg, Christiane

    2015-09-01

    Oligodendrocytes, the myelin forming cells of the CNS, are characterized by their numerous membranous extensions, which enwrap neuronal axons and form myelin sheaths. During differentiation oligodendrocytes pass different morphological stages, downregulate the expression of the proteoglycan NG2, and acquire major myelin specific proteins, such as myelin basic proteins (MBP) and proteolipid protein. MBP mRNA is transported in RNA granules along the microtubules (MTs) to the periphery and translated locally. MTs participate in the elaboration and stabilization of the myelin forming extensions and are essential for cellular sorting processes. Their dynamic properties are regulated by microtubule associated proteins (MAPs). The MAP tau is present in oligodendrocytes and involved in the regulation and stabilization of the MT network. To further elucidate the functional significance of tau in oligodendrocytes, we have downregulated tau by siRNA technology and studied the effects on cell differentiation and neuron-glia contact formation. The data show that tau knockdown impairs process outgrowth and leads to a decrease in MBP expression. Furthermore, MBP mRNA transport to distant cellular extensions is impaired and cells remain in the NG2 stage. In myelinating cocultures with dorsal root ganglion neurons, oligodendrocyte precursor cells after tau miR RNA lentiviral knockdown develop into NG2 positive cells with very long and thin processes, contacting axons loosely, but fail to form internodes. This demonstrates that tau is important for MBP mRNA transport and involved in process formation. The disturbance of the balance of tau leads to abnormalities in oligodendrocyte differentiation, neuron-glia contact formation and the early myelination process.

  2. Development and maturation of central nervous system myelin: Comparison of immunohistochemical localization of proteolipid protein and basic protein in myelin and oligodendrocytes

    OpenAIRE

    Hartman, Boyd K.; Agrawal, Harish C.; Agrawal, Daya; Kalmbach, Sandra

    1982-01-01

    The immunohistochemical localization of two myelin specific proteins—basic protein (BP) and proteolipid protein (PLP)—was compared during the process of myelination. Although both proteins were present in oligodendrocytes, (i) neither protein was observed in oligodendrocytes not already closely associated with nerve fibers exhibiting a fluorescent coating; (ii) in any discrete anatomical area oligodendrocytes were positive for BP before PLP was visible; and (iii) as myelination progressed, im...

  3. Loss of Myelin Basic Protein Function Triggers Myelin Breakdown in Models of Demyelinating Diseases.

    Science.gov (United States)

    Weil, Marie-Theres; Möbius, Wiebke; Winkler, Anne; Ruhwedel, Torben; Wrzos, Claudia; Romanelli, Elisa; Bennett, Jeffrey L; Enz, Lukas; Goebels, Norbert; Nave, Klaus-Armin; Kerschensteiner, Martin; Schaeren-Wiemers, Nicole; Stadelmann, Christine; Simons, Mikael

    2016-07-12

    Breakdown of myelin sheaths is a pathological hallmark of several autoimmune diseases of the nervous system. We employed autoantibody-mediated animal models of demyelinating diseases, including a rat model of neuromyelitis optica (NMO), to target myelin and found that myelin lamellae are broken down into vesicular structures at the innermost region of the myelin sheath. We demonstrated that myelin basic proteins (MBP), which form a polymer in between the myelin membrane layers, are targeted in these models. Elevation of intracellular Ca(2+) levels resulted in MBP network disassembly and myelin vesiculation. We propose that the aberrant phase transition of MBP molecules from their cohesive to soluble and non-adhesive state is a mechanism triggering myelin breakdown in NMO and possibly in other demyelinating diseases. PMID:27346352

  4. A thermodynamic investigation on the binding of mercury ion with myelin basic protein at different temperatures

    Institute of Scientific and Technical Information of China (English)

    G. Rezaei Behbehani; L. Barzegar; A.A. Saboury; S. Ghammami

    2011-01-01

    A thermodynamic study on the interaction of myelin basic protein with mercury ion was studied by using isothermal titration calorimetry, ITC, at 300.15, 310.15 and 320.15 K in Tris buffer solution at pH 7. The enthalpies of MBP + Hg2+ interaction are reported and analysed in terms of the extended solvation model. It was found that MBP has two identical and non-cooperative binding sites for Hg2+ ions. The intrinsic dissociation equilibrium constants are 99.904,112.968 and 126.724 |μmol/L, and the molar enthalpy of binding are -11.634, -10.768 and -10.117 kJ mol 1 at 300.15, 310.15 and 320.15 K, respectively.

  5. Loss of Myelin Basic Protein Function Triggers Myelin Breakdown in Models of Demyelinating Diseases.

    Science.gov (United States)

    Weil, Marie-Theres; Möbius, Wiebke; Winkler, Anne; Ruhwedel, Torben; Wrzos, Claudia; Romanelli, Elisa; Bennett, Jeffrey L; Enz, Lukas; Goebels, Norbert; Nave, Klaus-Armin; Kerschensteiner, Martin; Schaeren-Wiemers, Nicole; Stadelmann, Christine; Simons, Mikael

    2016-07-12

    Breakdown of myelin sheaths is a pathological hallmark of several autoimmune diseases of the nervous system. We employed autoantibody-mediated animal models of demyelinating diseases, including a rat model of neuromyelitis optica (NMO), to target myelin and found that myelin lamellae are broken down into vesicular structures at the innermost region of the myelin sheath. We demonstrated that myelin basic proteins (MBP), which form a polymer in between the myelin membrane layers, are targeted in these models. Elevation of intracellular Ca(2+) levels resulted in MBP network disassembly and myelin vesiculation. We propose that the aberrant phase transition of MBP molecules from their cohesive to soluble and non-adhesive state is a mechanism triggering myelin breakdown in NMO and possibly in other demyelinating diseases.

  6. The proform of eosinophil major basic protein: a new maternal serum marker for adverse pregnancy outcome

    DEFF Research Database (Denmark)

    Pihl, Kasper; Larsen, Torben; Rasmussen, Steen;

    2009-01-01

    MBP median was significantly reduced in pregnancies with SGA (0.81 MoM), spontaneous preterm delivery (0.83 MoM), preeclampsia (0.88 MoM) and gestational hypertension (0.60 MoM). The best screening performance was found for preeclampsia including the covariates proMBP and nulliparity yielding an area under......OBJECTIVE: To establish the first trimester serum levels of the proform of eosinophil major basic protein (proMBP) in pregnancies with adverse outcome. Furthermore, to determine the screening performance using proMBP alone and in combination with other first trimester markers. METHODS: A case......-control study was conducted in a primary hospital setting. The proMBP concentration was measured in cases with small-for-gestational age (SGA) (n = 150), spontaneous preterm delivery (n = 88), preeclampsia (n = 40), gestational hypertension (n = 10) and in controls (n = 500). Concentrations were converted...

  7. Pattern recognition in pulmonary tuberculosis defined by high content peptide microarray chip analysis representing 61 proteins from M. tuberculosis.

    Directory of Open Access Journals (Sweden)

    Simani Gaseitsiwe

    Full Text Available BACKGROUND: Serum antibody-based target identification has been used to identify tumor-associated antigens (TAAs for development of anti-cancer vaccines. A similar approach can be helpful to identify biologically relevant and clinically meaningful targets in M. tuberculosis (MTB infection for diagnosis or TB vaccine development in clinically well defined populations. METHOD: We constructed a high-content peptide microarray with 61 M. tuberculosis proteins as linear 15 aa peptide stretches with 12 aa overlaps resulting in 7446 individual peptide epitopes. Antibody profiling was carried with serum from 34 individuals with active pulmonary TB and 35 healthy individuals in order to obtain an unbiased view of the MTB epitope pattern recognition pattern. Quality data extraction was performed, data sets were analyzed for significant differences and patterns predictive of TB+/-. FINDINGS: Three distinct patterns of IgG reactivity were identified: 89/7446 peptides were differentially recognized (in 34/34 TB+ patients and in 35/35 healthy individuals and are highly predictive of the division into TB+ and TB-, other targets were exclusively recognized in all patients with TB (e.g. sigmaF but not in any of the healthy individuals, and a third peptide set was recognized exclusively in healthy individuals (35/35 but no in TB+ patients. The segregation between TB+ and TB- does not cluster into specific recognition of distinct MTB proteins, but into specific peptide epitope 'hotspots' at different locations within the same protein. Antigen recognition pattern profiles in serum from TB+ patients from Armenia vs. patients recruited in Sweden showed that IgG-defined MTB epitopes are very similar in individuals with different genetic background. CONCLUSIONS: A uniform target MTB IgG-epitope recognition pattern exists in pulmonary tuberculosis. Unbiased, high-content peptide microarray chip-based testing of clinically well-defined populations allows to visualize

  8. Thermoresponsive anionic copolymer brushes containing strong acid moieties for effective separation of basic biomolecules and proteins.

    Science.gov (United States)

    Nagase, Kenichi; Kobayashi, Jun; Kikuchi, Akihiko; Akiyama, Yoshikatsu; Kanazawa, Hideko; Okano, Teruo

    2014-10-13

    A thermoresponsive copolymer brush possessing the sulfonic acid group, poly(N-isopropylacrylamide (IPAAm)-co-2-acrylamido-2-methylpropanesulfonic acid (AMPS)-co-tert-butylacrylamide (tBAAm)), was grafted onto the surface of silica beads through surface-initiated atom transfer radical polymerization. Prepared copolymer and copolymer brushes on silica beads were characterized by observing the phase transition profile, CHNS elemental analysis, X-ray photoelectron spectroscopy, and gel permeation chromatography. The phase transition profile indicated that an appropriate AMPS composition for enabling thermally modulated property changes is 5 mol %, while excessive amounts of sulfonic acid groups prevented copolymer phase transition. Chromatographic elutions of catecholamine derivatives and basic proteins were observed, using the prepared copolymer brush-modified beads as chromatographic matrices, and the results suggest that the beads interact with these analytes through relatively strong electrostatic interactions. Thus, poly(IPAAm-co-AMPS-co-tBAAm) brush-modified beads will be useful for effective thermoresponsive chromatography matrices that separate basic biomolecules through strong electrostatic interactions. PMID:25220634

  9. Post-translational Modifications of Chicken Myelin Basic Protein Charge Components

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeongkwon; Zhang, Rui; Strittmatter, Eric F.; Smith, Richard D.; Zand, Robert

    2008-07-11

    Purified myelin basic protein (MBP) from various species contains several post-translationally modified forms termed charge components or charge isomers. Chicken MBP contains four charge components denoted as C1, C2, C3 and C8. (The C8 isomer is a complex mixture and was not investigated in this study.) These findings are in contrast to those found for human, bovine and other mammalian MBP’s. Mammalian MBP’s, each of which contain seven or eight charge components depending on the analysis of the CM-52 chromatographic curves and the PAGE gels obtained under basic pH conditions. Chicken MBP components C1, C2 and C3 were treated with trypsin and endoproteinase Glu-C. The resulting digests were analyzed by capillary liquid chromatography combined with either an ion trap tandem mass spectrometer or with a Fourier transform ion cyclotron resonance mass spectrometer. This instrumentation permitted establishing the amino acid composition and the determination of the posttranslational modifications for each of the three charge components C1-C3. With the exception of N-terminal acetylation, the post-translational modifications were partial.

  10. Classic and Golli Myelin Basic Protein have distinct developmental trajectories in human visual cortex.

    Science.gov (United States)

    Siu, Caitlin R; Balsor, Justin L; Jones, David G; Murphy, Kathryn M

    2015-01-01

    Traditionally, myelin is viewed as insulation around axons, however, more recent studies have shown it also plays an important role in plasticity, axonal metabolism, and neuroimmune signaling. Myelin is a complex multi-protein structure composed of hundreds of proteins, with Myelin Basic Protein (MBP) being the most studied. MBP has two families: Classic-MBP that is necessary for activity driven compaction of myelin around axons, and Golli-MBP that is found in neurons, oligodendrocytes, and T-cells. Furthermore, Golli-MBP has been called a "molecular link" between the nervous and immune systems. In visual cortex specifically, myelin proteins interact with immune processes to affect experience-dependent plasticity. We studied myelin in human visual cortex using Western blotting to quantify Classic- and Golli-MBP expression in post-mortem tissue samples ranging in age from 20 days to 80 years. We found that Classic- and Golli-MBP have different patterns of change across the lifespan. Classic-MBP gradually increases to 42 years and then declines into aging. Golli-MBP has early developmental changes that are coincident with milestones in visual system sensitive period, and gradually increases into aging. There are three stages in the balance between Classic- and Golli-MBP expression, with Golli-MBP dominating early, then shifting to Classic-MBP, and back to Golli-MBP in aging. Also Golli-MBP has a wave of high inter-individual variability during childhood. These results about cortical MBP expression are timely because they compliment recent advances in MRI techniques that produce high resolution maps of cortical myelin in normal and diseased brain. In addition, the unique pattern of Golli-MBP expression across the lifespan suggests that it supports high levels of neuroimmune interaction in cortical development and in aging.

  11. Classic and Golli Myelin Basic Protein have distinct developmental trajectories in human visual cortex

    Directory of Open Access Journals (Sweden)

    Caitlin R Siu

    2015-04-01

    Full Text Available Traditionally myelin is viewed as insulation around axons however more recent studies have shown it plays an important role in plasticity, axonal metabolism and neuroimmune signalling. Myelin is a complex multi-protein structure composed of hundreds of proteins, with Myelin Basic Protein (MBP being the most studied. MBP has two families: Classic-MBP that is necessary for activity driven compaction of myelin around axons, and Golli-MBP that is found in neurons, oligodendrocytes, and T cells, and has been called a 'molecular link' between the nervous and immune systems. In visual cortex myelin proteins interact with immune processes to affect experience-dependent plasticity. We studied myelin in human visual cortex using Western blotting to quantify Classic- and Golli-MBP expression in post-mortem tissue samples ranging in age from 20 days to 80 years. We found that Classic- and Golli-MBP have different patterns of change across the lifespan: Classic-MBP gradually increases to 42 years and then declines into aging; Golli-MBP has changes that are coincident with milestones in visual system sensitive period, before gradually increasing into aging. There are 3 stages in the balance between Classic- and Golli-MBP expression, with Golli-MBP dominating early, then shifting to Classic-MBP, and back to Golli-MBP in aging. Also Golli-MBP has a wave of high inter-individual variability during childhood. These results about cortical MBP expression are timely because they compliment recent advances in MRI techniques that produce high resolution maps of cortical myelin in normal and diseased brain. In addition the unique pattern of Golli-MBP expression across the lifespan suggests that it supports high levels of neuroimmune interaction in cortical development and in aging.

  12. The dengue virus type 2 envelope protein fusion peptide is essential for membrane fusion

    International Nuclear Information System (INIS)

    The flaviviral envelope (E) protein directs virus-mediated membrane fusion. To investigate membrane fusion as a requirement for virus growth, we introduced 27 unique mutations into the fusion peptide of an infectious cDNA clone of dengue 2 virus and recovered seven stable mutant viruses. The fusion efficiency of the mutants was impaired, demonstrating for the first time the requirement for specific FP AAs in optimal fusion. Mutant viruses exhibited different growth kinetics and/or genetic stabilities in different cell types and adult mosquitoes. Virus particles could be recovered following RNA transfection of cells with four lethal mutants; however, recovered viruses could not re-infect cells. These viruses could enter cells, but internalized virus appeared to be retained in endosomal compartments of infected cells, thus suggesting a fusion blockade. Mutations of the FP also resulted in reduced virus reactivity with flavivirus group-reactive antibodies, confirming earlier reports using virus-like particles.

  13. On the zwitterionic nature of gas-phase peptides and protein ions.

    Directory of Open Access Journals (Sweden)

    Roberto Marchese

    2010-05-01

    Full Text Available Determining the total number of charged residues corresponding to a given value of net charge for peptides and proteins in gas phase is crucial for the interpretation of mass-spectrometry data, yet it is far from being understood. Here we show that a novel computational protocol based on force field and massive density functional calculations is able to reproduce the experimental facets of well investigated systems, such as angiotensin II, bradykinin, and tryptophan-cage. The protocol takes into account all of the possible protomers compatible with a given charge state. Our calculations predict that the low charge states are zwitterions, because the stabilization due to intramolecular hydrogen bonding and salt-bridges can compensate for the thermodynamic penalty deriving from deprotonation of acid residues. In contrast, high charge states may or may not be zwitterions because internal solvation might not compensate for the energy cost of charge separation.

  14. Co-assembly, spatiotemporal control and morphogenesis of a hybrid protein-peptide system.

    Science.gov (United States)

    Inostroza-Brito, Karla E; Collin, Estelle; Siton-Mendelson, Orit; Smith, Katherine H; Monge-Marcet, Amàlia; Ferreira, Daniela S; Rodríguez, Raúl Pérez; Alonso, Matilde; Rodríguez-Cabello, José Carlos; Reis, Rui L; Sagués, Francesc; Botto, Lorenzo; Bitton, Ronit; Azevedo, Helena S; Mata, Alvaro

    2015-11-01

    Controlling molecular interactions between bioinspired molecules can enable the development of new materials with higher complexity and innovative properties. Here we report on a dynamic system that emerges from the conformational modification of an elastin-like protein by peptide amphiphiles and with the capacity to access, and be maintained in, non-equilibrium for substantial periods of time. The system enables the formation of a robust membrane that displays controlled assembly and disassembly capabilities, adhesion and sealing to surfaces, self-healing and the capability to undergo morphogenesis into tubular structures with high spatiotemporal control. We use advanced microscopy along with turbidity and spectroscopic measurements to investigate the mechanism of assembly and its relation to the distinctive membrane architecture and the resulting dynamic properties. Using cell-culture experiments with endothelial and adipose-derived stem cells, we demonstrate the potential of this system to generate complex bioactive scaffolds for applications such as tissue engineering. PMID:26492010

  15. Co-assembly, spatiotemporal control and morphogenesis of a hybrid protein-peptide system

    Science.gov (United States)

    Inostroza-Brito, Karla E.; Collin, Estelle; Siton-Mendelson, Orit; Smith, Katherine H.; Monge-Marcet, Amàlia; Ferreira, Daniela S.; Rodríguez, Raúl Pérez; Alonso, Matilde; Rodríguez-Cabello, José Carlos; Reis, Rui L.; Sagués, Francesc; Botto, Lorenzo; Bitton, Ronit; Azevedo, Helena S.; Mata, Alvaro

    2015-11-01

    Controlling molecular interactions between bioinspired molecules can enable the development of new materials with higher complexity and innovative properties. Here we report on a dynamic system that emerges from the conformational modification of an elastin-like protein by peptide amphiphiles and with the capacity to access, and be maintained in, non-equilibrium for substantial periods of time. The system enables the formation of a robust membrane that displays controlled assembly and disassembly capabilities, adhesion and sealing to surfaces, self-healing and the capability to undergo morphogenesis into tubular structures with high spatiotemporal control. We use advanced microscopy along with turbidity and spectroscopic measurements to investigate the mechanism of assembly and its relation to the distinctive membrane architecture and the resulting dynamic properties. Using cell-culture experiments with endothelial and adipose-derived stem cells, we demonstrate the potential of this system to generate complex bioactive scaffolds for applications such as tissue engineering.

  16. AMYLOID-β PEPTIDE BINDS TO MICROTUBULE-ASSOCIATED PROTEIN 1B (MAP1B)

    Science.gov (United States)

    Gevorkian, Goar; Gonzalez-Noriega, Alfonso; Acero, Gonzalo; Ordoñez, Jorge; Michalak, Colette; Munguia, Maria Elena; Govezensky, Tzipe; Cribbs, David H.; Manoutcharian, Karen

    2008-01-01

    Extracellular and intraneuronal formation of amyloid-beta aggregates have been demonstrated to be involved in the pathogenesis of Alzheimer’s disease. However, the precise mechanism of amyloid-beta neurotoxicity is not completely understood. Previous studies suggest that binding of amyloid-beta to a number of targets have deleterious effects on cellular functions. In the present study we have shown for the first time that amyloid-beta 1-42 bound to a peptide comprising the microtubule binding domain of the heavy chain of microtubule-associated protein 1B by the screening of a human brain cDNA library expressed on M13 phage. This interaction may explain, in part, the loss of neuronal cytoskeletal integrity, impairment of microtubule-dependent transport and synaptic dysfunction observed previously in Alzheimer’s disease. PMID:18079022

  17. Functionalized poly(ethylene glycol) diacrylate microgels by microfluidics: In situ peptide encapsulation for in serum selective protein detection.

    Science.gov (United States)

    Celetti, Giorgia; Natale, Concetta Di; Causa, Filippo; Battista, Edmondo; Netti, Paolo A

    2016-09-01

    Polymeric microparticles represent a robustly platform for the detection of clinically relevant analytes in biological samples; they can be functionalized encapsulating a multiple types of biologics entities, enhancing their applications as a new class of colloid materials. Microfluidic offers a versatile platform for the synthesis of monodisperse and engineered microparticles. In this work, we report microfluidic synthesis of novel polymeric microparticles endowed with specific peptide due to its superior specificity for target binding in complex media. A peptide sequence was efficiently encapsulated into the polymeric network and protein binding occurred with high affinity (KD 0.1-0.4μM). Fluidic dynamics simulation was performed to optimize the production conditions for monodisperse and stable functionalized microgels. The results demonstrate the easy and fast realization, in a single step, of functionalized monodisperse microgels using droplet-microfluidic technique, and how the inclusion of the peptide within polymeric network improve both the affinity and the specificity of protein capture. PMID:27137799

  18. Analysis of whey protein hydrolysates: peptide profile and ACE inhibitory activity

    Directory of Open Access Journals (Sweden)

    Marialice Pinto Coelho Silvestre

    2012-12-01

    Full Text Available The aim of this study was to prepare enzymatic hydrolysates from whey protein concentrate with a nutritionally adequate peptide profile and the ability to inhibit angiotensin-converting enzyme (ACE activity. The effects of the type of enzyme used (pancreatin or papain, the enzyme:substrate ratio (E:S ratio=0.5:100, 1:100, 2:100 and 3:100 and the use of ultrafiltration (UF were investigated. The fractionation of peptides was performed by size-exclusion-HPLC, and the quantification of the components of the chromatographic fractions was carried out by a rapid Corrected Fraction Area method. The ACE inhibitory activity (ACE-IA was determined by Reverse Phase-HPLC. All parameters tested affected both the peptide profile and the ACE-IA. The best peptide profile was achieved for the hydrolysates obtained with papain, whereas pancreatin was more advantageous in terms of ACE-IA. The beneficial effect of using a lower E:S ratio on the peptide profile and ACE-IA was observed for both enzymes depending on the conditions used to prepare the hydrolysates. The beneficial effect of not using UF on the peptide profile was observed in some cases for pancreatin and papain. However, the absence of UF yielded greater ACE-IA only when using papain.O objetivo deste estudo foi preparar hidrolisados enzimáticos do concentrado proteico do soro de leite com perfil peptídico nutricionalmente adequado e com capacidade para inibir a atividade da enzima conversora da angiotensina (ECA. Os efeitos do tipo de enzima usado (pancreatina ou papaína, da relação enzima:substrato (E:S=0,5:100, 1:100, 2:100 e 3:100 e do uso da ultrafiltração (UF foram investigados. O fracionamento dos peptídeos foi feito por CLAE de exclusão molecular e a quantificação dos componentes das frações cromatográficas foi realizada pelo método da Área Corrigida da Fração. A atividade inibitória da ECA (AI-ECA foi determinada por CLAE de fase reversa. Todos os parâmetros testados afetaram

  19. The potential of chitosan in enhancing peptide and protein absorption across the TR146 cell culture model-an in vitro model of the buccal epithelium

    DEFF Research Database (Denmark)

    Portero, Ana; Remuñán-López, Carmen; Nielsen, Hanne Mørck

    2002-01-01

    To investigate the potential of chitosan (CS) to enhance buccal peptide and protein absorption, the TR146 cell culture model, a model of the buccal epithelium, was used.......To investigate the potential of chitosan (CS) to enhance buccal peptide and protein absorption, the TR146 cell culture model, a model of the buccal epithelium, was used....

  20. Synthetic peptide homologous to β protein from Alzheimer's disease forms amyloid-like fibrils in vitro

    International Nuclear Information System (INIS)

    Progressive amyloid deposition in senile plaques and cortical blood vessels may play a central role in the pathogenesis of Alzheimer's disease. The authors have used x-ray diffraction and electron microscopy to study the molecular organization and morphology of macromolecular assemblies formed by three synthetic peptides homologous to β protein of brain amyloid: β-(1-28), residues 1-28 of the β protein; [Ala1-β-(1-28), β-(1-28) with alanine substituted for lysine at position 16; and β-(18-28), residues 18-28 of the β protein. β-(1-28) readily formed fibrils in vitro that were similar in ultrastructure to the in vivo amyloid and aggregated into large bundles resembling those of senile plaque cores. X-ray patterns from partially dried, oriented pellets showed a cross-β-conformation. [Ala16]β-(1-28) formed β-pleated sheet assemblies that were dissimilar to in vivo fibrils. The width of the 10-A spacing indicated stacks of about six sheets. Thus, substitution of the uncharged alanine for the positively charged lysine in the β-strand region enhances the packing of the sheets and dramatically alters the type of macromolecular aggregate formed. Β-(18-28) formed assemblies that had even a greater number of stacked sheets. The findings on these homologous synthetic assemblies help to define the specific sequence that is required to form Alzheimer's-type amyloid fibrils, thus providing an in vitro model of age-related cerebral amyloidogenesis

  1. Thermal expansivities of peptides, polypeptides and proteins as measured by pressure perturbation calorimetry.

    Science.gov (United States)

    Pandharipande, Pranav P; Makhatadze, George I

    2015-04-01

    The main goal of this work was to provide direct experimental evidence that the expansivity of peptides, polypeptides and proteins as measured by pressure perturbation calorimetry (PPC), can serve as a proxy to characterize relative compactness of proteins, especially the denatured state ensemble. This is very important as currently only small angle X-ray scattering (SAXS), intrinsic viscosity and, to a lesser degree, fluorescence resonance transfer (FRET) experiments are capable of reporting on the compactness of denatured state ensembles. We combined the expansivity measurements with other biophysical methods (far-UV circular dichroism spectroscopy, differential scanning calorimetry, and small angle X-ray scattering). Three case studies of the effects of conformational changes on the expansivity of polypeptides in solution are presented. We have shown that expansivity appears to be insensitive to the helix-coil transition, and appears to reflect the changes in hydration of the side-chains. We also observed that the expansivity is sensitive to the global conformation of the polypeptide chain and thus can be potentially used to probe hydration of different collapsed states of denatured or even intrinsically disordered proteins.

  2. A novel cell penetrating peptide carrier for the delivery of nematocidal proteins drug

    Science.gov (United States)

    Kim, Jea Hyun

    Nematodes have recently become a primary source of harmful diseases to the environment that inflict harsh damages to pine trees and marine species. However, nematodes cannot be killed by normal pesticides or chemicals due to their thick outer protective layer mainly composed of collagen and cuticles. Thus, a novel approach to trigger intracellular delivery of chemicals through the layers of nematodes is required. In this study, the selection of the novel CPP was carefully progressed through protein database and serial digested fragmentation, internalization of each amino sequence was analyzed through flow cytometry and confocal microscope. As one of the most effective CPP material, JH 1.6 was compared with other major CPPs and its cellular toxicity was investigated. Furthermore, JH 1.6 was attached to various RNA, DNA, and proteins and internalization efficiency was evaluated for mammalian cells. To examine its effects on nematodes in vivo, JH 1.6 was conjugated with nematocidal protein - botulinum neurotoxin (BnT) and treated in C.elegans as a model animal. The results showed that JH 1.6 had high relative internalization rate and low cellular toxicity compared to other major CPP such as TAT and GV1001 peptides.

  3. Determining the Secondary Structure of Membrane Proteins and Peptides Via Electron Spin Echo Envelope Modulation (ESEEM) Spectroscopy

    Science.gov (United States)

    Liu, Lishan; Mayo, Daniel J.; Sahu, Indra D.; Zhou, Andy; Zhang, Rongfu; McCarrick, Robert M.; Lorigan, Gary A.

    2016-01-01

    Revealing detailed structural and dynamic information of membrane embedded or associated proteins is challenging due to their hydrophobic nature which makes NMR and X-ray crystallographic studies challenging or impossible. Electron paramagnetic resonance (EPR) has emerged as a powerful technique to provide essential structural and dynamic information for membrane proteins with no size limitations in membrane systems which mimic their natural lipid bilayer environment. Therefore, tremendous efforts have been devoted toward the development and application of EPR spectroscopic techniques to study the structure of biological systems such as membrane proteins and peptides. This chapter introduces a novel approach established and developed in the Lorigan lab to investigate membrane protein and peptide local secondary structures utilizing the pulsed EPR technique electron spin echo envelope modulation (ESEEM) spectroscopy. Detailed sample preparation strategies in model membrane protein systems and the experimental setup are described. Also, the ability of this approach to identify local secondary structure of membrane proteins and peptides with unprecedented efficiency is demonstrated in model systems. Finally, applications and further developments of this ESEEM approach for probing larger size membrane proteins produced by over-expression systems are discussed. PMID:26477255

  4. The negatively charged regions of lactoferrin binding protein B, an adaptation against anti-microbial peptides.

    Directory of Open Access Journals (Sweden)

    Ari Morgenthau

    Full Text Available Lactoferrin binding protein B (LbpB is a bi-lobed membrane bound lipoprotein that is part of the lactoferrin receptor complex in a variety of Gram-negative pathogens. Despite high sequence diversity among LbpBs from various strains and species, a cluster of negatively charged amino acids is invariably present in the protein's C-terminal lobe in all species except Moraxella bovis. The function of LbpB in iron acquisition has yet to be experimentally demonstrated, whereas in vitro studies have shown that LbpB confers protection against lactoferricin, a short cationic antimicrobial peptide released from the N- terminus of lactoferrin. In this study we demonstrate that the negatively charged regions can be removed from the Neisseria meningitidis LbpB without compromising stability, and this results in the inability of LbpB to protect against the bactericidal effects of lactoferricin. The release of LbpB from the cell surface by the autotransporter NalP reduces the protection against lactoferricin in the in vitro killing assay, attributed to removal of LbpB during washing steps, but is unlikely to have a similar impact in vivo. The protective effect of the negatively charged polysaccharide capsule in the killing assay was less than the protection conferred by LbpB, suggesting that LbpB plays a major role in protection against cationic antimicrobial peptides in vivo. The selective release of LbpB by NalP has been proposed to be a mechanism for evading the adaptive immune response, by reducing the antibody binding to the cell surface, but may also provide insights into the primary function of LbpB in vivo. Although TbpB and LbpB have been shown to be major targets of the human immune response, the selective release of LbpB suggests that unlike TbpB, LbpB may not be essential for iron acquisition, but important for protection against cationic antimicrobial peptides.

  5. The negatively charged regions of lactoferrin binding protein B, an adaptation against anti-microbial peptides.

    Science.gov (United States)

    Morgenthau, Ari; Beddek, Amanda; Schryvers, Anthony B

    2014-01-01

    Lactoferrin binding protein B (LbpB) is a bi-lobed membrane bound lipoprotein that is part of the lactoferrin receptor complex in a variety of Gram-negative pathogens. Despite high sequence diversity among LbpBs from various strains and species, a cluster of negatively charged amino acids is invariably present in the protein's C-terminal lobe in all species except Moraxella bovis. The function of LbpB in iron acquisition has yet to be experimentally demonstrated, whereas in vitro studies have shown that LbpB confers protection against lactoferricin, a short cationic antimicrobial peptide released from the N- terminus of lactoferrin. In this study we demonstrate that the negatively charged regions can be removed from the Neisseria meningitidis LbpB without compromising stability, and this results in the inability of LbpB to protect against the bactericidal effects of lactoferricin. The release of LbpB from the cell surface by the autotransporter NalP reduces the protection against lactoferricin in the in vitro killing assay, attributed to removal of LbpB during washing steps, but is unlikely to have a similar impact in vivo. The protective effect of the negatively charged polysaccharide capsule in the killing assay was less than the protection conferred by LbpB, suggesting that LbpB plays a major role in protection against cationic antimicrobial peptides in vivo. The selective release of LbpB by NalP has been proposed to be a mechanism for evading the adaptive immune response, by reducing the antibody binding to the cell surface, but may also provide insights into the primary function of LbpB in vivo. Although TbpB and LbpB have been shown to be major targets of the human immune response, the selective release of LbpB suggests that unlike TbpB, LbpB may not be essential for iron acquisition, but important for protection against cationic antimicrobial peptides. PMID:24465982

  6. Predicted class-I aminoacyl tRNA synthetase-like proteins in non-ribosomal peptide synthesis

    Directory of Open Access Journals (Sweden)

    Iyer Lakshminarayan M

    2010-08-01

    Full Text Available Abstract Background Recent studies point to a great diversity of non-ribosomal peptide synthesis systems with major roles in amino acid and co-factor biosynthesis, secondary metabolism, and post-translational modifications of proteins by peptide tags. The least studied of these systems are those utilizing tRNAs or aminoacyl-tRNA synthetases (AAtRS in non-ribosomal peptide ligation. Results Here we describe novel examples of AAtRS related proteins that are likely to be involved in the synthesis of widely distributed peptide-derived metabolites. Using sensitive sequence profile methods we show that the cyclodipeptide synthases (CDPSs are members of the HUP class of Rossmannoid domains and are likely to be highly derived versions of the class-I AAtRS catalytic domains. We also identify the first eukaryotic CDPSs in fungi and in animals; they might be involved in immune response in the latter organisms. We also identify a paralogous version of the methionyl-tRNA synthetase, which is widespread in bacteria, and present evidence using contextual information that it might function independently of protein synthesis as a peptide ligase in the formation of a peptide- derived secondary metabolite. This metabolite is likely to be heavily modified through multiple reactions catalyzed by a metal-binding cupin domain and a lysine N6 monooxygenase that are strictly associated with this paralogous methionyl-tRNA synthetase (MtRS. We further identify an analogous system wherein the MtRS has been replaced by more typical peptide ligases with the ATP-grasp or modular condensation-domains. Conclusions The prevalence of these predicted biosynthetic pathways in phylogenetically distant, pathogenic or symbiotic bacteria suggests that metabolites synthesized by them might participate in interactions with the host. More generally, these findings point to a complete spectrum of recruitment of AAtRS to various non-ribosomal biosynthetic pathways, ranging from the

  7. Lupin Peptides Modulate the Protein-Protein Interaction of PCSK9 with the Low Density Lipoprotein Receptor in HepG2 Cells

    Science.gov (United States)

    Lammi, Carmen; Zanoni, Chiara; Aiello, Gilda; Arnoldi, Anna; Grazioso, Giovanni

    2016-07-01

    Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been recently identified as a new useful target for hypercholesterolemia treatment. This work demonstrates that natural peptides, deriving from the hydrolysis of lupin protein and absorbable at intestinal level, are able to inhibit the protein-protein interaction between PCSK9 and the low density lipoprotein receptor (LDLR). In order to sort out the best potential inhibitors among these peptides, a refined in silico model of the PCSK9/LDLR interaction was developed. Docking, molecular dynamics (MD) simulations and peptide binding energy estimations, by MM-GBSA approach, permitted to select the two best candidates among tested peptides that were synthesized and evaluated for their inhibitory activity. The most active was P5 that induced a concentration dependent inhibition of the PCSK9-LDLR binding, with an IC50 value equal to 1.6 ± 0.33 μM. Tested at a 10 μM concentration, this peptide increased by 66 ± 21.4% the ability of HepG2 cells to take up LDL from the extracellular environment.

  8. Disulfide Linkage Characterization of Disulfide Bond-Containing Proteins and Peptides by Reducing Electrochemistry and Mass Spectrometry

    DEFF Research Database (Denmark)

    Cramer, Christian N; Haselmann, Kim F; Olsen, Jesper V;

    2016-01-01

    Unravelling of disulfide linkage patterns is a crucial part of protein characterization, whether it is for a previously uncharacterized protein in basic research or a recombinant pharmaceutical protein. In the biopharmaceutical industry, elucidation of the cysteine connectivities is a necessity t...

  9. Reduced myelin basic protein and actin-related gene expression in visual cortex in schizophrenia.

    Science.gov (United States)

    Matthews, Paul R; Eastwood, Sharon L; Harrison, Paul J

    2012-01-01

    Most brain gene expression studies of schizophrenia have been conducted in the frontal cortex or hippocampus. The extent to which alterations occur in other cortical regions is not well established. We investigated primary visual cortex (Brodmann area 17) from the Stanley Neuropathology Consortium collection of tissue from 60 subjects with schizophrenia, bipolar disorder, major depression, or controls. We first carried out a preliminary array screen of pooled RNA, and then used RT-PCR to quantify five mRNAs which the array identified as differentially expressed in schizophrenia (myelin basic protein [MBP], myelin-oligodendrocyte glycoprotein [MOG], β-actin [ACTB], thymosin β-10 [TB10], and superior cervical ganglion-10 [SCG10]). Reduced mRNA levels were confirmed by RT-PCR for MBP, ACTB and TB10. The MBP reduction was limited to transcripts containing exon 2. ACTB and TB10 mRNAs were also decreased in bipolar disorder. None of the transcripts were altered in subjects with major depression. Reduced MBP mRNA in schizophrenia replicates findings in other brain regions and is consistent with oligodendrocyte involvement in the disorder. The decreases in expression of ACTB, and the actin-binding protein gene TB10, suggest changes in cytoskeletal organisation. The findings confirm that the primary visual cortex shows molecular alterations in schizophrenia and extend the evidence for a widespread, rather than focal, cortical pathophysiology.

  10. Reduced myelin basic protein and actin-related gene expression in visual cortex in schizophrenia.

    Directory of Open Access Journals (Sweden)

    Paul R Matthews

    Full Text Available Most brain gene expression studies of schizophrenia have been conducted in the frontal cortex or hippocampus. The extent to which alterations occur in other cortical regions is not well established. We investigated primary visual cortex (Brodmann area 17 from the Stanley Neuropathology Consortium collection of tissue from 60 subjects with schizophrenia, bipolar disorder, major depression, or controls. We first carried out a preliminary array screen of pooled RNA, and then used RT-PCR to quantify five mRNAs which the array identified as differentially expressed in schizophrenia (myelin basic protein [MBP], myelin-oligodendrocyte glycoprotein [MOG], β-actin [ACTB], thymosin β-10 [TB10], and superior cervical ganglion-10 [SCG10]. Reduced mRNA levels were confirmed by RT-PCR for MBP, ACTB and TB10. The MBP reduction was limited to transcripts containing exon 2. ACTB and TB10 mRNAs were also decreased in bipolar disorder. None of the transcripts were altered in subjects with major depression. Reduced MBP mRNA in schizophrenia replicates findings in other brain regions and is consistent with oligodendrocyte involvement in the disorder. The decreases in expression of ACTB, and the actin-binding protein gene TB10, suggest changes in cytoskeletal organisation. The findings confirm that the primary visual cortex shows molecular alterations in schizophrenia and extend the evidence for a widespread, rather than focal, cortical pathophysiology.

  11. SncRNA715 Inhibits Schwann Cell Myelin Basic Protein Synthesis.

    Science.gov (United States)

    Müller, Christina; Hochhaus, Nina M; Fontana, Xavier; Luhmann, Heiko J; White, Robin

    2015-01-01

    Myelin basic proteins (MBP) are major constituents of the myelin sheath in the central nervous system (CNS) and the peripheral nervous system (PNS). In the CNS Mbp translation occurs locally at the axon-glial contact site in a neuronal activity-dependent manner. Recently we identified the small non-coding RNA 715 (sncRNA715) as a key inhibitor of Mbp translation during transport in oligodendrocytes. Mbp mRNA localization in Schwann cells has been observed, but has not been investigated in much detail. Here we could confirm translational repression of Mbp mRNA in Schwann cells. We show that sncRNA715 is expressed and its levels correlate inversely with MBP in cultured Schwann cells and in the sciatic nerve in vivo. Furthermore we could reduce MBP protein levels in cultured Schwann cells by increasing the levels of the inhibitory sncRNA715. Our findings suggest similarities in sncRNA715-mediated translational repression of Mbp mRNA in oligodendrocytes and Schwann cells.

  12. Molecular evolution of myelin basic protein, an abundant structural myelin component.

    Science.gov (United States)

    Nawaz, Schanila; Schweitzer, Jörn; Jahn, Olaf; Werner, Hauke B

    2013-08-01

    Rapid nerve conduction in jawed vertebrates is facilitated by the myelination of axons, which evolved in ancient cartilaginous fish. We aim to understand the coevolution of myelin and the major myelin proteins. We found that myelin basic protein (MBP) derived from living cartilaginous fish (sharks and rays) associated with the plasma membrane of glial cells similar to the phosphatidylinositol (4,5)-bisphosphate (PIP₂)-binding marker PH-PLCδ1, and that ionomycin-induced PIP₂-hydrolysis led to its cellular redistribution. We identified two paralogous mbp genes in multiple teleost species, consistent with a genome duplication at the root of the teleost clade. Zebrafish mbpb is organized in a complex transcription unit together with the unrelated gene-of-the-oligodendrocyte-lineage (golli) while mbpa does not encode GOLLI. Moreover, the embryonic expression of mbpa and mbpb differed, indicating functional specialization after duplication. However, both mbpa and mbpb-mRNAs were detected in mature oligodendrocytes and Schwann cells, MBPa and MBPb were mass spectrometrically identified in zebrafish myelin, both associated with the plasma membrane via PIP₂, and the ratio of nonsynonymous to synonymous nucleotide-substitution rates (Ka/Ks) was low. Together, this indicates selective pressure to conserve many aspects of the cellular expression and function of MBP across vertebrate species. We propose that the PIP₂-binding function of MBP is evolutionarily old and that its emergence in ancient gnathostomata provided glial cells with the competence to myelinate.

  13. Lipid domains control myelin basic protein adsorption and membrane interactions between model myelin lipid bilayers.

    Science.gov (United States)

    Lee, Dong Woog; Banquy, Xavier; Kristiansen, Kai; Kaufman, Yair; Boggs, Joan M; Israelachvili, Jacob N

    2014-02-25

    The surface forces apparatus and atomic force microscope were used to study the effects of lipid composition and concentrations of myelin basic protein (MBP) on the structure of model lipid bilayers, as well as the interaction forces and adhesion between them. The lipid bilayers had a lipid composition characteristic of the cytoplasmic leaflets of myelin from "normal" (healthy) and "disease-like" [experimental allergic encephalomyelitis (EAE)] animals. They showed significant differences in the adsorption mechanism of MBP. MBP adsorbs on normal bilayers to form a compact film (3-4 nm) with strong intermembrane adhesion (∼0.36 mJ/m(2)), in contrast to its formation of thicker (7-8 nm) swelled films with weaker intermembrane adhesion (∼0.13 mJ/m(2)) on EAE bilayers. MBP preferentially adsorbs to liquid-disordered submicron domains within the lipid membranes, attributed to hydrophobic attractions. These results show a direct connection between the lipid composition of membranes and membrane-protein adsorption mechanisms that affects intermembrane spacing and adhesion and has direct implications for demyelinating diseases.

  14. Interaction of myelin basic protein isoforms with lipid bilayers studied by FTIR spectroscopy

    Science.gov (United States)

    Jackson, Michael; Choo, Lin-P'ing; Boulias, Christopher; Moscarello, Mario A.; Mantsch, Henry H.

    1993-05-01

    The secondary structure of the naturally occurring isoforms of myelin basic protein (MBP1-8) from human myelin was studied by Fourier transform infrared spectroscopy under a variety of experimental conditions. In aqueous solution each isoform was found to be unstructured. In the presence of negatively charged liquid bilayers MBP1-4 were shown to exhibit an amide I band maximum indicative of the adoption of (alpha) -helical secondary structures. A detailed analysis revealed that significant proportions of (beta) -sheet secondary structure were also present. MBP5 and MBP8, which have significantly less cationic charge than MBP1-4, exhibited an amide I maximum identical to that seen in solution, suggesting that no interaction with the bilayer occurred. Analysis of the lipid CH2 and C equals O stretching vibrations also pointed towards significant interaction of MBP1-4 with the bilayer. The changes in intensity and frequency of these bands which typically accompany the phase transition in the pure bilayer were abolished by addition of the proteins. No such effect was seen for MBP5 and 8, the normal lipid phase transition being apparent. The implications of these results in the aetiology of multiple sclerosis is discussed.

  15. Purification and identification of lactoperoxidase in milk basic proteins as an inhibitor of osteoclastogenesis.

    Science.gov (United States)

    Morita, Y; Ono, A; Serizawa, A; Yogo, K; Ishida-Kitagawa, N; Takeya, T; Ogawa, T

    2011-05-01

    A milk protein fraction with alkaline isoelectric points (milk basic protein, MBP) inhibits both bone resorption and osteoclastogenesis for in vitro models. We previously identified bovine angiogenin as a component of MBP that inhibits bone resorption. However, purified angiogenin had no effect on osteoclastogenesis, suggesting that MBP contains unidentified component(s) that inhibit osteoclast formation. In this study, we purified lactoperoxidase (LPO) as the predominant inhibitor of osteoclastogenesis in MBP. The LPO treatment downregulated levels of reactive oxygen species in osteoclasts. Signaling by receptor activator of NF-kappa-B ligand/receptor activator of NF-kappa-B (RANKL/RANK) was downregulated in LPO-treated cells, and, in particular, the ubiquitination of tumor necrosis factor receptor associate factor 6 (TRAF6) and activation of downstream signaling cascades (JNK, p38, ERK, and NFκB) were suppressed. Ultimately, LPO treatment led to decreased expression of c-Fos and NFAT2. These results suggest that MBP contains at least 2 components that independently suppress bone resorption through a unique mechanism: angiogenin inhibits bone resorption and LPO inhibits RANKL-induced osteoclast differentiation. These data explain many of the positive aspects of milk consumption on bone health.

  16. The Expression of Sperm Membrane Peptide-Hepatitis B Surface Antigen Fusion Protein with Recombinant Vaccinia Virus

    Institute of Scientific and Technical Information of China (English)

    杨晓鸣; 赵峰; 严缘昌; 李光地; 汪垣

    1998-01-01

    A synthetic oligonucleotide, HSD-2a, encoding a peptide segment of the extracellular domain of a human sperm membrane protein, YWK-Ⅱ, was fused with hepatitis B surface antigen gene (HBs gene). The fused gene was then cloned to pUC18 plasmid.

  17. Performance of coupled enzymatic hydrolysis and membrane separation bioreactor for antihypertensive peptides production from Porphyra yezoensis protein

    Science.gov (United States)

    To explore more efficient production methods of antihypertensive peptides from Porphyra yezoensis protein, three methods of coupling of enzymatic hydrolysis and membrane separation (CEH-MS) were studied and compared with the traditional EH and offline MS method. The results showed that the conversio...

  18. Investigating the microstructure of keratin extracted from wool: peptide sequence (MALDI-TOF/TOF) and protein conformation (FTIR)

    Science.gov (United States)

    Keratin was extracted from wool by reduction with 2-mercaptoethanol. It was isolated as intact keratin and characterized by its similar molecular weight, protein composition, and secondary structure to native keratin. Gel electrophoresis patterns and MALDI-TOF/TOF peptide sequences provided the ide...

  19. Probing the role of backbone hydrogen bonds in protein-peptide interactions by amide-to-ester mutations

    DEFF Research Database (Denmark)

    Eildal, Jonas N N; Hultqvist, Greta; Balle, Thomas;

    2013-01-01

    -protein interactions, those of the PDZ domain family involve formation of intermolecular hydrogen bonds: C-termini or internal linear motifs of proteins bind as β-strands to form an extended antiparallel β-sheet with the PDZ domain. Whereas extensive work has focused on the importance of the amino acid side chains...... of the protein ligand, the role of the backbone hydrogen bonds in the binding reaction is not known. Using amide-to-ester substitutions to perturb the backbone hydrogen-bonding pattern, we have systematically probed putative backbone hydrogen bonds between four different PDZ domains and peptides corresponding...... to natural protein ligands. Amide-to-ester mutations of the three C-terminal amides of the peptide ligand severely affected the affinity with the PDZ domain, demonstrating that hydrogen bonds contribute significantly to ligand binding (apparent changes in binding energy, ΔΔG = 1.3 to >3.8 kcal mol(-1...

  20. Analysis of the induction of the myelin basic protein binding to the plasma membrane phospholipid monolayer

    Science.gov (United States)

    Zhang, Lei; Hao, Changchun; Feng, Ying; Gao, Feng; Lu, Xiaolong; Li, Junhua; Sun, Runguang

    2016-09-01

    Myelin basic protein (MBP) is an essential structure involved in the generation of central nervous system (CNS) myelin. Myelin shape has been described as liquid crystal structure of biological membrane. The interactions of MBP with monolayers of different lipid compositions are responsible for the multi-lamellar structure and stability of myelin. In this paper, we have designed MBP-incorporated model lipid monolayers and studied the phase behavior of MBP adsorbed on the plasma membrane at the air/water interface by thermodynamic method and atomic force microscopy (AFM). By analyzing the pressure-area (π-A) and pressure-time (π-T) isotherms, univariate linear regression equation was obtained. In addition, the elastic modulus, surface pressure increase, maximal insertion pressure, and synergy factor of monolayers were detected. These parameters can be used to modulate the monolayers binding of protein, and the results show that MBP has the strongest affinity for 1,2-dipalmitoyl-sn-glycero-3- phosphoserine (DPPS) monolayer, followed by DPPC/DPPS mixed and 1,2-dipalmitoyl-sn-glycero-3-phospho-choline (DPPC) monolayers via electrostatic and hydrophobic interactions. AFM images of DPPS and DPPC/DPPS mixed monolayers in the presence of MBP (5 nM) show a phase separation texture at the surface pressure of 20 mN/m and the incorporation of MBP put into the DPPC monolayers has exerted a significant effect on the domain structure. MBP is not an integral membrane protein but, due to its positive charge, interacts with the lipid head groups and stabilizes the membranes. The interaction between MBP and phospholipid membrane to determine the nervous system of the disease has a good biophysical significance and medical value. Project supported by the National Natural Science Foundation of China (Grant Nos. 21402114 and 11544009), the Natural Science Basic Research Plan in Shaanxi Province of China (Grant No. 2016JM2010), the Fundamental Research Funds for the Central

  1. Ion mobility mass spectrometry of peptide, protein, and protein complex ions using a radio-frequency confining drift cell.

    Science.gov (United States)

    Allen, Samuel J; Giles, Kevin; Gilbert, Tony; Bush, Matthew F

    2016-02-01

    Ion mobility mass spectrometry experiments enable the characterization of mass, assembly, and shape of biological molecules and assemblies. Here, a new radio-frequency confining drift cell is characterized and used to measure the mobilities of peptide, protein, and protein complex ions. The new drift cell replaced the traveling-wave ion mobility cell in a Waters Synapt G2 HDMS. Methods for operating the drift cell and determining collision cross section values using this experimental set up are presented within the context of the original instrument control software. Collision cross sections for 349 cations and anions are reported, 155 of which are for ions that have not been characterized previously using ion mobility. The values for the remaining ions are similar to those determined using a previous radio-frequency confining drift cell and drift tubes without radial confinement. Using this device under 2 Torr of helium gas and an optimized drift voltage, denatured and native-like ions exhibited average apparent resolving powers of 14.2 and 16.5, respectively. For ions with high mobility, which are also low in mass, the apparent resolving power is limited by contributions from ion gating. In contrast, the arrival-time distributions of low-mobility, native-like ions are not well explained using only contributions from ion gating and diffusion. For those species, the widths of arrival-time distributions are most consistent with the presence of multiple structures in the gas phase. PMID:26739109

  2. Ion mobility mass spectrometry of peptide, protein, and protein complex ions using a radio-frequency confining drift cell.

    Science.gov (United States)

    Allen, Samuel J; Giles, Kevin; Gilbert, Tony; Bush, Matthew F

    2016-02-01

    Ion mobility mass spectrometry experiments enable the characterization of mass, assembly, and shape of biological molecules and assemblies. Here, a new radio-frequency confining drift cell is characterized and used to measure the mobilities of peptide, protein, and protein complex ions. The new drift cell replaced the traveling-wave ion mobility cell in a Waters Synapt G2 HDMS. Methods for operating the drift cell and determining collision cross section values using this experimental set up are presented within the context of the original instrument control software. Collision cross sections for 349 cations and anions are reported, 155 of which are for ions that have not been characterized previously using ion mobility. The values for the remaining ions are similar to those determined using a previous radio-frequency confining drift cell and drift tubes without radial confinement. Using this device under 2 Torr of helium gas and an optimized drift voltage, denatured and native-like ions exhibited average apparent resolving powers of 14.2 and 16.5, respectively. For ions with high mobility, which are also low in mass, the apparent resolving power is limited by contributions from ion gating. In contrast, the arrival-time distributions of low-mobility, native-like ions are not well explained using only contributions from ion gating and diffusion. For those species, the widths of arrival-time distributions are most consistent with the presence of multiple structures in the gas phase.

  3. Interference of peptides and specific antibodies with the function of the Actinobacillus pleuropneumoniae transferrin-binding protein.

    OpenAIRE

    Strutzberg, K; Franz, B.; Gerlach, G F

    1997-01-01

    Multiple-antigenic peptides (MAPs) containing transferrin-binding domains of the Actinobacillus pleuropneumoniae serotype 7-derived transferrin-binding protein (TfbA) (K. Strutzberg, L. von Olleschik, B. Franz, C. Pyne, M. A. Schmidt, and G.-F. Gerlach, Infect. Immun. 63:3846-3850, 1995) were constructed. It was found that the MAPs inhibited transferrin binding of the recombinant TfbA protein, whereas antibodies directed against transferrin-binding domains failed to do so.

  4. Viral Coat Protein Peptides with Limited Sequence Homology Bind Similar Domains of Alfalfa Mosaic Virus and Tobacco Streak Virus RNAs

    Science.gov (United States)

    Swanson, Maud M.; Ansel-McKinney, Patricia; Houser-Scott, Felicia; Yusibov, Vidadi; Loesch-Fries, L. Sue; Gehrke, Lee

    1998-01-01

    An unusual and distinguishing feature of alfalfa mosaic virus (AMV) and ilarviruses such as tobacco streak virus (TSV) is that the viral coat protein is required to activate the early stages of viral RNA replication, a phenomenon known as genome activation. AMV-TSV coat protein homology is limited; however, they are functionally interchangeable in activating virus replication. For example, TSV coat protein will activate AMV RNA replication and vice versa. Although AMV and TSV coat proteins have little obvious amino acid homology, we recently reported that they share an N-terminal RNA binding consensus sequence (Ansel-McKinney et al., EMBO J. 15:5077–5084, 1996). Here, we biochemically compare the binding of chemically synthesized peptides that include the consensus RNA binding sequence and lysine-rich (AMV) or arginine-rich (TSV) environment to 3′-terminal TSV and AMV RNA fragments. The arginine-rich TSV coat protein peptide binds viral RNA with lower affinity than the lysine-rich AMV coat protein peptides; however, the ribose moieties protected from hydroxyl radical attack by the two different peptides are localized in the same area of the predicted RNA structures. When included in an infectious inoculum, both AMV and TSV 3′-terminal RNA fragments inhibited AMV RNA replication, while variant RNAs unable to bind coat protein did not affect replication significantly. The data suggest that RNA binding and genome activation functions may reside in the consensus RNA binding sequence that is apparently unique to AMV and ilarvirus coat proteins. PMID:9525649

  5. Extraction of consensus protein patterns in regions containing non-proline cis peptide bonds and their functional assessment

    Directory of Open Access Journals (Sweden)

    Rigas Georgios

    2011-05-01

    Full Text Available Abstract Background In peptides and proteins, only a small percentile of peptide bonds adopts the cis configuration. Especially in the case of amide peptide bonds, the amount of cis conformations is quite limited thus hampering systematic studies, until recently. However, lately the emerging population of databases with more 3D structures of proteins has produced a considerable number of sequences containing non-proline cis formations (cis-nonPro. Results In our work, we extract regular expression-type patterns that are descriptive of regions surrounding the cis-nonPro formations. For this purpose, three types of pattern discovery are performed: i exact pattern discovery, ii pattern discovery using a chemical equivalency set, and iii pattern discovery using a structural equivalency set. Afterwards, using each pattern as predicate, we search the Eukaryotic Linear Motif (ELM resource to identify potential functional implications of regions with cis-nonPro peptide bonds. The patterns extracted from each type of pattern discovery are further employed, in order to formulate a pattern-based classifier, which is used to discriminate between cis-nonPro and trans-nonPro formations. Conclusions In terms of functional implications, we observe a significant association of cis-nonPro peptide bonds towards ligand/binding functionalities. As for the pattern-based classification scheme, the highest results were obtained using the structural equivalency set, which yielded 70% accuracy, 77% sensitivity and 63% specificity.

  6. Insight into a molecular interaction force supporting peptide backbones and its implication to protein loops and folding.

    Science.gov (United States)

    Du, Qi-Shi; Chen, Dong; Xie, Neng-Zhong; Huang, Ri-Bo; Chou, Kuo-Chen

    2015-09-01

    Although not being classified as the most fundamental protein structural elements like α-helices and β-strands, the loop segment may play considerable roles for protein stability, flexibility, and dynamic activity. Meanwhile, the protein loop is also quite elusive; i.e. its interactions with the other parts of protein as well as its own shape-maintaining forces have still remained as a puzzle or at least not quite clear yet. Here, we report a molecular force, the so-called polar hydrogen-π interaction (Hp-π), which may play an important role in supporting the backbones of protein loops. By conducting the potential energy surface scanning calculations on the quasi π-plane of peptide bond unit, we have observed the following intriguing phenomena: (1) when the polar hydrogen atom of a peptide unit is perpendicularly pointing to the π-plane of other peptide bond units, a remarkable Hp-π interaction occurs; (2) the interaction is distance and orientation dependent, acting in a broad space, and belonging to the 'point-to-plane' one. The molecular force reported here may provide useful interaction concepts and insights into better understanding the loop's unique stability and flexibility feature, as well as the driving force of the protein global folding. PMID:25375237

  7. Dynamic behavior of small heat shock protein inhibition on amyloid fibrillization of a small peptide (SSTSAA) from RNase A

    International Nuclear Information System (INIS)

    Highlights: ► Mechanism of small heat shock protein inhibition on fibril formation was studied. ► Peptide SSTSAA with modified ends was used for amyloid fibril formation. ► FRET signal was followed during the fibril formation. ► Mj HSP16.5 inhibits fibril formation when introduced in the lag phase. ► Mj HSP16.5 slows down fibril formation when introduced after the lag phase. -- Abstract: Small heat shock proteins, a class of molecular chaperones, are reported to inhibit amyloid fibril formation in vitro, while the mechanism of inhibition remains unknown. In the present study, we investigated the mechanism by which Mj HSP16.5 inhibits amyloid fibril formation of a small peptide (SSTSAA) from RNase A. A model peptide (dansyl-SSTSAA-W) was designed by introducing a pair of fluorescence resonance energy transfer (FRET) probes into the peptide, allowing for the monitoring of fibril formation by this experimental model. Mj HSP16.5 completely inhibited fibril formation of the model peptide at a molar ratio of 1:120. The dynamic process of fibril formation, revealed by FRET, circular dichroism, and electron microscopy, showed a lag phase of about 2 h followed by a fast growth period. The effect of Mj HSP16.5 on amyloid fibril formation was investigated by adding it into the incubation solution during different growth phases. Adding Mj HSP16.5 to the incubating peptide before or during the lag phase completely inhibited fibril formation. However, introducing Mj HSP16.5 after the lag phase only slowed down the fibril formation process by adhering to the already formed fibrils. These findings provide insight into the inhibitory roles of small heat shock proteins on amyloid fibril formation at the molecular level.

  8. Control of silicification by genetically engineered fusion proteins: Silk–silica binding peptides

    Science.gov (United States)

    Zhou, Shun; Huang, Wenwen; Belton, David J.; Simmons, Leo O.; Perry, Carole C.; Wang, Xiaoqin; Kaplan, David L.

    2014-01-01

    In the present study, an artificial spider silk gene, 6mer, derived from the consensus sequence of Nephila clavipes dragline silk gene, was fused with different silica-binding peptides (SiBPs), A1, A3 and R5, to study the impact of the fusion protein sequence chemistry on silica formation and the ability to generate a silk–silica composite in two different bioinspired silicification systems: solution–solution and solution– solid. Condensed silica nanoscale particles (600–800 nm) were formed in the presence of the recombinant silk and chimeras, which were smaller than those formed by 15mer-SiBP chimeras [1], revealing that the molecular weight of the silk domain correlated to the sizes of the condensed silica particles in the solution system. In addition, the chimeras (6mer-A1/A3/R5) produced smaller condensed silica particles than the control (6mer), revealing that the silica particle size formed in the solution system is controlled by the size of protein assemblies in solution. In the solution–solid interface system, silicification reactions were performed on the surface of films fabricated from the recombinant silk proteins and chimeras and then treated to induce β-sheet formation. A higher density of condensed silica formed on the films containing the lowest β-sheet content while the films with the highest β-sheet content precipitated the lowest density of silica, revealing an inverse correlation between the β-sheet secondary structure and the silica content formed on the films. Intriguingly, the 6mer-A3 showed the highest rate of silica condensation but the lowest density of silica deposition on the films, compared with 6mer-A1 and -R5, revealing antagonistic crosstalk between the silk and the SiBP domains in terms of protein assembly. These findings offer a path forward in the tailoring of biopolymer–silica composites for biomaterial related needs. PMID:25462851

  9. A Review of the Latest Advances in Encrypted Bioactive Peptides from Protein-Rich Waste

    Science.gov (United States)

    Lemes, Ailton Cesar; Sala, Luisa; Ores, Joana da Costa; Braga, Anna Rafaela Cavalcante; Egea, Mariana Buranelo; Fernandes, Kátia Flávia

    2016-01-01

    Bioactive peptides are considered the new generation of biologically active regulators that not only prevent the mechanism of oxidation and microbial degradation in foods but also enhanced the treatment of various diseases and disorders, thus increasing quality of life. This review article emphasizes recent advances in bioactive peptide technology, such as: (i) new strategies for transforming bioactive peptides from residual waste into added-value products; (ii) nanotechnology for the encapsulation, protection and release of controlled peptides; and (iii) use of techniques of large-scale recovery and purification of peptides aiming at future applications to pharmaceutical and food industries. PMID:27322241

  10. Basic science and spine literature document bone morphogenetic protein increases cancer risk

    Directory of Open Access Journals (Sweden)

    Nancy E Epstein

    2014-01-01

    Full Text Available Background: Increasingly, clinical articles document that bone morphogenetic protein (BMP/INFUSE: Medtronic, Memphis, TN, USA and its derivatives utilized in spinal surgery increase the risk of developing cancer. However, there is also a large body of basic science articles that also document that various types of BMP and other members of the TGF-Beta (transforming growth factor beta family promote the growth of different types of cancers. Methods: This review looks at many clinical articles citing BMP/INFUSE′s role, largely "off-label", in contributing to complications encountered during spinal surgery. Next, however, specific attention is given to the clinical and basic science literature regarding how BMP and its derivatives (e.g. members of the TGF-beta family may also impact the development of breast and other cancers. Results: Utilizing BMP/INFUSE in spine surgery increased the risk of cancers/new malignancy as documented in several studies. For example, Carragee et al. found that for single-level instrumented posterolateral fusions (PLF using high-dose rhBMP-2 (239 patients vs. autograft (control group; n = 224, the risks of new cancers at 2 and 5 years postoperatively were increased. In laboratory studies, BMP′s along with other members of the TGF-Beta family also modulated/contributed to the proliferation/differentiation of breast cancer (e.g. bone formation/turnover, breast cancer-related solid tumors, and metastases, lung, adrenal, and colon cancer. Conclusions: BMP/INFUSE when utilized clinically in spinal fusion surgery appears to promote cancer at higher rates than observed in the overall population. Furthermore, BMP and TGF-beta are correlated with increased cancer growth both in the clinic and the laboratory.

  11. Identification of a Highly Conserved Epitope on Avian Influenza Virus Non-Structural Protein 1 Using a Peptide Microarray

    Science.gov (United States)

    Wen, Xuexia; Bao, Hongmei; Shi, Lin; Tao, Qimeng; Jiang, Yongping; Zeng, Xianying; Xu, Xiaolong; Tian, Guobin; Zheng, Shimin; Chen, Hualan

    2016-01-01

    Avian influenza virus (AIV) non-structural protein 1 (NS1) is a multifunctional protein. It is present at high levels in infected cells and can be used for AIV detection and diagnosis. In this study, we generated monoclonal antibody (MAb) D7 against AIV NS1 protein by immunization of BALB/c mice with purified recombinant NS1 protein expressed in Escherichia coli. Isotype determination revealed that the MAb was IgG1/κ-type subclass. To identify the epitope of the MAb D7, the NS1 protein was truncated into a total of 225 15-mer peptides with 14 amino acid overlaps, which were spotted for a peptide microarray. The results revealed that the MAb D7 recognized the consensus DAPF motif. Furthermore, the AIV NS1 protein with the DAPF motif deletion was transiently expressed in 293T cells and failed to react with MAb D7. Subsequently, the DAPF motif was synthesized with an elongated GSGS linker at both the C- and N-termini. The MAb D7 reacted with the synthesized peptide both in enzyme-linked immunosorbent assay (ELISA) and dot-blot assays. From these results, we concluded that DAPF motif is the epitope of MAb D7. To our knowledge, this is the first report of a 4-mer epitope on the NS1 protein of AIV that can be recognized by MAb using a peptide microarray, which is able to simplify epitope identification, and that could serve as the basis for immune responses against avian influenza. PMID:26938453

  12. Antioxidant activities and functional properties of protein and peptide fractions isolated from salted herring brine

    DEFF Research Database (Denmark)

    Taheri, Ali; Farvin, Sabeena; Jacobsen, Charlotte;

    2014-01-01

    In the present study proteins isolated from herring brine, which is a by-product of marinated herring production were evaluated for their functional properties and antioxidant activity. Herring brine was collected from the local herring industry and proteins were precipitated by adjusting the p......H to 4.5 and the obtained supernatant was further fractionated by using ultrafiltration membranes with molecular weight cut offs of 50, 10 and 1kDa. The obtained >50kDa, 50–10kDa, 10–1kDa fractions and pH precipitated fraction were studied for their functional properties and antioxidant activity....... Functional properties revealed that >50kDa polypeptides showed good emulsion activity index when compared to the other fractions. However all fractions had low emulsion stability index. The pH precipitated fraction showed the highest foaming capacity and stability at pH 10. The 50–10kDa and 10–1kDa peptide...

  13. Complement-related proteins control the flavivirus infection of Aedes aegypti by inducing antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Xiaoping Xiao

    2014-04-01

    Full Text Available The complement system functions during the early phase of infection and directly mediates pathogen elimination. The recent identification of complement-like factors in arthropods indicates that this system shares common ancestry in vertebrates and invertebrates as an immune defense mechanism. Thioester (TE-containing proteins (TEPs, which show high similarity to mammalian complement C3, are thought to play a key role in innate immunity in arthropods. Herein, we report that a viral recognition cascade composed of two complement-related proteins limits the flaviviral infection of Aedes aegypti. An A. aegypti macroglobulin complement-related factor (AaMCR, belonging to the insect TEP family, is a crucial effector in opposing the flaviviral infection of A. aegypti. However, AaMCR does not directly interact with DENV, and its antiviral effect requires an A. aegypti homologue of scavenger receptor-C (AaSR-C, which interacts with DENV and AaMCR simultaneously in vitro and in vivo. Furthermore, recognition of DENV by the AaSR-C/AaMCR axis regulates the expression of antimicrobial peptides (AMPs, which exerts potent anti-DENV activity. Our results both demonstrate the existence of a viral recognition pathway that controls the flaviviral infection by inducing AMPs and offer insights into a previously unappreciated antiviral function of the complement-like system in arthropods.

  14. Comprehensive peptidomic and glycomic evaluation reveals that sweet whey permeate from colostrum is a source of milk protein-derived peptides and oligosaccharides

    Science.gov (United States)

    Dallas, David C.; Weinborn, Valerie; de Moura Bell, Juliana M.L.N.; Wang, Meng; Parker, Evan A.; Guerrero, Andres; Hettinga, Kasper A.; Lebrilla, Carlito B.; German, J. Bruce; Barile, Daniela

    2014-01-01

    Whey permeate is a co-product obtained when cheese whey is passed through an ultrafiltration membrane to concentrate whey proteins. Whey proteins are retained by the membrane, whereas the low-molecular weight compounds such as lactose, salts, oligosaccharides and peptides pass through the membrane yielding whey permeate. Research shows that bovine milk from healthy cows contains hundreds of naturally occurring peptides – many of which are homologous with known antimicrobial and immunomodulatory peptides – and nearly 50 oligosaccharide compositions (not including structural isomers). As these endogenous peptides and oligosaccharides have low-molecular weight and whey permeate is currently an under-utilized product stream of the dairy industry, we hypothesized that whey permeate may serve as an inexpensive source of naturally occurring functional peptides and oligosaccharides. Laboratory fractionation of endogenous peptides and oligosaccharides from bovine colostrum sweet whey was expanded to pilot-scale. The membrane fractionation methodology used was similar to the methods commonly used industrially to produce whey protein concentrate and whey permeate. Pilot-scale fractionation was compared to laboratory-scale fractionation with regard to the identified peptides and oligosaccharide compositions. Results were interpreted on the basis of whether industrial whey permeate could eventually serve as a source of functional peptides and oligosaccharides. The majority (96%) of peptide sequences and the majority (96%) of oligosaccharide compositions found in the laboratory-scale process were mirrored in the pilot-scale process. Moreover, the pilot-scale process recovered an additional 33 peptides and 1 oligosaccharide not identified from the laboratory-scale extraction. Both laboratory- and pilot-scale processes yielded peptides deriving primarily from the protein β-casein. The similarity of the laboratory-and pilot-scale's resulting peptide and oligosaccharide

  15. Plant natriuretic peptides induce proteins diagnostic for an adaptive response to stress

    KAUST Repository

    Turek, Ilona

    2014-11-26

    In plants, structural and physiological evidence has suggested the presence of biologically active natriuretic peptides (PNPs). PNPs are secreted into the apoplast, are systemically mobile and elicit a range of responses signaling via cGMP. The PNP-dependent responses include tissue specific modifications of cation transport and changes in stomatal conductance and the photosynthetic rate. PNP also has a critical role in host defense responses. Surprisingly, PNP-homologs are produced by several plant pathogens during host colonization suppressing host defense responses. Here we show that a synthetic peptide representing the biologically active fragment of the Arabidopsis thaliana PNP (AtPNP-A) induces the production of reactive oxygen species in suspension-cultured A. thaliana (Col-0) cells. To identify proteins whose expression changes in an AtPNP-A dependent manner, we undertook a quantitative proteomic approach, employing tandem mass tag (TMT) labeling, to reveal temporal responses of suspension-cultured cells to 1 nM and 10 pM PNP at two different time-points post-treatment. Both concentrations yield a distinct differential proteome signature. Since only the higher (1 nM) concentration induces a ROS response, we conclude that the proteome response at the lower concentration reflects a ROS independent response. Furthermore, treatment with 1 nM PNP results in an over-representation of the gene ontology (GO) terms “oxidation-reduction process,” “translation” and “response to salt stress” and this is consistent with a role of AtPNP-A in the adaptation to environmental stress conditions.

  16. Plant Natriuretic Peptides induce proteins diagnostic for an adaptive response to stress

    Directory of Open Access Journals (Sweden)

    Ilona eTurek

    2014-11-01

    Full Text Available In plants, structural and physiological evidence has suggested the presence of biologically active natriuretic peptides (PNPs. PNPs are secreted into the apoplast, are systemically mobile and elicit a range of responses signaling via cGMP. The PNP-dependent responses include tissue specific modifications of cation transport and changes in stomatal conductance and the photosynthetic rate. PNP also has a critical role in host defense responses. Surprisingly, PNP-homologues are produced by several plant pathogens during host colonization suppressing host defense responses. Here we show that a synthetic peptide representing the biologically active fragment of the Arabidopsis thaliana PNP (AtPNP-A induces the production of reactive oxygen species in suspension-cultured A. thaliana (Col-0 cells. To identify proteins whose expression changes in an AtPNP-A dependent manner, we undertook a quantitative proteomic approach, employing tandem mass tag (TMT labeling, to reveal temporal responses of suspension-cultured cells to 1 nM and 10 pM PNP at two different time-points post-treatment. Both concentrations yield a distinct differential proteome signature. Since only the higher (1 nM concentration induces a ROS response, we conclude that the proteome response at the lower concentration reflects a ROS independent response. Furthermore, treatment with 1 nM PNP results in an over-representation of the gene ontology (GO terms oxidation-reduction process, translation and response to salt stress and this is consistent with a role of AtPNP-A in the adaptation to environmental stress conditions.

  17. Transduction of proteins into leishmania tarentolae by formation of non-covalent complexes with cell-penetrating peptides.

    Science.gov (United States)

    Keller, Andrea-Anneliese; Breitling, Reinhard; Hemmerich, Peter; Kappe, Katarina; Braun, Maria; Wittig, Berith; Schaefer, Buerk; Lorkowski, Stefan; Reissmann, Siegmund

    2014-02-01

    Cell-penetrating peptides (CPPs) are used to transport peptides, proteins, different types of ribonucleic acids (or mimics of these molecules), and DNA into live cells, both plant and mammalian. Leishmania belongs to the class of protozoa having, in comparison to mammalian cells, a different lipid composition of the membrane, proteoglycans on the surface, and signal pathways. We investigated the uptake of two different and easily detectable proteins into the non-pathogenic strain Leishmania tarentolae. From the large number of CPPs available, six and a histone were chosen specifically for their ability to form non-covalent complexes. For Leishmania we used the enzyme β-galactosidase and fluorescent labeled bovine serum albumin as cargoes. The results are compared to similar internalization studies using mammalian cells [Mussbach et al., ]. Leishmania cells can degrade CPPs by a secreted and membrane-bound chymotrypsin-like protease. Both cargo proteins were internalized with sufficient efficiency and achieved intramolecular concentrations similar to mammalian cells. The transport efficiencies of the CPPs differed from each other, and showed a different rank order for both cargoes. The intracellular distribution of fluorescent-labeled bovine serum albumin showed highest concentrations in the nucleus and kinetoplast. Leishmania are susceptible to high concentrations of some CPPs, although comparably dissimilar to mammalian cells. MPG-peptides are more cytotoxic in Leishmania than in mammalian cells, acting as antimicrobial peptides. Our results contribute to a better understanding of molecular interactions in Leishmania cells and possibly to new treatments of leishmaniasis.

  18. Strains of Actinomyces naeslundii and Actinomyces viscosus Exhibit Structurally Variant Fimbrial Subunit Proteins and Bind to Different Peptide Motifs in Salivary Proteins

    OpenAIRE

    Li, Tong; Johansson, Ingegerd; Hay, Donald I.; Strömberg, Nicklas

    1999-01-01

    Oral strains of Actinomyces spp. express type 1 fimbriae, which are composed of major FimP subunits, and bind preferentially to salivary acidic proline-rich proteins (APRPs) or to statherin. We have mapped genetic differences in the fimP subunit genes and the peptide recognition motifs within the host proteins associated with these differential binding specificities. The fimP genes were amplified by PCR from Actinomyces viscosus ATCC 19246, with preferential binding to statherin, and from Act...

  19. T cell determinants of myelin basic protein include a unique encephalitogenic I-E-restricted epitope for Lewis rats

    OpenAIRE

    1989-01-01

    The major encephalitogenic epitope for Lewis rats is the 72-89 sequence of guinea pig basic protein (GP-BP) or rat basic protein (Rt-BP). T cells responsive to this epitope are I-A restricted and preferentially express the V alpha 2:V beta 8 gene combination in their TCR. In this work, we describe for the first time the delayed appearance of T cells specific for additional discrete determinant of BP, the nonencephalitogenic 55-68 sequence of GP-BP restricted by I-A, and the encephalitogenic 8...

  20. Cyanine-based probe\\tag-peptide pair for fluorescence protein imaging and fluorescence protein imaging methods

    Science.gov (United States)

    Mayer-Cumblidge, M. Uljana; Cao, Haishi

    2010-08-17

    A molecular probe comprises two arsenic atoms and at least one cyanine based moiety. A method of producing a molecular probe includes providing a molecule having a first formula, treating the molecule with HgOAc, and subsequently transmetallizing with AsCl.sub.3. The As is liganded to ethanedithiol to produce a probe having a second formula. A method of labeling a peptide includes providing a peptide comprising a tag sequence and contacting the peptide with a biarsenical molecular probe. A complex is formed comprising the tag sequence and the molecular probe. A method of studying a peptide includes providing a mixture containing a peptide comprising a peptide tag sequence, adding a biarsenical probe to the mixture, and monitoring the fluorescence of the mixture.