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Sample records for bacteriocin-like peptide produced

  1. PRELIMINARY DETECTION OF BACTERIOCIN-LIKE INHIBITORY SUBSTANCES PRODUCED BY ENTEROCOCCUS SPECIESISOLATED FROM DIFFERENT SOURCES

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    Snehal P Nemade and M Musaddiq

    2012-06-01

    Full Text Available Some lactic acid bacteria and particularly species belonging to the genus Enetrococcus are known to produce bacteriocin like inhibitory substance (BLIS. Usually they are small cationic peptide with bactericidal activity. The antimicrobial peptide produced by bacteria that deserve considerable interest for their use as natural and non-toxic food preservatives. The use of bacteriocin is among the new approaches as it has major potential in preservatives. Broad spectrum activities against prominent pathogens make it an issue of medical interest. The ability to produce such a biocompound may play role in providing an ecological advantage on non-bacteriocin producer species. 34 strains of Enterococci were isolated from different sources. These strains were identified to species: E. faecalis and E. faecium. Direct antimicrobial activity against indicator strain S. aureus was detected in 34 of the tested isolates. From these, only 7 displayed strong inhibitory activity against this indicator strain. The antimicrobial activity was altered after treatment with trypsin, α-chymotrypsin, papain which confirms the proteinaceous nature of the inhibition. This fact suggests that bacteriocin-like substance produced by Enterococcus strains may find application as biopreservatives in food products. Hence, the focus here is put on bacteriocin like substance screened by Enterococcus species isolated from different sources

  2. Inhibition of propionibacterium acnes by bacteriocin-like inhibitory substances (BLIS) produced by Streptococcus salivarius.

    Science.gov (United States)

    Bowe, Whitney P; Filip, Jennifer C; DiRienzo, Joseph M; Volgina, Alla; Margolis, David J

    2006-10-01

    We report the in vitro inhibition of Propionibacterium acnes (P. acnes) by a bacteriocin-like inhibitory substance (BLIS-like substance) produced by Streptococcus salivarius (S. salivarius). Bacteriocins are proteinaceous substances produced by bacteria that are capable of inhibiting the growth of similar bacterial strains. Unlike classical antibiotics, they have a relatively narrow spectrum of killing activity, resulting in a reduction in the intensity of selection for resistance. These findings suggest that BLIS may potentially be used for its anti-P. acnes activity in the treatment of acne. PMID:17039652

  3. Characterization of a bacteriocin-like substance produced from a novel isolated strain of Bacillus subtilis SLYY-3

    Science.gov (United States)

    Li, Junfeng; Li, Hongfang; Zhang, Yuanyuan; Duan, Xiaohui; Liu, Jie

    2014-12-01

    In the present research, the strain SLYY-3 was isolated from sediments of Jiaozhou Bay, Qingdao, China. The strain SLYY-3, which produced a bacteriocin-like substance (BLS), was characterized to be a strain of Bacillus subtillis by biochemical profiling and 16S rDNA sequence analysis. It is the first time to report that Bacillus subtilis from Jiaozhou Bay sediments could produce a BLS. The BLS of B. subtillis SLYY-3 exhibited strong inhibitory activity against gram-positive bacteria (including Staphylococcus aureus and B. subtillis) and some fungi (including Penicillium glaucum, Aspergillus niger and Aspergillus flavus). The antimicrobial activity was detected from culture in the exponential growth phase and reached its maximum when culture entered into stationary growth phase. It was thermo-tolerant even when being kept at 100°C for 60 min without losing any activity and stable over a wide pH range from 1.0 to 12.0 while being inactivated by proteolytic enzyme and trypsin, indicating the proteinaceous nature of the BLS. The BLS was purified by precipitation with hydrochloric acid (HCl) and gel filteration (Sephadex G-100). SDS-PAGE analysis of the extracellular peptides of SLYY-3 revealed a bacteriocin-like protein with a molecular mass of 66 kDa. Altogether, these characteristics indicate the potential of the BLS for food industry as a protection against pathogenic and spoilage microorganisms.

  4. Diverse Ecological Strategies Are Encoded by Streptococcus pneumoniae Bacteriocin-Like Peptides.

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    Miller, Eric L; Abrudan, Monica I; Roberts, Ian S; Rozen, Daniel E

    2016-01-01

    The opportunistic pathogen Streptococcus pneumoniae is commonly carried asymptomatically in the human nasopharynx. Due to high rates of cocolonization with other pneumococcus strains, intraspecific competitive interactions partly determine the carriage duration of strains and thereby their potential to cause disease. These interactions may be mediated by bacteriocins, such as the type IIb bacteriocins encoded by the blp (bacteriocin-like peptide) locus. To understand blp diversity and evolution, we undertook a bioinformatic analysis of 4,418 pneumococcal genomes, including 168 newly sequenced genomes. We describe immense variation at all levels of genomic organization: Gene presence/absence, gene order, and allelic diversity. If we make the extreme and naive hypothesis that assumes all genes in this operon can assort randomly, this variation could lead to 10(15) distinct bacteriocin-related phenotypes, each potentially representing a unique ecological strategy; however, we provide several explanations for why this extreme is not realized. Although rarefaction analysis indicates that the number of unique strategies is not saturated, even after sampling thousands of genomes, we show that the variation is neither unbounded nor random. We delimit three bacteriocin groups, which contain group-specific bacteriocins, immunity genes, and blp operon gene order, and argue that this organization places a constraint on realized ecological strategies. We additionally show that ecological strategy diversity is significantly constrained by pneumococcal phylogeny and clonal structure. By examining patterns of association between alleles within the blp operon, we show that bacteriocin genes, which were believed to function in pairs, can be found with a broad diversity of partner alleles and immunity genes; this overall lack of allelic fidelity likely contributes to the fluid structure of this operon. Our results clarify the diversity of antagonistic ecological strategies in the

  5. Identification of a new Bacillus licheniformis strain producing a bacteriocin-like substance.

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    Guo, Yaoqi; Yu, Zhanqiao; Xie, Jianhua; Zhang, Rijun

    2012-06-01

    The emergence of antibiotic resistance has spurred a great number of studies for development of new antimicrobials in the past decade. The purpose of this study was to screen environmental samples for Bacillus strains producing potent antimicrobial agents. A new strain, which showed strong antimicrobial activity against Staphylococcus aureus and Salmonella enterica ser. Pullorum, was isolated from soil and designated as B116. This new isolate was identified as Bacillus licheniformis by morphological, biochemical and genetic analyses. The production of bacteriocin-like substance (BLS) started at early exponential phase and achieved highest level at early stationary phase. The BLS was precipitated by ammonium sulfate and its molecular mass was determined as ∼4 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Culture supernatant of the new isolate exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria, including Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Micrococcus luteus, Escherichia coli, and Salmonella spp. The BLS was resistant to heat, acid and alkaline treatment. Activity of the BLS was totally lost after digestion by pronase and partially lost after digestion by papain and lipase. The new isolate and relevant BLS are potentially useful in food and feed applications. PMID:22752909

  6. POTENTIAL IN VITRO ANTI-HELICOBACTER ACTIVITY OF BACTERIOCIN AND BACTERIOCIN-LIKE COMPOUNDS PRODUCED BY LACTOBACILLI

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    Mohammed A. Ramadan

    2014-10-01

    Full Text Available The study was designed for screening of the potential activity of lactic acid bacteria against Helicobacter pylori and other enteropathogenic organisms. A total of 40 samples including natural cow milk and fresh infant stools were tested for the presence of lactic acid bacteria. Of these samples, 73 lactic acid bacterial isolates were recovered on MRS agar medium using the streak-plate method. Isolates inducing probiotic effect were tested under microaerophilic conditions against standard cultures of H. pylori, Esherichia coli and Salmonella enteritidis. The data obtained showed that five isolates of lactic acid bacteria were able to produce bacteriocin or bacteriocin-like compounds. Sequencing of 16S rRNA gene revealed that five isolates belonged to Lactobacillus rhamnosus and Lactobacillus plantarum in addition to other lactic acid bacteria. The most effective isolate (LAB1 showed a marked large inhibition zone against H. pylori. The bacteriocin or bacteriocin like compound(s produced by lactobacilli were further analyzed and characterized. We can conclude that probiotics might be useful in the prophylaxis or as co-therapy for treatment of H. pylori infections.

  7. Description of two Enterococcus strains isolated from traditional Peruvian artisanal-produced cheeses with a bacteriocin-like inhibitory activity

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    Aguilar Galvez A.

    2009-01-01

    Full Text Available The aim of this work was to isolate and to characterize strains of lactic acid bacteria (LAB with bacteriocin-like inhibitory activity from 27 traditional cheeses artisanal-produced obtained from different Peruvian regions. Twenty Gram+ and catalasenegative strains among 2,277 isolates exhibited bacteriocin-like inhibitory activity against Listeria monocytogenes CWBIB2232 as target strain. No change in inhibitory activity was observed after organic acid neutralization and treatment with catalase of the cell-free supernatant (CFS. The proteinic nature of the antimicrobial activity was confirmed for the twenty LAB strains by proteolytic digestion of the CFS. Two strains, CWBI-B1431 and CWBI-B1430, with the best antimicrobial activity were selected for further researches. These strains were taxonomically identified by phenotypic and genotypic analyses as Enterococcus mundtii (CWBI-B1431 and Enterococcus faecium (CWBI-B1430. The two strains were sensitive to vancomycin (MIC 2 μg.ml-1 and showed absence of haemolysis.

  8. In vitro evaluation of bacteriocin-like inhibitory substances produced by lactic acid bacteria isolated during traditional Sicilian cheese making

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    Giusi Macaluso

    2016-02-01

    Full Text Available Bacteriocins are antimicrobial proteins produced by bacteria that inhibit the growth of other bacteria with a bactericidal or bacteriostatic mode of action. Many lactic acid bacteria (LAB produce a high diversity of different bacteriocins. Bacteriocinogenic LAB are generally recognised as safe (GRAS and useful to control the frequent development of pathogens and spoilage microorganisms. For this reason they are commonly used as starter cultures in food fermentations. In this study, the authors describe the results of a screening on 699 LAB isolated from wooden vat surfaces, raw milk and traditional Sicilian cheeses, for the production of bacteriocin-like inhibitory substances, by comparing two alternative methods. The antagonistic activity of LAB and its proteinaceous nature were evaluated using the spot-on-the-lawn and the well-diffusion assay (WDA and the sensitivity to proteolytic (proteinase K, protease B and trypsin, amylolytic (α-amylase and lipolytic (lipase enzymes. The indicator strains used were: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis. A total of 223 strains (belonging to the species Enterococcus spp., Lactobacillus spp., Pediococcus spp., Streptococcus spp., Leuconostoc spp. and Lactococcus lactis were found to inhibit the growth of Listeria monocytogenes by using the spot-on-the-lawn method; only 37 of these were confirmed by using the WDA. The direct addition of bacteriocin-producing cultures into dairy products can be a more practical and economic option for the improvement of the safety and quality of the final product.

  9. Production and characterization of a bacteriocin-like inhibitory substance produced by indigenous soil associated pseudomonas putida mas-1

    International Nuclear Information System (INIS)

    Bacteriocins have been the subject of extensive research globally due to wide range applications. The aim of this research was to investigate the production of bacteriocin(s) or bacteriocin like inhibitory substance(s) by Pseudomonas putida MAS-1 strain. The bacteriocin produced (Putidacin MAS-1) was found bioactive against clinical Staphylococcus aureus and Enterococcus faecalis strains. Bioactivity was observed by stab and overlay assay and multiwell antagonistic activity assay. Putidacin MAS-1 was sensitive beyond 70 degree C but stable at wide pH range (3 to 8). Bioactivity of putidacin MAS-1 was lost after treatment with trypsin and protease while partially lost after Proteinase K treatment. Treatment with ethanol, methanol, chloroform, acetone Tween 20 and Tween 80 showed partial decrease in bioactivity. SDS had stimulatory effect on putidacin MAS-1 bioactivity. EDTA however, showed no effect on the bacteriocin bioactivity. It was partially purified by ammonium sulphate precipitation. SDS-PAGE showed that Putidacin MAS-1 had 15 kDa molecular weight. (author)

  10. Purification and characterization of bacteriocin like substance produced from bacillus lentus with perspective of a new biopreservative for food preservation

    International Nuclear Information System (INIS)

    Molecular weight of bacteriocin like substance (BLIS) of a new strain of Bacillus lentus 121 was found to be approximately 11 kDa. Purification of BLIS was attained by single step gel exclusion chromatography. BLIS was characterized by studying the inhibitory spectrum. It was active at broad pH range, high temperature and high NaCl concentration and showed sensitivity to proteolytic enzymes like trypsin, alpha-chymotrypsin and papain, the characters desirable for food preservation. BLIS extended the shelf stability of milk upto 21 days as a biopreservative. (author)

  11. The effect of ingestion of milk supplemented with salivaricin A-producing Streptococcus salivarius on the bacteriocin-like inhibitory activity of streptococcal populations on the tongue.

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    Dierksen, Karen P; Moore, Chris J; Inglis, Megan; Wescombe, Philip A; Tagg, John R

    2007-03-01

    The colonization efficacies of salivaricin A (SalA)-producing Streptococcus salivarius strains 20P3 and 5 were compared when given in milk to 219 children, using either 2-day or 9-day dosing regimens. Colonization levels overall were superior for strain 5, and the 9-day dosing schedule resulted in higher levels of both initial colonization and strain persistence. The indigenous streptococcal tongue populations of 20 (10.9%) of the 189 children in the 2-day trial showed markedly increased SalA-like inhibitory activity following use of the S. salivarius-supplemented milk. All 20 of these children were found to have had relatively small (<5% of total S. salivarius) indigenous tongue populations of SalA-producing S. salivarius, and the relative proportions and/or inhibitory activity of these SalA producers on the childrens' tongues increased following ingestion of the S. salivarius-supplemented milk. Because SalA is known to be strongly inhibitory to Streptococcus pyogenes, an important implication of this study is that the consumption of SalA-producing probiotic S. salivarius could potentially help to effect a sustained increase in SalA-mediated protection against S. pyogenes infection. PMID:17069620

  12. Production of bacteriocin-like substances by lactic acid bacteria isolated from regional ovine cheese

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    Cássia Regina Nespolo; Adriano Brandelli

    2010-01-01

    Lactic acid bacteria (LAB) were isolated from ovine milk and cheeses manufactured in the South Region of Brazil. Among 112 bacterial isolates investigated, 59 were chosen through a screening for LAB. Among these 59 strains of LAB, 21% showed antimicrobial, proteolytic and lipolytic activities. Based on this screening, Lactobacillus plantarum LCN 17 and Lactobacillus rhamnosus LCN 43 were selected and tested for the production of bacteriocin-like substances (BLS). The BLS produced by both isol...

  13. Identification and partial characterization of a bacteriocin-like inhibitory substance (BLIS) from Lb. Bulgaricus K41 isolated from indigenous yogurts.

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    Zaeim, Davood; Soleimanian-Zad, Sabihe; Sheikh-Zeinoddin, Mahmoud

    2014-01-01

    Forty-two strains of Lactobacillus bulgaricus isolated from locally made yogurts were examined and compared for bacteriocin producing ability using spot on lawn assay which improved by taking photo and image processing. Lb. bulgaricus K41 exhibited the highest inhibition level against indicators. K41 Bacteriocin-like inhibitory substance is sensitive to proteolytic enzymes (proteinase K, pepsin, and trypsin) but α-amylase makes slight reduction in its activity and it is resistant to lipase. This antibacterial peptide is extremely heat-stable (121 °C for 15 min) and remains active over a wide pH range (pH = 2 to 10); also nonionic detergents (Tween-20, Tween-80, and Triton X100) showed no effect on its activity. The inhibitory spectrum is against Gram-positive bacteria (except Staphylococcus aureus) with extremely antilisterial activity and it is almost ineffective against Gram-negative bacteria. The mode of its action was identified as bactericidal against Listeria monocytogenes. The properties of K41 bacteriocin-like inhibitory substance add to its safety as a biopreservative produced by a generally recognized as safe (GRAS) bacterium suggesting it can be used in hurdle technology for ready-to-eat foods as one of the main sources of Listeria contaminations. PMID:24279356

  14. Production of bacteriocin-like substances by lactic acid bacteria isolated from regional ovine cheese

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    Cássia Regina Nespolo

    2010-12-01

    Full Text Available Lactic acid bacteria (LAB were isolated from ovine milk and cheeses manufactured in the South Region of Brazil. Among 112 bacterial isolates investigated, 59 were chosen through a screening for LAB. Among these 59 strains of LAB, 21% showed antimicrobial, proteolytic and lipolytic activities. Based on this screening, Lactobacillus plantarum LCN 17 and Lactobacillus rhamnosus LCN 43 were selected and tested for the production of bacteriocin-like substances (BLS. The BLS produced by both isolates showed antimicrobial activity against Listeria monocytogenes, whereas that produced by L. plantarum LCN 17 presented higher stability to different temperature, pH and enzyme treatments. These strains present potential for production of BLS, and for use as starter cultures.

  15. In Vitro Detection And Characterization Of Bacteriocin-Like Inhibitory Activity Of Lactic Acid Bacteria (Lab) Isolated From Senegalese Local Food Products

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    Diop, Mb.; Dubois Dauphin, Robin; Dortu, C.; Destain, Jacqueline; Tine, E.; Thonart, Philippe

    2008-01-01

    The prevalence of lactic acid bacteria (LAB) in Senegalese local food products was determined to be 109 CFU/g in millet flour and milk products, and 103 CFU/g in seafood products. These food products are generally preserved by spontaneous fermentation (without addition of starters). Of 220 lactic acid bacteria strains randomly selected from such products, 12 isolates capable of producing bacteriocin-like substances (bac+) were detected. Based on the use of API 50 CH test kits and 16S rDNA seq...

  16. Characterization of two antimicrobial peptides produced by a halotolerant Bacillus subtilis strain SK.DU.4 isolated from a rhizosphere soil sample.

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    Baindara, Piyush; Mandal, Santi M; Chawla, Niharika; Singh, Pradip Kumar; Pinnaka, Anil Kumar; Korpole, Suresh

    2013-01-01

    A bacterial strain producing two antimicrobial peptides was isolated from a rhizosphere soil sample and identified as Bacillus subtilis based on both phenotypic and 16S rRNA gene sequence phylogenetic analysis. It grew optimally up to 14% NaCl and produced antimicrobial peptide within 24 h of growth. The peptides were purified using a combination of chemical extraction and chromatographic techniques. The MALDI-TOF analysis of HPLC purified fractions revealed that the strain SK.DU.4 secreted a bacteriocin-like peptide with molecular mass of 5323.9 Da and a surface-active lipopeptide (m/z 1056 Da). The peptide mass fingerprinting of low-molecular-weight bacteriocin exhibited significant similarity with stretches of secreted lipoprotein of Methylomicrobium album BG8 and displayed 70% sequence coverage. MALDI MS/MS analysis elucidated the lipopeptide as a cyclic lipopeptide with a β-hydroxy fatty acid linked to Ser of a peptide with seven α-amino acids (Asp-Tyr-Asn-Gln-Pro-Asn-Ser) and assigned it to iturin-like group of antimicrobial biosurfactants. However, it differed in amino acid composition with other members of the iturin family. Both peptides were active against Gram-positive bacteria, suggesting that they had an additive effect. PMID:23289832

  17. The streptococcal inhibitor of complement (SIC) protects Streptococcus pyogenes from bacteriocin-like inhibitory substance (BLIS) from Streptococcus salivarius.

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    Minami, Masaaki; Ohmori, Daisuke; Tatsuno, Ichiro; Isaka, Masanori; Kawamura, Yoshiaki; Ohta, Michio; Hasegawa, Tadao

    2009-09-01

    Streptococcus salivarius inhibits the growth of Streptococcus pyogenes in vitro. Streptococcus pyogenes has various virulence factors, including the streptococcus inhibitor of complement (SIC). Although SIC inhibits the activity of the peptides LL-37 and NAP1, the relationship between SIC and the bacteriocin-like inhibitory substance (BLIS) has not been elucidated. Here, we evaluated whether S. salivarius BLIS affects S. pyogenes SIC. We created three deltasic mutant strains from three S. pyogenes strains and performed deferred antagonism assays. The test strains were BLIS-positive S. salivarius JCM5707 and BLIS-negative S. salivarius NCU12. Deferred antagonism assays with JCM5707 showed that the inhibitory zones in the three deltasic mutant strains were wider than those in the three wild-type strains. Streptococcus pyogenes was cultured in BLIS-containing broth and the change in SIC in the supernatant was assessed by two-dimensional gel electrophoresis (2-DE). The 2-DE analysis of S. pyogenes exoproteins with the JCM5707 supernatant showed reduced SIC compared with those without the JCM5707 supernatant. Changes in sic mRNA levels affected by S. salivarius BLIS were evaluated by a reverse transcriptase-PCR. The sic mRNA level was affected more by the BLIS-positive S. salivarius than by the BLIS-negative strain. Our result indicates that SIC plays a role in the inhibition of S. salivarius BLIS. PMID:19594623

  18. Antibacterial activity of bacteriocin-like substance P34 on Listeria monocytogenes in chicken sausage

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    Voltaire Sant'Anna

    2013-12-01

    Full Text Available The antimicrobial activity of the bacteriocin-like substance (BLS P34 against Listeria monocytogenes was investigated in chicken sausage. The BLS was applied to chicken sausages (256 AU g-1 previously inoculated with a suspension of 10² cfu g-1 of L. monocytogenes. BLS P34 inhibited the indicator microorganism in situ in all incubation times for up to 10 days at 5 °C. The effectiveness of BLS P34 was increased when it was added in combination with nisin. The bacteriocin was also tested in natural eatable natural bovine wrapping (salty semi-dried tripe against the same indicator microorganism, also showing inhibitory capability in vitro. BLS P34 showed potential to control L. monocytogenes in refrigerated meat products.

  19. Isolation and identification of Enterococcus faecium from seafoods: antimicrobial resistance and production of bacteriocin-like substances.

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    Valenzuela, Antonio Sánchez; Benomar, Nabil; Abriouel, Hikmate; Cañamero, Magdalena Martínez; Gálvez, Antonio

    2010-10-01

    A collection of isolates from uncooked seafoods (molluscs, fish, and fish fillets) were identified as Enterococcus faecium species and studied in further detail. Isolates were clustered in well-defined genomic groups according to food origin after ERIC-PCR analysis. Four isolates (FR 1-2, FB 1-3-B, FB 3-1, FTA 1-2) decarboxylated lysine, ornithine, and tyrosine. Isolate FR 1-2 also decarboxylated histidine. Most isolates were sensitive to antibiotics of clinical use, but resistance was detected more frequently towards nitrofurantoin (50%), erythromycin (33.33%) or rifampicin (33.33%) to quinupristin/dalfopristin (12.5%). Resistance to beta-lactams or vancomycin was not detected. The enterococcal antigen A was the presumed virulence trait detected most frequently. None of isolates carried haemolysin/cytolysin genes. Twelve isolates produced anti-listerial activity. Among them, seven isolates also produced bacteriocin-like inhibitory substances against other enterococci, and one isolate was also able to inhibit Staphylococcus aureus. Three isolates only were active against Listeria monocytogenes, and two only were active against enterococci. One bacteriocinogenic isolate carried the enterocin A structural gene, but genes corresponding to other enterocins (EntB, EntP, EntQ, Ent1071, EntL50A/EntL50B, and Ent31) were not detected. Bacteriocin-producing enterococci lacking undesirable traits (such as antibiotic resistance or biogenic amine production) or their produced bacteriocins could be potential candidates to aid in preservation of seafoods and other food products as well. PMID:20688238

  20. The structure of pyogenecin immunity protein, a novel bacteriocin-like immunity protein from streptococcus pyogenes.

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.; Coggill, P.; Bateman, A.; Finn, R.; Cymborowski, M.; Otwinowski, Z.; Minor, W.; Volkart, L.; Joachimiak, A.; Wellcome Trust Sanger Inst.; Univ. of Virginia; UT Southwestern Medical Center

    2009-12-17

    Many Gram-positive lactic acid bacteria (LAB) produce anti-bacterial peptides and small proteins called bacteriocins, which enable them to compete against other bacteria in the environment. These peptides fall structurally into three different classes, I, II, III, with class IIa being pediocin-like single entities and class IIb being two-peptide bacteriocins. Self-protective cognate immunity proteins are usually co-transcribed with these toxins. Several examples of cognates for IIa have already been solved structurally. Streptococcus pyogenes, closely related to LAB, is one of the most common human pathogens, so knowledge of how it competes against other LAB species is likely to prove invaluable. We have solved the crystal structure of the gene-product of locus Spy-2152 from S. pyogenes, (PDB: 2fu2), and found it to comprise an anti-parallel four-helix bundle that is structurally similar to other bacteriocin immunity proteins. Sequence analyses indicate this protein to be a possible immunity protein protective against class IIa or IIb bacteriocins. However, given that S. pyogenes appears to lack any IIa pediocin-like proteins but does possess class IIb bacteriocins, we suggest this protein confers immunity to IIb-like peptides. Combined structural, genomic and proteomic analyses have allowed the identification and in silico characterization of a new putative immunity protein from S. pyogenes, possibly the first structure of an immunity protein protective against potential class IIb two-peptide bacteriocins. We have named the two pairs of putative bacteriocins found in S. pyogenes pyogenecin 1, 2, 3 and 4.

  1. Method of producing a peptide mixture

    DEFF Research Database (Denmark)

    2000-01-01

    The present invention relates to a method for industrial production of a peptide preparation having specific specifications by hydrolysis of a protein material, preferably based on whey. The method comprises several steps, which makes it easy to control the method so as to obtain a product which, e...

  2. Aqueous two-phase flotation for primary recovery of bacteriocin-like inhibitory substance (BLIS) from Pediococcus acidilactici Kp10.

    Science.gov (United States)

    Md Sidek, Nurul Lyana; Tan, Joo Shun; Abbasiliasi, Sahar; Wong, Fadzlie Wong Faizal; Mustafa, Shuhaimi; Ariff, Arbakariya B

    2016-08-01

    An aqueous two-phase flotation (ATPF) system based on polyethylene glycol (PEG) and sodium citrate (NaNO3C6H5O7·2H2O) was considered for primary recovery of bacteriocin-like inhibitory substance (BLIS) from Pediococcus acidilactici Kp10. The effects of ATPF parameters namely phase composition, tie-line length (TLL), volume ratio between the two phases (VR), amount of crude load (CL), pH, nitrogen gas flow rate (FR) and flotation time (FT) on the performance of recovery were evaluated. BLIS was mainly concentrated into the upper PEG-rich phase in all systems tested so far. The optimum conditions for BLIS purification, which composed of PEG 8000/sodium citrate, were: TLL of 42.6, VR of 0.4, CL of 22% (w/w), pH 7, average FT of 30min and FR of 20mL/min. BLIS was partially purified up to 5.9-fold with a separation efficiency of 99% under this optimal conditions. A maximum yield of BLIS activity of about 70.3% was recovered in the PEG phase. The BLIS from the top phase was successfully recovered with a single band in SDS-gel with molecular weight of about 10-15kDa. ATPF was found to be an effective technique for the recovery of BLIS from the fermentation broth of P. acidilactici Kp10. PMID:27262666

  3. Bacteriocin-like activity of oral Fusobacterium nucleatum isolated from human and non-human primates Atividade semelhante a bacteriocina de Fusobacterium nucleatum orais isolados de primatas humanos e não-humanos

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    Elerson Gaetti-Jardim Júnior

    1999-12-01

    Full Text Available Fusobacterium nucleatum is indigenous of the human oral cavity and has been involved in different infectious processes. The production of bacteriocin-like substances may be important in regulation of bacterial microbiota in oral cavity. The ability to produce bacteriocin-like substances by 80 oral F. nucleatum isolates obtained from periodontal patients, healthy individuals and Cebus apella monkeys, was examinated. 17.5% of all tested isolates showed auto-antagonism and 78.8% iso- or hetero-antagonism. No isolate from monkey was capable to produce auto-inhibition. In this study, the antagonistic substances production was variable in all tested isolates. Most of the F. nucleatum showed antagonistic activity against tested reference strains. These data suggest a possible participation of these substances on the oral microbial ecology in humans and animals. However, the role of bacteriocins in regulating dental plaque microbiota in vivo is discussed.Fusobacterium nucleatum é indígena da cavidade oral humana e tem sido envolvido em diferentes processos infecciosos. A produção de substâncias semelhantes a bacteriocinas pode ser importante na regulação da microbiota bacteriana da cavidade oral. A capacidade de produzir substâncias tipo bacteriocina de 80 isolados de F. nucleatum orais, obtidos de pacientes com doença periodontal, indivíduos sadios e macaco Cebus apella, foi avaliada. 17,5% de todos os isolados mostrou auto-antagonismo e 78,8% iso- ou hetero-antagonismo. Nenhum isolado de macaco foi capaz de produzir auto-inibição. Neste estudo, a produção de substâncias antagonístas foi variável em todos os isolados testados. A maioria dos F. nucleatum mostrou atividade antagonísta para as cepas de referência testadas. Esses dados sugerem a possível participação dessas substâncias sobre a ecologia microbiana em humanos e animais. Entretanto, o papel das bacteriocinas na regulação da microbiota da placa dental in vivo

  4. Production of bacteriocin-like inhibitory substances (BLIS by Streptococcus salivarius strains isolated from the tongue and throat of children with and without sore throat Produção de substâncias inibidoras semelhantes à bacteriocina por cepas de Streptococcus salivarius, isoladas da língua e garganta de crianças com e sem dor de garganta

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    Vera Fantinato

    1999-12-01

    Full Text Available Streptococcus salivarius strains, isolated from children with and without sore throat, were tested for bacteriocin production against Streptococcus pyogenes. S. salivarius strains producing bacteriocin-like inhibitory substances (BLIS against S. pyogenes were more frequently found in children without sore throat. These results suggest that these children may be protected against sore throat by the presence of BLIS-positive S. salivarius strains.Cepas de Streptococcus salivarius, isoladas de crianças com e sem dor de garganta, foram testadas quanto à produção de bacteriocina contra Streptococcus pyogenes. Os resultados mostraram que as crianças que não tinham dor de garganta possuiam, na boca, cepas de bactérias produtoras de substâncias inibidoras semelhantes à bacteriocina contra S. pyogenes.

  5. The Ecology of Bacteriocin-producing Strains of Streptococcus salivarius

    OpenAIRE

    Tompkins, G R; Tagg, J. R.

    2011-01-01

    Interest in bacteriocin-producing components of the human normal oral microbiota centres on their possible interference with colonisation by potentially pathogenic bacteria. Certain strains of Streptococcus salivarius produce bacteriocin-like agents displaying exceptional inhibitory activity toward Lancefield Group A streptococci. Four individuals were identified as naturally harbouring high proportions (> 90 per cent) of bacteriocin-producing strains of S. salivarius. Bacteriocinogenic is...

  6. Potential of Lactic Streptococci to Produce Bacteriocin

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    Geis, Arnold; Singh, Jasjit; Teuber, Michael

    1983-01-01

    A survey was made on the bacteriocin-producing potential of lactic streptococci. Bacteriocin-like activities were isolated and partially purified from about 5% of the 280 strains investigated. The frequency of production varied from about 1% in Streptococcus lactis subsp. diacetylactis to 9 and 7.5% in S. lactis and Streptococcus cremoris, respectively. Eight strains of S. cremoris produced bacteriocins which, on the basis of heat stability at different pH values and inhibitory spectrum, coul...

  7. Coronamycins, peptide antibiotics produced by a verticillate Streptomyces sp. (MSU-2110) endophytic on Monstera sp.

    OpenAIRE

    Ezra, D; Castillo, UF; Strobel, GA; Hess, WM; Porter, H; Jensen, JB; Condron, MAM; Teplow, DB; J. Sears; Maranta, M; Hunter, M; Weber, B.; Yaver, D

    2004-01-01

    Coronamycin is a complex of novel peptide antibiotics with activity against pythiaceous fungi and the human fungal pathogen Cryptococcus neoformans. It is also active against the malarial parasite, Plasmodium falciparum, with an IC50 of 9.0 ng ml-1. Coronamycin is produced by a verticillate Streptomyces sp. isolated as an endophyte from an epiphytic vine, Monstera sp., found in the Manu region of the upper Amazon of Peru. Bioassay-guided fractionation of the fermentation broths of this endoph...

  8. Draft Genome Sequence of Bacillus subtilis Strain NKYL29, an Antimicrobial-Peptide-Producing Strain from Soil

    OpenAIRE

    Jiang, Yanbin; Xu, Haijin; Ying LI; Liu, Hongbin; Yu, Lei; Qiao, Mingqiang; Liu, Gang

    2014-01-01

    Bacillus subtilis strain NKYL29 is an antimicrobial-peptide-producing strain isolated from the soil of Ranzhuang Tunnel in Hebei Province, China. Here, we present the draft genome of this strain, which provides the genetic basis for application of the antimicrobial peptide.

  9. Identification of the Major ACE-Inhibitory Peptides Produced by Enzymatic Hydrolysis of a Protein Concentrate from Cuttlefish Wastewater

    OpenAIRE

    Isabel Rodríguez Amado; José Antonio Vázquez; Pilar González; Diego Esteban-Fernández; Mónica Carrera; Carmen Piñeiro

    2014-01-01

    The aim of this work was the purification and identification of the major angiotensin converting enzyme (ACE) inhibitory peptides produced by enzymatic hydrolysis of a protein concentrate recovered from a cuttlefish industrial manufacturing effluent. This process consisted on the ultrafiltration of cuttlefish softening wastewater, with a 10 kDa cut-off membrane, followed by the hydrolysis with alcalase of the retained fraction. Alcalase produced ACE inhibitors reaching the highest activity (I...

  10. Characterization of two antimicrobial peptides produced by a halotolerant Bacillus subtilis strain SK.DU.4 isolated from a rhizosphere soil sample

    OpenAIRE

    Baindara, Piyush; Mandal, Santi M.; Chawla, Niharika; Singh, Pradip Kumar; Pinnaka, Anil Kumar; Korpole, Suresh

    2013-01-01

    A bacterial strain producing two antimicrobial peptides was isolated from a rhizosphere soil sample and identified as Bacillus subtilis based on both phenotypic and 16S rRNA gene sequence phylogenetic analysis. It grew optimally up to 14% NaCl and produced antimicrobial peptide within 24 h of growth. The peptides were purified using a combination of chemical extraction and chromatographic techniques. The MALDI-TOF analysis of HPLC purified fractions revealed that the strain SK.DU.4 secreted a...

  11. A Comparative Examination of two Fmoc Removal Reagents for Process Improvement to Produce Peptide Drugs

    Science.gov (United States)

    Srivastava, K.; Davis, M.

    The importance of peptides as therapeutics has been recognized since they were found responsible for a wide variety of biological functions. The recent approval of peptide drugs such as Byetta® (Amylin Pharmaceuticals, Inc.), Fuzeon® (Hoffman-LaRoche Inc.), Integrelin™ (CDR Therapeutics, Inc.), Natrecor® (SCIOS Inc.), Symlin® (Amylin), Teriparatide, and Ziconotide, etc., which demonstrated applications for treatment of such problems as bone metabolism disorders, cardiovascular diseases, diabetes, viral infections and severe chronic pain control, has further endorsed the growing interest in peptides as a potential drug. This growing trend for peptide drugs has drawn our attention for their production in a cost-effective manner. To do so, the improvement in the quality of crude peptides during synthesis, the most critical parameter in the process, is important to prevent yield losses during the more expensive purification step. To accomplish it, we decided to examine the efficacy of the commonly used nucleophilic base piperidine and non-neucleophilic base DBU (1,8-Diazabicyclo[5.4.0]undec-7-ene) for the complete removal of Fmoc group during the synthesis of peptides. According to our investigation, application of piperidine was found more effective than DBU in solid phase synthesis. Details of the investigation will be discussed.

  12. Identification of the Major ACE-Inhibitory Peptides Produced by Enzymatic Hydrolysis of a Protein Concentrate from Cuttlefish Wastewater

    Directory of Open Access Journals (Sweden)

    Isabel Rodríguez Amado

    2014-03-01

    Full Text Available The aim of this work was the purification and identification of the major angiotensin converting enzyme (ACE inhibitory peptides produced by enzymatic hydrolysis of a protein concentrate recovered from a cuttlefish industrial manufacturing effluent. This process consisted on the ultrafiltration of cuttlefish softening wastewater, with a 10 kDa cut-off membrane, followed by the hydrolysis with alcalase of the retained fraction. Alcalase produced ACE inhibitors reaching the highest activity (IC50 = 76.8 ± 15.2 μg mL−1 after 8 h of proteolysis. Sequential ultrafiltration of the 8 h hydrolysate with molecular weight cut-off (MWCO membranes of 10 and 1 kDa resulted in the increased activity of each permeate, with a final IC50 value of 58.4 ± 4.6 μg mL−1. Permeate containing peptides lower than 1 kDa was separated by reversed-phase high performance liquid chromatography (RP-HPLC. Four fractions (A–D with potent ACE inhibitory activity were isolated and their main peptides identified using high performance liquid chromatography coupled to an electrospray ion trap Fourier transform ion cyclotron resonance-mass spectrometer (HPLC-ESI-IT-FTICR followed by comparison with databases and de novo sequencing. The amino acid sequences of the identified peptides contained at least one hydrophobic and/or a proline together with positively charged residues in at least one of the three C-terminal positions. The IC50 values of the fractions ranged from 1.92 to 8.83 μg mL−1, however this study fails to identify which of these peptides are ultimately responsible for the potent antihypertensive activity of these fractions.

  13. Tyrosine-containing peptides are precursors of tyramine produced by Lactobacillus plantarum strain IR BL0076 isolated from wine

    Directory of Open Access Journals (Sweden)

    Bonnin-Jusserand Maryse

    2012-09-01

    Full Text Available Abstract Background Biogenic amines are molecules with allergenic properties. They are found in fermented products and are synthesized by lactic acid bacteria through the decarboxylation of amino acids present in the food matrix. The concentration of biogenic amines in fermented foodstuffs is influenced by many environmental factors, and in particular, biogenic amine accumulation depends on the quantity of available precursors. Enological practices which lead to an enrichment in nitrogen compounds therefore favor biogenic amine production in wine. Free amino acids are the only known precursors for the synthesis of biogenic amines, and no direct link has previously been demonstrated between the use of peptides by lactic acid bacteria and biogenic amine synthesis. Results Here we demonstrate for the first time that a Lactobacillus plantarum strain isolated from a red wine can produce the biogenic amine tyramine from peptides containing tyrosine. In our conditions, most of the tyramine was produced during the late exponential growth phase, coinciding with the expression of the tyrDC and tyrP genes. The DNA sequences of tyrDC and tyrP in this strain share 98% identity with those in Lactobacillus brevis consistent with horizontal gene transfer from L. brevis to L. plantarum. Conclusion Peptides amino acids are precursors of biogenic amines for Lactobacillus plantarum strain IR BL0076.

  14. Purification and Identification of Two Antifungal Cyclic Peptides Produced by Bacillus amyloliquefaciens L-H15.

    Science.gov (United States)

    Han, Yuzhu; Zhang, Bao; Shen, Qian; You, Chengzhen; Yu, Yaqiong; Li, Pinglan; Shang, Qingmao

    2015-08-01

    Bacillus amyloliquefaciens L-H15 with broad spectrum antifungal activity was used as a biocontrol agent to suppress Fusarium oxysporum and other soil-borne fungal plant pathogens. Two antifungal fractions were isolated by bioactivity-guided reversed-phase high-performance liquid chromatography. The two compounds were identified by tandem Q-TOF mass spectroscopy as C15 Iturin A (1) and a novel cyclic peptide with a molecular weight of 852.4 Da (2). Both compounds showed good inhibitory activities against three plant fungal pathogens in cylinder-plate diffusion assay. To our best knowledge, this is the first report on a cyclic antifungal peptide with a molecular weight of 852.4 Da. The strong antifungal activity suggests that the B. amyloliquefaciens L-H15 and its bioactive components might provide an alternative resource for the biocontrol of plant diseases and sustainable agriculture. PMID:26123083

  15. Bimodular Peptide Synthetase SidE Produces Fumarylalanine in the Human Pathogen Aspergillus fumigatus

    OpenAIRE

    Steinchen, Wieland; Lackner, Gerald; Yasmin, Sabiha; Schrettl, Markus; Dahse, Hans-Martin; Haas, Hubertus; Hoffmeister, Dirk

    2013-01-01

    The filamentous mold Aspergillus fumigatus causes invasive aspergillosis, a potentially life-threatening infectious disease, in humans. The sidE gene encodes a bimodular peptide synthetase and was shown previously to be strongly upregulated during initiation of murine lung infection. In this study, we characterized the two adenylation domains of SidE with the ATP-[32P]pyrophosphate exchange assay in vitro, which identified fumarate and l-alanine, respectively, as the preferred substrates. Usi...

  16. Influence of peptides and proteins produced by cyanobacterium Microcystis aeruginosa on the coagulation of turbid waters

    Czech Academy of Sciences Publication Activity Database

    Šafaříková, Jana; Barešová, Magdalena; Pivokonský, Martin; Kopecká, Ivana

    2013-01-01

    Roč. 18, October (2013), s. 49-57. ISSN 1383-5866 R&D Projects: GA ČR GAP105/11/0247 Institutional research plan: CEZ:AV0Z20600510 Institutional support: RVO:67985874 Keywords : Cellular organic matter (COM) * Coagulation * Microcystis aeruginosa * Peptides/proteins * Turbidity removal Subject RIV: BK - Fluid Dynamics Impact factor: 3.065, year: 2013 http://www.sciencedirect.com/science/article/pii/S1383586613004152

  17. Safety Study of an Antimicrobial Peptide Lactocin 160, Produced by the Vaginal Lactobacillus rhamnosus

    OpenAIRE

    Dover, Sara E.; Alla A. Aroutcheva; S. Faro; Chikindas, Michael L.

    2007-01-01

    Objective. To evaluate the safety of the antimicrobial peptide, lactocin 160. Methods. Lactocin 160, a product of vaginal probiotic Lactobacillus rhamnosus 160 was evaluated for toxicity and irritation. An in vitro human organotypic vaginal-ectocervical tissue model (EpiVaginal) was employed for the safety testing by determining the exposure time to reduce tissue viability to 50% (ET-50). Hemolytic activity of lactocin160 was tested using 8% of human erythrocyte suspens...

  18. Safety Study of an Antimicrobial Peptide Lactocin 160, Produced by the Vaginal Lactobacillus rhamnosus

    Directory of Open Access Journals (Sweden)

    Sara E. Dover

    2007-01-01

    Full Text Available Objective. To evaluate the safety of the antimicrobial peptide, lactocin 160. Methods. Lactocin 160, a product of vaginal probiotic Lactobacillus rhamnosus 160 was evaluated for toxicity and irritation. An in vitro human organotypic vaginal-ectocervical tissue model (EpiVaginal was employed for the safety testing by determining the exposure time to reduce tissue viability to 50% (ET-50. Hemolytic activity of lactocin160 was tested using 8% of human erythrocyte suspension. Susceptibility of lactobacilli to lactocin160 was also studied. Rabbit vaginal irritation (RVI model was used for an in vivo safety evaluation. Results. The ET-50 value was 17.5 hours for lactocin 160 (4.9 hours for nonoxynol 9, N9. Hemolytic activity of lactocin 160 was 8.2% (N9 caused total hemolysis. Lactobacilli resisted to high concentrations of peptide preparation. The RVI model revealed slight vaginal irritation. An average irritation index grade was evaluated as “none.” Conclusions. Lactocin 160 showed minimal irritation and has a good potential for intravaginal application.

  19. Immobilization of Trypsin in Lignocellulosic Waste Material to Produce Peptides with Bioactive Potential from Whey Protein

    Directory of Open Access Journals (Sweden)

    Juliana Cristina Bassan

    2016-05-01

    Full Text Available In this study, trypsin (Enzyme Comission 3.4.21.4 was immobilized in a low cost, lignocellulosic support (corn cob powder—CCP with the goal of obtaining peptides with bioactive potential from cheese whey. The pretreated support was activated with glyoxyl groups, glutaraldehyde and IDA-glyoxyl. The immobilization yields of the derivatives were higher than 83%, and the retention of catalytic activity was higher than 74%. The trypsin-glyoxyl-CCP derivative was thermally stable at 65 °C, a value that was 1090-fold higher than that obtained with the free enzyme. The trypsin-IDA-glyoxyl-CCP and trypsin-glutaraldehyde-CCP derivatives had thermal stabilities that were 883- and five-fold higher, respectively, then those obtained with the free enzyme. In the batch experiments, trypsin-IDA-glyoxyl-CCP retained 91% of its activity and had a degree of hydrolysis of 12.49%, while the values for trypsin-glyoxyl-CCP were 87% and 15.46%, respectively. The stabilized derivative trypsin-glyoxyl-CCP was also tested in an upflow packed-bed reactor. The hydrodynamic characterization of this reactor was a plug flow pattern, and the kinetics of this system provided a relative activity of 3.04 ± 0.01 U·g−1 and an average degree of hydrolysis of 23%, which were suitable for the production of potentially bioactive peptides.

  20. Biochemical characterization of an anti-Candida factor produced by Enterococcus faecalis

    Directory of Open Access Journals (Sweden)

    Shekh Raeesh M

    2012-07-01

    Full Text Available Abstract Background Because Candida albicans is resistant to several antifungal antibiotics, there is a need to identify other less toxic natural products, particularly antimicrobial proteins, peptides or bacteriocin like inhibitory substances. An attempt has been made to purify and characterise an anti-Candida compound produced by Enterococcus faecalis. Results An anti-Candida protein (ACP produced by E. faecalis active against 8 C. albicans strains was characterised and partially purified. The ACP showed a broad-spectrum activity against multidrug resistant C. albicans MTCC 183, MTCC 7315, MTCC 3958, NCIM 3557, NCIM 3471 and DI. It was completely inactivated by treatment with proteinase K and partially by pronase E. The ACP retained biological stability after heat-treatment at 90°C for 20 min, maintained activity over a pH range 6–10, and remained active after treatment with α-amylase, lipase, organic solvents, and detergents. The antimicrobial activity of the E. faecalis strain was found exclusively in the extracellular filtrate produced in the late logarithmic growth phase. The highest activity (1600 AU mL-1 against C. albicans MTCC 183 was recorded at 48 h of incubation, and activity decreased thereafter. The peptide showed very low haemagglutination and haemolytic activities against human red blood cells. The antimicrobial substance was purified by salt-fractionation and chromatography. Partially purified ACP had a molecular weight of approximately 43 KDa in Tricine-PAGE analysis. The 12 amino acid N terminal sequence was obtained by Edman degradation. The peptide was de novo sequenced by ESI-MS, and the deduced combined sequence when compared to other bacteriocins and antimicrobial peptide had no significant sequence similarity. Conclusions The inhibitory activity of the test strain is due to the synthesis of an antimicrobial protein. To our knowledge, this is the first report on the isolation of a promising non-haemolytic anti

  1. Angiotensin I-Converting Enzyme Inhibitory Peptides of Chia (Salvia hispanica Produced by Enzymatic Hydrolysis

    Directory of Open Access Journals (Sweden)

    Maira Rubi Segura Campos

    2013-01-01

    Full Text Available Synthetic angiotensin I-converting enzyme (ACE-I inhibitors can have undesirable side effects, while natural inhibitors have no side effects and are potential nutraceuticals. A protein-rich fraction from chia (Salvia hispanica L. seed was hydrolyzed with an Alcalase-Flavourzyme sequential system and the hydrolysate ultrafiltered through four molecular weight cut-off membranes (1 kDa, 3 kDa, 5 kDa, and 10 kDa. ACE-I inhibitory activity was quantified in the hydrolysate and ultrafiltered fractions. The hydrolysate was extensive (DH = 51.64% and had 58.46% ACE-inhibitory activity. Inhibition ranged from 53.84% to 69.31% in the five ultrafiltered fractions and was highest in the <1 kDa fraction (69.31%. This fraction’s amino acid composition was identified and then it was purified by gel filtration chromatography and ACE-I inhibition measured in the purified fractions. Amino acid composition suggested that hydrophobic residues contributed substantially to chia peptide ACE-I inhibitory strength, probably by blocking angiotensin II production. Inhibitory activity ranged from 48.41% to 62.58% in the purified fractions, but fraction F1 (1.5–2.5 kDa exhibited the highest inhibition (IC50 = 3.97 μg/mL; 427–455 mL elution volume. The results point out the possibility of obtaining bioactive peptides from chia proteins by means of a controlled protein hydrolysis using Alcalase-Flavourzyme sequentional system.

  2. Encapsulated glucagon-like peptide-1-producing mesenchymal stem cells have a beneficial effect on failing pig hearts

    DEFF Research Database (Denmark)

    Wright, Elizabeth J; Farrell, Kelly A; Malik, Nadim;

    2012-01-01

    function and reduced epicardial infarct size. This was associated with increased angiogenesis and an altered remodeling response. Combined benefits of paracrine stem cell factors and GLP-1 were superior to those of stem cells alone. These results suggest that encapsulated genetically modified MSCs would......Stem cell therapy is an exciting and emerging treatment option to promote post-myocardial infarction (post-MI) healing; however, cell retention and efficacy in the heart remain problematic. Glucagon-like peptide-1 (GLP-1) is an incretin hormone with cardioprotective properties but a short half......-life in vivo. The effects of prolonged GLP-1 delivery from stromal cells post-MI were evaluated in a porcine model. Human mesenchymal stem cells immortalized and engineered to produce a GLP-1 fusion protein were encapsulated in alginate (bead-GLP-1 MSC) and delivered to coronary artery branches. Control groups...

  3. Structural Characterization of New Peptide Variants Produced by Cyanobacteria from the Brazilian Atlantic Coastal Forest Using Liquid Chromatography Coupled to Quadrupole Time-of-Flight Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Miriam Sanz

    2015-06-01

    Full Text Available Cyanobacteria from underexplored and extreme habitats are attracting increasing attention in the search for new bioactive substances. However, cyanobacterial communities from tropical and subtropical regions are still largely unknown, especially with respect to metabolite production. Among the structurally diverse secondary metabolites produced by these organisms, peptides are by far the most frequently described structures. In this work, liquid chromatography/electrospray ionization coupled to high resolution quadrupole time-of-flight tandem mass spectrometry with positive ion detection was applied to study the peptide profile of a group of cyanobacteria isolated from the Southeastern Brazilian coastal forest. A total of 38 peptides belonging to three different families (anabaenopeptins, aeruginosins, and cyanopeptolins were detected in the extracts. Of the 38 peptides, 37 were detected here for the first time. New structural features were proposed based on mass accuracy data and isotopic patterns derived from full scan and MS/MS spectra. Interestingly, of the 40 surveyed strains only nine were confirmed to be peptide producers; all of these strains belonged to the order Nostocales (three Nostoc sp., two Desmonostoc sp. and four Brasilonema sp..

  4. Elucidation of sevadicin, a novel non-ribosomal peptide secondary metabolite produced by the honey bee pathogenic bacterium Paenibacillus larvae.

    Science.gov (United States)

    Garcia-Gonzalez, Eva; Müller, Sebastian; Ensle, Paul; Süssmuth, Roderich D; Genersch, Elke

    2014-05-01

    American foulbrood (AFB) caused by the bee pathogenic bacterium Paenibacillus larvae is the most devastating bacterial disease of honey bees worldwide. From AFB-dead larvae, pure cultures of P. larvae can normally be cultivated indicating that P. larvae is able to defend its niche against all other bacteria present. Recently, comparative genome analysis within the species P. larvae suggested the presence of gene clusters coding for multi-enzyme complexes, such as non-ribosomal peptide synthetases (NRPSs). The products of these enzyme complexes are known to have a wide range of biological activities including antibacterial activities. We here present our results on antibacterial activity exhibited by vegetative P. larvae and the identification and analysis of a novel antibacterially active P. larvae tripeptide (called sevadicin; Sev) produced by a NRPS encoded by a gene cluster found in the genome of P. larvae. Identification of Sev was ultimately achieved by comparing the secretome of wild-type P. larvae with knockout mutants of P. larvae lacking production of Sev. Subsequent mass spectrometric studies, enantiomer analytics and chemical synthesis revealed the sequence and configuration of the tripeptide, D-Phe-D-ALa-Trp, which was shown to have antibacterial activity. The relevance of our findings is discussed in respect to host-pathogen interactions. PMID:25118351

  5. 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...

  6. 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.

  7. The chain length of biologically produced (R)-3-hydroxyalkanoic acid affects biological activity and structure of anti-cancer peptides.

    Science.gov (United States)

    Szwej, Emilia; Devocelle, Marc; Kenny, Shane; Guzik, Maciej; O'Connor, Stephen; Nikodinovic-Runic, Jasmina; Radivojevic, Jelena; Maslak, Veselin; Byrne, Annete T; Gallagher, William M; Zulian, Qun Ren; Zinn, Manfred; O'Connor, Kevin E

    2015-06-20

    Conjugation of DP18L peptide with (R)-3-hydroxydecanoic acid, derived from the biopolymer polyhydroxyalkanoate, enhances its anti-cancer activity (O'Connor et al., 2013. Biomaterials 34, 2710-2718). However, it is unknown if other (R)-3-hydroxyalkanoic acids (R3HAs) can enhance peptide activity, if chain length affects enhancement, and what effect R3HAs have on peptide structure. Here we show that the degree of enhancement of peptide (DP18L) anti-cancer activity by R3HAs is carbon chain length dependent. In all but one example the R3HA conjugated peptides were more active against cancer cells than the unconjugated peptides. However, R3HAs with 9 and 10 carbons were most effective at improving DP18L activity. DP18L peptide variant DP17L, missing a hydrophobic amino acid (leucine residue 4) exhibited lower efficacy against MiaPaCa cells. Circular dichroism analysis showed DP17L had a lower alpha helix content and the conjugation of any R3HA ((R)-3-hydroxyhexanoic acid to (R)-3-hydroxydodecanoic acid) to DP17L returned the helix content back to levels of DP18L. However (R)-3-hydroxyhexanoic did not enhance the anti-cancer activity of DP17L and at least 7 carbons were needed in the R3HA to enhance activity of D17L. DP17L needs a longer chain R3HA to achieve the same activity as DP18L conjugated to an R3HA. As a first step to assess the synthetic potential of polyhydroxyalkanoate derived R3HAs, (R)-3-hydroxydecanoic acid was synthetically converted to (±)3-chlorodecanoic acid, which when conjugated to DP18L improved its antiproliferative activity against MiaPaCa cells. PMID:25820126

  8. Characterization of the Antimicrobial Peptide Penisin, a Class Ia Novel Lantibiotic from Paenibacillus sp. Strain A3.

    Science.gov (United States)

    Baindara, Piyush; Chaudhry, Vasvi; Mittal, Garima; Liao, Luciano M; Matos, Carolina O; Khatri, Neeraj; Franco, Octavio L; Patil, Prabhu B; Korpole, Suresh

    2016-01-01

    Attempts to isolate novel antimicrobial peptides from microbial sources have been on the rise recently, despite their low efficacy in therapeutic applications. Here, we report identification and characterization of a new efficient antimicrobial peptide from a bacterial strain designated A3 that exhibited highest identity with Paenibacillus ehimensis. Upon purification and subsequent molecular characterization of the antimicrobial peptide, referred to as penisin, we found the peptide to be a bacteriocin-like peptide. Consistent with these results, RAST analysis of the entire genome sequence revealed the presence of a lantibiotic gene cluster containing genes necessary for synthesis and maturation of a lantibiotic. While circular dichroism and one-dimension nuclear magnetic resonance experiments confirmed a random coil structure of the peptide, similar to other known lantibiotics, additional biochemical evidence suggests posttranslational modifications of the core peptide yield six thioether cross-links. The deduced amino acid sequence of the putative biosynthetic gene penA showed approximately 74% similarity with elgicin A and 50% similarity with the lantibiotic paenicidin A. Penisin effectively killed methicillin-resistant Staphylococcus aureus (MRSA) and did not exhibit hemolysis activity. Unlike other lantibiotics, it effectively inhibited the growth of Gram-negative bacteria. Furthermore, 80 mg/kg of body weight of penisin significantly reduced bacterial burden in a mouse thigh infection model and protected BALB/c mice in a bacteremia model entailing infection with Staphylococcus aureus MTCC 96, suggesting that it could be a promising new antimicrobial peptide. PMID:26574006

  9. 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

  10. Localization of an O-glycosylated site in the recombinant barley alpha-amylase 1 produced in yeast and correction of the amino acid sequence using matrix-assisted laser desorption/ionization mass spectrometry of peptide mixtures

    DEFF Research Database (Denmark)

    Andersen, Jens S.; Søgaard, M; Svensson, B;

    1994-01-01

    Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) of peptide mixtures was used to characterize recombinant barley alpha-amylase 1, produced in yeast. Three peptide mixtures were generated by cleavage with CNBr, digestion with endoproteinase Lys-C and Asp-N, respectively, and...

  11. Insulin C-peptide test

    Science.gov (United States)

    C-peptide ... the test depends on the reason for the C-peptide measurement. Ask your health care provider if ... C-peptide is measured to tell the difference between insulin produced by the body and insulin injected ...

  12. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined.......To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  13. Expression and Immunogenicity of the Mycobacterial Ag85B/ESAT-6 Antigens Produced in Transgenic Plants by Elastin-Like Peptide Fusion Strategy

    Directory of Open Access Journals (Sweden)

    Doreen Manuela Floss

    2010-01-01

    Full Text Available This study explored a novel system combining plant-based production and the elastin-like peptide (ELP fusion strategy to produce vaccinal antigens against tuberculosis. Transgenic tobacco plants expressing the mycobacterial antigens Ag85B and ESAT-6 fused to ELP (TBAg-ELP were generated. Purified TBAg-ELP was obtained by the highly efficient, cost-effective, inverse transition cycling (ICT method and tested in mice. Furthermore, safety and immunogenicity of the crude tobacco leaf extracts were assessed in piglets. Antibodies recognizing mycobacterial antigens were produced in mice and piglets. A T-cell immune response able to recognize the native mycobacterial antigens was detected in mice. These findings showed that the native Ag85B and ESAT-6 mycobacterial B- and T-cell epitopes were conserved in the plant-expressed TBAg-ELP. This study presents the first results of an efficient plant-expression system, relying on the elastin-like peptide fusion strategy, to produce a safe and immunogenic mycobacterial Ag85B-ESAT-6 fusion protein as a potential vaccine candidate against tuberculosis.

  14. Radiolabeling of DOTA-like conjugated peptides with generator-produced (68)Ga and using NaCl-based cationic elution method.

    Science.gov (United States)

    Mueller, Dirk; Breeman, Wouter A P; Klette, Ingo; Gottschaldt, Michael; Odparlik, Andreas; Baehre, Manfred; Tworowska, Izabela; Schultz, Michael K

    2016-06-01

    Gallium-68 ((68)Ga) is a generator-produced radionuclide with a short half-life (t½ = 68 min) that is particularly well suited for molecular imaging by positron emission tomography (PET). Methods have been developed to synthesize (68)Ga-labeled imaging agents possessing certain drawbacks, such as longer synthesis time because of a required final purification step, the use of organic solvents or concentrated hydrochloric acid (HCl). In our manuscript, we provide a detailed protocol for the use of an advantageous sodium chloride (NaCl)-based method for radiolabeling of chelator-modified peptides for molecular imaging. By working in a lead-shielded hot-cell system,(68)Ga(3+) of the generator eluate is trapped on a cation exchanger cartridge (100 mg, ∼8 mm long and 5 mm diameter) and then eluted with acidified 5 M NaCl solution directly into a sodium acetate-buffered solution containing a DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) or DOTA-like chelator-modified peptide. The main advantages of this procedure are the high efficiency and the absence of organic solvents. It can be applied to a variety of peptides, which are stable in 1 M NaCl solution at a pH value of 3-4 during reaction. After labeling, neutralization, sterile filtration and quality control (instant thin-layer chromatography (iTLC), HPLC and pH), the radiopharmaceutical can be directly administered to patients, without determination of organic solvents, which reduces the overall synthesis-to-release time. This procedure has been adapted easily to automated synthesis modules, which leads to a rapid preparation of (68)Ga radiopharmaceuticals (12-16 min). PMID:27172166

  15. Potential of Lactic Streptococci to Produce Bacteriocin

    Science.gov (United States)

    Geis, Arnold; Singh, Jasjit; Teuber, Michael

    1983-01-01

    A survey was made on the bacteriocin-producing potential of lactic streptococci. Bacteriocin-like activities were isolated and partially purified from about 5% of the 280 strains investigated. The frequency of production varied from about 1% in Streptococcus lactis subsp. diacetylactis to 9 and 7.5% in S. lactis and Streptococcus cremoris, respectively. Eight strains of S. cremoris produced bacteriocins which, on the basis of heat stability at different pH values and inhibitory spectrum, could be divided into four types. From 54 S. lactis strains, 5 strains produced inhibitory substances, namely, three nisin-like antibiotics and two different bacteriocins. Only 1 of 93 S. lactis subsp. diacetylactis strains produced a bacteriocin which was very similar to bacteriocins of type I in S. cremoris. All of the bacteriocins that were partially purified by ammonium sulfate precipitation showed very limited inhibitory spectra. Most of the lactic streptococci and a few members of the genera Clostridium, Leuconostoc, and Pediococcus were inhibited. None of the bacteriocins acted on gram-negative bacteria. The bacteriocinogenic strains were also characterized on the basis of plasmid content. All strains possessed between one and nine plasmids ranging from 1 to 50 megadaltons. Images PMID:16346166

  16. The selection of alkaline protease-producing yeasts from marine environments and evaluation of their bioactive peptide production

    Institute of Scientific and Technical Information of China (English)

    LI Jing; CHI Zhenming; WANG Xianghong; PENG Ying; CHI Zhe

    2009-01-01

    A total of 400 yeast strains from seawater, sediments, saltern mud, marine fish guts, and marine algae were obtained. The protease activity of the yeast cultures was estimated, after which four strains (HN3.11, N11b, YF04C and HN4.9) capable of secreting extracellular alkaline protease were isolated. The isolated strains were identified as Aureobasidium pullulans, Yarrowia lipolytica, Issatchenkia orientalis and Cryptococcus cf. aureus. The optimal pH of the protease activity produced by strains HN3.11, YF04C, and HN4.9 was 9.0, while that of the protease produced by strain N11b was 10.0. The optimal temperature for protease activity was 45°C for strains HN3.11, N11b, and YF04C, and 50°C for strain HN4.9. After digestion of shrimp (Penaeus vannamei) protein and spirulina (Arthospira platensis) protein with the four crude alkaline proteases, the filtrate from spirulina (Arthrospira platensis) powder digested by the crude alkaline protease of strain HN3.11 was found to have the highest antioxidant activity (61.4%) and the highest angiotensin I converting enzyme (ACE)-inhibitory activities (68.4%). The other filtrates had much lower antioxidant activity and ACE-inhibitory activities.

  17. Isolation, structural characterization, and properties of mattacin (polymyxin M), a cyclic peptide antibiotic produced by Paenibacillus kobensis M.

    Science.gov (United States)

    Martin, Nathaniel I; Hu, Haijing; Moake, Matthew M; Churey, John J; Whittal, Randy; Worobo, Randy W; Vederas, John C

    2003-04-11

    Mattacin is a nonribosomally synthesized, decapeptide antibiotic produced by Paenibacillus kobensis M. The producing strain was isolated from a soil/manure sample and identified using 16 S rRNA sequence homology along with chemical and morphological characterization. An efficient production and isolation procedure was developed to afford pure mattacin. Structure elucidation using a combination of chemical degradation, multidimensional NMR studies (COSY, HMBC, HMQC, ROESY), and mass spectrometric (MALDI MS/MS) analyses showed that mattacin is identical to polymyxin M, an uncommon antibiotic reported previously in certain Bacillus species by Russian investigators. Mattacin (polymyxin M) is cyclic and possesses an amide linkage between the C-terminal threonine and the side chain amino group of the diaminobutyric acid residue at position 4. It contains an (S)-6-methyloctanoic acid moiety attached as an amide at the N-terminal amino group, one D-leucine, six L-alpha,gamma-diaminobutyric acid, and three L-threonine residues. Transfer NOE experiments on the conformational preferences of mattacin when bound to lipid A and microcalorimetry studies on binding to lipopolysaccharide showed that its behavior was very similar to that observed in previous studies of polymyxin B (a commercial antibiotic), suggesting an identical mechanism of action. It was capable of inhibiting the growth of a wide variety of Gram-positive and Gram-negative bacteria, including several human and plant pathogens with activity comparable with purified polymyxin B. The biosynthesis of mattacin was also examined briefly using transpositional mutagenesis by which 10 production mutants were obtained, revealing a set of genes involved in production. PMID:12569104

  18. Cellular and molecular insight into the inhibition of primary root growth of Arabidopsis induced by peptaibols, a class of linear peptide antibiotics mainly produced by Trichoderma spp.

    Science.gov (United States)

    Shi, Wei-Ling; Chen, Xiu-Lan; Wang, Li-Xia; Gong, Zhi-Ting; Li, Shuyu; Li, Chun-Long; Xie, Bin-Bin; Zhang, Wei; Shi, Mei; Li, Chuanyou; Zhang, Yu-Zhong; Song, Xiao-Yan

    2016-04-01

    Trichodermaspp. are well known biocontrol agents that produce a variety of antibiotics. Peptaibols are a class of linear peptide antibiotics mainly produced byTrichoderma Alamethicin, the most studied peptaibol, is reported as toxic to plants at certain concentrations, while the mechanisms involved are unclear. We illustrated the toxic mechanisms of peptaibols by studying the growth-inhibitory effect of Trichokonin VI (TK VI), a peptaibol fromTrichoderma longibrachiatumSMF2, onArabidopsisprimary roots. TK VI inhibited root growth by suppressing cell division and cell elongation, and disrupting root stem cell niche maintenance. TK VI increased auxin content and disrupted auxin response gradients in root tips. Further, we screened theArabidopsisTK VI-resistant mutanttkr1tkr1harbors a point mutation inGORK, which encodes gated outwardly rectifying K(+)channel proteins. This mutation alleviated TK VI-induced suppression of K(+)efflux in roots, thereby stabilizing the auxin gradient. Thetkr1mutant also resisted the phytotoxicity of alamethicin. Our results indicate that GORK channels play a key role in peptaibol-plant interaction and that there is an inter-relationship between GORK channels and maintenance of auxin homeostasis. The cellular and molecular insight into the peptaibol-induced inhibition of plant root growth advances our understanding ofTrichoderma-plant interactions. PMID:26850879

  19. The insect pathogen Serratia marcescens Db10 uses a hybrid non-ribosomal peptide synthetase-polyketide synthase to produce the antibiotic althiomycin.

    Directory of Open Access Journals (Sweden)

    Amy J Gerc

    Full Text Available There is a continuing need to discover new bioactive natural products, such as antibiotics, in genetically-amenable micro-organisms. We observed that the enteric insect pathogen, Serratia marcescens Db10, produced a diffusible compound that inhibited the growth of Bacillis subtilis and Staphyloccocus aureus. Mapping the genetic locus required for this activity revealed a putative natural product biosynthetic gene cluster, further defined to a six-gene operon named alb1-alb6. Bioinformatic analysis of the proteins encoded by alb1-6 predicted a hybrid non-ribosomal peptide synthetase-polyketide synthase (NRPS-PKS assembly line (Alb4/5/6, tailoring enzymes (Alb2/3 and an export/resistance protein (Alb1, and suggested that the machinery assembled althiomycin or a related molecule. Althiomycin is a ribosome-inhibiting antibiotic whose biosynthetic machinery had been elusive for decades. Chromatographic and spectroscopic analyses confirmed that wild type S. marcescens produced althiomycin and that production was eliminated on disruption of the alb gene cluster. Construction of mutants with in-frame deletions of specific alb genes demonstrated that Alb2-Alb5 were essential for althiomycin production, whereas Alb6 was required for maximal production of the antibiotic. A phosphopantetheinyl transferase enzyme required for althiomycin biosynthesis was also identified. Expression of Alb1, a predicted major facilitator superfamily efflux pump, conferred althiomycin resistance on another, sensitive, strain of S. marcescens. This is the first report of althiomycin production outside of the Myxobacteria or Streptomyces and paves the way for future exploitation of the biosynthetic machinery, since S. marcescens represents a convenient and tractable producing organism.

  20. Antimicrobial peptides (AMPs) produced by Saccharomyces cerevisiae induce alterations in the intracellular pH, membrane permeability and culturability of Hanseniaspora guilliermondii cells

    DEFF Research Database (Denmark)

    Branco, Patrícia; Monteiro Lomba Viana, Tiago; Albergaria, Helena;

    2015-01-01

    Saccharomyces cerevisiae produces antimicrobial peptides (AMPs) during alcoholic fermentation that are active against several wine-related yeasts (e.g. Hanseniaspora guilliermondii) and bacteria (e.g. Oenococcus oeni). In the present study, the physiological changes induced by those AMPs on...

  1. Intracerebroventricular injection of encapsulated human mesenchymal cells producing glucagon-like peptide 1 prolongs survival in a mouse model of ALS.

    Directory of Open Access Journals (Sweden)

    Sarah Knippenberg

    Full Text Available BACKGROUND: As pharmacological therapies have largely failed so far, stem cell therapy has recently come into the focus of ALS research. Neuroprotective potential was shown for several types of stem and progenitor cells, mainly due to release of trophic factors. In the present study, we assessed the effects of intracerebroventricular injection of glucagon-like peptide 1 (GLP-1 releasing mesenchymal stromal cells (MSC in mutant SOD1 (G93A transgenic mice. METHODOLOGY/PRINCIPAL FINDINGS: To improve the neuroprotective effects of native MSC, they had been transfected with a plasmid vector encoding a GLP-1 fusion gene prior to the injection, as GLP-1 was shown to exhibit neuroprotective properties before. Cells were encapsulated and therefore protected against rejection. After intracerebroventricular injection of these GLP-1 MSC capsules in presymptomatic SOD1 (G93A mice, we assessed possible protective effects by survival analysis, measurement of body weight, daily monitoring and evaluation of motor performance by rotarod and footprint analyses. Motor neuron numbers in the spinal cord as well as the amount of astrocytosis, microglial activation, heat shock response and neuronal nitric oxide synthase (nNOS expression were analyzed by immunohistological methods. Treatment with GLP-1 producing MSC capsules significantly prolonged survival by 13 days, delayed symptom onset by 15 days and weight loss by 14 days and led to significant improvements in motor performance tests compared to vehicle treated controls. Histological data are mainly in favour of anti-inflammatory effects of GLP-1 producing MSC capsules with reduced detection of inflammatory markers and a significant heat shock protein increase. CONCLUSION/SIGNIFICANCE: Intracerebroventricular injection of GLP-1 MSC capsules shows neuroprotective potential in the SOD1 (G93A mouse model.

  2. Changes produced by bound tryptophan in the ribosome peptidyl transferase center in response to TnaC, a nascent leader peptide.

    Science.gov (United States)

    Cruz-Vera, Luis Rogelio; Gong, Ming; Yanofsky, Charles

    2006-03-01

    Studies in vitro have established that free tryptophan induces tna operon expression by binding to the ribosome that has just completed synthesis of TnaC-tRNA(Pro), the peptidyl-tRNA precursor of the leader peptide of this operon. Tryptophan acts by inhibiting Release Factor 2-mediated cleavage of this peptidyl-tRNA at the tnaC stop codon. Here we analyze the ribosomal location of free tryptophan, the changes it produces in the ribosome, and the role of the nascent TnaC-tRNA(Pro) peptide in facilitating tryptophan binding and induction. The positional changes of 23S rRNA nucleotides that occur during induction were detected by using methylation protection and binding/competition assays. The ribosome-TnaC-tRNA(Pro) complexes analyzed were formed in vitro; they contained either wild-type TnaC-tRNA(Pro) or its nonfunctional substitute, TnaC(W12R)-tRNA(Pro). Upon comparing these two peptidyl-tRNA-ribosome complexes, free tryptophan was found to block methylation of nucleotide A2572 of wild-type ribosome-TnaC-tRNA(Pro) complexes but not of ribosome-TnaC(W12R)-tRNA(Pro) complexes. Nucleotide A2572 is in the ribosomal peptidyl transferase center. Tryptophanol, a noninducing competitor of tryptophan, was ineffective in blocking A2572 methylation; however, it did reverse the protective effect of tryptophan. Free tryptophan inhibited puromycin cleavage of TnaC-tRNA(Pro); it also inhibited binding of the antibiotic sparsomycin. These effects were not observed with TnaC(W12R)-tRNA(Pro) mutant complexes. These findings establish that Trp-12 of TnaC-tRNA(Pro) is required for introducing specific changes in the peptidyl transferase center of the ribosome that activate free tryptophan binding, resulting in peptidyl transferase inhibition. Free tryptophan appears to act at or near the binding sites of several antibiotics in the peptidyl transferase center. PMID:16505360

  3. Hyaluronic Acid-Based Nanogels Produced by Microfluidics-Facilitated Self-Assembly Improves the Safety Profile of the Cationic Host Defense Peptide Novicidin

    DEFF Research Database (Denmark)

    Water, Jorrit J; Kim, YongTae; Maltesen, Morten J;

    2015-01-01

    have hampered their commercial development. To overcome these challenges a novel nanogel-based drug delivery system was designed. METHOD: The peptide novicidin was self-assembled with an octenyl succinic anhydride-modified analogue of hyaluronic acid, and this formulation was optimized using a...... peptide loading of 36 ± 4%. The nanogels exhibited good colloidal stability under different ionic strength conditions and allowed complete release of the peptide over 14 days. Furthermore, self-assembly of novicidin with hyaluronic acid into nanogels significantly improved the safety profile at least five...

  4. Antimicrobial peptides (AMPs) produced by Saccharomyces cerevisiae induce alterations in the intracellular pH, membrane permeability and culturability of Hanseniaspora guilliermondii cells.

    Science.gov (United States)

    Branco, Patrícia; Viana, Tiago; Albergaria, Helena; Arneborg, Nils

    2015-07-16

    Saccharomyces cerevisiae produces antimicrobial peptides (AMPs) during alcoholic fermentation that are active against several wine-related yeasts (e.g. Hanseniaspora guilliermondii) and bacteria (e.g. Oenococcus oeni). In the present study, the physiological changes induced by those AMPs on sensitive H. guilliermondii cells were evaluated in terms of intracellular pH (pHi), membrane permeability and culturability. Membrane permeability was evaluated by staining cells with propidium iodide (PI), pHi was determined by a fluorescence ratio imaging microscopy (FRIM) technique and culturability by a classical plating method. Results showed that the average pHi of H. guilliermondii cells dropped from 6.5 (healthy cells) to 5.4 (damaged cells) after 20 min of exposure to inhibitory concentrations of AMPs, and after 24 h 77.0% of the cells completely lost their pH gradient (∆pH=pHi-pHext). After 24h of exposure to AMPs, PI-stained (dead) cells increased from 0% to 77.7% and the number of viable cells fell from 1×10(5) to 10 CFU/ml. This means that virtually all cells (99.99%) became unculturable but that a sub-population of 22.3% of the cells remained viable (as determined by PI staining). Besides, pHi results showed that after 24h, 23% of the AMP-treated cells were sub-lethally injured (with 0<∆pH<3). Taken together, these results indicated that this subpopulation was under a viable but non-culturable (VBNC) state, which was further confirmed by recuperation assays. In summary, our study reveals that these AMPs compromise the plasma membrane integrity (and possibly also the vacuole membrane) of H. guilliermondii cells, disturbing the pHi homeostasis and inducing a loss of culturability. PMID:25897995

  5. Isolation and characterization of marine Brevibacillus sp. S-1 collected from South China Sea and a novel antitumor peptide produced by the strain.

    Directory of Open Access Journals (Sweden)

    Lanhong Zheng

    Full Text Available A Gram-positive, rod-shaped bacterium, designated as S-1, was isolated from a marine sediment sample collected from South China Sea. Phylogenetic analysis based on 16S rRNA gene sequence showed that S-1 belongs to the genus Brevibacillus. A novel cytotoxic peptide was isolated from the fermentation broth of the marine-derived bacterium Brevibacillus sp. S-1, using ion-exchange chromatography and reverse-phase HPLC chromatography. The molecular weight of this peptide was determined as 1570 Da by MALDI-TOF mass spectrometry, and its structure was proposed as a cyclic peptide elucidated by MALDI-TOF/TOF mass spectrometry and de novo sequencing. 3-(4,5-dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide (MTT assay showed that this peptide exhibited cytotoxicity against BEL-7402 human hepatocellular carcinoma cells, RKO human colon carcinoma cells, A549 human lung carcinoma cells, U251 human glioma cells and MCF-7 human breast carcinoma cells. Additionally, SBP exhibited low cytotoxicity against HFL1 human normal fibroblast lung cells. The result suggested that the cytotoxic effect of the peptide is specific to tumor cells.

  6. Classification of anti hepatitis peptides using Support Vector Machine with hybrid Ant Colony OptimizationThe Luxembourg database of trichothecene type B F. graminearum and F. culmorum producers.

    Science.gov (United States)

    Mishra, Gunjan; Ananth, Vivek; Shelke, Kalpesh; Sehgal, Deepak; Deepak, Jayaraman

    2016-01-01

    Hepatitis is an emerging global threat to public health due to associated mortality, morbidity, cancer and HIV co-infection. Available diagnostics and therapeutics are inadequate to intercept the course and transmission of the disease. Antimicrobial peptides (AMP) are widely studied and broad-spectrum host defense peptides are investigated as a targeted anti-viral. Therefore, it is of interest to describe the supervised identification of anti-hepatitis peptides. We used a hybrid Support Vector Machine (SVM) with Ant Colony Optimization (ACO) algorithm for simultaneous classification and domain feature selection. The described model shows a 10 fold cross-validation accuracy of 94 percent. This is a reliable and a useful tool for the prediction and identification of hepatitis specific drug activity. PMID:27212838

  7. Rapid acidolysis of benzyl group as a suitable approach for syntheses of peptides naturally produced by oxidative stress and containing 3-nitrotyrosine

    Czech Academy of Sciences Publication Activity Database

    Niederhafner, Petr; Šafařík, Martin; Brichtová, Eva; Šebestík, Jaroslav

    2016-01-01

    Roč. 48, č. 4 (2016), s. 1087-1098. ISSN 0939-4451 R&D Projects: GA ČR(CZ) GA14-00431S Institutional support: RVO:61388963 Keywords : nitrotyrosine * peptide synthesis * alpha-synuclein * reaction rate Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.293, year: 2014

  8. Peptide dendrimers

    Czech Academy of Sciences Publication Activity Database

    Niederhafner, Petr; Šebestík, Jaroslav; Ježek, Jan

    2005-01-01

    Roč. 11, - (2005), 757-788. ISSN 1075-2617 R&D Projects: GA ČR(CZ) GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : multiple antigen peptides * peptide dendrimers * synthetic vaccine * multipleantigenic peptides Subject RIV: CC - Organic Chemistry Impact factor: 1.803, year: 2005

  9. Production and characterization of peptide antibodies

    DEFF Research Database (Denmark)

    Trier, Nicole Hartwig; Hansen, Paul Robert; Houen, Gunnar

    2012-01-01

    Proteins are effective immunogens for generation of antibodies. However, occasionally the native protein is known but not available for antibody production. In such cases synthetic peptides derived from the native protein are good alternatives for antibody production. These peptide antibodies are...... powerful tools in experimental biology and are easily produced to any peptide of choice. A widely used approach for production of peptide antibodies is to immunize animals with a synthetic peptide coupled to a carrier protein. Very important is the selection of the synthetic peptide, where factors such as......, including solid-phase peptide-carrier conjugation and peptide-carrier conjugation in solution. Upon immunization, adjuvants such as Al(OH)(3) are added together with the immunogenic peptide-carrier conjugate, which usually leads to high-titred antisera. Following immunization and peptide antibody...

  10. Laserspray Ionization, a New Atmospheric Pressure MALDI Method for Producing Highly Charged Gas-phase Ions of Peptides and Proteins Directly from Solid Solutions*

    OpenAIRE

    Trimpin, Sarah; Inutan, Ellen D.; Herath, Thushani N.; McEwen, Charles N.

    2009-01-01

    The first example of a matrix-assisted laser desorption/ionization (MALDI) process producing multiply charged mass spectra nearly identical to those observed with electrospray ionization (ESI) is presented. MALDI is noted for its ability to produce singly charged ions, but in the experiments described here multiply charged ions are produced by laser ablation of analyte incorporated into a common MALDI matrix, 2,5-dihydroxybenzoic acid, using standard solvent-based sample preparation protocols...

  11. Ectopic Corticotropin-Producing Neuroendocrine Tumor of the Pancreas Treated With 177Lu DOTATATE Induction and Maintenance Peptide Receptor Radionuclide Therapy.

    Science.gov (United States)

    Makis, William; McCann, Karey; Riauka, Terence A; McEwan, Alexander J B

    2016-01-01

    A 57-year-old woman diagnosed with ectopic Cushing syndrome was found to have a 111In-octreotide-avid corticotropin-producing pancreatic neuroendocrine tumor with liver metastases. She was treated with 4 induction and 4 maintenance cycles of 177Lu-DOTATATE, which normalized her serum corticotropin levels and dramatically reduced the size of the pancreatic primary and liver metastases. PMID:26359569

  12. The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides

    Directory of Open Access Journals (Sweden)

    Florin Barla

    2016-06-01

    Full Text Available Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi, narezushi, konkazuke, and ishiru. Various kinds of lactic acid bacteria (LAB are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates, Lactobacillus brevis (6 isolates, and Weissella hellenica (2 isolates had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates, L. buchneri (2 isolates, and W. hellenica (2 isolates was stronger than that of all whey cultured with soy protein media, and these IC50 were < 1 mg protein/ml. Three of 10 isolates had high GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.

  13. Production of peptide antisera specific for mouse and rat proinsulin C-peptide 2

    DEFF Research Database (Denmark)

    Blume, N; Madsen, O D; Kofod, Hans;

    1990-01-01

    Mice and rats have two functional non-allelic insulin genes. By using a synthetic peptide representing a common sequence in mouse and rat C-peptide 2 as antigen, we have produced rabbit antisera specific for an epitope which is not present in mouse or rat C-peptide 1. Long-term immunization did n...

  14. An evaluation and partial characterization of a bacteriocin produced by Lactococcus lactis subsp lactis ST1 isolated from goat milk.

    Science.gov (United States)

    Taheri, Parinaz; Samadi, Nasrin; Ehsani, Mohammad Reza; Khoshayand, Mohammad Reza; Jamalifar, Hossein

    2012-10-01

    A bacteriocin-like inhibitory substance producing Lactococcus lactis subsp lactis strain, ST1, isolated from goat milk of Iranian origin and with broad spectrum of activity and desirable technical properties was used for evaluating some futures of bacteriocin inhibitory activity. Cell growth and bacteriocin production studies were carried out in MRS medium incubated statically under uncontrolled pH condition. The antibacterial activity presented a primary metabolite pattern and showed a rapid decrease at the stationary phase. Microaerobiosis and capnophily growth conditions resulted in higher bacteriocin production while aerobiosis showed negative effect on both cell growth and bacteriocin production. Bacteriocin production, on the other hand, was favored in MRS broth (pH; 6.5) inoculated with 0.1 ml l(-1) fresh culture when incubation was carried out at 30 °C. This indicated that the conditions resulted in higher levels of growth were frequently favoring bacteriocin production by ST1 as well. Decrease in activity, at the stationary growth phase, was much pronounced in favored growth condition. Nutrient depletion, deferent effect of low pH on bacteriocin production and/or protein degradation seemed more responsible for this phenomenon. The study also provided further data on new method for bacteriocin release from the cell wall of producer. It was clearly shown that both heating and ultrasound shock for 5 min at pH 2 could increase bacteriocin activity significantly. The release was more pronounced in the presence of 0.5% Tween80. PMID:24031976

  15. An evaluation and partial characterization of a bacteriocin produced by Lactococcus lactis subsp lactis ST1 isolated from goat milk

    Directory of Open Access Journals (Sweden)

    Parinaz Taheri

    2012-12-01

    Full Text Available A bacteriocin-like inhibitory substance producing Lactococcus lactis subsp lactis strain, ST1, isolated from goat milk of Iranian origin and with broad spectrum of activity and desirable technical properties was used for evaluating some futures of bacteriocin inhibitory activity. Cell growth and bacteriocin production studies were carried out in MRS medium incubated statically under uncontrolled pH condition. The antibacterial activity presented a primary metabolite pattern and showed a rapid decrease at the stationary phase. Microaerobiosis and capnophily growth conditions resulted in higher bacteriocin production while aerobiosis showed negative effect on both cell growth and bacteriocin production. Bacteriocin production, on the other hand, was favored in MRS broth (pH; 6.5 inoculated with 0.1 ml l-1 fresh culture when incubation was carried out at 30 °C. This indicated that the conditions resulted in higher levels of growth were frequently favoring bacteriocin production by ST1 as well. Decrease in activity, at the stationary growth phase, was much pronounced in favored growth condition. Nutrient depletion, deferent effect of low pH on bacteriocin production and/or protein degradation seemed more responsible for this phenomenon. The study also provided further data on new method for bacteriocin release from the cell wall of producer. It was clearly shown that both heating and ultrasound shock for 5 min at pH 2 could increase bacteriocin activity significantly. The release was more pronounced in the presence of 0.5% Tween80.

  16. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  17. [Brain natriuretic peptide].

    Science.gov (United States)

    La Villa, G; Lazzeri, C; Fronzaroli, C; Franchi, F; Gentilini, P

    1995-01-01

    Brain natriuretic peptide (BNP) is a cardiac hormone with a spectrum of activities quite similar to those of atrial natriuretic peptide (ANP), including diuretic, natriuretic, hypotensive and smooth muscle relaxant activities. These effects are due to the stimulation of guanylate cyclase-linked natriuretic peptide receptors, leading to an increase in cyclic GMP concentration in target cells. BNP has a lower affinity than ANP for C (clearance) receptors, and is less susceptible to degradation by neutral endopeptidase-24.11, resulting in a longer half-life. In the kidney, BNP increases the glomerular filtration rate and inhibits sodium reabsorption in the distal tubule. It also inhibits the release of renin and aldosterone. Unlike ANP, produced by the atria, BNP is mainly synthesized and released into circulation by the left ventricle and is therefore influenced by stimuli involving this cardiac chamber, such as an increase in arterial pressure, left ventricular hypertrophy and dilation. Plasma BNP levels are very low in healthy subjects, and respond modestly, although significantly to physiological stimuli such as changes in posture or sodium intake. In contrast, plasma BNP concentrations increase in disease states such as cirrhosis with ascites, hypertension, chronic renal failure, acute myocardial infarction and congestive heart failure. In the latter condition, plasma BNP concentration is a reliable prognostic index. Evidence obtained by administering BNP to healthy subjects and hypertensive patients suggests that BNP, at physiological and pathophysiological plasma concentrations, markedly influences cardiovascular homeostasis, mainly due to its effects on sodium excretion and the renin-aldosterone axis. PMID:8718658

  18. Polyclonal Peptide Antisera.

    Science.gov (United States)

    Pihl, Tina H; Illigen, Kristin E; Houen, Gunnar

    2015-01-01

    Polyclonal antibodies are relatively easy to produce and may supplement monoclonal antibodies for some applications or even have some advantages. The choice of species for production of (peptide) antisera is based on practical considerations, including availability of immunogen (vaccine) and animals. Two major factors govern the production of antisera: the nature of adaptive immune responses, which take place over days/weeks and ethical guidelines for animal welfare. Here, simple procedures for immunization of mice, rabbits, sheep, goats, pigs, horses, and chickens are presented. PMID:26424267

  19. Collagen-like peptides and peptide-polymer conjugates in the design of assembled materials

    OpenAIRE

    Luo, Tianzhi; Kiick, Kristi L.

    2013-01-01

    Collagen is the most abundant protein in mammals, and there has been long-standing interest in understanding and controlling collagen assembly in the design of new materials. Collagen-like peptides (CLP), also known as collagen-mimetic peptides (CMP) or collagen-related peptides (CRP), have thus been widely used to elucidate collagen triple helix structure as well as to produce higher-order structures that mimic natural collagen fibers. This mini-review provides an overview of recent progress...

  20. Human peptide transporters

    DEFF Research Database (Denmark)

    Nielsen, Carsten Uhd; Brodin, Birger; Jørgensen, Flemming Steen;

    2002-01-01

    Peptide transporters are epithelial solute carriers. Their functional role has been characterised in the small intestine and proximal tubules, where they are involved in absorption of dietary peptides and peptide reabsorption, respectively. Currently, two peptide transporters, PepT1 and PepT2, wh...

  1. Automated solid-phase peptide synthesis to obtain therapeutic peptides

    Directory of Open Access Journals (Sweden)

    Veronika Mäde

    2014-05-01

    Full Text Available The great versatility and the inherent high affinities of peptides for their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS offers a suitable technology to produce chemically engineered peptides. This review concentrates on the application of SPPS by Fmoc/t-Bu protecting-group strategy, which is most commonly used. Critical issues and suggestions for the synthesis are covered. The development of automated methods from conventional to essentially improved microwave-assisted instruments is discussed. In order to improve pharmacokinetic properties of peptides, lipidation and PEGylation are described as covalent conjugation methods, which can be applied by a combination of automated and manual synthesis approaches. The synthesis and application of SPPS is described for neuropeptide Y receptor analogs as an example for bioactive hormones. The applied strategies represent innovative and potent methods for the development of novel peptide drug candidates that can be manufactured with optimized automated synthesis technologies.

  2. Separation, Purification and Biological Activity Detection of Antibacterial Peptide Produced by Streptococcus lactis%乳酸链球菌抗菌肽的分离纯化及生物活性检测

    Institute of Scientific and Technical Information of China (English)

    盛博文; 杨海君; 关向杰

    2012-01-01

    This study aimed to separate and purify the Streptococcus lactis -antimicrobial peptides which had wide antimicrobial properties by gel filtration chromatography and HPLC. Staphyiococcus aureus (ATCC25923), Escherkkia coli (ATCC25922), Pseudomonas aeruginosa, Bacillus subtilh, Yersinia and Enterococcw fat calls were used to research the bactericidal mechanism and antibacterial spectrum of the Streptococcus lactis -antimicrobial peptide . The results showed that a species of Streptococcus /aeas-antimicrobial peptides which had killing effects on all bacterial cells except Pseudomonas aerugiiwsa was obtained by separation and purification. The microporous structure of Staphyiococcus aureus (ATCC25923) was observed by transmission electron microscopy when Ihe Streptococcus lactis -antimicrobial peptide was added. The transmission electron microscopy results showed that the Streptococcus lactis -antimicrobial peptide caused the Staphyiococcus aureus (ATCC25923) cells broken, swelling and leakage .accompanied cytoplasmic diluted, cell membrane boundaries blurred or even completely dissolved, and made them apoptosis ultimately.%通过凝胶过滤层析及制备型高效液相色谱法,从乳酸链球菌发酵液中筛选分离出了具有广谱抗菌活性的物质,利用金黄色葡萄球菌( ATCC25923)、大肠杆菌(ATCC25922)、绿脓杆菌、枯草芽孢杆菌、耶尔森菌.粪肠球菌对该活性物质的抗菌谱及杀菌机理进行了研究.结果表明:经过分离纯化,得到的较纯的活性物质为乳酸链球抗菌肽,该物质除了对绿脓杆菌没有杀伤作用, 对其他5种细菌均具有杀伤作用.透射电镜观察结果显示,金黄色葡萄球菌(ATCC25923)经抗菌肽处理后,细胞出现破损或肿胀,有部分细胞内容物外泄,并伴有细胞质稀释的现象,细胞膜界限模糊不清,细胞膜甚至完全溶解.由于细胞内容物外渗,最终导致菌体死亡.

  3. Effect of antimicrobial peptide APNT-6 produced by Bacillus natto on fresh-keeping of Litopenaeus vannamei at low temperature%纳豆菌抗菌肽APNT-6对凡纳滨对虾的低温保鲜效果

    Institute of Scientific and Technical Information of China (English)

    王东; 孙力军; 王雅玲; 刘唤明; 徐德峰; 邓楚津; 杜焕妍; 励建荣

    2012-01-01

    A new biological preservative—antimicrobial peptide APNT-6 produced by Bacillus natto NT-6 and purified by column chromatography will be applied in the fresh-keeping of Litopenaeus vannamei. Bacillus antimicrobial peptides are a series of lipopeptides substances produced by represented Bacillus strains of B. subtilis, B. amyloliquefaciens and B. natto, which include surfactin, iturin, fengycin, subtilin and so on. Numerous studies show that Bacillus antimicrobial peptides have a startling range of antimicrobial activities that can include action against most Gram-negative and Gram-positive bacteria, fungi, enveloped viruses, and eukaryotic parasites. Recently, our research group isolated a highly antibiotic activity and largely antimicrobial spectrum strain—B. natto NT-6 from the Chinese traditional food—lobster sauce. According to the mass spectrometry (ESI /MS /CID) analysis,we know the mainly antimicrobial substances produced by this strain is Bacillus antimicrobial peptides, mainly including surfactin, fengycin, and iturin(called after APNT-6). Through oral acute toxicity in mice we found that its LDso greater than 5000 mg/kg body weight, indicating that antimicrobial peptide APNT-6 has high food safety. In this paper, the antibacterial activities of antimicrobial peptide on spoilage organisms were determined by Oxford cup assay. Then the quality changes of L vannamei during storage at (4±1) ℃ were investigated, including the pH, total volatile basic nitrogen (TVB-N), aerobic plate count (APC) and sensory assessment. The results showed that antimicrobial peptide APNT-6 can effectively inhibit 8 strains of spoilage organisms isolated from L. vannamei. During storage at (4±1) ℃, with the extension of storage time, the gradually increasing values of pH, TVB-N and APC of L.vannamei were observed during the 7 days storage. However, incubated 0.5 mg/mL antimicrobial peptide can effectively slow down the value increasing, which extends the shelf-life of L

  4. Transfer, composition and technological characterization of the lactic acid bacterial populations of the wooden vats used to produce traditional stretched cheeses.

    Science.gov (United States)

    Scatassa, Maria Luisa; Gaglio, Raimondo; Macaluso, Giusi; Francesca, Nicola; Randazzo, Walter; Cardamone, Cinzia; Di Grigoli, Antonino; Moschetti, Giancarlo; Settanni, Luca

    2015-12-01

    The biofilms of 12 wooden vats used for the production of the traditional stretched cheeses Caciocavallo Palermitano and PDO Vastedda della valle del Belìce were investigated. Salmonella spp. and Listeria monocytogenes were never detected. Total coliforms were at low numbers with Escherichia coli found only in three vats. Coagulase-positive staphylococci (CPS) were below the enumeration limit, whereas lactic acid bacteria (LAB) dominated the surfaces of all vats. In general, the dominance was showed by coccus LAB. Enterococci were estimated at high numbers, but usually between 1 and 2 Log cycles lower than other LAB. LAB populations were investigated at species and strain level and for their technological properties relevant in cheese production. Eighty-five strains were analysed by a polyphasic genetic approach and allotted into 16 species within the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Streptococcus. Enterococcus faecium was found in all wooden vats and the species most frequently isolated were Enterococcus faecalis, Lactococcus lactis, Leuconostoc mesenteroides, Pediococcus acidilactici and Streptococcus thermophilus. The study of the quantitative data on acidification rate, autolysis kinetics, diacetyl production, antibacterial compound generation and proteolysis by cluster and principal component analysis led to the identification of some strains with promising dairy characteristics. Interestingly, a consistent percentage of LAB was bacteriocin-like inhibitory substances (BLIS) producer. Thus, the microbial biofilms of the wooden vats analysed in this study might contribute actively to the stability of the final cheeses. PMID:26338114

  5. PeptideAtlas

    Data.gov (United States)

    U.S. Department of Health & Human Services — PeptideAtlas is a multi-organism, publicly accessible compendium of peptides identified in a large set of tandem mass spectrometry proteomics experiments. Mass...

  6. Peptider holder krabben rask

    DEFF Research Database (Denmark)

    Buchmann, Kurt

    Antimikrobielle Peptider har hos mere primitive dyr en vigtig funktion i organismernes immunforsvar Udgivelsesdato: 1. februar......Antimikrobielle Peptider har hos mere primitive dyr en vigtig funktion i organismernes immunforsvar Udgivelsesdato: 1. februar...

  7. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  8. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  9. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  10. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  11. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  12. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  13. Evolution of antimicrobial peptides to self-assembled peptides for biomaterial applications.

    Science.gov (United States)

    McCloskey, Alice P; Gilmore, Brendan F; Laverty, Garry

    2014-01-01

    Biomaterial-related infections are a persistent burden on patient health, recovery, mortality and healthcare budgets. Self-assembled antimicrobial peptides have evolved from the area of antimicrobial peptides. Peptides serve as important weapons in nature, and increasingly medicine, for combating microbial infection and biofilms. Self-assembled peptides harness a "bottom-up" approach, whereby the primary peptide sequence may be modified with natural and unnatural amino acids to produce an inherently antimicrobial hydrogel. Gelation may be tailored to occur in the presence of physiological and infective indicators (e.g. pH, enzymes) and therefore allow local, targeted antimicrobial therapy at the site of infection. Peptides demonstrate inherent biocompatibility, antimicrobial activity, biodegradability and numerous functional groups. They are therefore prime candidates for the production of polymeric molecules that have the potential to be conjugated to biomaterials with precision. Non-native chemistries and functional groups are easily incorporated into the peptide backbone allowing peptide hydrogels to be tailored to specific functional requirements. This article reviews an area of increasing interest, namely self-assembled peptides and their potential therapeutic applications as innovative hydrogels and biomaterials in the prevention of biofilm-related infection. PMID:25436505

  14. Bicyclic Peptide Inhibitor of Urokinase-Type Plasminogen Activator

    DEFF Research Database (Denmark)

    Roodbeen, Renée; Paaske, Berit; Jiang, Longguang;

    2013-01-01

    The development of protease inhibitors for pharmacological intervention has taken a new turn with the use of peptidebased inhibitors. Here, we report the rational design of bicyclic peptide inhibitors of the serine protease urokinase-type plasminogen activator (uPA), based on the established...... monocyclic peptide, upain-2. It was successfully converted to a bicyclic peptide, without loss of inhibitory properties. The aim was to produce a peptide cyclised by an amide bond with an additional stabilising across-the-ring covalent bond. We expected this bicyclic peptide to exhibit a lower entropic...... burden upon binding. Two bicyclic peptides were synthesised with affinities similar to that of upain-2, and their binding energetics were evaluated by isothermal titration calorimetry. Indeed, compared to upain-2, the bicyclic peptides showed reduced loss of entropy upon binding to uPA. We also...

  15. [Plant signaling peptides. Cysteine-rich peptides].

    Science.gov (United States)

    Ostrowski, Maciej; Kowalczyk, Stanisław

    2015-01-01

    Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding. Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function. The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group. There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation. PMID:26281357

  16. A peptide & peptide nucleic acid synthesis technology for transporter molecules and theranostics--the SPPS.

    Science.gov (United States)

    Pipkorn, Ruediger; Braun, Klaus; Wiessler, Manfred; Waldeck, Waldemar; Schrenk, Hans-Hermann; Koch, Mario; Semmler, Wolfhard; Komljenovic, Dorde

    2014-01-01

    Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and function of proteins is widely investigated, especially by using computer-assisted methods. Nowadays the solid phase synthesis (SPPS) chemistry emerges as a key technology and is considered as a promising methodology to design peptides for the investigation of molecular pharmacological processes at the transcriptional level. SPPS syntheses could be carried out in core facilities producing peptides for large-scale scientific implementations as presented here. PMID:24843319

  17. A Peptide & Peptide Nucleic Acid Synthesis Technology for Transporter Molecules and Theranostics - The SPPS

    Science.gov (United States)

    Pipkorn, Ruediger; Braun, Klaus; Wiessler, Manfred; Waldeck, Waldemar; Schrenk, Hans-Hermann; Koch, Mario; Semmler, Wolfhard; Komljenovic, Dorde

    2014-01-01

    Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and function of proteins is widely investigated, especially by using computer-assisted methods. Nowadays the solid phase synthesis (SPPS) chemistry emerges as a key technology and is considered as a promising methodology to design peptides for the investigation of molecular pharmacological processes at the transcriptional level. SPPS syntheses could be carried out in core facilities producing peptides for large-scale scientific implementations as presented here. PMID:24843319

  18. Conus venom peptide pharmacology.

    Science.gov (United States)

    Lewis, Richard J; Dutertre, Sébastien; Vetter, Irina; Christie, MacDonald J

    2012-04-01

    Conopeptides are a diverse group of recently evolved venom peptides used for prey capture and/or defense. Each species of cone snails produces in excess of 1000 conopeptides, with those pharmacologically characterized (≈ 0.1%) targeting a diverse range of membrane proteins typically with high potency and specificity. The majority of conopeptides inhibit voltage- or ligand-gated ion channels, providing valuable research tools for the dissection of the role played by specific ion channels in excitable cells. It is noteworthy that many of these targets are found to be expressed in pain pathways, with several conopeptides having entered the clinic as potential treatments for pain [e.g., pyroglutamate1-MrIA (Xen2174)] and one now marketed for intrathecal treatment of severe pain [ziconotide (Prialt)]. This review discusses the diversity, pharmacology, structure-activity relationships, and therapeutic potential of cone snail venom peptide families acting at voltage-gated ion channels (ω-, μ-, μO-, δ-, ι-, and κ-conotoxins), ligand-gated ion channels (α-conotoxins, σ-conotoxin, ikot-ikot, and conantokins), G-protein-coupled receptors (ρ-conopeptides, conopressins, and contulakins), and neurotransmitter transporters (χ-conopeptides), with expanded discussion on the clinical potential of sodium and calcium channel inhibitors and α-conotoxins. Expanding the discovery of new bioactives using proteomic/transcriptomic approaches combined with high-throughput platforms and better defining conopeptide structure-activity relationships using relevant membrane protein crystal structures are expected to grow the already significant impact conopeptides have had as both research probes and leads to new therapies. PMID:22407615

  19. Towards Identify Selective Antibacterial Peptides Based on Abstracts Meaning.

    Science.gov (United States)

    Barbosa-Santillán, Liliana I; Sánchez-Escobar, Juan J; Calixto-Romo, M Angeles; Barbosa-Santillán, Luis F

    2016-01-01

    We present an Identify Selective Antibacterial Peptides (ISAP) approach based on abstracts meaning. Laboratories and researchers have significantly increased the report of their discoveries related to antibacterial peptides in primary publications. It is important to find antibacterial peptides that have been reported in primary publications because they can produce antibiotics of different generations that attack and destroy the bacteria. Unfortunately, researchers used heterogeneous forms of natural language to describe their discoveries (sometimes without the sequence of the peptides). Thus, we propose that learning the words meaning instead of the antibacterial peptides sequence is possible to identify and predict antibacterial peptides reported in the PubMed engine. The ISAP approach consists of two stages: training and discovering. ISAP founds that the 35% of the abstracts sample had antibacterial peptides and we tested in the updated Antimicrobial Peptide Database 2 (APD2). ISAP predicted that 45% of the abstracts had antibacterial peptides. That is, ISAP found that 810 antibacterial peptides were not classified like that, so they are not reported in APD2. As a result, this new search tool would complement the APD2 with a set of peptides that are candidates to be antibacterial. Finally, 20% of the abstracts were not semantic related to APD2. PMID:27366202

  20. 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.

  1. Plant signalling peptides

    OpenAIRE

    Wiśniewska, Justyna; Trejgell, Alina; Tretyn, Andrzej

    2003-01-01

    Biochemical and genetic studies have identified peptides that play crucial roles in plant growth and development, including defence mechanisms in response to wounding by pests, the control of cell division and expansion, and pollen self-incompatibility. The first two signalling peptides to be described in plants were tomato systemin and phytosulfokine (PSK). There is also biochemical evidence that natriuretic peptide-like molecules, immunologically-relatedt o those found ...

  2. Polycyclic peptide therapeutics.

    Science.gov (United States)

    Baeriswyl, Vanessa; Heinis, Christian

    2013-03-01

    Owing to their excellent binding properties, high stability, and low off-target toxicity, polycyclic peptides are an attractive molecule format for the development of therapeutics. Currently, only a handful of polycyclic peptides are used in the clinic; examples include the antibiotic vancomycin, the anticancer drugs actinomycin D and romidepsin, and the analgesic agent ziconotide. All clinically used polycyclic peptide drugs are derived from natural sources, such as soil bacteria in the case of vancomycin, actinomycin D and romidepsin, or the venom of a fish-hunting coil snail in the case of ziconotide. Unfortunately, nature provides peptide macrocyclic ligands for only a small fraction of therapeutic targets. For the generation of ligands of targets of choice, researchers have inserted artificial binding sites into natural polycyclic peptide scaffolds, such as cystine knot proteins, using rational design or directed evolution approaches. More recently, large combinatorial libraries of genetically encoded bicyclic peptides have been generated de novo and screened by phage display. In this Minireview, the properties of existing polycyclic peptide drugs are discussed and related to their interesting molecular architectures. Furthermore, technologies that allow the development of unnatural polycyclic peptide ligands are discussed. Recent application of these technologies has generated promising results, suggesting that polycyclic peptide therapeutics could potentially be developed for a broad range of diseases. PMID:23355488

  3. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a...

  4. PNA Peptide chimerae

    DEFF Research Database (Denmark)

    Koch, T.; Næsby, M.; Wittung, P.; Jørgensen, M.; Larsson, C.; Buchardt, O.; Stanly, C.J.; Norden, B.; Nielsen, P.E.; Ørum, H.

    1995-01-01

    Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields.......Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields....

  5. 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.

  6. Antimicrobial peptides in crustaceans

    Directory of Open Access Journals (Sweden)

    RD Rosa

    2010-11-01

    Full Text Available Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP families are currently recognized, although the great majority (14 families comes from members of the order Decapoda. Crustacean AMPs are generally cationic, gene-encoded molecules that are mainly produced by circulating immune-competent cells (hemocytes or are derived from unrelated proteins primarily involved in other biological functions. In this review, we tentatively classified the crustacean AMPs into four main groups based on their amino acid composition, structural features and multi-functionality. We also attempted to summarize the current knowledge on their implication both in an efficient response to microbial infections and in crustacean survival.

  7. Relaxin family peptides and their receptors.

    Science.gov (United States)

    Bathgate, R A D; Halls, M L; van der Westhuizen, E T; Callander, G E; Kocan, M; Summers, R J

    2013-01-01

    There are seven relaxin family peptides that are all structurally related to insulin. Relaxin has many roles in female and male reproduction, as a neuropeptide in the central nervous system, as a vasodilator and cardiac stimulant in the cardiovascular system, and as an antifibrotic agent. Insulin-like peptide-3 (INSL3) has clearly defined specialist roles in male and female reproduction, relaxin-3 is primarily a neuropeptide involved in stress and metabolic control, and INSL5 is widely distributed particularly in the gastrointestinal tract. Although they are structurally related to insulin, the relaxin family peptides produce their physiological effects by activating a group of four G protein-coupled receptors (GPCRs), relaxin family peptide receptors 1-4 (RXFP1-4). Relaxin and INSL3 are the cognate ligands for RXFP1 and RXFP2, respectively, that are leucine-rich repeat containing GPCRs. RXFP1 activates a wide spectrum of signaling pathways to generate second messengers that include cAMP and nitric oxide, whereas RXFP2 activates a subset of these pathways. Relaxin-3 and INSL5 are the cognate ligands for RXFP3 and RXFP4 that are closely related to small peptide receptors that when activated inhibit cAMP production and activate MAP kinases. Although there are still many unanswered questions regarding the mode of action of relaxin family peptides, it is clear that they have important physiological roles that could be exploited for therapeutic benefit. PMID:23303914

  8. Human C-peptide. Pt. 1

    International Nuclear Information System (INIS)

    Synthetic human C-peptide bearing a tyrosine group at its amino end is labelled with 125iodine using chloramin T or hydrogen peroxide and lactoperoxidase. The results of the two methods are compared. Antiserum to synthetic human C-peptide (without tyrosine), which was partially coupled to rabbit albumin, is raised in guinea pigs and goats. Goats show to be superior to guinea pips concerning antibody production. The so-called 'hook effect' phenomenon is observed when setting up the standard curves for the radioimmunoassay. Monotonically decreasing standard curves are obtained on dilution of antiserum with a high antibody titer which was produced by repeated immunization in goats. Free C-peptide and C-peptide bound to antiserum are separated using the anion exchange resin amberlite. Using this separation technique we excluded unspecific binding of labelled C-peptide to protein fractions in serum of diabetics. The sensitivity of our radioimmunoassay is approx. 0.3 ng C-peptide/ml serum. Intra- and interassay variability are below 10%. Human proinsulin is the only substance found to crossreact with the antiserum. (orig.)

  9. Self-Assembly of Tetraphenylalanine Peptides.

    Science.gov (United States)

    Mayans, Enric; Ballano, Gema; Casanovas, Jordi; Díaz, Angélica; Pérez-Madrigal, Maria M; Estrany, Francesc; Puiggalí, Jordi; Cativiela, Carlos; Alemán, Carlos

    2015-11-16

    Three different tetraphenylalanine (FFFF) based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies under a variety of conditions. The FFFF peptide assembles into nanotubes that show more structural imperfections at the surface than those formed by the diphenylalanine (FF) peptide under the same conditions. Periodic DFT calculations (M06L functional) were used to propose a model that consists of three FFFF molecules defining a ring through head-to-tail NH3(+)⋅⋅⋅(-)OOC interactions, which in turn stack to produce deformed channels with internal diameters between 12 and 16 Å. Depending on the experimental conditions used for the peptide incubation, N-fluorenylmethoxycarbonyl (Fmoc) protected FFFF self-assembles into a variety of polymorphs: ultra-thin nanoplates, fibrils, and star-like submicrometric aggregates. DFT calculations indicate that Fmoc-FFFF prefers a parallel rather than an antiparallel β-sheet assembly. Finally, coexisting multiple assemblies (up to three) were observed for Fmoc-FFFF-OBzl (OBzl = benzyl ester), which incorporates aromatic protecting groups at the two peptide terminals. This unusual and noticeable feature is attributed to the fact that the assemblies obtained by combining the Fmoc and OBzl groups contained in the peptide are isoenergetic. PMID:26419936

  10. Peptide conversations in Gram-positive bacteria.

    Science.gov (United States)

    Monnet, Véronique; Juillard, Vincent; Gardan, Rozenn

    2016-05-01

    Within Gram-positive bacteria, the expression of target genes is controlled at the population level via signaling peptides, also known as pheromones. Pheromones control a wide range of functions, including competence, virulence, and others that remain unknown. Until now, their role in bacterial gene regulation has probably been underestimated; indeed, bacteria are able to produce, by ribosomal synthesis or surface protein degradation, an extraordinary variety of peptides which are released outside bacteria and among which, some are pheromones that mediate cell-to-cell communication. The review aims at giving an updated overview of these peptide-dependant communication pathways. More specifically, it follows the whole peptide circuit from the peptide production and secretion in the extracellular medium to its interaction with sensors at bacterial surface or re-import into the bacteria where it plays its regulation role. In recent years, as we have accumulated more knowledge about these systems, it has become apparent that they are more complex than they first appeared. For this reason, more research on peptide-dependant pathways is needed to develop new strategies for controlling functions of interest in Gram-positive bacteria. In particular, such research could lead to alternatives to the use of antibiotics against pathogenic bacteria. In perspective, the review identifies new research questions that emerge in this field and that have to be addressed. PMID:25198780

  11. Oxidative stress can alter the antigenicity of immunodominant peptides

    DEFF Research Database (Denmark)

    Weiskopf, Daniela; Schwanninger, Angelika; Weinberger, Birgit; Almanzar, Giovanni; Parson, Walther; Buus, Søren; Lindner, Herbert; Grubeck-Loebenstein, Beatrix

    2010-01-01

    APCs operate frequently under oxidative stress induced by aging, tissue damage, pathogens, or inflammatory responses. Phagocytic cells produce peroxides and free-radical species that facilitate pathogen clearance and can in the case of APCs, also lead to oxidative modifications of antigenic...... proteins and peptides. Little information is available presently about the consequences of such modifications on the immune response. To model oxidative modification of an immunodominant antigenic peptide, we oxidized the methionine residue of the human CMV pp65(495-503) (NLVPMVATV) peptide. Such...... modifications of an antigenic peptide can affect MHC binding or TCR recognition. Using binding and dissociation assays, we demonstrate that oxidative modification of the CMVpp65(495-503) peptide leads to a decreased binding of the pMHC complex to the TCR, whereas binding of the peptide to the MHC class I...

  12. Steps Towards the Formation of A Protocell: The Possible Role of Short Peptides

    Science.gov (United States)

    Fishkis, Maya

    2007-12-01

    The paper deals with molecular self-organization leading to formation of a protocell. Plausible steps towards a protocell include: polymerization of peptides and oligonucleotides on mineral surfaces; coevolution of peptides and oligonucleotides with formation of collectively autocatalytic sets; self-organization of short peptides into vesicles; entrapment of the peptide/oligonucleotide systems in mixed peptide and simple amphiphile membranes; and formation of functioning protocells with metabolism and cell division. The established propensity of short peptides to self-ordering and to formation of vesicles makes this sequence plausible. We further suggest that evolution of a protocell produced cellular ancestors of viruses as well as ancestors of cellular organisms.

  13. The crystal structure of the calcium-bound con-G[Q6A] peptide reveals a novel metal-dependent helical trimer

    OpenAIRE

    Cnudde, Sara E.; Prorok, Mary; Jia, Xaofei; Castellino, Francis J.; Geiger, James H.

    2010-01-01

    The ability to form and control both secondary structure and oligomerization in short peptides has proven to be challenging due to the structural instability of such peptides. The conantokin peptides are a family of gamma-carboxy-glutamic acid containing peptides produced in the venoms of predatory sea snails of the conus family. They are examples of short peptides that form stable helical structures, especially in the presence of divalent cations. Both monomeric and dimeric conantokin peptid...

  14. Release of opioid peptides in anaesthetized cats?

    OpenAIRE

    Dashwood, M. R.; Feldberg, W.

    1980-01-01

    1 The effect on arterial blood pressure of intravenous injections of naloxone (200 μg) was examined in cats anaesthetized with chloralose. Usually these injections have no effect on blood pressure unless morphine or opioid peptides have been injected, when they produce a pressor response with tachycardia.

  15. Peptide Hormones in the Gastrointestinal Tract

    DEFF Research Database (Denmark)

    Rehfeld, Jens F.

    2015-01-01

    Gastrointestinal hormones are peptides released from endocrine cells and neurons in the digestive tract. More than 30 hormone genes are currently known to be expressed in the gastrointestinal tract, which makes the gut the largest hormone-producing organ in the body. Modern biology makes it feasi...

  16. Review: Formation of Peptide Radical Ions Through Dissociative Electron Transfer in Ternary Metal-Ligand-Peptide Complexes

    International Nuclear Information System (INIS)

    The formation and fragmentation of odd-electron ions of peptides and proteins is of interest to applications in biological mass spectrometry. Gas-phase redox chemistry occurring during collision-induced dissociation of ternary metal-ligand-peptide complexes enables the formation of a variety of peptide radicals including the canonical radical cations, M+#smbullet#, radical dications, (M+H)2+#smbullet#, radical anions, (M-2H)-#smbullet#. In addition, odd-electron peptide ions with well-defined initial location of the radical site are produced through side chain losses from the radical ions. Subsequent fragmentation of these species provides information on the role of charge and the location of the radical site on the competition between radical-induced and proton-driven fragmentation of odd-electron peptide ions. This account summarizes current understanding of the factors that control the efficiency of the intramolecular electron transfer (ET) in ternary metal-ligand-peptide complexes resulting in formation of odd-electron peptide ions. Specifically, we discuss the effect of the metal center, the ligand and the peptide structure on the competition between the ET, proton transfer (PT), and loss of neutral peptide and neutral peptide fragments from the complex. Fundamental studies of the structures, stabilities, and the energetics and dynamics of fragmentation of such complexes are also important for detailed molecular-level understanding of photosynthesis and respiration in biological systems.

  17. ANTIMICROBIAL PEPTIDES: AN EFFECTIVE ALTERNATIVE FOR ANTIBIOTIC THERAPY

    Directory of Open Access Journals (Sweden)

    KK PULICHERLA

    2013-01-01

    Full Text Available Extensive use of classical antibiotics has led to the growing emergence of many resistant strains of pathogenic bacteria. Evidence has suggested that cationic antimicrobial peptides (AMP’s are of greatest potential to represent a new class of antibiotics. These peptides have a good scope in current antibiotic research. During the past two decades several AMPs have been isolated from a wide variety of animals (both vertebrates and invertebrates, and plants as well as from bacteria and fungi. These are relatively small (<10kDa, cationic and amphipathic peptides of variable length, sequence and structure. These peptides exhibit broad-spectrum activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, protozoa, yeast, fungi and viruses. Most of these peptides are believed to act by disrupting the plasma membrane leading to the lysis of the cell. Antimicrobial peptides encompass a wide variety of structural motifs such as α -helical peptides, β -sheet peptides, looped peptides and extended peptides. Preparations enriched by a specific protein are rarely easily obtained from natural host cells. Hence, recombinant protein production is frequently the sole applicable procedure. Several fusion strategies have been developed for the expression and purification of small antimicrobial peptides (AMPs in recombinant bacterial expression systems which were produced by cloning. This article aims to review in brief the sources of antimicrobial peptides, diversity in structural features, mode of action, production strategies and insight into the current data on their antimicrobial activity followed by a brief comment on the peptides that have entered clinical trials.

  18. Insulin and C-peptide in human brain neurons (insulin/C-peptide/brain peptides/immunohistochemistry/radioimmunoassay)

    International Nuclear Information System (INIS)

    The regional distribution and cellular localization of insulin and C-peptide immunoreactivities were studied in human cadaver brains using the indirect immunofluorescence method, the peroxidase-antiperoxidase technique, and radioimmunoassay. Products of the immune reactions to both polypeptides were observed in most nerve cells in all areas of the brain examined. Immunostaining was mainly restricted to the cell soma and proximal dendrites. Radioimmunoassay revealed that human brain contains insulin and C-peptide in concentrations much higher than the blood, the highest being in the hypothalamus. These findings support the hypothesis that the 'brain insulin' is - at least in part - produced in the CNS. (author)

  19. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    Introduction: A frightening increase in the number of isolated multidrug resistant bacterial strains linked to the decline in novel antimicrobial drugs entering the market is a great cause for concern. Cationic antimicrobial peptides (AMPs) have lately been introduced as a potential new class of...... antimicrobial drugs, and computational methods utilizing molecular descriptors can significantly accelerate the development of new peptide drug candidates. Areas covered: This paper gives a broad overview of peptide and amino-acid scale descriptors available for AMP modeling and highlights which of these are...

  20. 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...

  1. An efficient method for isolating antibody fragments against small peptides by antibody phage display

    DEFF Research Database (Denmark)

    Duan, Zhi; Siegumfeldt, Henrik

    2010-01-01

    We generated monoclonal scFv (single chain variable fragment) antibodies from an antibody phage display library towards three small synthetic peptides derived from the sequence of s1-casein. Key difficulties for selection of scFv-phages against small peptides were addressed. Small peptides do not...... scFvs were sequenced and characterized, and specificity was characterized by ELISA. The methods developed in this study are universally applicable for antibody phage display to efficiently produce antibody fragments against small peptides....

  2. Enzymatic hydrolysis of ovomucin and the functional and structural characteristics of peptides in the hydrolysates.

    Science.gov (United States)

    Abeyrathne, E D N S; Lee, H Y; Jo, C; Suh, J W; Ahn, D U

    2016-02-01

    Ovomucin was hydrolyzed using enzymes or by heating under alkaline conditions (pH 12.0), and the functional, structural and compositional characteristics of the peptides in the hydrolysates were determined. Among the treatments, heating at 100 °C for 15 min under alkaline conditions (OM) produced peptides with the highest iron-binding and antioxidant capacities. Ovomucin hydrolyzed with papain (OMPa) or alcalase (OMAl) produced peptides with high ACE-inhibitory activity. The mass spectrometry analysis indicated that most of the peptides from OMPa were 2 kDa. OMAl hydrolyzed ovomucin almost completely and no peptides within 700-5000 Da were found in the hydrolasate. The results indicated that the number and size of peptides were closely related to the functionality of the hydrolysates. Considering the time, cost and activities of the hydrolysates, OM was the best treatment for hydrolyzing ovomucin to produce functional peptides. PMID:26304326

  3. PNA Peptide chimerae

    DEFF Research Database (Denmark)

    Koch, T.; Næsby, M.; Wittung, P.;

    1995-01-01

    Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields....

  4. Tumor penetrating peptides

    Directory of Open Access Journals (Sweden)

    ErkkiRuoslahti

    2013-08-01

    Full Text Available Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC, contains the integrin-binding RGD motif. RGD mediates tumor homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular “zip code” of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is

  5. Introduction to Peptide Synthesis

    OpenAIRE

    Stawikowski, Maciej; Fields, Gregg B.

    2002-01-01

    A number of synthetic peptides are significant commercial or pharmaceutical products, ranging from the dipeptide sugar-substitute aspartame to clinically used hormones, such as oxytocin, adrenocorticotropic hormone, and calcitonin. This unit provides an overview of the field of synthetic peptides and proteins. It discusses selecting the solid support and common coupling reagents. Additional information is provided regarding common side reactions and synthesizing modified residues.

  6. Lasso peptide, a highly stable structure and designable multifunctional backbone.

    Science.gov (United States)

    Zhao, Ning; Pan, Yongxu; Cheng, Zhen; Liu, Hongguang

    2016-06-01

    Lasso peptide belongs to a new class of natural product with highly compact and stable structure. It has varieties of biological activities, among which the most important one is its antibacterial efficacy. Novel lasso peptides have been constantly discovered and analyzed by advanced techniques, and the biosynthesis or even chemical synthesis of lasso peptide has been studied after learning its constituent amino acids and maturation process. Structural identification of lasso peptide provides information for elucidating the mechanisms of its antibacterial activity and basis for further modifications. Ring of lasso peptide is the key to both its highly compact and stable structure and its intrinsic antibacterial property. The loop has been considered as suitable modification region of lasso peptide, such as V11-S18 of MccJ25 being modifiable without disrupting the lasso structure in biosynthesis. The tail is the immunity protein that can export lasso peptide out of its produced strain and serve as a self-protection mechanism at the same time. Most of currently known lasso peptides are non-pathogenic, which implies that the modified lasso peptides are promising candidates for medical applications. Arginine, glycine, and aspartic acid as a ligands of cancer-specific receptor have been grafted to the loop of lasso peptide without losing its bioactivity, and many other targets are expected to be used for lasso peptide modification. Multi-molecular modification and large-scale production need to be studied and solved in future for designing and using multifunctional lasso peptide based on its extraordinary stable structure. PMID:27074719

  7. Glucagon-Like Peptide-1 Gene Therapy

    Directory of Open Access Journals (Sweden)

    Anne M. Rowzee

    2011-01-01

    Full Text Available Glucagon-like peptide 1 (GLP-1 is a small peptide component of the prohormone, proglucagon, that is produced in the gut. Exendin-4, a GLP-1 receptor agonist originally isolated from the saliva of H. suspectum or Gila monster, is a peptide that shares sequence and functional homology with GLP-1. Both peptides have been demonstrated to stimulate insulin secretion, inhibit glucagon secretion, promote satiety and slow gastric emptying. As such, GLP-1 and Exendin-4 have become attractive pharmaceutical targets as an adjunctive therapy for individuals with type II diabetes mellitus, with several products currently available clinically. Herein we summarize the cell biology leading to GLP-1 production and secretion from intestinal L-cells and the endocrine functions of this peptide and Exendin-4 in humans. Additionally, gene therapeutic applications of GLP-1 and Exendin-4 are discussed with a focus on recent work using the salivary gland as a gene therapy target organ for the treatment of diabetes mellitus.

  8. Antimicrobial Peptides from Plants

    Science.gov (United States)

    Tam, James P.; Wang, Shujing; Wong, Ka H.; Tan, Wei Liang

    2015-01-01

    Plant antimicrobial peptides (AMPs) have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs) of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic), lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms. PMID:26580629

  9. Antimicrobial Peptides from Plants

    Directory of Open Access Journals (Sweden)

    James P. Tam

    2015-11-01

    Full Text Available Plant antimicrobial peptides (AMPs have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic, lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms.

  10. Electromembrane extraction of peptides.

    Science.gov (United States)

    Balchen, Marte; Reubsaet, Léon; Pedersen-Bjergaard, Stig

    2008-06-20

    Rapid extraction of eight different peptides using electromembrane extraction (EME) was demonstrated for the first time. During an extraction time of 5 min, the model peptides migrated from a 500 microL aqueous acidic sample solution, through a thin supported liquid membrane (SLM) of an organic liquid sustained in the pores in the wall of a porous hollow fiber, and into a 25 microL aqueous acidic acceptor solution present inside the lumen of the hollow fiber. The driving force of the extraction was a 50 V potential sustained across the SLM, with the positive electrode in the sample and the negative electrode in the acceptor solution. The nature and the composition of the SLM were highly important for the EME process, and a mixture of 1-octanol and 15% di(2-ethylhexyl) phosphate was found to work properly. Using 1mM HCl as background electrolyte in the sample and 100 mM HCl in the acceptor solution, and agitation at 1050 rpm, enrichment up to 11 times was achieved. Recoveries were found to be dependent on the structure of the peptide, indicating that the polarity and the number of ionized groups were important parameters affecting the extraction efficiency. The experimental findings suggested that electromembrane extraction of peptides is possible and may be a valuable tool for future extraction of peptides. PMID:18479691

  11. 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

  12. Epithelial antimicrobial peptides in host defense against infection

    Directory of Open Access Journals (Sweden)

    Bals Robert

    2000-10-01

    Full Text Available Abstract One component of host defense at mucosal surfaces seems to be epithelium-derived antimicrobial peptides. Antimicrobial peptides are classified on the basis of their structure and amino acid motifs. Peptides of the defensin, cathelicidin, and histatin classes are found in humans. In the airways, α-defensins and the cathelicidin LL-37/hCAP-18 originate from neutrophils. β-Defensins and LL-37/hCAP-18 are produced by the respiratory epithelium and the alveolar macrophage and secreted into the airway surface fluid. Beside their direct antimicrobial function, antimicrobial peptides have multiple roles as mediators of inflammation with effects on epithelial and inflammatory cells, influencing such diverse processes as proliferation, immune induction, wound healing, cytokine release, chemotaxis, protease-antiprotease balance, and redox homeostasis. Further, antimicrobial peptides qualify as prototypes of innovative drugs that might be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation.

  13. Interaction of peptides with cell membranes: insights from molecular modeling

    International Nuclear Information System (INIS)

    The investigation of the interaction of peptides with cell membranes is the focus of active research. It can enhance the understanding of basic membrane functions such as membrane transport, fusion, and signaling processes, and it may shed light on potential applications of peptides in biomedicine. In this review, we will present current advances in computational studies on the interaction of different types of peptides with the cell membrane. Depending on the properties of the peptide, membrane, and external environment, the peptide–membrane interaction shows a variety of different forms. Here, on the basis of recent computational progress, we will discuss how different peptides could initiate membrane pores, translocate across the membrane, induce membrane endocytosis, produce membrane curvature, form fibrils on the membrane surface, as well as interact with functional membrane proteins. Finally, we will present a conclusion summarizing recent progress and providing some specific insights into future developments in this field. (topical review)

  14. Interactions of Gastrointestinal Peptides: Ghrelin and Its Anorexigenic Antagonists

    Directory of Open Access Journals (Sweden)

    Anna-Sophia Wisser

    2010-01-01

    Full Text Available Food intake behaviour and energy homeostasis are strongly regulated by a complex system of humoral factors and nerval structures constituting the brain-gut-axis. To date the only known peripherally produced and centrally acting peptide that stimulates food intake is ghrelin, which is mainly synthesized in the stomach. Recent data indicate that the orexigenic effect of ghrelin might be influenced by other gastrointestinal peptides such as cholecystokinin (CCK, bombesin, desacyl ghrelin, peptide YY (PYY, as well as glucagon-like peptide (GLP. Therefore, we will review on the interactions of ghrelin with several gastrointestinal factors known to be involved in appetite regulation in order to elucidate the interdependency of peripheral orexigenic and anorexigenic peptides in the control of appetite.

  15. Growth-Blocking Peptides As Nutrition-Sensitive Signals for Insulin Secretion and Body Size Regulation

    OpenAIRE

    Koyama, Takashi; Mirth, Christen K.

    2016-01-01

    In Drosophila, the fat body, functionally equivalent to the mammalian liver and adipocytes, plays a central role in regulating systemic growth in response to nutrition. The fat body senses intracellular amino acids through Target of Rapamycin (TOR) signaling, and produces an unidentified humoral factor(s) to regulate insulin-like peptide (ILP) synthesis and/or secretion in the insulin-producing cells. Here, we find that two peptides, Growth-Blocking Peptide (GBP1) and CG11395 (GBP2), are prod...

  16. Synthetic antibiofilm peptides.

    Science.gov (United States)

    de la Fuente-Núñez, César; Cardoso, Marlon Henrique; de Souza Cândido, Elizabete; Franco, Octavio Luiz; Hancock, Robert E W

    2016-05-01

    Bacteria predominantly exist as multicellular aggregates known as biofilms that are associated with at least two thirds of all infections and exhibit increased adaptive resistance to conventional antibiotic therapies. Therefore, biofilms are major contributors to the global health problem of antibiotic resistance, and novel approaches to counter them are urgently needed. Small molecules of the innate immune system called host defense peptides (HDPs) have emerged as promising templates for the design of potent, broad-spectrum antibiofilm agents. Here, we review recent developments in the new field of synthetic antibiofilm peptides, including mechanistic insights, synergistic interactions with available antibiotics, and their potential as novel antimicrobials against persistent infections caused by biofilms. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26724202

  17. Biomimetic peptide nanosensors.

    Science.gov (United States)

    Cui, Yue; Kim, Sang N; Naik, Rajesh R; McAlpine, Michael C

    2012-05-15

    The development of a miniaturized sensing platform tailored for sensitive and selective detection of a variety of biochemical analytes could offer transformative fundamental and technological opportunities. Due to their high surface-to-volume ratios, nanoscale materials are extremely sensitive sensors. Likewise, peptides represent robust substrates for selective recognition due to the potential for broad chemical diversity within their relatively compact size. Here we explore the possibilities of linking peptides to nanosensors for the selective detection of biochemical targets. Such systems raise a number of interesting fundamental challenges: What are the peptide sequences, and how can rational design be used to derive selective binders? What nanomaterials should be used, and what are some strategies for assembling hybrid nanosensors? What role does molecular modeling play in elucidating response mechanisms? What is the resulting performance of these sensors, in terms of sensitivity, selectivity, and response time? What are some potential applications? This Account will highlight our early attempts to address these research challenges. Specifically, we use natural peptide sequences or sequences identified from phage display as capture elements. The sensors are based on a variety of nanomaterials including nanowires, graphene, and carbon nanotubes. We couple peptides to the nanomaterial surfaces via traditional surface functionalization methods or self-assembly. Molecular modeling provides detailed insights into the hybrid nanostructure, as well as the sensor detection mechanisms. The peptide nanosensors can distinguish chemically camouflaged mixtures of vapors and detect chemical warfare agents with sensitivities as low as parts-per-billion levels. Finally, we anticipate future uses of this technology in biomedicine: for example, devices based on these sensors could detect disease from the molecular components in human breath. Overall, these results provide a

  18. Therapeutic HIV Peptide Vaccine

    DEFF Research Database (Denmark)

    Fomsgaard, Anders

    2015-01-01

    Therapeutic vaccines aim to control chronic HIV infection and eliminate the need for lifelong antiretroviral therapy (ART). Therapeutic HIV vaccine is being pursued as part of a functional cure for HIV/AIDS. We have outlined a basic protocol for inducing new T cell immunity during chronic HIV-1...... infection directed to subdominant conserved HIV-1 epitopes restricted to frequent HLA supertypes. The rationale for selecting HIV peptides and adjuvants are provided. Peptide subunit vaccines are regarded as safe due to the simplicity, quality, purity, and low toxicity. The caveat is reduced immunogenicity...

  19. Cationic Antimicrobial Peptide Cytotoxicity

    OpenAIRE

    Laverty, Garry; Gilmore, Brendan

    2014-01-01

    Fluorescence microscopy serves as a valuable tool for assessing the structural integrity and viability of eukaryotic cells. Through the use of calcein AM and the DNA stain 4,6-diamidino-2 phenylindole (DAPI), cell viability and membrane integrity can be qualified. Our group has previously shown the ultra-short cationic antimicrobial peptide H-OOWW-NH2; the amphibian derived 27-mer peptide Maximin-4and the ultra-short lipopeptide C12-OOWW-NH2 to be effective against a range of bacterial biofil...

  20. Biosynthesis of cardiac natriuretic peptides

    DEFF Research Database (Denmark)

    Goetze, Jens Peter

    2010-01-01

    Cardiac-derived peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac natriuretic peptides and their molecular precursors as useful markers of heart disease. In contrast to the clinical applications, the biogenesis of cardiac p...... competent endocrine cells. The structurally related atrial natriuretic peptide will be mentioned where appropriate, whereas C-type natriuretic peptide will not be considered as a cardiac peptide of relevance in mammalian physiology....... characterized. An ongoing characterization of the molecular heterogeneity will help appreciate the biosynthetic capacity of the endocrine heart and could introduce new diagnostic possibilities. Notably, different biosynthetic products may not be equal markers of the same pathophysiological processes. An...... inefficient post-translational prohormone maturation will also affect the biology of the cardiac natriuretic peptide system. This review aims at summarizing the myocardial synthesis of natriuretic peptides focusing on B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly...

  1. Biosynthesis of cardiac natriuretic peptides

    DEFF Research Database (Denmark)

    Goetze, Jens Peter

    2010-01-01

    Cardiac-derived peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac natriuretic peptides and their molecular precursors as useful markers of heart disease. In contrast to the clinical applications, the biogenesis of cardiac...... inefficient post-translational prohormone maturation will also affect the biology of the cardiac natriuretic peptide system. This review aims at summarizing the myocardial synthesis of natriuretic peptides focusing on B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly...... competent endocrine cells. The structurally related atrial natriuretic peptide will be mentioned where appropriate, whereas C-type natriuretic peptide will not be considered as a cardiac peptide of relevance in mammalian physiology....

  2. 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...

  3. Identification of non-random sequence properties in groups of signature peptides obtained in random sequence peptide microarray experiments.

    Science.gov (United States)

    Kuznetsov, Igor B

    2016-05-01

    Immunosignaturing is an emerging experimental technique that uses random sequence peptide microarrays to detect antibodies produced by the immune system in response to a particular disease. Two important questions regarding immunosignaturing are "Do microarray peptides that exhibit a strong affinity to a given type of antibodies share common sequence properties?" and "If so, what are those properties?" In this work, three statistical tests designed to detect non-random patterns in the amino acid makeup of a group of microarray peptides are presented. One test detects patterns of significantly biased amino acid usage, whereas the other two detect patterns of significant bias in the biochemical properties. These tests do not require a large number of peptides per group. The tests were applied to analyze 19 groups of peptides identified in immunosignaturing experiments as being specific for antibodies produced in response to various types of cancer and other diseases. The positional distribution of the biochemical properties of the amino acids in these 19 peptide groups was also studied. Remarkably, despite the random nature of the sequence libraries used to design the microarrays, a unique group-specific non-random pattern was identified in the majority of the peptide groups studied. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 318-329, 2016. PMID:27037995

  4. Rational design of purely peptidic amphiphiles for drug delivery applications

    OpenAIRE

    Bruyn Ouboter, Dirk de

    2011-01-01

    A broad range of new properties is emerging from supramolecular aggregates. Self-assembled structures of purely peptidic amphiphiles exploit these properties to produce biocompatible, biodegradable, smart materials for drug administration. This thesis explores the design, synthesis, purification, characterization of purely peptidic amphiphiles, and evaluates potential applications. The first chapter provides a general introduction to the field of self-assembly, and of drug delivery as com...

  5. Synthesis of gold structures by gold-binding peptide governed by concentration of gold ion and peptide.

    Science.gov (United States)

    Kim, Jungok; Kim, Dong-Hun; Lee, Sylvia J; Rheem, Youngwoo; Myung, Nosang V; Hur, Hor-Gil

    2016-08-01

    Although biological synthesis methods for the production of gold structures by microorganisms, plant extracts, proteins, and peptide have recently been introduced, there have been few reports pertaining to controlling their size and morphology. The gold ion and peptide concentrations affected on the size and uniformity of gold plates by a gold-binding peptide Midas-11. The higher concentration of gold ions produced a larger size of gold structures reached 125.5 μm, but an increased amount of Midas-11 produced a smaller size of gold platelets and increased the yield percentage of polygonal gold particles rather than platelets. The mechanisms governing factors controlling the production of gold structures were primarily related to nucleation and growth. These results indicate that the synthesis of gold architectures can be controlled by newly isolated and substituted peptides under different reaction conditions. PMID:27108675

  6. Biochemical functionalization of peptide nanotubes with phage displayed peptides

    Science.gov (United States)

    Swaminathan, Swathi; Cui, Yue

    2016-09-01

    The development of a general approach for the biochemical functionalization of peptide nanotubes (PNTs) could open up existing opportunities in both fundamental studies as well as a variety of applications. PNTs are spontaneously assembled organic nanostructures made from peptides. Phage display has emerged as a powerful approach for identifying selective peptide binding motifs. Here, we demonstrate for the first time the biochemical functionalization of PNTs via peptides identified from a phage display peptide library. The phage-displayed peptides are shown to recognize PNTs. These advances further allow for the development of bifunctional peptides for the capture of bacteria and the self-assembly of silver particles onto PNTs. We anticipate that these results could provide significant opportunities for using PNTs in both fundamental studies and practical applications, including sensors and biosensors nanoelectronics, energy storage devices, drug delivery, and tissue engineering.

  7. Peptide iodination on phenylalanine residues

    International Nuclear Information System (INIS)

    Peptide labelling with radioactive isotopes is always a compromise between peptide chemistry, labelling chemistry, and biological receptor tolerance. Therefore new ways for isotope introduction are always useful. The present contribution describes the introduction of iodine isotopes onto synthetic polypeptides by means of the Gattermann/ Sandmeyer reactions. Peptides containing the nitrophenylalanyl residue are reduced to the corresponding aminophenylalanyl, diazolized to the diazonium phenylalanyl peptide and converted to the iodophenylalanyl peptide in the presence of copper. Two examples are presented: angiotensin II and enkephalin. In both cases, the iodophenylalanyl residue is well accepted by the biological target. (author). 13 refs.; 4 figs

  8. Structural pattern matching of nonribosomal peptides

    Directory of Open Access Journals (Sweden)

    Leclère Valérie

    2009-03-01

    Full Text Available Abstract Background Nonribosomal peptides (NRPs, bioactive secondary metabolites produced by many microorganisms, show a broad range of important biological activities (e.g. antibiotics, immunosuppressants, antitumor agents. NRPs are mainly composed of amino acids but their primary structure is not always linear and can contain cycles or branchings. Furthermore, there are several hundred different monomers that can be incorporated into NRPs. The NORINE database, the first resource entirely dedicated to NRPs, currently stores more than 700 NRPs annotated with their monomeric peptide structure encoded by undirected labeled graphs. This opens a way to a systematic analysis of structural patterns occurring in NRPs. Such studies can investigate the functional role of some monomeric chains, or analyse NRPs that have been computationally predicted from the synthetase protein sequence. A basic operation in such analyses is the search for a given structural pattern in the database. Results We developed an efficient method that allows for a quick search for a structural pattern in the NORINE database. The method identifies all peptides containing a pattern substructure of a given size. This amounts to solving a variant of the maximum common subgraph problem on pattern and peptide graphs, which is done by computing cliques in an appropriate compatibility graph. Conclusion The method has been incorporated into the NORINE database, available at http://bioinfo.lifl.fr/norine. Less than one second is needed to search for a pattern in the entire database.

  9. Radiolabelled peptides for oncological diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Laverman, Peter; Boerman, Otto C.; Oyen, Wim J.G. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Queen Mary University of London, Centre for Molecular Oncology, Barts Cancer Institute, London (United Kingdom)

    2012-02-15

    Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The {sup 111}In-labelled somatostatin analogue octreotide (OctreoScan trademark) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours. (orig.)

  10. Sequencing Lys-N Proteolytic Peptides by ESI and MALDI Tandem Mass Spectrometry

    Science.gov (United States)

    Dupré, Mathieu; Cantel, Sonia; Verdié, Pascal; Martinez, Jean; Enjalbal, Christine

    2011-02-01

    In this study, we explored the MS/MS behavior of various synthetic peptides that possess a lysine residue at the N-terminal position. These peptides were designed to mimic peptides produced upon proteolysis by the Lys-N enzyme, a metalloendopeptidase issued from a Japanese fungus Grifola frondosa that was recently investigated in proteomic studies as an alternative to trypsin digestion, as a specific cleavage at the amide X-Lys chain is obtained that provides N-terminal lysine peptide fragments. In contrast to tryptic peptides exhibiting a lysine or arginine residue solely at the C-terminal position, and are thus devoid of such basic amino acids within the sequence, these Lys-N proteolytic peptides can contain the highly basic arginine residue anywhere within the peptide chain. The fragmentation patterns of such sequences with the ESI-QqTOF and MALDI-TOF/TOF mass spectrometers commonly used in proteomic bottom-up experiments were investigated.

  11. Identification of binding peptides of the ADAM15 disintegrin domain using phage display

    Indian Academy of Sciences (India)

    Jing Wu; Min-Chen Wu; Lian-Fen Zhang; Jian-Yong Lei; Lei Feng; Jian Jin

    2009-06-01

    ADAM15 plays an important role in tumour development by interacting with integrins. In this study, we investigated the target peptides of the ADAM15 disintegrin domain. First, we successfully produced the recombinant human ADAM15 disintegrin domain (RADD) that could inhibit melanoma cell adhesion by using Escherichia coli. Second, four specific binding peptides (peptides A, B, C, and D) were selected using a phage display 12-mer peptide library. The screening protocol involved 4 rounds of positive panning on RADD and 2 rounds of subtractive selection with streptavidin. By using the BLAST software and a relevant protein database, integrin v3 was found to be homologous to peptide A. Synthetic peptide A had a highly inhibitory effect on RADD–integrin v3 binding. The results demonstrate the potential application of short peptides for disrupting high-affinity ADAM–integrin interactions.

  12. Antimicrobial peptides in crustaceans

    OpenAIRE

    RD Rosa; MA Barracco

    2010-01-01

    Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs) are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP fam...

  13. Synthetic peptides with antigenic specificity for bacterial toxins.

    Science.gov (United States)

    Sela, M; Arnon, R; Jacob, C O

    1986-01-01

    The attachment of a diphtheria toxin-specific synthetic antigenic determinant and a synthetic adjuvant to a synthetic polymeric carrier led to production of a totally synthetic macromolecule which provoked protective antibodies against diphtheria when administered in aqueous solution. When peptides related to the B subunit of cholera toxin were synthesized and attached to tetanus toxoid, antibodies produced against the conjugate reacted in some but not all cases with intact cholera toxin and (especially with peptide CTP 3, residues 50-64) neutralized toxin reactivity, as tested by permeability in rabbit skin, fluid accumulation in ligated small intestinal loops and adenylate cyclase activation. Polymerization of the peptide without any external carrier, or conjugation with the dipalmityl lysine group, had as good an effect in enhancing the immune response as its attachment to tetanus toxoid. Prior exposure to the carrier suppressed the immune response to the epitope attached to it, whereas prior exposure to the synthetic peptide had a good priming effect when the intact toxin was given; when two different peptides were attached to the same carrier, both were expressed. Antisera against peptide CTP 3 were highly cross-reactive with the heat-labile toxin of Escherichia coli and neutralized it to the same extent as cholera toxin, which is not surprising in view of the great homology between the two proteins. A synthetic oligonucleotide coding for CTP 3 has been used to express the peptide in a form suitable for immunization. It led to a priming effect against the intact cholera toxin. PMID:2426052

  14. Requirement of pro-peptide in proper folding of subtilisin-like serine protease TK0076

    International Nuclear Information System (INIS)

    Subtilisin-like proteases are characterized by a catalytic triad of the three amino acids Asp His and Ser. TK0076 is a subtilisin-like serine protease originated from Thermococcus kodakaraensis. Regions corresponding to signal-peptide, pro peptide and the mature protein were predicted by homology modeling. Homology comparison revealed that Asp215, His247 and Ser424 constitute the catalytic triad of the protein. Gene encoding TK0076 was cloned and expressed in Escherichia coli. The protein was produced in the soluble form when the gene contained the sequence corresponding to the pro-peptide whereas it was produced in the insoluble form without the sequence corresponding to pro-peptide under the same expression system. Attempts to refold the protein properly in the absence of pro-peptide were unsuccessful indicating that pro-peptide is essential for proper folding of Tk0076. (author)

  15. Immunogenicity of a synthetic HBsAg peptide: enhancement by conjugation to a fatty acid carrier.

    Science.gov (United States)

    Hopp, T P

    1984-01-01

    Effective immunization with short polypeptide antigens has typically only been possible when the peptide is conjugated to a large carrier substance, usually a protein. Such immunizations suffer from difficulties in producing conjugates of reliable composition, and from unwanted anti-carrier immune responses. When a chemically synthesized peptide, bearing hepatitis B virus a-determinant specificity, was conjugated to a dipalmityl-lysine moiety, a significant improvement in anti-hepatitis B surface antigen response was obtained, in comparison to the corresponding peptide-keyhole limpet hemocyanin conjugate. Dipalmityl lysyl peptide conjugates are readily made by standard Merrifield synthesis procedures, and are relatively free of byproducts that might cause unwanted immune responses. Gel filtration experiments suggest that the conjugates form large aggregates, possibly micelles, which may play a significant role in the enhancement of the anti-peptide response. These properties suggest that fatty acid conjugation may be a useful procedure for producing chemically synthesized peptide vaccines. PMID:6423970

  16. 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.

  17. Accurate Peptide Fragment Mass Analysis: Multiplexed Peptide Identification and Quantification

    OpenAIRE

    Weisbrod, Chad R.; Eng, Jimmy K.; Hoopmann, Michael R.; Baker, Tahmina; Bruce, James E.

    2012-01-01

    FT All Reaction Monitoring (FT-ARM) is a novel approach for the identification and quantification of peptides that relies upon the selectivity of high mass accuracy data and the specificity of peptide fragmentation patterns. An FT-ARM experiment involves continuous, data-independent, high mass accuracy MS/MS acquisition spanning a defined m/z range. Custom software was developed to search peptides against the multiplexed fragmentation spectra by comparing theoretical or empirical fragment ion...

  18. Radioimmunoassay for C-peptide in diabetic children

    International Nuclear Information System (INIS)

    Direct insulin radioimmunoassay (RIA) studies in a diabetic are no longer meaningful once insulin therapy has been instituted. For this reason, use is made of RIA for blood C-peptide, a proinsulin component reflecting endogenous insulin secretion independently of insulin therapy. The paper reports experience with C-peptide RIA studies carried out on blood from 273 diabetic children of normal body weight and 11.3 years average age, as well as 31 healthy children (control group). Diabetes duration ranged from 7 days to 14 years. The basic level of C-peptide in diabetic children is lower than that of healthy ones. Glucose stimulation produces C-peptide elevation in healthy but not in diabetic children. Glucagon stimulation produced a further rise of blood C-peptide in the healthy children. Diabetics showed very modest response to glucagon stimulation. C-peptide secretion in diabetic children proved to be inversely proportional to the duration of the diabetes. These findings in children with diabetes mellitus indicated their insulin secretion by beta cells of the pancreatic islets of Langerhans to be substantially decreased and unresponsive to glucose and glucagon stimulation. 3 figs, 1 tab

  19. Immature transformed rat islet beta-cells differentially express C-peptides derived from the genes coding for insulin I and II as well as a transfected human insulin gene

    DEFF Research Database (Denmark)

    Blume, N; Petersen, J S; Andersen, L C;

    1992-01-01

    Synthetic peptides representing unique sequences in rat proinsulin C-peptide I and II were used to generate highly specific antisera, which, when applied on sections of normal rat pancreas, confirm a homogeneous coexpression of the two C-peptides in all islet beta-cells. Insulin gene expression is...... insulin-producing cells showed highly differential expression at the cellular level of the three proinsulin C-peptide immunoreactivities, as follows: C-peptide I greater than human C-peptide greater than C-peptide II. The fractions of cells expressing human C-peptide and C-peptide II decreased in time and...... species of proinsulin-C-peptide immunoreactivity but still at high levels. However, rat C-peptide II and human C-peptide were often colocalized, even in later passages. In situ hybridization studies combined with the immunocytochemical data suggest that the differential expression occurs at the level of...

  20. Generation and characterisation of biologically active milk-derived protein and peptide fractions

    OpenAIRE

    McGrath, Brian Andrew

    2014-01-01

    In recent years, extensive research has been carried out on the health benefits of milk proteins and peptides. Biologically active peptides are defined as specific protein fragments which have a positive impact on the physiological functions of the body; such peptides are produced naturally in vivo, but can also be generated by physical and/or chemical processes, enzymatic hydrolysis and/or microbial fermentation. The aims of this thesis were to investigate not only the traditional methods us...

  1. Urinary C-Peptide Tracks Seasonal and Individual Variation in Energy Balance in Wild Chimpanzees

    OpenAIRE

    Wrangham, Richard W.; Thompson, Melissa Emery; Muller, Martin N; Lwanga, Jeremiah S; Potts, Kevin B.

    2009-01-01

    C-peptide of insulin presents a promising new tool for behavioral ecologists that allows for regular, noninvasive assessment of energetic condition in wild animals. C-peptide is produced on an equimolar basis with insulin, thus is indicative of the body's response to available glucose and, with repeated measurement, provides a biomarker of energy balance. As yet, few studies have validated the efficacy of C-peptide for monitoring energy balance in wild animals. Here, we assess seasonal and in...

  2. Peptide Bond Formation in Water Mediated by Carbon Disulfide.

    Science.gov (United States)

    Leman, Luke J; Huang, Zheng-Zheng; Ghadiri, M Reza

    2015-09-01

    Demonstrating plausible nonenzymatic polymerization mechanisms for prebiotic monomers represents a fundamental goal in prebiotic chemistry. While a great deal is now known about the potentially prebiotic synthesis of amino acids, our understanding of abiogenic polymerization processes to form polypeptides is less well developed. Here, we show that carbon disulfide (CS2), a component of volcanic emission and sulfide mineral weathering, and a widely used synthetic reagent and solvent, promotes peptide bond formation in modest yields (up to ∼20%) from α-amino acids under mild aqueous conditions. Exposure of a variety of α-amino acids to CS2 initially yields aminoacyl dithiocarbamates, which in turn generate reactive 2-thiono-5-oxazolidone intermediates, the thio analogues of N-carboxyanhydrides. Along with peptides, thiourea and thiohydantoin species are produced. Amino acid stereochemistry was preserved in the formation of peptides. Our findings reveal that CS2 could contribute to peptide bond formation, and possibly other condensation reactions, in abiogenic settings. PMID:26308392

  3. Characterization of a highly potent antimicrobial peptide microcin N from uropathogenic Escherichia coli.

    Science.gov (United States)

    Kaur, Kamaljit; Tarassova, Oxana; Dangeti, Ramana Venkata; Azmi, Sarfuddin; Wishart, David; McMullen, Lynn; Stiles, Michael

    2016-06-01

    Microcin N is a low-molecular weight, highly active antimicrobial peptide produced by uropathogenic Escherichia coli In this study, the native peptide was expressed and purified from pGOB18 plasmid carrying E. coli in low yield. The pure peptide was characterized using mass spectrometry, N-terminal sequencing by Edman degradation as well as trypsin digestion. We found that the peptide is 74-residue long, cationic (+2 total charge), highly hydrophobic and consists of glycine as the first N-terminal residue. The minimum inhibitory concentration of the peptide against Salmonella enteritidis was found to be 150 nM. Evaluation of the solution conformation of the peptide using circular dichroism spectroscopy showed that the peptide is well folded in 40% trifluoroethanol with helical structure whereas the folded structure is lost in aqueous solution. To increase the yield of this potent peptide, we overexpressed GST-tagged microcin N using E. coli BL21. Recombinant GST-tagged microcin N was successfully expressed in E. coli BL21; however, the cleaved mature microcin N did not show activity against the indicator strain (S. enterica) most likely due to the extreme hydrophobic nature of the peptide. Efforts to produce active microcin N in large scale are discussed as this peptide has huge potential to be the next generation antimicrobial agent. PMID:27190283

  4. Characterisation and cytomodulatory properties of peptides from Mozzarella di Bufala Campana cheese whey.

    Science.gov (United States)

    De Simone, Carmela; Picariello, Gianluca; Mamone, Gianfranco; Stiuso, Paola; Dicitore, Alessandra; Vanacore, Daniela; Chianese, Lina; Addeo, Francesco; Ferranti, Pasquale

    2009-03-01

    Bioactive peptides are present in a latent state, encrypted within the amino acid sequence of milk proteins, requiring enzymatic proteolysis for their release. They can be produced by gastrointestinal digestion or food processing, thus they can be present in fermented milks, cheese and also in the by-products of dairy industry such as waste whey. The spectrum of biological activity covered by milk-derived peptides is extremely wide, including antibacterial, immunostimulating, antihypertensive, antithrombotic and opioid actions. However, the characterisation of milk-derived peptides with classical analytical methodologies is severely challenged by the complexity of the milk protein fraction and by the wide dynamic range of relative peptide abundance in both dairy products and by-products. Here we report the characterisation of the peptide fraction released in the whey during the different production stages of Mozzarella di Bufala Campana cheese. The peptide extracts were separated by RP HPLC and analysed by MS in order to identify the peptides produced and to trace the pathway of formation of potential bioactive peptides. The antioxidant properties and the modulatory effect on the cell cycle exerted by the peptide extracts were also studied in CaCo2 cell line. We found that a significant antiproliferative effect on CaCo2 was exerted by Mozzarella di Bufala waste whey peptides. PMID:19035578

  5. Peptides for radiotherapy of neuroendocrine cancers

    International Nuclear Information System (INIS)

    During the last decade there has been a resurgence of interest in therapeutic nuclear medicine, due to the limitation of conventional or external beam radiotherapy in the treatment of secondary or metastatic cancer sites outside of the primary treatment area. Some of the human tumours that produce metastases express high levels of somatostatin receptors. In order to make possible the diagnostic and radiotherapeutic treatment of these kind of tumours, various somatostatin analogue peptides have been developed in recent years. Peptides have become an important class of radiopharmaceuticals,due to its unique ability to detect specific sites as receptors or enzymes. This paper describes the work with 99m Tc to establish the labelling and analytical conditions for a somatostatin analogue as a precursor, to undertake a therapeutic radiopharmaceutical labelled with 188 Re for treatment of somatostatin receptor positive tumours. (Author)

  6. NCAM Mimetic Peptides: An Update

    DEFF Research Database (Denmark)

    Berezin, Vladimir; Bock, Elisabeth

    2008-01-01

    pharmacological tools interfering with NCAM functions. Recent progress in our understanding of the structural basis of NCAM-mediated cell adhesion and signaling has allowed a structure-based design of NCAM mimetic peptides. Using this approach a number of peptides termed P2, P1-B, P-3-DE and P-3-G, whose...... sequences contain one or several NCAM homophilic binding sites involved in NCAM binding to itself, have been identified. By means of NMR titration analysis and molecular modeling a number of peptides derived from NCAM and targeting NCAM heterophilic ligands such as the fibroblast growth factor receptor and...... heparan sulfate proteoglycans (HSPG) have been identified. The FGL, dekaCAM, FRM/EncaminA, BCL, EncaminC and EncaminE peptides all target the FGF receptor whereas the heparin binding peptide HBP targets HSPG. Moreover, a number of NCAM binding peptides have been identified employing screening of...

  7. The PeptideAtlas Project

    OpenAIRE

    Deutsch, Eric W.

    2010-01-01

    PeptideAtlas is a multi-species compendium of peptides observed with tandem mass spectrometry methods. Raw mass spectrometer output files are collected from the community and reprocessed through a uniform analysis and validation pipeline that continues to advance. The results are loaded into a database and the information derived from the raw data is returned to the community via several web-based data exploration tools. The PeptideAtlas resource is useful for experiment planning, improving g...

  8. 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 ...

  9. Improving Peptide Applications Using Nanotechnology.

    Science.gov (United States)

    Narayanaswamy, Radhika; Wang, Tao; Torchilin, Vladimir P

    2016-01-01

    Peptides are being successfully used in various fields including therapy and drug delivery. With advancement in nanotechnology and targeted delivery carrier systems, suitable modification of peptides has enabled achievement of many desirable goals over-riding some of the major disadvantages associated with the delivery of peptides in vivo. Conjugation or physical encapsulation of peptides to various nanocarriers, such as liposomes, micelles and solid-lipid nanoparticles, has improved their in vivo performance multi-fold. The amenability of peptides to modification in chemistry and functionalization with suitable nanocarriers are very relevant aspects in their use and have led to the use of 'smart' nanoparticles with suitable linker chemistries that favor peptide targeting or release at the desired sites, minimizing off-target effects. This review focuses on how nanotechnology has been used to improve the number of peptide applications. The paper also focuses on the chemistry behind peptide conjugation to nanocarriers, the commonly employed linker chemistries and the several improvements that have already been achieved in the areas of peptide use with the help of nanotechnology. PMID:26279082

  10. Peptides that influence membrane topology

    Science.gov (United States)

    Wong, Gerard C. L.

    2014-03-01

    We examine the mechanism of a range of polypeptides that influence membrane topology, including antimicrobial peptides, cell penetrating peptides, viral fusion peptides, and apoptosis proteins, and show how a combination of geometry, coordination chemistry, and soft matter physics can be used to approach a unified understanding. We will also show how such peptides can impact biomedical problems such as auto-immune diseases (psoriasis, lupus), infectious diseases (viral and bacterial infections), and mitochondrial pathologies (under-regulated apoptosis leads to neurodegenerative diseases whereas over-regulated apoptosis leads to cancer.)

  11. Prion-Specific Antibodies Produced in Wild-Type Mice.

    Science.gov (United States)

    Heegaard, Peter M H; Bergström, Ann-Louise; Andersen, Heidi Gertz; Cordes, Henriette

    2015-01-01

    Peptide-specific antibodies produced against synthetic peptides are of high value in probing protein structure and function, especially when working with challenging proteins, including not readily available, non-immunogenic, toxic, and/or pathogenic proteins. Here, we present a straightforward method for production of mouse monoclonal antibodies (MAbs) against peptides representing two sites of interest in the bovine prion protein (boPrP), the causative agent of bovine spongiform encephalopathy ("mad cow disease") and new variant Creutzfeldt-Jakob's disease (CJD) in humans, as well as a thorough characterization of their reactivity with a range of normal and pathogenic (misfolded) prion proteins. It is demonstrated that immunization of wild-type mice with ovalbumin-conjugated peptides formulated with Freund's adjuvant induces a good immune response, including high levels of specific anti-peptide antibodies, even against peptides very homologous to murine protein sequences. In general, using the strategies described here for selecting, synthesizing, and conjugating peptides and immunizing 4-5 mice with 2-3 different peptides, high-titered antibodies reacting with the target protein are routinely obtained with at least one of the peptides after three to four immunizations with incomplete Freund's adjuvant. PMID:26424281

  12. Optimization of heavy chain and light chain signal peptides for high level expression of therapeutic antibodies in CHO cells.

    Directory of Open Access Journals (Sweden)

    Ryan Haryadi

    Full Text Available Translocation of a nascent protein from the cytosol into the ER mediated by its signal peptide is a critical step in protein secretion. The aim of this work was to develop a platform technology to optimize the signal peptides for high level production of therapeutic antibodies in CHO cells. A database of signal peptides from a large number of human immunoglobulin (Ig heavy chain (HC and kappa light chain (LC was generated. Most of the HC signal peptides contain 19 amino acids which can be divided into three domains and the LC signal peptides contain 22 amino acids. The signal peptides were then clustered according to sequence similarity. Based on the clustering, 8 HC and 2 LC signal peptides were analyzed for their impacts on the production of 5-top selling antibody therapeutics, namely, Herceptin, Avastin, Remicade, Rituxan, and Humira. The best HC and LC signal peptides for producing these 5 antibodies were identified. The optimized signal peptides for Rituxan is 2-fold better compared to its native signal peptides which are available in the public database. Substitution of a single amino acid in the optimized HC signal peptide for Avastin reduced its production significantly. Mass spectrometry analyses revealed that all optimized signal peptides are accurately removed in the mature antibodies. The results presented in this report are particularly important for the production of these 5 antibodies as biosimilar drugs. They also have the potential to be the best signal peptides for the production of new antibodies in CHO cells.

  13. Optimization of heavy chain and light chain signal peptides for high level expression of therapeutic antibodies in CHO cells.

    Science.gov (United States)

    Haryadi, Ryan; Ho, Steven; Kok, Yee Jiun; Pu, Helen X; Zheng, Lu; Pereira, Natasha A; Li, Bin; Bi, Xuezhi; Goh, Lin-Tang; Yang, Yuansheng; Song, Zhiwei

    2015-01-01

    Translocation of a nascent protein from the cytosol into the ER mediated by its signal peptide is a critical step in protein secretion. The aim of this work was to develop a platform technology to optimize the signal peptides for high level production of therapeutic antibodies in CHO cells. A database of signal peptides from a large number of human immunoglobulin (Ig) heavy chain (HC) and kappa light chain (LC) was generated. Most of the HC signal peptides contain 19 amino acids which can be divided into three domains and the LC signal peptides contain 22 amino acids. The signal peptides were then clustered according to sequence similarity. Based on the clustering, 8 HC and 2 LC signal peptides were analyzed for their impacts on the production of 5-top selling antibody therapeutics, namely, Herceptin, Avastin, Remicade, Rituxan, and Humira. The best HC and LC signal peptides for producing these 5 antibodies were identified. The optimized signal peptides for Rituxan is 2-fold better compared to its native signal peptides which are available in the public database. Substitution of a single amino acid in the optimized HC signal peptide for Avastin reduced its production significantly. Mass spectrometry analyses revealed that all optimized signal peptides are accurately removed in the mature antibodies. The results presented in this report are particularly important for the production of these 5 antibodies as biosimilar drugs. They also have the potential to be the best signal peptides for the production of new antibodies in CHO cells. PMID:25706993

  14. De novo peptide design and experimental validation of histone methyltransferase inhibitors.

    Directory of Open Access Journals (Sweden)

    James Smadbeck

    Full Text Available Histones are small proteins critical to the efficient packaging of DNA in the nucleus. DNA–protein complexes, known as nucleosomes, are formed when the DNA winds itself around the surface of the histones. The methylation of histone residues by enhancer of zeste homolog 2 (EZH2 maintains gene repression over successive cell generations. Overexpression of EZH2 can silence important tumor suppressor genes leading to increased invasiveness of many types of cancers. This makes the inhibition of EZH2 an important target in the development of cancer therapeutics. We employed a three-stage computational de novo peptide design method to design inhibitory peptides of EZH2. The method consists of a sequence selection stage and two validation stages for fold specificity and approximate binding affinity. The sequence selection stage consists of an integer linear optimization model that was solved to produce a rank-ordered list of amino acid sequences with increased stability in the bound peptide-EZH2 structure. These sequences were validated through the calculation of the fold specificity and approximate binding affinity of the designed peptides. Here we report the discovery of novel EZH2 inhibitory peptides using the de novo peptide design method. The computationally discovered peptides were experimentally validated in vitro using dose titrations and mechanism of action enzymatic assays. The peptide with the highest in vitro response, SQ037, was validated in nucleo using quantitative mass spectrometry-based proteomics. This peptide had an IC50 of 13.5 mM, demonstrated greater potency as an inhibitor when compared to the native and K27A mutant control peptides, and demonstrated competitive inhibition versus the peptide substrate. Additionally, this peptide demonstrated high specificity to the EZH2 target in comparison to other histone methyltransferases. The validated peptides are the first computationally designed peptides that directly inhibit EZH2

  15. De novo peptide design and experimental validation of histone methyltransferase inhibitors.

    Directory of Open Access Journals (Sweden)

    James Smadbeck

    Full Text Available Histones are small proteins critical to the efficient packaging of DNA in the nucleus. DNA-protein complexes, known as nucleosomes, are formed when the DNA winds itself around the surface of the histones. The methylation of histone residues by enhancer of zeste homolog 2 (EZH2 maintains gene repression over successive cell generations. Overexpression of EZH2 can silence important tumor suppressor genes leading to increased invasiveness of many types of cancers. This makes the inhibition of EZH2 an important target in the development of cancer therapeutics. We employed a three-stage computational de novo peptide design method to design inhibitory peptides of EZH2. The method consists of a sequence selection stage and two validation stages for fold specificity and approximate binding affinity. The sequence selection stage consists of an integer linear optimization model that was solved to produce a rank-ordered list of amino acid sequences with increased stability in the bound peptide-EZH2 structure. These sequences were validated through the calculation of the fold specificity and approximate binding affinity of the designed peptides. Here we report the discovery of novel EZH2 inhibitory peptides using the de novo peptide design method. The computationally discovered peptides were experimentally validated in vitro using dose titrations and mechanism of action enzymatic assays. The peptide with the highest in vitro response, SQ037, was validated in nucleo using quantitative mass spectrometry-based proteomics. This peptide had an IC50 of 13.5 [Formula: see text]M, demonstrated greater potency as an inhibitor when compared to the native and K27A mutant control peptides, and demonstrated competitive inhibition versus the peptide substrate. Additionally, this peptide demonstrated high specificity to the EZH2 target in comparison to other histone methyltransferases. The validated peptides are the first computationally designed peptides that directly

  16. Phytosulfokine peptide signalling.

    Science.gov (United States)

    Sauter, Margret

    2015-08-01

    Phytosulfokine (PSK) belongs to the group of plant peptide growth factors. It is a disulfated pentapeptide encoded by precursor genes that are ubiquitously present in higher plants, suggestive of universal functions. Processing of the preproprotein involves sulfonylation by a tyrosylprotein sulfotransferase in the trans-golgi and proteolytic cleavage in the apoplast. The secreted peptide is perceived at the cell surface by a membrane-bound receptor kinase of the leucine-rich repeat family. The PSK receptor PSKR1 from Arabidopsis thaliana is an active kinase and has guanylate cyclase activity resulting in dual-signal outputs. Receptor activity is regulated by calmodulin. While PSK may be an autocrine growth factor, it also acts non-cell autonomously by promoting growth of cells that are receptor-deficient. In planta, PSK has multiple functions. It promotes cell growth, acts in the quiescent centre cells of the root apical meristem, contributes to funicular pollen tube guidance, and differentially alters immune responses depending on the pathogen. It has been suggested that PSK integrates growth and defence signals to balance the competing metabolic costs of these responses. This review summarizes our current understanding of PSK synthesis, signalling, and activity. PMID:25754406

  17. A liver metalloendopeptidase which degrades the circulating hypotensive peptide hormones bradykinin and atrial natriuretic peptide

    Directory of Open Access Journals (Sweden)

    Carvalho K.M.

    1999-01-01

    Full Text Available A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-200. The purified enzyme hydrolyzed the Pro7-Phe8 bond of bradykinin and the Ser25-Tyr26 bond of atrial natriuretic peptide. No cleavage was produced in other peptide hormones such as vasopressin, oxytocin or Met- and Leu-enkephalin. This enzyme activity was inhibited by 1 mM divalent cation chelators such as EDTA, EGTA and o-phenanthroline and was insensitive to 1 µM phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (EC 3.4.24.11 and angiotensin-converting enzyme (EC 3.4.15.1, respectively. With Mr 85 kDa, the enzyme exhibits optimal activity at pH 7.5. The high affinity of this endopeptidase for bradykinin (Km = 10 µM and for atrial natriuretic peptide (Km = 5 µM suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones.

  18. Urinary Peptides in Rett Syndrome.

    Science.gov (United States)

    Solaas, K. M.; Skjeldal, O.; Gardner, M. L. G.; Kase, B. F.; Reichelt, K. L.

    2002-01-01

    A study found a significantly higher level of peptides in the urine of 53 girls with Rett syndrome compared with controls. The elevation was similar to that in 35 girls with infantile autism. Levels of peptides were lower in girls with classic Rett syndrome than those with congenital Rett syndrome. (Contains references.) (Author/CR)

  19. Peptide-LNA oligonucleotide conjugates

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Hansen, Lykke Haastrup; Vester, Birte; Wengel, Jesper

    2013-01-01

    Although peptide-oligonucleotide conjugates (POCs) are well-known for nucleic acids delivery and therapy, reports on internal attachment of peptides to oligonucleotides are limited in number. To develop a convenient route for preparation of internally labeled POCs with improved biomedical...

  20. Solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Jensen, Knud Jørgen

    This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....

  1. Radiolabelled peptides for oncological diagnosis.

    NARCIS (Netherlands)

    Laverman, P.; Sosabowski, J.K.; Boerman, O.C.; Oyen, W.J.G.

    2012-01-01

    Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of resea

  2. 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

  3. Ribosome evolution: Emergence of peptide synthesis machinery

    Indian Academy of Sciences (India)

    Koji Tamura

    2011-12-01

    Proteins, the main players in current biological systems, are produced on ribosomes by sequential amide bond (peptide bond) formations between amino-acid-bearing tRNAs. The ribosome is an exquisite super-complex of RNA-proteins, containing more than 50 proteins and at least 3 kinds of RNAs. The combination of a variety of side chains of amino acids (typically 20 kinds with some exceptions) confers proteins with extraordinary structure and functions. The origin of peptide bond formation and the ribosome is crucial to the understanding of life itself. In this article, a possible evolutionary pathway to peptide bond formation machinery (proto-ribosome) will be discussed, with a special focus on the RNA minihelix (primordial form of modern tRNA) as a starting molecule. Combining the present data with recent experimental data, we can infer that the peptidyl transferase center (PTC) evolved from a primitive system in the RNA world comprising tRNA-like molecules formed by duplication of minihelix-like small RNA.

  4. Diversity of peptide toxins from stinging ant venoms.

    Science.gov (United States)

    Aili, Samira R; Touchard, Axel; Escoubas, Pierre; Padula, Matthew P; Orivel, Jérôme; Dejean, Alain; Nicholson, Graham M

    2014-12-15

    Ants (Hymenoptera: Formicidae) represent a taxonomically diverse group of arthropods comprising nearly 13,000 extant species. Sixteen ant subfamilies have individuals that possess a stinger and use their venom for purposes such as a defence against predators, competitors and microbial pathogens, for predation, as well as for social communication. They exhibit a range of activities including antimicrobial, haemolytic, cytolytic, paralytic, insecticidal and pain-producing pharmacologies. While ant venoms are known to be rich in alkaloids and hydrocarbons, ant venoms rich in peptides are becoming more common, yet remain understudied. Recent advances in mass spectrometry techniques have begun to reveal the true complexity of ant venom peptide composition. In the few venoms explored thus far, most peptide toxins appear to occur as small polycationic linear toxins, with antibacterial properties and insecticidal activity. Unlike other venomous animals, a number of ant venoms also contain a range of homodimeric and heterodimeric peptides with one or two interchain disulfide bonds possessing pore-forming, allergenic and paralytic actions. However, ant venoms seem to have only a small number of monomeric disulfide-linked peptides. The present review details the structure and pharmacology of known ant venom peptide toxins and their potential as a source of novel bioinsecticides and therapeutic agents. PMID:25448389

  5. New insights into the bioactivity of peptides from probiotics.

    Science.gov (United States)

    Mandal, Santi M; Pati, Bikas R; Chakraborty, Ranadhir; Franco, Octavio L

    2016-01-01

    Probiotics are unique bacteria that offer several therapeutic benefits to human beings when administered in optimum amounts. Probiotics are able to produce antimicrobial substances, which stimulate the body's immune responses. Here, we review in detail the anti-infective peptides derived from probiotics and their potential immunomodulatory and anti-inflammatory activities, including a major role in cross-talk between probiotics and gut microbiota under adverse conditions. Insights from the engineered cell surface of probiotics may provide novel anti-infective therapy by heterologous expression of receptor peptides of bacterial toxins. It may be possible to use antigenic peptides from viral pathogens as live vaccines. Another possibility is to generate antiviral peptides that bind directly to virus particles, while some peptides exert anti-inflammatory and anticancer effects. Some extracellular polymeric substances might serve as anti-infective peptides. These avenues of treatment have remained largely unexplored to date, despite their potential in generating powerful anti-inflammatory and anti-infective products. PMID:27100351

  6. The Role Of Milk Peptide As Antimicrobial Agent In Supporting Health Status

    Directory of Open Access Journals (Sweden)

    Eni Kusumaningtyas

    2013-06-01

    Full Text Available Antimicrobial peptide is commonly present in all species as a component of their innate immune defense against infection. Antimicrobial peptides derived from milk such as isracidin, casocidin, casecidin and other fragments with variety of amino acid sequence are released upon enzymatic hydrolysis from milk protein К-casein, α-casein, β-casein, α-lactalbumin and β- lactoglobulin. These peptides were produced by the activity of digestive or microbial protease such as trypsin, pepsin, chymosin or alcalase. The mode of action of these peptides is by interaction of their positive with negative charge of target cell membrane leading to disruption of membrane associated with physiological event such as cell division or translocation of peptide across the membrane to interact with cytoplasmic target. Modification of charged or nonpolar aliphatic residues within peptides can enhance or reduce the activities of the peptides against a number of microbial strains and it seems to be strain dependent. Several peptides act not only as an antimicrobial but also as an angiotensin-converting enzyme inhibitor, antioxidant, immunomodulator, antiinflamation, food and feed preservative. Although the commercial production of these peptides is still limited due to lack of suitable large-scale technologies, fast development of some methods for peptide production will hopefully increase the possibility for mass production.

  7. Hepcidin, a new iron regulatory peptide.

    Science.gov (United States)

    Nicolas, Gaël; Viatte, Lydie; Bennoun, Myriam; Beaumont, Carole; Kahn, Axel; Vaulont, Sophie

    2002-01-01

    Maintaining normal iron homeostasis is essential for the organism, as both iron deficiency and iron excess are associated with cellular dysfunction. Recently, several lines of evidence have suggested that hepcidin, a peptide mainly produced by the liver, plays a major role in the control of body iron homeostasis. The subject of this paper is to summarize the advances toward the understanding of function and regulation of hepcidin in iron metabolism and to provide new data on the regulation of hepcidin gene expression by erythropoietin, the major regulator of mammalian erythropoiesis. PMID:12547223

  8. Urodilatin. A renal natriuretic peptide

    International Nuclear Information System (INIS)

    Development and validation of a radioimmunoassay for endogenous URO in urine and synthetic URO in plasma is described. The first obstacle to overcome was to produce an antibody specific for URO. A polyclonal URO antibody with a cross-reactivity with the structural highly homologous atrial natriuretic peptide (ANP) was developed by immunization of rabbits with the whole URO(95-126). Purification of the polyclonal URO antiserum with CNBr-activated Sepharose affinity chromatography was a simple way of producing a URO-specific antibody without cross-reactivity with ANP analogues. A reliable 125I-labelled URO tracer was made with the Iodo-Gen method. Prior to the assay, the urine samples were prepared by ethanol with a recovery of unlabelled URO between 80 - 100% and the plasma samples were Sep-Pak C18 extracted with a recovery of about 50%. The radioimmunoassay is performed in 3 days, using polyethylene glycol for separation. The sensitivity of the assay was improved by sample preparation and concentration, reducing the amount of tracer and late addition, reducing the amount of antibody and increasing the incubation time and lowering the temperature of incubation. The infusion rate of 20 ng URO kg-1 min-1 was most potential and well tolerated in healthy subjects. The short-term natriuretic and diuretic effects were closely associated with a significant diminished sodium reabsorption in the distal nephron. Further studies are needed to exploit the therapeutical potential of URO, for example in patients with sodium-water retaining disorders. The therapeutical dose range will probably be narrow due to the blood pressure lowering effect of URO with infusion rates higher than 20-30 ng kg-1 min-1. (EHS)

  9. Production of stable isotope enriched antimicrobial peptides in Escherichia coli: An application to the production of a 15N-enriched fragment of lactoferrin

    International Nuclear Information System (INIS)

    A method is described for the production of recombinant isotopically enriched peptides in E. coli. Peptides are produced in high yield as fusion proteins with ketosteroid isomerase which form insoluble inclusion bodies. This insoluble form allows easy purification, stabilizes the peptide against degradation and prevents bactericidal activity of the peptide. Cyanogen bromide cleavage released peptide which was conjugated with alkylamines to form lipopeptide. An important advantage of this system is that it allows production of peptides that are toxic to bacteria, which we have demonstrated on a dodecapeptide based on residues 21-31 of human bactericidal protein lactoferrin

  10. Engineering Dehydrated Amino Acid Residues in the Antimicrobial Peptide Nisin

    NARCIS (Netherlands)

    Kuipers, Oscar P.; Rollema, Harry S.; Yap, Wyanda M.G.J.; Boot, Hein J.; Siezen, Roland J.; Vos, Willem M. de

    1992-01-01

    The small antimicrobial peptide nisin, produced by Lactococcus lactis, contains the uncommon amino acid residues dehydroalanine and dehydrobutyrine and five thio ether bridges. Since these structures are posttranslationally formed from Ser, Thr, and Cys residues, it is feasible to study their role i

  11. Efficient Covalent Bond Formation in Gas-Phase Peptide-Peptide Ion Complexes with the Photoleucine Stapler

    Science.gov (United States)

    Shaffer, Christopher J.; Andrikopoulos, Prokopis C.; Řezáč, Jan; Rulíšek, Lubomír; Tureček, František

    2016-04-01

    Noncovalent complexes of hydrophobic peptides GLLLG and GLLLK with photoleucine (L*) tagged peptides G(L* n L m )K (n = 1,3, m = 2,0) were generated as singly charged ions in the gas phase and probed by photodissociation at 355 nm. Carbene intermediates produced by photodissociative loss of N2 from the L* diazirine rings underwent insertion into X-H bonds of the target peptide moiety, forming covalent adducts with yields reaching 30%. Gas-phase sequencing of the covalent adducts revealed preferred bond formation at the C-terminal residue of the target peptide. Site-selective carbene insertion was achieved by placing the L* residue in different positions along the photopeptide chain, and the residues in the target peptide undergoing carbene insertion were identified by gas-phase ion sequencing that was aided by specific 13C labeling. Density functional theory calculations indicated that noncovalent binding to GL*L*L*K resulted in substantial changes of the (GLLLK + H)+ ground state conformation. The peptide moieties in [GL*L*LK + GLLLK + H]+ ion complexes were held together by hydrogen bonds, whereas dispersion interactions of the nonpolar groups were only secondary in ground-state 0 K structures. Born-Oppenheimer molecular dynamics for 100 ps trajectories of several different conformers at the 310 K laboratory temperature showed that noncovalent complexes developed multiple, residue-specific contacts between the diazirine carbons and GLLLK residues. The calculations pointed to the substantial fluidity of the nonpolar side chains in the complexes. Diazirine photochemistry in combination with Born-Oppenheimer molecular dynamics is a promising tool for investigations of peptide-peptide ion interactions in the gas phase.

  12. The structural determinants of insulin-like peptide 3 activity

    Directory of Open Access Journals (Sweden)

    Ross AD Bathgate

    2012-02-01

    Full Text Available INSL3 is a hormone and/or paracrine factor which is a member of the relaxin peptide family. It has key roles as a fertility regulator in both males and females. The receptor for INSL3 is the leucine rich repeat (LRR containing G-protein coupled receptor 8 (LGR8 which is now known as relaxin family peptide receptor 2 (RXFP2. Receptor activation by INSL3 involves binding to the LRRs in the large ectodomain of RXFP2 by residues within the B-chain of INSL3 as well as an interaction with the transmembrane exoloops of the receptor. Although the binding to the LRRs is well characterized the features of the peptide and receptor involved in the exoloop interaction are currently unknown. This study was designed to determine the key INSL3 determinants for RXFP2 activation. A chimeric peptide approach was first utilized to demonstrate that the A-chain is critical for receptor activation. Replacement of the INSL3 A-chain with that from the related peptides INSL5 and INSL6 resulted in complete loss of activity despite only minor changes in binding affinity. Subsequent replacement of specific A-chain residues with those from the INSL5 peptide highlighted that the N-terminus of the A-chain of INSL3 is critical for its activity. Remarkably, replacement of the entire N-terminus with four or five alanine residues resulted in peptides with near native activity suggesting that specific residues are not necessary for activity. Additionally removal of two amino acids at the C-terminus of the A-chain and mutation of Lys-8 in the B-chain also resulted in minor decreases in peptide activity. Therefore we have demonstrated that the activity of the INSL3 peptide is driven predominantly by residues 5-9 in the A-chain, with minor additional contributions from the two C-terminal A-chain residues and Lys-8 in the B-chain. Using this new knowledge, we were able to produce a truncated INSL3 peptide structure which retained native activity, despite having 14 fewer residues than

  13. INDUCEMENT OF ANTITUMOR-IMMUNITY BY DC ACTIVATED BY HSP70-H22 TUMOR ANTIGEN PEPTIDE

    Institute of Scientific and Technical Information of China (English)

    冯作化; 黄波; 张桂梅; 李东; 王洪涛

    2003-01-01

    Objective: To investigate the feasibility of decreasing the dosage of tumor antigen peptides by dendritic cell (DC)-presenting and the characteristics of modification of DC by heat shock protein (Hsp70) and antigen peptides. Methods: Peptides were bound to Hsp70 and used to modify DC in vitro. The metabolism of the modified DC and the cytokines secreted by the modified DC were determined. The activation of lymphocytes by the modified DC and Hsp70-H22 peptides was tested. The cytotoxicity of the activated lymphocytes to H22 tumor cells was analyzed. The inhibitory effect of tumor in mice by the injection of DC and Hsp70-H22 peptides was tested. Results: 0.15μg of H22 peptides bound with Hsp70 could make 2×105 DC mature. 4×103 matured DC could activate 2×106 lymphocytes. The same amount of lymphocytes could be activated to produce similar cytotoxicity to tumor cells by either DC modified by 0.003μg of peptides bound with Hsp70 or by direct stimulation with 0.15μg of peptides bound with Hsp70. The dosage of peptides could be reduced by about 50 folds if the modified DC was used for injection instead of Hsp70-peptides. Peptides from normal hepatocytes, bound with Hsp70, could not make DC mature, nor activate lymphocytes through DC. Conclusion: The dosage of Hsp70-H22 peptides can be reduced significantly by DC-presenting to activate lymphocytes. Peptides from normal cells could not activate lymphocytes by either Hsp70-presenting or DC-presenting and they have little chance to induce autoimmunity.

  14. Calcium Carbonate Formation by Genetically Engineered Inorganic Binding Peptides

    Science.gov (United States)

    Gresswell, Carolyn Gayle

    -based selection and sequence identification, can be designed to have recognition capability to a given crystal structure, specifically, in this case, of calcium carbonate. Calcite mineralization with the peptides produced vaterite when several of the peptides were used in the synthesis process, many having unique morphologies studied using scanning electron microscopy (SEM). The amount of vaterite crystal percentage in these biomineralized mixtures was calculated and it was found to be closely related to peptide concentration for the aragonite-binding peptides. In the aragonite mineralization experiments, a separate solid phase, namely, calcium nitrate hydrate, was produced for one of the peptides along with the other polymorphs of calcite carbonate (ie., aragonite, calcite and vaterite) in the solution in the form of a flat film. These biomineralization results are examined in the light of the effects of peptide sequences and their related solid-binding characteristics

  15. Radiopharmaceutical development of radiolabelled peptides

    Energy Technology Data Exchange (ETDEWEB)

    Fani, Melpomeni; Maecke, Helmut R. [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany)

    2012-02-15

    Receptor targeting with radiolabelled peptides has become very important in nuclear medicine and oncology in the past few years. The overexpression of many peptide receptors in numerous cancers, compared to their relatively low density in physiological organs, represents the molecular basis for in vivo imaging and targeted radionuclide therapy with radiolabelled peptide-based probes. The prototypes are analogs of somatostatin which are routinely used in the clinic. More recent developments include somatostatin analogs with a broader receptor subtype profile or with antagonistic properties. Many other peptide families such as bombesin, cholecystokinin/gastrin, glucagon-like peptide-1 (GLP-1)/exendin, arginine-glycine-aspartic acid (RGD) etc. have been explored during the last few years and quite a number of potential radiolabelled probes have been derived from them. On the other hand, a variety of strategies and optimized protocols for efficient labelling of peptides with clinically relevant radionuclides such as {sup 99m}Tc, M{sup 3+} radiometals ({sup 111}In, {sup 86/90}Y, {sup 177}Lu, {sup 67/68}Ga), {sup 64/67}Cu, {sup 18}F or radioisotopes of iodine have been developed. The labelling approaches include direct labelling, the use of bifunctional chelators or prosthetic groups. The choice of the labelling approach is driven by the nature and the chemical properties of the radionuclide. Additionally, chemical strategies, including modification of the amino acid sequence and introduction of linkers/spacers with different characteristics, have been explored for the improvement of the overall performance of the radiopeptides, e.g. metabolic stability and pharmacokinetics. Herein, we discuss the development of peptides as radiopharmaceuticals starting from the choice of the labelling method and the conditions to the design and optimization of the peptide probe, as well as some recent developments, focusing on a selected list of peptide families, including somatostatin

  16. Peptide primary messengers in plants

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The peptide primary messengers regulate embryonic development,cell growth and many other activities in animal cells. But recent evidence verified that peptide primary messengers are also involved in plant defense responses, the recognition between pollen and stigma and keep the balance between cell proliferation and differentiations in shoot apical meristems. Those results suggest that plants may actually make wide use of peptide primary messengers, both in embryonic development and late life when they rally their cells to defend against pathogens and insect pests. The recent advance in those aspects is reviewed.

  17. Screening of TACE Peptide Inhibitors from Phage Display Peptide Library

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To obtain the recombinant tumor necrosis factor-α converting enzyme (TACE) ectodomain and use it as a selective molecule for the screening of TACE peptide inhibitors, the cDNA coding catalytic domain (T800) and full-length ectodomain (T1300) of TACE were amplified by RTPCR, and the expression plasmids were constructed by inserting T800 and T1300 into plasmid pET28a and pET-28c respectively. The recombinant T800 and T1300 were induced by IPTG, and SDSPAGE and Western blotting analysis results revealed that T800 and T1300 were highly expressed in the form of inclusion body. After Ni2+-NTA resin affinity chromatography, the recombinant proteins were used in the screening of TACE-binding peptides from phage display peptide library respectively. After 4 rounds of biopanning, the positive phage clones were analyzed by ELISA, competitive inhibition assay and DNA sequencing. A common amino acid sequence (TRWLVYFSRPYLVAT) was found and synthesized. The synthetic peptide could inhibit the TNF-α release from LPS-stimulated human peripheral blood mononuclear cells (PBMC) up to 60.3 %. FACS analysis revealed that the peptide mediated the accumulation of TNF-α on the cell surface. These results demonstrate that the TACE-binding peptide is an effective antagonist of TACE.

  18. The Equine PeptideAtlas

    DEFF Research Database (Denmark)

    Bundgaard, Louise; Jacobsen, Stine; Sorensen, Mette A.;

    2014-01-01

    Progress in MS-based methods for veterinary research and diagnostics is lagging behind compared to the human research, and proteome data of domestic animals is still not well represented in open source data repositories. This is particularly true for the equine species. Here we present a first...... current release comprises 24 131 distinct peptides representing 2636 canonical proteins observed at false discovery rates of 0.2% at the peptide level and 1.4% at the protein level. Data from the Equine PeptideAtlas are available for experimental planning, validation of new datasets, and as a proteomic...... data mining resource. The advantages of the Equine PeptideAtlas are demonstrated by examples of mining the contents for information on potential and well-known equine acute phase proteins, which have extensive general interest in the veterinary clinic. The extracted information will support further...

  19. Peptide nanostructures in biomedical technology.

    Science.gov (United States)

    Feyzizarnagh, Hamid; Yoon, Do-Young; Goltz, Mark; Kim, Dong-Shik

    2016-09-01

    Nanostructures of peptides have been investigated for biomedical applications due to their unique mechanical and electrical properties in addition to their excellent biocompatibility. Peptides may form fibrils, spheres and tubes in nanoscale depending on the formation conditions. These peptide nanostructures can be used in electrical, medical, dental, and environmental applications. Applications of these nanostructures include, but are not limited to, electronic devices, biosensing, medical imaging and diagnosis, drug delivery, tissue engineering and stem cell research. This review offers a discussion of basic synthesis methods, properties and application of these nanomaterials. The review concludes with recommendations and future directions for peptide nanostructures. WIREs Nanomed Nanobiotechnol 2016, 8:730-743. doi: 10.1002/wnan.1393 For further resources related to this article, please visit the WIREs website. PMID:26846352

  20. Targeting cancer with peptide aptamers

    OpenAIRE

    Seigneuric, Renaud; Gobbo, Jessica; Colas, Pierre; Garrido, Carmen

    2011-01-01

    A major endeavour in cancer chemotherapy is to develop agents that specifically target a biomolecule of interest. There are two main classes of targeting agents: small molecules and biologics. Among biologics (e.g.: antibodies), DNA, RNA but also peptide aptamers are relatively recent agents. Peptide aptamers are seldom described but represent attractive agents that can inhibit a growing panel of oncotargets including Heat Shock Proteins. Potential pitfalls and coming challenges towards succe...

  1. Manufacturing of peptides exhibiting biological activity

    OpenAIRE

    Zambrowicz, Aleksandra; Timmer, Monika; Polanowski, Antoni; Lubec, Gert; Trziszka, Tadeusz

    2012-01-01

    Numerous studies have shown that food proteins may be a source of bioactive peptides. Those peptides are encrypted in the protein sequence. They stay inactive within the parental protein until release by proteolytic enzymes (Mine and Kovacs-Nolan in Worlds Poult Sci J 62(1):87–95, 2006; Hartman and Miesel in Curr Opin Biotechnol 18:163–169, 2007). Once released the bioactive peptides exhibit several biofunctionalities and may serve therapeutic roles in body systems. Opioid peptides, peptides ...

  2. Antimicrobial peptides in annelids

    Directory of Open Access Journals (Sweden)

    A Tasiemski

    2008-06-01

    Full Text Available Gene encoded antimicrobial peptides (AMPs are widely distributed among living organisms including plants, invertebrates and vertebrates. They constitute important effectors of the innate immune response by exerting multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis and immune induction. In invertebrates, most of the data describe the characterization and/or the function of AMPs in the numerically and economically most representative group which are arthropods. Annelids are among the first coelomates and are therefore of special phylogenetic interest. Compared to other invertebrate groups, data on annelid’s immunity reveal heavier emphasis on the cellular than on the humoral response suggesting that immune defense of annelids seems to be principally developed as cellular immunity.This paper gives an overview of the variety of AMPs identified in the three classes of annelids, i.e. polychaetes, oligochaetes and achaetes. Their functions, when they have been studied, in the humoral or cellular response of annelids are also mentioned.

  3. Kinins and peptide receptors.

    Science.gov (United States)

    Regoli, Domenico; Gobeil, Fernand

    2016-04-01

    This paper is divided into two sections: the first contains the essential elements of the opening lecture presented by Pr. Regoli to the 2015 International Kinin Symposium in S. Paulo, Brazil on June 28th and the second is the celebration of Dr. Regoli's 60 years of research on vasoactive peptides. The cardiovascular homeostasis derives from a balance of two systems, the renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS). The biologically active effector entity of RAS is angiotensin receptor-1 (AT-1R), and that of KKS is bradykinin B2 receptor (B2R). The first mediates vasoconstriction, the second is the most potent and efficient vasodilator. Thanks to its complex and multi-functional mechanism of action, involving nitric oxide (NO), prostacyclin and endothelial hyperpolarizing factor (EDHF). B2R is instrumental for the supply of blood, oxygen and nutrition to tissues. KKS is present on the vascular endothelium and functions as an autacoid playing major roles in cardiovascular diseases (CVDs) and diabetes. KKS exerts a paramount role in the prevention of thrombosis and atherosclerosis. Such knowledge emphasizes the already prominent value of the ACE-inhibitors (ACEIs) for the treatment of CVDs and diabetes. Indeed, the ACEIs, thanks to their double action (block of the RAS and potentiation of the KKS) are the ideal agents for a rational treatment of these diseases. PMID:26408609

  4. Material Binding Peptides for Nanotechnology

    Directory of Open Access Journals (Sweden)

    Urartu Ozgur Safak Seker

    2011-02-01

    Full Text Available Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. This combinatorial approach has also been adapted over the past decade to select material-specific peptides. Screening and selection of such phage displayed material binding peptides has attracted great interest, in particular because of their use in nanotechnology. Phage display selected peptides are either synthesized independently or expressed on phage coat protein. Selected phage particles are subsequently utilized in the synthesis of nanoparticles, in the assembly of nanostructures on inorganic surfaces, and oriented protein immobilization as fusion partners of proteins. In this paper, we present an overview on the research conducted on this area. In this review we not only focus on the selection process, but also on molecular binding characterization and utilization of peptides as molecular linkers, molecular assemblers and material synthesizers.

  5. Collagen-like antimicrobial peptides.

    Science.gov (United States)

    Masuda, Ryo; Kudo, Masakazu; Dazai, Yui; Mima, Takehiko; Koide, Takaki

    2016-11-01

    Combinatorial library composed of rigid rod-like peptides with a triple-helical scaffold was constructed. The component peptides were designed to have various combinations of basic and neutral (or hydrophobic) amino acid residues based on collagen-like (Gly-Pro-Yaa)-repeating sequences, inspired from the basic and amphiphilic nature of naturally occurring antimicrobial peptides. Screening of the peptide pools resulted in identification of antimicrobial peptides. A structure-activity relationship study revealed that the position of Arg-cluster at N-terminus and cystine knots at C-terminus in the triple helix significantly contributed to the antimicrobial activity. The most potent peptide RO-A showed activity against Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. In addition, Escherichia coli exposed to RO-A resulted in abnormal elongation of the cells. RO-A was also shown to have remarkable stability in human serum and low cytotoxicity to mammalian cells. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 453-459, 2016. PMID:27271210

  6. 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.

  7. Urinary C-peptide tracks seasonal and individual variation in energy balance in wild chimpanzees.

    Science.gov (United States)

    Emery Thompson, Melissa; Muller, Martin N; Wrangham, Richard W; Lwanga, Jeremiah S; Potts, Kevin B

    2009-02-01

    C-peptide of insulin presents a promising new tool for behavioral ecologists that allows for regular, non-invasive assessment of energetic condition in wild animals. C-peptide is produced on an equimolar basis with insulin, thus is indicative of the body's response to available glucose and, with repeated measurement, provides a biomarker of energy balance. As yet, few studies have validated the efficacy of C-peptide for monitoring energy balance in wild animals. Here, we assess seasonal and interindividual variation in urinary C-peptide concentrations of East African chimpanzees (Pan troglodytes schweinfurthii). We assayed 519 urine samples from 13 adult male chimpanzees in the Kanyawara community of Kibale National Park, Uganda. C-peptide levels were significantly predicted by the total amount of fruit and the amount of preferred fruit in the diet. However, chimpanzees had very low C-peptide titers during an epidemic of severe respiratory illness, despite highly favorable feeding conditions. Kanyawara males had significantly lower C-peptide levels than males at Ngogo, a nearby chimpanzee community occupying a more productive habitat. Among Kanyawara males, low-ranking males had consistently higher C-peptide levels than dominant males. While counterintuitive, this result supports previous findings of costs associated with dominance in male chimpanzees. Our preliminary investigations demonstrate that C-peptide has wide applications in field research, providing an accessible tool for evaluating seasonal and individual variation in energetic condition, as well as the costs of processes such as immune function and reproduction. PMID:19084530

  8. Modeling the QSAR of ACE-Inhibitory Peptides with ANN and Its Applied Illustration

    Directory of Open Access Journals (Sweden)

    Ronghai He

    2012-01-01

    Full Text Available A quantitative structure-activity relationship (QSAR model of angiotensin-converting enzyme- (ACE- inhibitory peptides was built with an artificial neural network (ANN approach based on structural or activity data of 58 dipeptides (including peptide activity, hydrophilic amino acids content, three-dimensional shape, size, and electrical parameters, the overall correlation coefficient of the predicted versus actual data points is =0.928, and the model was applied in ACE-inhibitory peptides preparation from defatted wheat germ protein (DWGP. According to the QSAR model, the C-terminal of the peptide was found to have principal importance on ACE-inhibitory activity, that is, if the C-terminal is hydrophobic amino acid, the peptide's ACE-inhibitory activity will be high, and proteins which contain abundant hydrophobic amino acids are suitable to produce ACE-inhibitory peptides. According to the model, DWGP is a good protein material to produce ACE-inhibitory peptides because it contains 42.84% of hydrophobic amino acids, and structural information analysis from the QSAR model showed that proteases of Alcalase and Neutrase were suitable candidates for ACE-inhibitory peptides preparation from DWGP. Considering higher DH and similar ACE-inhibitory activity of hydrolysate compared with Neutrase, Alcalase was finally selected through experimental study.

  9. Bioactive Peptides in Milk and Dairy Products: A Review

    Science.gov (United States)

    Park, Young Woo; Nam, Myoung Soo

    2015-01-01

    Functionally and physiologically active peptides are produced from several food proteins during gastrointestinal digestion and fermentation of food materials with lactic acid bacteria. Once bioactive peptides (BPs) are liberated, they exhibit a wide variety of physiological functions in the human body such as gastrointestinal, cardiovascular, immune, endocrine, and nervous systems. These functionalities of the peptides in human health and physiology include antihypertensive, antimicrobial, antioxidative, antithrombotic, opioid, anti-appetizing, immunomodulatory and mineral-binding activities. Most of the bioactivities of milk proteins are latent, being absent or incomplete in the original native protein, but full activities are manifested upon proteolytic digestion to release and activate encrypted bioactive peptides from the original protein. Bioactive peptides have been identified within the amino acid sequences of native milk proteins. Due to their physiological and physico-chemical versatility, milk peptides are regarded as greatly important components for health promoting foods or pharmaceutical applications. Milk and colostrum of bovine and other dairy species are considered as the most important source of natural bioactive components. Over the past a few decades, major advances and developments have been achieved on the science, technology and commercial applications of bioactive components which are present naturally in the milk. Although the majority of published works are associated with the search of bioactive peptides in bovine milk samples, some of them are involved in the investigation of ovine or caprine milk. The advent of functional foods has been facilitated by increasing scientific knowledge about the metabolic and genomic effects of diet and specific dietary components on human health. PMID:26877644

  10. A molecular model for membrane fusion based on solution studies of an amphiphilic peptide from HIV gp41.

    OpenAIRE

    Fujii, G; Horvath, S.; Woodward, S.; Eiserling, F.; Eisenberg, D.

    1992-01-01

    The mechanism of protein-mediated membrane fusion and lysis has been investigated by solution-state studies of the effects of peptides on liposomes. A peptide (SI) corresponding to a highly amphiphilic C-terminal segment from the envelope protein (gp41) of the human immunodeficiency virus (HIV) was synthesized and tested for its ability to cause lipid membranes to fuse together (fusion) or to break open (lysis). These effects were compared to those produced by the lytic and fusogenic peptide ...

  11. An ancestral HIV-2/simian immunodeficiency virus peptide with potent HIV-1 and HIV-2 fusion inhibitor activity

    OpenAIRE

    Borrego, Pedro; Calado, Rita; Marcelino, José M.; Pereira, Patrícia MR; Quintas, Alexandre; Barroso, Helena; Taveira, Nuno

    2013-01-01

    "Objectives: To produce new fusion inhibitor peptides for HIV-1 and HIV-2 based on ancestral envelope sequences. Methods: HIV-2/simian immunodeficiency virus (SIV) ancestral transmembrane protein sequences were reconstructed and ancestral peptides were derived from the helical region 2 (HR2). The activity of one ancestral peptide (named P3) was examined against a panel of HIV-1 and HIV-2 primary isolates in TZM-bl cells and peripheral blood mononuclear cells and compared to ...

  12. ERAP1-ERAP2 dimerization increases peptide-trimming efficiency.

    Science.gov (United States)

    Evnouchidou, Irini; Weimershaus, Mirjana; Saveanu, Loredana; van Endert, Peter

    2014-07-15

    The endoplasmic reticulum aminopeptidases (ERAP)1 and ERAP2 play a critical role in the production of final epitopes presented by MHC class I molecules. Formation of heterodimers by ERAP1 and ERAP2 has been proposed to facilitate trimming of epitope precursor peptides, but the effects of dimerization on ERAP function remain unknown. In this study, we produced stabilized ERAP1-ERAP2 heterodimers and found that they produced several mature epitopes more efficiently than a mix of the two enzymes unable to dimerize. Physical interaction with ERAP2 changes basic enzymatic parameters of ERAP1 and improves its substrate-binding affinity. Thus, by bringing the two enzymes in proximity and by producing allosteric effects on ERAP1, dimerization of ERAP1/2 creates complexes with superior peptide-trimming efficacy. Such complexes are likely to enhance Ag presentation by cells displaying coordinated expression of the two enzymes. PMID:24928998

  13. Turnover of Ia-peptide complexes is facilitated in viable antigen-presenting cells: biosynthetic turnover of Ia vs. peptide exchange.

    OpenAIRE

    Harding, C V; Roof, R W; Unanue, E R

    1989-01-01

    Macrophages and B cells process antigens to produce antigenic peptides that associate with class II major histocompatibility complex molecules (e.g., Ia molecules); these Ia-peptide complexes are recognized by CD4+ T lymphocytes. Processing of the antigen hen egg white lysozyme was inhibited by cycloheximide in peritoneal exudate cells (PECs, largely macrophages), but not in TA3 B-lymphoma cells. The uptake and metabolism of hen egg white lysozyme was largely intact in cycloheximide-treated P...

  14. Perspectives and Peptides of the Next Generation

    Science.gov (United States)

    Brogden, Kim A.

    Shortly after their discovery, antimicrobial peptides from prokaryotes and eukaryotes were recognized as the next potential generation of pharmaceuticals to treat antibiotic-resistant bacterial infections and septic shock, to preserve food, or to sanitize surfaces. Initial research focused on identifying the spectrum of antimicrobial agents, determining the range of antimicrobial activities against bacterial, fungal, and viral pathogens, and assessing the antimicrobial activity of synthetic peptides versus their natural counterparts. Subsequent research then focused on the mechanisms of antimicrobial peptide activity in model membrane systems not only to identify the mechanisms of antimicrobial peptide activity in microorganisms but also to discern differences in cytotoxicity for prokaryotic and eukaryotic cells. Recent, contemporary work now focuses on current and future efforts to construct hybrid peptides, peptide congeners, stabilized peptides, peptide conjugates, and immobilized peptides for unique and specific applications to control the growth of microorganisms in vitro and in vivo.

  15. Exploration of the Medicinal Peptide Space.

    Science.gov (United States)

    Gevaert, Bert; Stalmans, Sofie; Wynendaele, Evelien; Taevernier, Lien; Bracke, Nathalie; D'Hondt, Matthias; De Spiegeleer, Bart

    2016-01-01

    The chemical properties of peptide medicines, known as the 'medicinal peptide space' is considered a multi-dimensional subset of the global peptide space, where each dimension represents a chemical descriptor. These descriptors can be linked to biofunctional, medicinal properties to varying degrees. Knowledge of this space can increase the efficiency of the peptide-drug discovery and development process, as well as advance our understanding and classification of peptide medicines. For 245 peptide drugs, already available on the market or in clinical development, multivariate dataexploration was performed using peptide relevant physicochemical descriptors, their specific peptidedrug target and their clinical use. Our retrospective analysis indicates that clusters in the medicinal peptide space are located in a relatively narrow range of the physicochemical space: dense and empty regions were found, which can be explored for the discovery of novel peptide drugs. PMID:26876881

  16. Helospectin-like peptides

    DEFF Research Database (Denmark)

    Uddman, R; Goadsby, P J; Jansen-Olesen, I;

    1999-01-01

    -dependent relaxations. Intracerebral microinjection of helospectin and helodermin produced a moderate concentration-dependent increase of the cerebral blood flow of alpha-chloralose anesthetized cats. The maximum increase (21 +/- 5%) was observed after the injection of 5 microg helodermin, whereas 16 +/- 7% was seen...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    such as the cell penetrating peptides (CPPs) and the tight junction modulating peptides (TJMPs), which are able to translocate across the cellular membranes in a non-disruptive way or reversibly modulate the integrity of intercellular tight junctions (TJs), respectively. However, because of the harsh...... 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...

  18. 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

  19. Association of WT1 IgG antibody against WT1 peptide with prolonged survival in glioblastoma multiforme patients vaccinated with WT1 peptide.

    Science.gov (United States)

    Oji, Yusuke; Hashimoto, Naoya; Tsuboi, Akihiro; Murakami, Yui; Iwai, Miki; Kagawa, Naoki; Chiba, Yasuyoshi; Izumoto, Shuichi; Elisseeva, Olga; Ichinohasama, Ryo; Sakamoto, Junichi; Morita, Satoshi; Nakajima, Hiroko; Takashima, Satoshi; Nakae, Yoshiki; Nakata, Jun; Kawakami, Manabu; Nishida, Sumiyuki; Hosen, Naoki; Fujiki, Fumihiro; Morimoto, Soyoko; Adachi, Mayuko; Iwamoto, Masahiro; Oka, Yoshihiro; Yoshimine, Toshiki; Sugiyama, Haruo

    2016-09-15

    We previously evaluated Wilms' tumor gene 1 (WT1) peptide vaccination in a large number of patients with leukemia or solid tumors and have reported that HLA-A*24:02 restricted, 9-mer WT1-235 peptide (CYTWNQMNL) vaccine induces cellular immune responses and elicits WT1-235-specific cytotoxic T lymphocytes (CTLs). However, whether this vaccine induces humoral immune responses to produce WT1 antibody remains unknown. Thus, we measured IgG antibody levels against the WT1-235 peptide (WT1-235 IgG antibody) in patients with glioblastoma multiforme (GBM) receiving the WT1 peptide vaccine. The WT1-235 IgG antibody, which was undetectable before vaccination, became detectable in 30 (50.8%) of a total of 59 patients during 3 months of WT1 peptide vaccination. The dominant WT1-235 IgG antibody subclass was Th1-type, IgG1 and IgG3 . WT1-235 IgG antibody production was significantly and positively correlated with both progression-free survival (PFS) and overall survival (OS). Importantly, the combination of WT1-235 IgG antibody production and positive delayed type-hypersensitivity (DTH) to the WT1-235 peptide was a better prognostic marker for long-term OS than either parameter alone. These results suggested that WT1-235 peptide vaccination induces not only WT1-235-specific CTLs as previously described but also WT1-235-specific humoral immune responses associated with antitumor cellular immune response. Our results indicate that the WT1 IgG antibody against the WT1 peptide may be a useful predictive marker, with better predictive performance in combination with DTH to WT1 peptide, and provide a new insight into the antitumor immune response induction in WT1 peptide vaccine-treated patients. PMID:27170523

  20. Double-Stranded Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2001-01-01

    A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker.......A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  1. Recent development of peptide self-assembly

    Institute of Scientific and Technical Information of China (English)

    Xiubo Zhao; Fang Pan; Jian R. Lu

    2008-01-01

    Amino acids are the building blocks to build peptides and proteins. Recent development in peptide synthesis has however enabled us to mimic this natural process by preparing various long and short peptides possessing different conformations and biological functions. The self-assembly of short designed peptides into molecular nanostructures is becoming a growing interest in nanobiotechnology. Self-assembled peptides exhibit several attractive features for applications in tissue regeneration, drug delivery, biological surface engineering as well as in food science, cosmetic industry and antibiotics. The aim of this review is to introduce the readers to a number of representative studies on peptide self-assembly.

  2. Resistance to Antimicrobial Peptides in Vibrios

    Directory of Open Access Journals (Sweden)

    Delphine Destoumieux-Garzón

    2014-10-01

    Full Text Available Vibrios are associated with a broad diversity of hosts that produce antimicrobial peptides (AMPs as part of their defense against microbial infections. In particular, vibrios colonize epithelia, which function as protective barriers and express AMPs as a first line of chemical defense against pathogens. Recent studies have shown they can also colonize phagocytes, key components of the animal immune system. Phagocytes infiltrate infected tissues and use AMPs to kill the phagocytosed microorganisms intracellularly, or deliver their antimicrobial content extracellularly to circumvent tissue infection. We review here the mechanisms by which vibrios have evolved the capacity to evade or resist the potent antimicrobial defenses of the immune cells or tissues they colonize. Among their strategies to resist killing by AMPs, primarily vibrios use membrane remodeling mechanisms. In particular, some highly resistant strains substitute hexaacylated Lipid A with a diglycine residue to reduce their negative surface charge, thereby lowering their electrostatic interactions with cationic AMPs. As a response to envelope stress, which can be induced by membrane-active agents including AMPs, vibrios also release outer membrane vesicles to create a protective membranous shield that traps extracellular AMPs and prevents interaction of the peptides with their own membranes. Finally, once AMPs have breached the bacterial membrane barriers, vibrios use RND efflux pumps, similar to those of other species, to transport AMPs out of their cytoplasmic space.

  3. Antiviral active peptide from oyster

    Science.gov (United States)

    Zeng, Mingyong; Cui, Wenxuan; Zhao, Yuanhui; Liu, Zunying; Dong, Shiyuan; Guo, Yao

    2008-08-01

    An active peptide against herpes virus was isolated from the enzymic hydrolysate of oyster ( Crassostrea gigas) and purified with the definite direction hydrolysis technique in the order of alcalase and bromelin. The hydrolysate was fractioned into four ranges of molecular weight (>10 kDa, 10 5 kDa, 5 1 kDa and <1 kDa) using ultrafiltration membranes and dialysis. The fraction of 10 5 kDa was purified using consecutive chromatographic methods including DEAE Sephadex A-25 column, Sephadex G-25 column, and high performance liquid chromatogram (HPLC) by activity-guided isolation. The antiviral effect of the obtained peptide on herpetic virus was investigated in Vero cells by observing cytopathic effect (CPE). The result shows that the peptide has high inhibitory activity on herpetic virus.

  4. Radioactive labelling of peptidic hormones

    International Nuclear Information System (INIS)

    The labelling of peptidic hormones requires stability, specificity and sensitivity of the label. Introduction of a radioactive atome is one way to satisfy these criteria. Several processes have been described to prepare radioactive TRF: synthesis of the peptide with labelled aminoacids or introduction of the label into the hormone. In that approach, tritium can be substituted in the imidazole ring, via precursors activating the proper carbon. Monoiodo TRF leads essentially to tritium labelling of the 5 positions whereas monoazo TRF allows the preparation of 3H TRF labelled in the 2 positions. Di-substituted TRF leads to labelling into the 2 and 5 carbons. Labelled analogs of TRF can be prepared with labelled iodine; further developments of peptide labelling, will be presented. In particular, the homolytic scission of the C-iodine, bond by photochemical activation. The nascent carbon radical can be stabilized by a tritiated scavenger. This approach eliminates the use of heavy metal catalysts

  5. Antiviral active peptide from oyster

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An active peptide against herpes virus was isolated from the enzymic hydrolysate of oyster (Crassostrea gigas) and purified with the definite direction hydrolysis technique in the order of alcalase and bromelin. The hydrolysate was fractioned into four ranges of molecular weight (>10 kDa, 10-5 kDa, 5-1 kDa and <1 kDa) using ultrafiltration membranes and dialysis. The fraction of 10?5 kDa was purified using consecutive chromatographic methods including DEAE Sephadex A-25 column, Sephadex G-25 column, and high performance liquid chromatogram (HPLC) by activity-guided isolation. The antiviral effect of the obtained peptide on herpetic virus was investigated in Vero cells by observing cytopathic effect (CPE). The result shows that the peptide has high inhibitory activity on herpetic virus.

  6. Nonribosomal Peptide Synthetase Genes pesL and pes1 Are Essential for Fumigaclavine C Production in Aspergillus fumigatus

    DEFF Research Database (Denmark)

    O'Hanlon, Karen A.; Gallagher, Lorna; Schrettl, Markus;

    2012-01-01

    The identity of metabolites encoded by the majority of nonribosomal peptide synthetases in the opportunistic pathogen, Aspergillus fumigatus, remains outstanding. We found that the nonribosomal peptide (NRP) synthetases PesL and Pes1 were essential for fumigaclavine C biosynthesis, the end produc...

  7. Milk peptides increase iron solubility in water but do not affect DMT-1 expression in Caco-2 cells

    Science.gov (United States)

    In vitro digestion of milk produces peptide fractions that enhance iron uptake by Caco-2 cells. Our objectives were to investigate whether these fractions a) exert their effect by increasing relative gene expression of DMT-1 in Caco-2 cells b) enhance iron dialyzability when added in meals. Peptid...

  8. 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.

  9. The Two-Peptide (Class-IIb) Bacteriocins: Genetics, Biosynthesis, Structure, and Mode of Action

    Science.gov (United States)

    Nissen-Meyer, Jon; Oppegård, Camilla; Rogne, Per; Haugen, Helen Sophie; Kristiansen, Per Eugen

    The two-peptide (class-IIb) bacteriocins consist of two different peptides, both of which are required to obtain high antimicrobial activity. These bacteriocins kill target-cells by inducing membrane-leakage and they seem to display some specificity with respect to the molecules they transfer across membranes. The genes encoding the two peptides of two-peptide bacteriocins are next to each other on the same operon. In the same or a nearby operon are genes encoding (i) the immunity protein that protects the bacteriocin-producer from its own bacteriocin, (ii) a dedicated ABC-transporter that exports the bacteriocin from cells and cleaves off the N-terminal bacteriocin leader sequence, and (iii) an accessory protein whose exact function has not been fully clarified. Some two-peptide bacteriocins appear to be produced constitutively, whereas the production of other two-peptide bacteriocins is regulated through a three-component regulatory system that consists of a peptide pheromone, a membrane-associated histidine protein kinase, and response regulators. It has recently been proposed that the two peptides of (some) two-peptide bacteriocins may form a membrane-penetrating helix-helix structure involving helix-helix interacting GxxxG-motifs present in all currently characterized two-peptide bacteriocins. It has also been suggested that the helix-helix structure interacts with an integrated membrane (transport) protein, thus inducing a conformational change in the protein, which in turn causes membrane-leakage. This proposed mode-of-action is similar to that of the pediocin-like (class-IIa) bacteriocins and lactococcin A, which bind to a part of the mannose phosphotransferase permease that is embedded in the cell membrane, thereby altering the conformation of the ­permease in a manner that causes membrane-leakage and cell death.

  10. Peptide Antibiotics for ESKAPE Pathogens

    DEFF Research Database (Denmark)

    Thomsen, Thomas Thyge

    developed from a cecropin-mellitin hybrid peptide and proved effective in killing colistin resistant Gram-negative A. baumannii in vitro. The molecule was improved with regard to toxicity, as measured by hemolytic ability. Further, this peptide is capable of specifically killing non-growing cells of...... colistin resistant A. baumannii, also known as persisters. Using D. melanogaster as an in vivo efficacy model it was demonstrated that the Lantibiotic NAI- 107, currently undergoing pre-clinical studies, rescues D. melanogaster from MRSA infection with similar efficacy to last resort antimicrobial...

  11. Novel Formulations for Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2014-10-01

    Full Text Available Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.

  12. Peptides and the new endocrinology

    Science.gov (United States)

    Schwyzer, Robert

    1982-01-01

    The discovery of regulatory peptides common to the nervous and the endocrine systems (brain, gut, and skin) has brought about a revolution in our concepts of endocrinology and neurology. We are beginning to understand some of the complex interrelationships between soma and psyche that might, someday, be important for an integrated treatment of diseases. Examples of the actions of certain peptides in the periphery and in the central nervous system are given, and their biosynthesis and molecular anatomy as carriers for information are discussed.

  13. Natriuretic peptides and cerebral hemodynamics

    DEFF Research Database (Denmark)

    Guo, Song; Barringer, Filippa; Zois, Nora Elisabeth;

    2014-01-01

    decompensated disease. In contrast, their biological effects on the cerebral hemodynamics are poorly understood. In this mini-review, we summarize the hemodynamic effects of the natriuretic peptides with a focus on the cerebral hemodynamics. In addition, we will discuss its potential implications in diseases...... where alteration of the cerebral hemodynamics plays a role such as migraine and acute brain injury including stroke. We conclude that a possible role of the peptides is feasible as evaluated from animal and in vitro studies, but more research is needed in humans to determine the precise response on...... cerebral vessels....

  14. 18F-Labeled proinsulin connecting peptide (C-peptide): In vivo distribution and pharmacokinetics using PET

    International Nuclear Information System (INIS)

    C-peptide, produced and released in equimolar amounts with insulin, was previously considered biologically inactive. Administration to type 1 (insulin-dependent) diabetes mellitus (DM) patients has, however, indicated that C-peptide exerts a number of beneficial effects, improving long-term complications of type 1 DM on e.g. renal and nerve function (Wahren, Am J Physiol Endocrinol Metab 278: E759, 2000). Aim: To evaluate biodistribution and regional pharmacokinetics in humans using the 18F-labeled C-peptide and positron emission tomography. Materials and Methods: Five, fasting, male IDDM patients were scanned after injection of N-4-[18F]fluorobenzoyl-C-peptide. Dynamic scans over kidneys (4 pat: 2 no-carrier-added (n.c.a.); 2 carrier C-peptide added (c.a.)) and heart (1 pat, n.c.a) and static scans (n.c.a) over body segments (2 pat), CNS and urinary bladder were performed. Plasma radioactivity was also measured. Results: PET images showed predominant distribution of radioactivity to the kidneys (renal cortex 7% of injected dose (i.d.) at peak). Distinguishable amounts of radioactivity were also observed in heart, lungs and liver, but not in CNS at late times. Low amounts were observed in what was presumed to be pancreas. Uptake in total muscle, based on concentrations in a skeletal muscle ROI at 10-75 min, could account for up to 15% i.d. Radioactivity was excreted to the urinary bladder. Time-radioactivity curves for renal cortex peaked within the first 6 min and then decreased to ca 0.01±0.002% i.d./mL at 15 min. Radioactivity peaked in the second time frame (≤ 4 min) in liver and in the first time frame (≤ 2 min) in other organs and plasma. Washout for all organs and for plasma was biphasic. The kinetics in the renal cortex were different when carrier C-peptide was co-injected. Conclusion: The main distribution to the kidneys observed here is consistent with previous findings on C-peptide's catabolism and it's documented effects on renal function. This PET

  15. 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

  16. 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.

  17. Neuroprotective peptides related to Alzheimer's disease

    Czech Academy of Sciences Publication Activity Database

    Slaninová, Jiřina; Borovičková, Lenka; Krejčová, G.; Patočka, J.

    2004-01-01

    Roč. 10, S (2004), s. H33. ISSN 1075-2617. [Hellenic Forum on Bioactive Peptides /4./. 22.04.2004-24.04.2004, Patras-Hellas] Keywords : neuroprotective peptides * Alzheimer's disease Subject RIV: CE - Biochemistry

  18. Histidine-Containing Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2000-01-01

    Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics.......Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics....

  19. Lipoxygenase inhibitor peptides and their use

    OpenAIRE

    Schurink, M.; Boeriu, C.G.; Berkel, van, A.M.; Wichers, H.J.

    2006-01-01

    The present invention is in the field of enzyme inhibition. In particular it relates to peptide inhibitors for lipoxygenases. The lipoxygenase peptide inhibitors of have the potential to be used as therapeutic drugs as well as food preservatives.

  20. Strategic approaches to optimizing peptide ADME properties.

    Science.gov (United States)

    Di, Li

    2015-01-01

    Development of peptide drugs is challenging but also quite rewarding. Five blockbuster peptide drugs are currently on the market, and six new peptides received first marketing approval as new molecular entities in 2012. Although peptides only represent 2% of the drug market, the market is growing twice as quickly and might soon occupy a larger niche. Natural peptides typically have poor absorption, distribution, metabolism, and excretion (ADME) properties with rapid clearance, short half-life, low permeability, and sometimes low solubility. Strategies have been developed to improve peptide drugability through enhancing permeability, reducing proteolysis and renal clearance, and prolonging half-life. In vivo, in vitro, and in silico tools are available to evaluate ADME properties of peptides, and structural modification strategies are in place to improve peptide developability. PMID:25366889

  1. Self-assembly of cyclo-diphenylalanine peptides in vacuum.

    Science.gov (United States)

    Jeon, Joohyun; Shell, M Scott

    2014-06-19

    The diphenylalanine (FF) peptide self-assembles into a variety of nanostructures, including hollow nanotubes that form in aqueous solution with an unusually high degree of hydrophilic surface area. In contrast, diphenylalanine can also be vapor-deposited in vacuum to produce rodlike assemblies that are extremely hydrophobic; in this process FF has been found to dehydrate and cyclize to cyclo-diphenylalanine (cyclo-FF). An earlier study used all-atom molecular dynamics (MD) simulations to understand the early stages of the self-assembly of linear-FF peptides in solution. Here, we examine the self-assembly of cyclo-FF peptides in vacuum and compare it to these previous results to understand the differences underlying the two cases. Using all-atom replica exchange MD simulations, we consider systems of 50 cyclo-FF peptides and examine free energies along various structural association coordinates. We find that cyclo-FF peptides form ladder-like structures connected by double hydrogen bonds, and that multiple such ladders linearly align in a cooperative manner to form larger-scale, elongated assemblies. Unlike linear-FFs which mainly assemble through the interplay between hydrophobic and hydrophilic interactions, the assembly of cyclo-FFs in vacuum is primarily driven by electrostatic interactions along the backbone that induce alignment at long-range, followed by van der Waals interactions between side chains that become important for close-range packing. While both solution and vacuum phase driving forces result in ladder-like structures, the clustering of ladders is opposite: linear-FF peptide ladders form assemblies with side-chains buried inward, while cyclo-FF ladders point outward. PMID:24877752

  2. B-type Natriuretic Peptide circulating forms: Analytical and bioactivity issues.

    Science.gov (United States)

    Yandle, Tim G; Richards, A Mark

    2015-08-25

    B-type Natriuretic Peptide (BNP), A-type and C-type Natriuretic Peptides (ANP and CNP) comprise a family of peptides that retain a common ring structure and conserved amino acid sequences. All are present in the heart, but only BNP and ANP are regarded as primarily cardiac secretory products. BNP and ANP, acting through a guanylyl cyclase receptor, increase sodium and water excretion by the kidney, induce vasodilation, reduce blood pressure, counteract the bioactivity of the renin-angiotensin-aldosterone and sympathetic nervous systems and possess anti-hypertrophic and anti-fibrotic properties. BNP is synthesised in cardiomyocytes first as the precursor peptide preproBNP. Removal of the signal peptide from preproBNP produces proBNP which is cleaved to produce the biologically active carboxy-terminal BNP peptide and the inactive N-terminal fragment, NT-proBNP. BNP, NT-proBNP, proBNP and the C-terminal portion of the BNP signal peptide have been detected in human plasma as well as multiple sub-forms including truncated forms of BNP and NT-proBNP, as well as variable glycosylation of NT-proBNP and proBNP. The origin of these circulating forms, their potential bioactivity and their detection by current analytical methods are presented in this review. PMID:26160054

  3. 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

  4. Cost-effective expression and purification of antimicrobial and host defense peptides in Escherichia coli

    DEFF Research Database (Denmark)

    Bommarius, B.; Jenssen, Håvard; Elliott, M.;

    2010-01-01

    therapeutic application. High manufacturing costs associated with amino acid precursors have limited the delivery of inexpensive therapeutics through industrial-scale chemical synthesis. Conversely, the production of peptides in bacteria by recombinant DNA technology has been impeded by the antimicrobial...... activity of these peptides and their susceptibility to proteolytic degradation, while subsequent purification of recombinant peptides often requires multiple steps and has not been cost-effective. Here we have developed methodologies appropriate for large-scale industrial production of HDPs; in particular......, CRAMP, HHC-10, E5 and E6). Using this technology, pilot-scale fermentation (10 L) was performed to produce large quantities of biologically active cationic peptides. Together, these data indicate that this new method represents a cost-effective means to enable commercial enterprises to produce HDPs in...

  5. Cloning an artificial gene encoding angiostatic anginex: From designed peptide to functional recombinant protein

    International Nuclear Information System (INIS)

    Anginex, a designed peptide 33-mer, is a potent angiogenesis inhibitor and anti-tumor agent in vivo. Anginex functions by inhibiting endothelial cell (EC) proliferation and migration leading to detachment and apoptosis of activated EC's. To better understand tumor endothelium targeting properties of anginex and enable its use in gene therapy, we constructed an artificial gene encoding the biologically exogenous peptide and produced the protein recombinantly in Pichia pastoris. Mass spectrometry shows recombinant anginex to be a dimer and circular dichroism shows the recombinant protein folds with β-strand structure like the synthetic peptide. Moreover, like parent anginex, the recombinant protein is active at inhibiting EC growth and migration, as well as inhibiting angiogenesis in vivo in the chorioallantoic membrane of the chick embryo. This study demonstrated that it is possible to produce a functionally active protein version of a rationally designed peptide, using an artificial gene and the recombinant protein approach

  6. Purification, structure and function of bioactive peptides

    OpenAIRE

    Eriste, Elo

    2004-01-01

    Peptides are vitally important molecules and many evoke cellular responses. The completion of several genome sequencing projects has revealed a number of new genes. However, as functional peptides often contain posttranslational modifications and/or occur at various lengths, it is of great importance to detect, purify and characterize novel bioactive peptides. To achieve these goals, new methods for peptide detection, isolation and functional characterization have to be d...

  7. Natriuretic Peptide Metabolism, Clearance and Degradation

    OpenAIRE

    Potter, Lincoln R.

    2011-01-01

    Atrial natriuretic peptide, B-type natriuretic peptide and C-type natriuretic peptide compose a family of three structurally related, but genetically distinct, signaling molecules that regulate the cardiovascular, skeletal, nervous, reproductive and other systems by activating transmembrane guanylyl cyclases and elevating intracellular cGMP concentrations. This review broadly discusses the general characteristics of natriuretic peptides and their cognate signaling receptors, then specifically...

  8. Milk proteins as precursors of bioactive peptides

    OpenAIRE

    Marta Dziuba; Bartłomiej Dziuba; Anna Iwaniak

    2009-01-01

    Milk proteins, a source of bioactive peptides, are the subject of numerous research studies aiming to, among others, evaluate their properties as precursors of biologically active peptides. Physiologically active peptides released from their precursors may interact with selected receptors and affect the overall condition and health of humans. By relying on the BIOPEP database of proteins and bioactive peptides, developed by the Department of Food Biochemistry at the University of Warmia and M...

  9. Crystallizing Transmembrane Peptides in Lipidic Mesophases

    Energy Technology Data Exchange (ETDEWEB)

    Höfer, Nicole; Aragão, David; Caffrey, Martin (Trinity)

    2011-09-28

    Structure determination of membrane proteins by crystallographic means has been facilitated by crystallization in lipidic mesophases. It has been suggested, however, that this so-called in meso method, as originally implemented, would not apply to small protein targets having {le}4 transmembrane crossings. In our study, the hypothesis that the inherent flexibility of the mesophase would enable crystallogenesis of small proteins was tested using a transmembrane pentadecapeptide, linear gramicidin, which produced structure-grade crystals. This result suggests that the in meso method should be considered as a viable means for high-resolution structure determination of integral membrane peptides, many of which are predicted to be coded for in the human genome.

  10. Coexistence of peptides with classical neurotransmitters.

    Science.gov (United States)

    Hökfelt, T; Millhorn, D; Seroogy, K; Tsuruo, Y; Ceccatelli, S; Lindh, B; Meister, B; Melander, T; Schalling, M; Bartfai, T

    1987-07-15

    In the present article the fact is emphasized that neuropeptides often are located in the same neurons as classical transmitters such as acetylcholine, 5-hydroxy-tryptamine, catecholamines, gamma-aminobutyric acid (GABA) etc. This raises the possibility that neurons produce, store and release more than one messenger molecule. The exact functional role of such coexisting peptides is often difficult to evaluate, especially in the central nervous system. In the periphery some studies indicate apparently meaningful interactions of different types with the classical transmitter, but other types of actions including trophic effects have been observed. More recently it has been shown that some neurons contain more than one classical transmitter, e.g. 5-HT plus GABA, further underlining the view that transfer of information across synapses may be more complex than perhaps hitherto assumed. PMID:2885215

  11. Peptide Fragmentation and Surface Structural Analysis by Means of ToF-SIMS Using Large Cluster Ion Sources.

    Science.gov (United States)

    Yokoyama, Yuta; Aoyagi, Satoka; Fujii, Makiko; Matsuo, Jiro; Fletcher, John S; Lockyer, Nicholas P; Vickerman, John C; Passarelli, Melissa K; Havelund, Rasmus; Seah, Martin P

    2016-04-01

    Peptide or protein structural analysis is crucial for the evaluation of biochips and biodevices, therefore an analytical technique with the ability to detect and identify protein and peptide species directly from surfaces with high lateral resolution is required. In this report, the efficacy of ToF-SIMS to analyze and identify proteins directly from surfaces is evaluated. Although the physics governing the SIMS bombardment process precludes the ability for researchers to detect intact protein or larger peptides of greater than a few thousand mass unit directly, it is possible to obtain information on the partial structures of peptides or proteins using low energy per atom argon cluster ion beams. Large cluster ion beams, such as Ar clusters and C60 ion beams, produce spectra similar to those generated by tandem MS. The SIMS bombardment process also produces peptide fragment ions not detected by conventional MS/MS techniques. In order to clarify appropriate measurement conditions for peptide structural analysis, peptide fragmentation dependency on the energy of a primary ion beam and ToF-SIMS specific fragment ions are evaluated. It was found that the energy range approximately 6 ≤ E/n ≤ 10 eV/atom is most effective for peptide analysis based on peptide fragments and [M + H] ions. We also observed the cleaving of side chain moieties at extremely low-energy E/n ≤ 4 eV/atom. PMID:26916620

  12. Specific interactions between amyloid-β peptide and curcumin derivatives: Ab initio molecular simulations

    Science.gov (United States)

    Ishimura, Hiromi; Kadoya, Ryushi; Suzuki, Tomoya; Murakawa, Takeru; Shulga, Sergiy; Kurita, Noriyuki

    2015-07-01

    Alzheimer's disease is caused by accumulation of amyloid-β (Aβ) peptides in a brain. To suppress the production of Aβ peptides, it is effective to inhibit the cleavage of amyloid precursor protein (APP) by secretases. However, because the secretases also play important roles to produce vital proteins for human body, inhibitors for the secretases may have side effects. To propose new agents for protecting the cleavage site of APP from the attacking of the γ-secretase, we have investigated here the specific interactions between a short APP peptide and curcumin derivatives, using protein-ligand docking as well as ab initio molecular simulations.

  13. Cadmium-sulfide crystallites in Cd-(. gamma. EC) sub n G peptide complexes from tomato. [Lycopersicon esculentum

    Energy Technology Data Exchange (ETDEWEB)

    Reese, R.N.; White, C.A.; Winge, D.R. (South Dakota State Univ., Brookings (United States) Univ. of Utah, Salt Lake City (United States))

    1992-01-01

    Hydroponically grown tomato plants (Lycopersicon esculentum P. Mill cv Golden Boy) exposed to 100 micromolar cadmium sulfate produced metal-({gamma}EC){sub n}G peptide complexes containing acid-labile sulfur. The properties of the complexes resemble those of the cadmium-({gamma}EC){sub n}G peptide complexes from Schizo-saccharomyces pombe and Candida glabrata known to contain a cadmium sulfide crystallite core. The crystallite is stabilized by a sheath of peptides of general structure ({gamma}Glu-Cys){sub n}-Gly. The cadmium-peptide complexes of tomato contained predominantly peptides of n{sub 3}, n{sub 4}, and n{sub 5}. Spectroscopic analyses indicated that the tomato cadmium-sulfide-peptide complex contained CdS crystallite core particles smaller than 2.0 nanometers in diameter.

  14. Diversity of wheat anti-microbial peptides.

    Science.gov (United States)

    Egorov, Tsezi A; Odintsova, Tatyana I; Pukhalsky, Vitaliy A; Grishin, Eugene V

    2005-11-01

    From seeds of Triticum kiharae Dorof. et Migusch., 24 novel anti-microbial peptides were isolated and characterized by a combination of three-step HPLC (affinity, size-exclusion and reversed-phase) with matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and Edman degradation. Based on sequence similarity and cysteine motifs, partially sequenced peptides were assigned to 7 families: defensins, thionins, lipid-transfer proteins, hevein-like peptides, knottin-like peptides, glycine-rich peptides, and MBP-1 homologs. A novel subfamily of defensins consisting of 6 peptides and a new family of glycine-rich (8 peptides with different repeat motifs) were identified. Three 6-cysteine knottin-like peptides represented by N- and C-terminally truncated variants revealed no sequence homology to any known plant anti-microbial peptides. A new 8-cysteine hevein-like peptide and three 4-cysteine peptides homologous to MBP-1 from maize were isolated. This is the first communication on the occurrence of nearly all families of plant anti-microbial peptides in a single species. PMID:16269343

  15. Characterization of Synthetic Peptides by Mass Spectrometry

    DEFF Research Database (Denmark)

    Prabhala, Bala K; Mirza, Osman; Højrup, Peter;

    2015-01-01

    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI-TOF-MS and...

  16. Unsupervised Identification of Isotope-Labeled Peptides.

    Science.gov (United States)

    Goldford, Joshua E; Libourel, Igor G L

    2016-06-01

    In vivo isotopic labeling coupled with high-resolution proteomics is used to investigate primary metabolism in techniques such as stable isotope probing (protein-SIP) and peptide-based metabolic flux analysis (PMFA). Isotopic enrichment of carbon substrates and intracellular metabolism determine the distribution of isotopes within amino acids. The resulting amino acid mass distributions (AMDs) are convoluted into peptide mass distributions (PMDs) during protein synthesis. With no a priori knowledge on metabolic fluxes, the PMDs are therefore unknown. This complicates labeled peptide identification because prior knowledge on PMDs is used in all available peptide identification software. An automated framework for the identification and quantification of PMDs for nonuniformly labeled samples is therefore lacking. To unlock the potential of peptide labeling experiments for high-throughput flux analysis and other complex labeling experiments, an unsupervised peptide identification and quantification method was developed that uses discrete deconvolution of mass distributions of identified peptides to inform on the mass distributions of otherwise unidentifiable peptides. Uniformly (13)C-labeled Escherichia coli protein was used to test the developed feature reconstruction and deconvolution algorithms. The peptide identification was validated by comparing MS(2)-identified peptides to peptides identified from PMDs using unlabeled E. coli protein. Nonuniformly labeled Glycine max protein was used to demonstrate the technology on a representative sample suitable for flux analysis. Overall, automatic peptide identification and quantification were comparable or superior to manual extraction, enabling proteomics-based technology for high-throughput flux analysis studies. PMID:27145348

  17. Bioactive peptides in dairy products

    Directory of Open Access Journals (Sweden)

    Donata Marletta

    2010-01-01

    Full Text Available Bioactive peptides are specific protein fragments that have a positive impact on body functions and conditions and may ultimately influence health. Most of the biological activities are encrypted within the primary sequence of the native protein and can be released by enzymatic hydrolysis and proteolysis or by food processing. Milk is a rich source of bioactive peptides which may contribute to regulate the nervous, gastrointestinal and cardiovascular systems as well as the immune system, confirming the added value of dairy products that, in certain cases, can be considered functional foods. The main biological activities of these peptides and their bioavailability in dairy products are reviewed. The natural concentration of these biomolecules is quite low and, to date one of the main goals has been to realize products enriched with bioactive peptides that have beneficial effects on human health and proven safety. Even though several health-enhancing products have already been launched and their integration in the diet could help in the prevention of chronic diseases such as hypertension, cancer and osteoporosis, more clinical trials are required in order to develop a deeper understanding of the activity of biopeptides on the human physiological mechanisms and also to assess the efficacy of their effects in a long term view. New scientific data are also needed to support their commercialisation in compliance with current regulations.

  18. Collectins and Cationic Antimicrobial Peptides of the Respiratory Epithelia

    OpenAIRE

    Grubor, B.; Meyerholz, D. K.; Ackermann, M R

    2006-01-01

    The respiratory epithelium is a primary site for the deposition of microorganisms that are acquired during inspiration. The innate immune system of the respiratory tract eliminates many of these potentially harmful agents preventing their colonization. Collectins and cationic antimicrobial peptides are antimicrobial components of the pulmonary innate immune system produced by respiratory epithelia, which have integral roles in host defense and inflammation in the lung. Synthesis and secretion...

  19. Systematic evaluation of alternating CID and ETD fragmentation for phosphorylated peptides

    OpenAIRE

    Kim, Min-Sik; Zhong, Jun; Kandasamy, Kumaran; Delanghe, Bernard; Pandey, Akhilesh

    2011-01-01

    CID has become a routine method for fragmentation of peptides in shotgun proteomics while electron transfer dissociation (ETD) has been described as a preferred method for peptides carrying labile PTMs. Though both of these fragmentation techniques have their obvious advantages, they also have their own drawbacks. By combining data from CID and ETD fragmentation, some of these disadvantages can potentially be overcome because of the complementarity of fragment ions produced. To evaluate alter...

  20. 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...

  1. 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...

  2. Oxpholipin 11D: An Anti-Inflammatory Peptide That Binds Cholesterol and Oxidized Phospholipids

    OpenAIRE

    Piotr Ruchala; Mohamad Navab; Chun-Ling Jung; Susan Hama-Levy; Micewicz, Ewa D.; Hai Luong; Reyles, Jonathan E.; Shantanu Sharma; Waring, Alan J.; Fogelman, Alan M.; Lehrer, Robert I.

    2010-01-01

    BACKGROUND: Many gram-positive bacteria produce pore-forming exotoxins that contain a highly conserved, 12-residue domain (ECTGLAWEWWRT) that binds cholesterol. This domain is usually flanked N-terminally by arginine and C-terminally by valine. We used this 14-residue sequence as a template to create a small library of peptides that bind cholesterol and other lipids. METHODOLOGY/RESULTS: Several of these peptides manifested anti-inflammatory properties in a predictive in vitro monocyte chemot...

  3. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

    Science.gov (United States)

    McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

    2016-05-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

  4. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides.

    Science.gov (United States)

    McMillen, Chelsea L; Wright, Patience M; Cassady, Carolyn J

    2016-05-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides. Graphical Abstract ᅟ. PMID:26864792

  5. Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

    Science.gov (United States)

    McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

    2016-02-01

    Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

  6. Formation of Peptide Bound Pyrraline in the Maillard Model Systems with Different Lys-Containing Dipeptides and Tripeptides

    Directory of Open Access Journals (Sweden)

    Zhili Liang

    2016-04-01

    Full Text Available Peptide-bound advanced glycation end-products (peptide-bound AGEs can be formed when peptides are heated with reducing saccharides. Pyrraline is the one of most commonly studied AGEs in foods, but the relative importance of the precursor peptide structure is uncertain. In the present study, model systems were prepared by heating peptides with glucose from 60 °C to 220 °C for up to 65 min, and the amounts of peptide-bound pyrraline formed were monitored to evaluate the effect of the neighboring amino acids on the peptide-bound pyrraline formation. The physico-chemical properties were introduced to explore the quantitative structure-reactivity relationships between physicochemical properties and peptide bound formation. 3-DG content in dipeptide-glucose model system was higher than that in the corresponding tripeptide-glucose model systems. Dipeptides produced higher amounts of peptide-bound pyrraline than the corresponding tripeptides. The peptide-bound pyrraline and 3-DG production were influenced by the physico-chemical properties of the side chain of amino acids adjacent to Lys in the following order: Lys-Leu/glucose > Lys-Ile/glucose > Lys-Val/ glucose > Lys-Thr/glucose > Lys-Ser/glucose > Lys-Ala/ glucose > Lys-Gly/glucose; Lys-Leu-Gly/glucose > Lys-Ile-Gly/glucose > Lys-Val-Gly/glucose > Lys-Thr-Gly/glucose > Lys-Ser-Gly/glucose > Lys-Ala-Gly/glucose > Lys-Gly-Gly/glucose. For the side chain of amino acids adjacent to Lys in dipeptides, residue volume, polarizability, molecular volume and localized electrical effect were positively related to the yield of peptide bound pyrraline, while hydrophobicity and pKb were negatively related to the yield of peptide bound pyrraline. In terms of side chain of amino acid adjacent to Lys in tripeptides, a similar result was observed, except hydrophobicity was positively related to the yield of peptide bound pyrraline.

  7. Study of antimicrobial peptides by capillary electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav

    Sofia: Bulgarian Peptide Society, 2015 - (Naydenova, E.; Pajpanova, T.; Danalev, D.), s. 304-305 ISBN 978-619-90427-2-4. [Peptides 2014. European Peptide Symposium /33./. Sofia (BG), 31.08.2014-05.09.2014] R&D Projects: GA ČR(CZ) GAP206/12/0453; GA ČR(CZ) GA13-17224S Institutional support: RVO:61388963 Keywords : peptides * antimicrobial activity * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation http://bulpepsoc.info/wp-content/uploads/2015/06/PEPTIDES-2014-electronic-version.pdf

  8. Phytochemicals that modulate amino acid and peptide catabolism by caprine rumen microbes

    Science.gov (United States)

    Background: Microbe-derived ionophores and macrolide antibiotics are often added to ruminant diets, and growth promotion and feed efficiency are among the benefits. One mechanism is inhibition of microbes that catabolize amino acids or peptides and produce ammonia. Plants also produce antimicrobial ...

  9. Molecular mechanical properties of short-sequence peptide enzyme mimics.

    Science.gov (United States)

    Takahashi, Tsukasa; Vo Ngo, Bao C; Xiao, Leyang; Arya, Gaurav; Heller, Michael J

    2016-03-01

    While considerable attempts have been made to recreate the high turnover rates of enzymes using synthetic enzyme mimics, most have failed and only a few have produced minimal reaction rates that can barely be considered catalytic. One particular approach we have focused on is the use of short-sequence peptides that contain key catalytic groups in close proximity. In this study, we designed six different peptides and tested their ability to mimic the catalytic mechanism of the cysteine proteases. Acetylation and deacylation by Ellman's Reagent trapping experiments showed the importance of having phenylalanine groups surrounding the catalytic sites in order to provide greater proximity between the cysteine, histidine, and aspartate amino acid R-groups. We have also carried out all-atom molecular dynamics simulations to determine the distance between these catalytic groups and the overall mechanical flexibility of the peptides. We found strong correlations between the magnitude of fluctuations in the Cys-His distance, which determines the flexibility and interactions between the cysteine thiol and histidine imidazole groups, and the deacylation rate. We found that, in general, shorter Cys-His distance fluctuations led to a higher deacylation rate constant, implying that greater confinement of the two residues will allow a higher frequency of the acetyl exchange between the cysteine thiol and histidine imidazole R-groups. This may be the key to future design of peptide structures with molecular mechanical properties that lead to viable enzyme mimics. PMID:25921736

  10. Solid Phase Formylation of N-Terminus Peptides

    Directory of Open Access Journals (Sweden)

    Anna Lucia Tornesello

    2016-06-01

    Full Text Available Formylation of amino groups is a critical reaction involved in several biological processes including post-translational modification of histones. The addition of a formyl group (CHO to the N-terminal end of a peptide chain generates biologically active molecules. N-formyl-peptides can be produced by different methods. We performed the N-formylation of two chemotactic hexapetides, Met1-Leu2-Lys3-Leu4-Ile5-Val6 and Met1-Met2-Tyr3-Ala4-Leu5-Phe6, carrying out the reaction directly on peptidyl-resin following pre-activation of formic acid with N,N-dicyclohexylcarbodiimmide (DCC in liquid phase. The overnight incubation at 4 °C resulted in a significant increase in production yields of formylated peptides compared to the reaction performed at room temperature. The method is consistently effective, rapid, and inexpensive. Moreover, the synthetic strategy can be applied for the formylation of all primary amines at N-terminus of peptide chains or amino groups of lysine side-chains in solid phase.

  11. Control of phospholipid flip-flop by transmembrane peptides

    Energy Technology Data Exchange (ETDEWEB)

    Kaihara, Masanori; Nakao, Hiroyuki; Yokoyama, Hirokazu [Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); Endo, Hitoshi [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Ishihama, Yasushi [Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); Handa, Tetsurou [Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, 3500-3 Minami-Tamagaki-cho, Suzuka, Mie 513-8670 (Japan); Nakano, Minoru, E-mail: mnakano@pha.u-toyama.ac.jp [Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan)

    2013-06-20

    Highlights: ► Phospholipid flip-flop in transmembrane peptide-containing vesicles was investigated. ► Peptides that contained polar residues in the center of the transmembrane region promoted phospholipid flip-flop. ► A bioinformatics approach revealed the presence of polar residues in the transmembrane region of ER membrane proteins. ► Polar residues in ER membrane proteins possibly provide flippase-like activity. - Abstract: We designed three types of transmembrane model peptides whose sequence originates from a frequently used model peptide KALP23, and we investigated their effects on phospholipid flip-flop. Time-resolved small-angle neutron scattering and a dithionite fluorescent quenching assay demonstrated that TMP-L, which has a fully hydrophobic transmembrane region, did not enhance phospholipid flip-flop, whereas TMP-K and TMP-E, which have Lys and Glu, respectively, in the center of their transmembrane regions, enhanced phospholipid flip-flop. Introduction of polar residues in the membrane-spanning helices is considered to produce a locally polar region and enable the lipid head group to interact with the polar side-chain inside the bilayers, thereby reducing the activation energy for the flip-flop. A bioinformatics approach revealed that acidic and basic residues account for 4.5% of the central region of the transmembrane domain in human ER membrane proteins. Therefore, polar residues in ER membrane proteins are considered to provide flippase-like activity.

  12. DRAMP: a comprehensive data repository of antimicrobial peptides.

    Science.gov (United States)

    Fan, Linlin; Sun, Jian; Zhou, Meifeng; Zhou, Jie; Lao, Xingzhen; Zheng, Heng; Xu, Hanmei

    2016-01-01

    The growing problem of antibiotic-resistant microorganisms results in an urgent need for substitutes to conventional antibiotics with novel modes of action and effective activities. Antimicrobial peptides (AMPs), produced by a wide variety of living organisms acting as a defense mechanism against invading pathogenic microbes, are considered to be such promising alternatives. AMPs display a broad spectrum of antimicrobial activity and a low propensity for developing resistance. Therefore, a thorough understanding of AMPs is essential to exploit them as antimicrobial drugs. Considering this, we developed a comprehensive user-friendly data repository of antimicrobial peptides (DRAMP), which holds 17349 antimicrobial sequences, including 4571 general AMPs, 12704 patented sequences and 74 peptides in drug development. Entries in the database have detailed annotations, especially detailed antimicrobial activity data (shown as target organism with MIC value) and structure information. Annotations also include accession numbers crosslinking to Pubmed, Swiss-prot and Protein Data Bank (PDB). The website of the database comes with easy-to-operate browsing as well as searching with sorting and filtering functionalities. Several useful sequence analysis tools are provided, including similarity search, sequence alignment and conserved domain search (CD-Search). DRAMP should be a useful resource for the development of novel antimicrobial peptide drugs. PMID:27075512

  13. Design and characterization of an acid-activated antimicrobial peptide.

    Science.gov (United States)

    Li, Lina; He, Jian; Eckert, Randal; Yarbrough, Daniel; Lux, Renate; Anderson, Maxwell; Shi, Wenyuan

    2010-01-01

    Dental caries is a microbial biofilm infection in which the metabolic activities of plaque bacteria result in a dramatic pH decrease and shift the demineralization/remineralization equilibrium on the tooth surface towards demineralization. In addition to causing a net loss in tooth minerals, creation of an acidic environment favors growth of acid-enduring and acid-generating species, which causes further reduction in the plaque pH. In this study, we developed a prototype antimicrobial peptide capable of achieving high activity exclusively at low environmental pH to target bacterial species like Streptococcus mutans that produce acid and thrive under the low pH conditions detrimental for tooth integrity. The features of clavanin A, a naturally occurring peptide rich in histidine and phenylalanine residues with pH-dependent antimicrobial activity, served as a design basis for these prototype 'acid-activated peptides' (AAPs). Employing the major cariogenic species S. mutans as a model system, the two AAPs characterized in this study exhibited a striking pH-dependent antimicrobial activity, which correlated well with the calculated charge distribution. This type of peptide represents a potential new way to combat dental caries. PMID:19878192

  14. Vasoactive intestinal peptide and electrical activity influence neuronal survival

    International Nuclear Information System (INIS)

    Blockage of electrical activity in dissociated spinal cord cultures results in a significant loss of neurons during a critical period in development. Decreases in neuronal cell numbers and 125I-labeled tetanus toxin fixation produced by electrical blockage with tetrodotoxin (TTX) were prevented by addition of vasoactive intestinal peptide (VIP) to the nutrient medium. The most effective concentration of VIP was 0.1 nM. At higher concentrations, the survival-enhancing effect of VIP on TTX-treated cultures was attenuated. Addition of the peptide alone had no significant effect on neuronal cell counts or tetanus toxin fixation. With the same experimental conditions, two closely related peptides, PHI-27 (peptide, histidyl-isoleucine amide) and secretin, were found not to increase the number of neurons in TTX-treated cultures. Interference with VIP action by VIP antiserum resulted in neuronal losses that were not significantly different from those observed after TTX treatment. These data indicate that under conditions of electrical blockade a neurotrophic action of VIP on neuronal survival can be demonstrated

  15. Control of phospholipid flip-flop by transmembrane peptides

    International Nuclear Information System (INIS)

    Highlights: ► Phospholipid flip-flop in transmembrane peptide-containing vesicles was investigated. ► Peptides that contained polar residues in the center of the transmembrane region promoted phospholipid flip-flop. ► A bioinformatics approach revealed the presence of polar residues in the transmembrane region of ER membrane proteins. ► Polar residues in ER membrane proteins possibly provide flippase-like activity. - Abstract: We designed three types of transmembrane model peptides whose sequence originates from a frequently used model peptide KALP23, and we investigated their effects on phospholipid flip-flop. Time-resolved small-angle neutron scattering and a dithionite fluorescent quenching assay demonstrated that TMP-L, which has a fully hydrophobic transmembrane region, did not enhance phospholipid flip-flop, whereas TMP-K and TMP-E, which have Lys and Glu, respectively, in the center of their transmembrane regions, enhanced phospholipid flip-flop. Introduction of polar residues in the membrane-spanning helices is considered to produce a locally polar region and enable the lipid head group to interact with the polar side-chain inside the bilayers, thereby reducing the activation energy for the flip-flop. A bioinformatics approach revealed that acidic and basic residues account for 4.5% of the central region of the transmembrane domain in human ER membrane proteins. Therefore, polar residues in ER membrane proteins are considered to provide flippase-like activity

  16. Natural and synthetic peptides with antifungal activity.

    Science.gov (United States)

    Ciociola, Tecla; Giovati, Laura; Conti, Stefania; Magliani, Walter; Santinoli, Claudia; Polonelli, Luciano

    2016-08-01

    In recent years, the increase of invasive fungal infections and the emergence of antifungal resistance stressed the need for new antifungal drugs. Peptides have shown to be good candidates for the development of alternative antimicrobial agents through high-throughput screening, and subsequent optimization according to a rational approach. This review presents a brief overview on antifungal natural peptides of different sources (animals, plants, micro-organisms), peptide fragments derived by proteolytic cleavage of precursor physiological proteins (cryptides), synthetic unnatural peptides and peptide derivatives. Antifungal peptides are schematically reported based on their structure, antifungal spectrum and reported effects. Natural or synthetic peptides and their modified derivatives may represent the basis for new compounds active against fungal infections. PMID:27502155

  17. Encapsulation of bioactive whey peptides in soy lecithin-derived nanoliposomes: Influence of peptide molecular weight.

    Science.gov (United States)

    Mohan, Aishwarya; McClements, David Julian; Udenigwe, Chibuike C

    2016-12-15

    Encapsulation of peptides can be used to enhance their stability, delivery and bioavailability. This study focused on the effect of the molecular weight range of whey peptides on their encapsulation within soy lecithin-derived nanoliposomes. Peptide molecular weight did not have a major impact on encapsulation efficiency or liposome size. However, it influenced peptide distribution amongst the surface, core, and bilayer regions of the liposomes, as determined by electrical charge (ζ-potential) and FTIR analysis. The liposome ζ-potential depended on peptide molecular weight, suggesting that the peptide charged groups were in different locations relative to the liposome surfaces. FTIR analysis indicated that the least hydrophobic peptide fractions interacted more strongly with choline on the liposome surfaces. The results suggested that the peptides were unequally distributed within the liposomes, even at the same encapsulation efficiency. These findings are important for designing delivery systems for commercial production of encapsulated peptides with improved functional attributes. PMID:27451165

  18. New vasoactive peptides in cirrhosis

    DEFF Research Database (Denmark)

    Kimer, Nina; Goetze, Jens Peter; Bendtsen, Flemming;

    2014-01-01

    to haemodynamic changes in the pro-peptides copeptin, proadrenomedullin and pro-atrial natriuretic peptide (proANP) in patients with cirrhosis. MATERIALS AND METHODS: Fifty-four cirrhotic patients and 15 controls were characterized haemodynamically during a liver vein catheterization. Copeptin......, proadrenomedullin and proANP were measured in hepatic and renal veins and the femoral artery. RESULTS: We found no differences in concentrations of copeptin and proadrenomedullin between patients and controls. ProANPs were higher in cirrhotic patients, median 138 pm (25/75 percentiles 101-194) compared with....... We found no extraction of copeptin, proadrenomedullin or proANP over the liver. Copeptin correlated with portal pressure (R=0·50, P<0·001). Proadrenomedullin correlated with portal pressure (R=0·48, P<0·001) and heart rate (R=0·36, P<0·01). ProANP correlated with cardiac output (R=0·46, P<0·002) and...

  19. Structural transition in peptide nanotubes.

    Science.gov (United States)

    Amdursky, Nadav; Beker, Peter; Koren, Itai; Bank-Srour, Becky; Mishina, Elena; Semin, Sergey; Rasing, Theo; Rosenberg, Yuri; Barkay, Zahava; Gazit, Ehud; Rosenman, Gil

    2011-04-11

    Phase transitions in organic and inorganic materials are well-studied classical phenomena, where a change in the crystal space group symmetry induces a wide variation of physical properties, permitted by the crystalline symmetry in each phase. Here we observe a conformational induced transition in bioinspired peptide nanotubes (PNTs). We found that the PNTs change their original molecular assembly from a linear peptide conformation to a cyclic one, followed by a change of the nanocrystalline structure from a noncentrosymmetric hexagonal space group to a centrosymmetric orthorhombic space group. The observed transition is irreversible and induces a profound variation in the PNTs properties, from the microscopic to the macroscopic level. In this context, we follow the unique changes in the molecular, morphological, piezoelectric, second harmonic generation, and wettability properties of the PNTs. PMID:21388228

  20. *600781 PEPTIDE YY; PYY [OMIM

    Lifescience Database Archive (English)

    Full Text Available FIELD NO 600781 FIELD TI 600781 PEPTIDE YY; PYY FIELD TX CLONING PYY is secreted from endocrine ... acologically active PYY(3-36)) were measured in 66 lean , 18 anorectic, 63 obese, and 16 morbidly obese hum ... +/- 12.9 pg/ml, P = less than 0.05) compared with lean ... (52.4 +/- 4.6 pg/ml), obese (43.9 +/- 3.8 pg/ml), ...

  1. Antibody Peptide Based Antifungal Immunotherapy

    OpenAIRE

    Magliani, Walter; Conti, Stefania; Giovati, Laura; Zanello, Pier Paolo; Sperindè, Martina; Ciociola, Tecla; Polonelli, Luciano

    2012-01-01

    Fungal infections still represent relevant human illnesses worldwide and some are accompanied by unacceptably high mortality rates. The limited current availability of effective and safe antifungal agents makes the development of new drugs and approaches of antifungal vaccination/immunotherapy every day more needed. Among them, small antibody(Ab)-derived peptides are arousing great expectations as new potential antifungal agents. In this topic, the search path from the study of the yeast kill...

  2. Antimicrobial Peptides: Versatile Biological Properties

    Directory of Open Access Journals (Sweden)

    Muthuirulan Pushpanathan

    2013-01-01

    Full Text Available Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries.

  3. 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.

  4. Three-dimensional structure in lipid micelles of the pediocin-like antimicrobial peptide curvacin A.

    Science.gov (United States)

    Haugen, Helen Sophie; Fimland, Gunnar; Nissen-Meyer, Jon; Kristiansen, Per Eugen

    2005-12-13

    The 3D structure of the membrane-permeabilizing 41-mer pediocin-like antimicrobial peptide curvacin A produced by lactic acid bacteria has been studied by NMR spectroscopy. In DPC micelles, the cationic and hydrophilic N-terminal half of the peptide forms an S-shaped beta-sheet-like domain stabilized by a disulfide bridge and a few hydrogen bonds. This domain is followed by two alpha-helices: a hydrophilic 6-mer helix between residues 19 and 24 and an amphiphilic/hydrophobic 11-mer helix between residues 29 and 39. There are two hinges in the peptide, one at residues 16-18 between the N-terminal S-shaped beta-sheet-like structure and the central 6-mer helix and one at residues 26-28 between the central helix and the 11-mer C-terminal helix. The latter helix is the only amphiphilic/hydrophobic part of the peptide and is thus presumably the part that penetrates into the hydrophobic phase of target-cell membranes. The hinge between the two helices may introduce the flexibility that allows the helix to dip into membranes. The helix-hinge-helix structure in the C-terminal half of curvacin A clearly distinguishes this peptide from the other pediocin-like peptides whose structures have been analyzed and suggests that curvacin A along with the structural homologues enterocin P and carnobacteriocin BM1 belong to a subgroup of the pediocin-like family of antimicrobial peptides. PMID:16331975

  5. 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

  6. Successful adjuvant-free vaccination of BALB/c mice with mutated amyloid β peptides

    Directory of Open Access Journals (Sweden)

    Wahi Monika M

    2008-02-01

    Full Text Available Abstract Background A recent human clinical trial of an Alzheimer's disease (AD vaccine using amyloid beta (Aβ 1–42 plus QS-21 adjuvant produced some positive results, but was halted due to meningoencephalitis in some participants. The development of a vaccine with mutant Aβ peptides that avoids the use of an adjuvant may result in an effective and safer human vaccine. Results All peptides tested showed high antibody responses, were long-lasting, and demonstrated good memory response. Epitope mapping indicated that peptide mutation did not lead to epitope switching. Mutant peptides induced different inflammation responses as evidenced by cytokine profiles. Ig isotyping indicated that adjuvant-free vaccination with peptides drove an adequate Th2 response. All anti-sera from vaccinated mice cross-reacted with human Aβ in APP/PS1 transgenic mouse brain tissue. Conclusion Our study demonstrated that an adjuvant-free vaccine with different Aβ peptides can be an effective and safe vaccination approach against AD. This study represents the first report of adjuvant-free vaccines utilizing Aβ peptides carrying diverse mutations in the T-cell epitope. These largely positive results provide encouragement for the future of the development of human vaccinations for AD.

  7. Identification of novel human immunodeficiency virus type 1-inhibitory peptides based on the antimicrobial peptide database.

    Science.gov (United States)

    Wang, Guangshun; Watson, Karen M; Peterkofsky, Alan; Buckheit, Robert W

    2010-03-01

    To identify novel anti-HIV-1 peptides based on the antimicrobial peptide database (APD; http://aps.unmc.edu/AP/main.php), we have screened 30 candidates and found 11 peptides with 50% effective concentrations (EC(50)) of 1, increases in the Arg contents of amphibian maximin H5 and dermaseptin S9 peptides and the database-derived GLK-19 peptide improved the TIs. These examples demonstrate that the APD is a rich resource and a useful tool for developing novel HIV-1-inhibitory peptides. PMID:20086159

  8. The order of expression is a key factor in the production of active transglutaminase in Escherichia coli by co-expression with its pro-peptide

    Directory of Open Access Journals (Sweden)

    Liu Song

    2011-12-01

    Full Text Available Abstract Background Streptomyces transglutaminase (TGase is naturally synthesized as zymogen (pro-TGase, which is then processed to produce active enzyme by the removal of its N-terminal pro-peptide. This pro-peptide is found to be essential for overexpression of soluble TGase in E. coli. However, expression of pro-TGase by E. coli requires protease-mediated activation in vitro. In this study, we developed a novel co- expression method for the direct production of active TGase in E. coli. Results A TGase from S. hygroscopicus was expressed in E. coli only after fusing with the pelB signal peptide, but fusion with the signal peptide induced insoluble enzyme. Therefore, alternative protocol was designed by co-expressing the TGase and its pro-peptide as independent polypeptides under a single T7 promoter using vector pET-22b(+. Although the pro-peptide was co-expressed, the TGase fused without the signal peptide was undetectable in both soluble and insoluble fractions of the recombinant cells. Similarly, when both genes were expressed in the order of the TGase and the pro-peptide, the solubility of TGase fused with the signal peptide was not improved by the co-expression with its pro-peptide. Interestingly, active TGase was only produced by the cells in which the pro-peptide and the TGase were fused with the signal peptide and sequentially expressed. The purified recombinant and native TGase shared the similar catalytic properties. Conclusions Our results indicated that the pro-peptide can assist correct folding of the TGase inter-molecularly in E. coli, and expression of pro-peptide prior to that of TGase was essential for the production of active TGase. The co-expression strategy based on optimizing the order of gene expression could be useful for the expression of other functional proteins that are synthesized as a precursor.

  9. Toxins and antimicrobial peptides: interactions with membranes

    Science.gov (United States)

    Schlamadinger, Diana E.; Gable, Jonathan E.; Kim, Judy E.

    2009-08-01

    The innate immunity to pathogenic invasion of organisms in the plant and animal kingdoms relies upon cationic antimicrobial peptides (AMPs) as the first line of defense. In addition to these natural peptide antibiotics, similar cationic peptides, such as the bee venom toxin melittin, act as nonspecific toxins. Molecular details of AMP and peptide toxin action are not known, but the universal function of these peptides to disrupt cell membranes of pathogenic bacteria (AMPs) or a diverse set of eukaryotes and prokaryotes (melittin) is widely accepted. Here, we have utilized spectroscopic techniques to elucidate peptide-membrane interactions of alpha-helical human and mouse AMPs of the cathelicidin family as well as the peptide toxin melittin. The activity of these natural peptides and their engineered analogs was studied on eukaryotic and prokaryotic membrane mimics consisting of melittin and human cathelicidin embedded in bilayer vesicles. Collectively, our results provide clues to the functional structures of the engineered and toxic peptides and may impact the design of synthetic antibiotic peptides that can be used against the growing number of antibiotic-resistant pathogens.

  10. 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.

  11. Predicting protein-peptide interactions from scratch

    Science.gov (United States)

    Yan, Chengfei; Xu, Xianjin; Zou, Xiaoqin; Zou lab Team

    Protein-peptide interactions play an important role in many cellular processes. The ability to predict protein-peptide complex structures is valuable for mechanistic investigation and therapeutic development. Due to the high flexibility of peptides and lack of templates for homologous modeling, predicting protein-peptide complex structures is extremely challenging. Recently, we have developed a novel docking framework for protein-peptide structure prediction. Specifically, given the sequence of a peptide and a 3D structure of the protein, initial conformations of the peptide are built through protein threading. Then, the peptide is globally and flexibly docked onto the protein using a novel iterative approach. Finally, the sampled modes are scored and ranked by a statistical potential-based energy scoring function that was derived for protein-peptide interactions from statistical mechanics principles. Our docking methodology has been tested on the Peptidb database and compared with other protein-peptide docking methods. Systematic analysis shows significantly improved results compared to the performances of the existing methods. Our method is computationally efficient and suitable for large-scale applications. Nsf CAREER Award 0953839 (XZ) NIH R01GM109980 (XZ).

  12. Construction of Lasso Peptide Fusion Proteins.

    Science.gov (United States)

    Zong, Chuhan; Maksimov, Mikhail O; Link, A James

    2016-01-15

    Lasso peptides are a family of ribosomally synthesized and post-translationally modified peptides (RiPPs) typified by an isopeptide-bonded macrocycle between the peptide N-terminus and an aspartate or glutamate side chain. The C-terminal portion of the peptide threads through the N-terminal macrocycle to give the characteristic lasso fold. Because of the inherent stability, both proteolytic and often thermal, of lasso peptides, we became interested in whether proteins could be fused to the free C-terminus of lasso peptides. Here, we demonstrate fusion of two model proteins, the artificial leucine zipper A1 and the superfolder variant of GFP, to the C-terminus of the lasso peptide astexin-1. Successful lasso cyclization of the N-terminus of these fusion proteins requires a flexible linker in between the C-terminus of the lasso peptide and the N-terminus of the protein of interest. The ability to fuse lasso peptides to a protein of interest is an important step toward phage and bacterial display systems for the high-throughput screening of lasso peptide libraries for new functions. PMID:26492187

  13. 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.

  14. Diet-induced neuropeptide expression: feasibility of quantifying extended and highly charged endogenous peptide sequences by selected reaction monitoring.

    Science.gov (United States)

    Schmidlin, Thierry; Boender, Arjen J; Frese, Christian K; Heck, Albert J R; Adan, Roger A H; Altelaar, A F Maarten

    2015-10-01

    Understanding regulation and action of endogenous peptides, especially neuropeptides, which serve as inter- and intracellular signal transmitters, is key in understanding a variety of functional processes, such as energy balance, memory, circadian rhythm, drug addiction, etc. Therefore, accurate and reproducible quantification of these bioactive endogenous compounds is highly relevant. The biosynthesis of endogenous peptides, involving multiple possible trimming and modification events, hinders the de novo prediction of the active peptide sequences, making MS-based measurements very valuable in determining the actual active compounds. Here, we report an extended selected reaction monitoring (SRM)-based strategy to reproducibly and quantitatively monitor the abundances of a set of 15 endogenously occurring peptides from Rattus norvegicus hypothalamus. We demonstrate that SRM can be extended toward reproducible detection and quantification of peptides, bearing characteristics very different from tryptic peptides. We show that long peptide sequences, producing precursors with up to five and MS2 fragment ions with up to three charges, can be targeted by SRM on a triple quadrupole instrument. Using this approach to quantify endogenous peptide levels in hypothalami of animals subjected to different diets revealed several significant changes, most notably the significant upregulation of VGF-derived signaling peptide AQEE-30 upon high caloric feeding. PMID:26376940

  15. Characterization and Recombinant Expression of Terebrid Venom Peptide from Terebra guttata.

    Science.gov (United States)

    Moon, John; Gorson, Juliette; Wright, Mary Elizabeth; Yee, Laurel; Khawaja, Samer; Shin, Hye Young; Karma, Yasmine; Musunri, Rajeeva Lochan; Yun, Michelle; Holford, Mande

    2016-03-01

    Venom peptides found in terebrid snails expand the toolbox of active compounds that can be applied to investigate cellular physiology and can be further developed as future therapeutics. However, unlike other predatory organisms, such as snakes, terebrids produce very small quantities of venom, making it difficult to obtain sufficient amounts for biochemical characterization. Here, we describe the first recombinant expression and characterization of terebrid peptide, teretoxin Tgu6.1, from Terebra guttata. Tgu6.1 is a novel forty-four amino acid teretoxin peptide with a VI/VII cysteine framework (C-C-CC-C-C) similar to O, M and I conotoxin superfamilies. A ligation-independent cloning strategy with an ompT protease deficient strain of E. coli was employed to recombinantly produce Tgu6.1. Thioredoxin was introduced in the plasmid to combat disulfide folding and solubility issues. Specifically Histidine-6 tag and Ni-NTA affinity chromatography were applied as a purification method, and enterokinase was used as a specific cleavage protease to effectively produce high yields of folded Tgu6.1 without extra residues to the primary sequence. The recombinantly-expressed Tgu6.1 peptide was bioactive, displaying a paralytic effect when injected into a Nereis virens polychaete bioassay. The recombinant strategy described to express Tgu6.1 can be applied to produce high yields of other disulfide-rich peptides. PMID:26950153

  16. Characterization and Recombinant Expression of Terebrid Venom Peptide from Terebra guttata

    Directory of Open Access Journals (Sweden)

    John Moon

    2016-03-01

    Full Text Available Venom peptides found in terebrid snails expand the toolbox of active compounds that can be applied to investigate cellular physiology and can be further developed as future therapeutics. However, unlike other predatory organisms, such as snakes, terebrids produce very small quantities of venom, making it difficult to obtain sufficient amounts for biochemical characterization. Here, we describe the first recombinant expression and characterization of terebrid peptide, teretoxin Tgu6.1, from Terebra guttata. Tgu6.1 is a novel forty-four amino acid teretoxin peptide with a VI/VII cysteine framework (C–C–CC–C–C similar to O, M and I conotoxin superfamilies. A ligation-independent cloning strategy with an ompT protease deficient strain of E. coli was employed to recombinantly produce Tgu6.1. Thioredoxin was introduced in the plasmid to combat disulfide folding and solubility issues. Specifically Histidine-6 tag and Ni-NTA affinity chromatography were applied as a purification method, and enterokinase was used as a specific cleavage protease to effectively produce high yields of folded Tgu6.1 without extra residues to the primary sequence. The recombinantly-expressed Tgu6.1 peptide was bioactive, displaying a paralytic effect when injected into a Nereis virens polychaete bioassay. The recombinant strategy described to express Tgu6.1 can be applied to produce high yields of other disulfide-rich peptides.

  17. Anticancer properties of peptide fragments of hair proteins.

    Directory of Open Access Journals (Sweden)

    Sergiusz Markowicz

    Full Text Available The primary function of hair and fur covering mammalian skin is to provide mechanical and thermal protection for the body. The proteins that constitute hair are extremely resistant to degradation by environmental factors. However, even durable materials can be slowly broken down by mechanical stresses, biodegradation mediated by endogenous enzymes in the skin or host microbes. We hypothesised that the biodegradation products of hair may possess bioprotective properties, which supplement their physical protective properties. Although evolutionary processes have led to a reduction in the amount of hair on the human body, it is possible that the bioprotective properties of hair biodegradation products have persisted. The human skin is exposed to various environmental carcinogenic factors. Therefore, we hypothesised that the potential bioprotective mechanisms of hair degradation products affect melanoma growth. We used pepsin to partially digest hair enzymatically, and this process produced a water-soluble lysate containing a mixture of peptides, including fragments of keratin and keratin-associated proteins. We found out that the mixtures of soluble peptides obtained from human hair inhibited the proliferation of human melanoma cells in vitro. Moreover, the hair-derived peptide mixtures also inhibited the proliferation of B lymphoma cells and urinary bladder cancer cells. Normal human cells varied in their susceptibility to the effects of the lysate; the hair-derived peptide mixtures modulated the proliferation of normal human fibroblasts but did not inhibit the proliferation of human mesenchymal cells derived from umbilical cord stromal cells. These results suggest that hair-derived peptides may represent a new class of anti-proliferative factors derived from basically structural proteins. Identification of active regulatory compounds and recognition of the mechanism of their action might pave the way to elaboration of new anticancer drugs.

  18. Expression pattern of arenicins - the antimicrobial peptides of polychaete Arenicolamarina

    Directory of Open Access Journals (Sweden)

    Arina L. Maltseva

    2014-12-01

    Full Text Available Immune responses of invertebrate animals are mediated through innate mechanisms, among which production of antimicrobial peptides play an important role. Although evolutionary Polychaetes represent an interesting group closely related to a putative common ancestor of other coelomates, their immune mechanisms still remain scarcely investigated. Previously our group has identified arenicins - new antimicrobial peptides of the lugworm Arenicola marina, since then these peptides were thoroughly characterized in terms of their structure and inhibitory potential. In the present study we addressed the question of the physiological functions of arenicins in the lugworm body. Using molecular and immunocytochemical methods we demonstrated that arencins are expressed in the wide range of the lugworm tissues - coelomocytes, body wall, extravasal tissue and the gut. The expression of arenicins is constitutive and does not depend on stimulation of various infectious stimuli. Most intensively arenicins are produced by mature coelomocytes where they function as killing agents inside the phagolysosome. In the gut and the body wall epithelia arenicins are released from producing cells via secretion as they are found both inside the epithelial cells and in the contents of the cuticle. Collectively our study showed that arenicins are found in different body compartments responsible for providing a first line of defence against infections, which implies their important role as key components of both epithelial and systemic branches of host defence.

  19. Study on the Funcitonal Peptides in Low Salt Sufu Making

    Institute of Scientific and Technical Information of China (English)

    ZhangXiaofeng; LiLite; WangJiahuai; MasayoshiSaito; EizoTatsumi

    2002-01-01

    Sufu in this project was prepared with Actinomucor elegans (CICC-3318)as the starter and with soybean as the material.Different with the sufu with 10% salt produced by traditional process,a sufu product with 6% salt was produced in this project by reducing the salt content in salting process.To determine peptides,the water-soluble extracts obtained saparetly from frozen dried powders of soybean,tofu,pehtze pehtze and sufu ripening for 50 days were analyzed by high-pressure lipid chromatography (HPLC).Antioxidative activity and antihypertensive activity of the extract due to the peptides contained were evaluated respectively by radical scavenging ability and angiotensin converting enzyme (ACS) inhibitory activity.According to the HPLC patterns,the peptides content was nearly zero in soybean and tofu,but increassed gradually during maturing in the further process of making pehtze,salted pehtze and final product sufu,Correspondingly,the antioxidative and antihypertensive activities of the extracts strengthened with maturing.For our product,sufu with 6% salt,the antioxidative and antihypertensive activities reached peak values at about 30 d maturing,and still remained medium values in final product sufu.In comarison,the antioxidative and antihypertensive activities for the sufu with 10% salt reached peack values at 40 d maturing,but remained medium values inferior to those for the sufu with 6% salt.

  20. 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

  1. Characterization of peptides found in unprocessed and extruded amaranth (Amaranthus hypochondriacus) pepsin/pancreatin hydrolysates.

    Science.gov (United States)

    Montoya-Rodríguez, Alvaro; Milán-Carrillo, Jorge; Reyes-Moreno, Cuauhtémoc; González de Mejía, Elvira

    2015-01-01

    The objectives of this study were to characterize peptides found in unprocessed amaranth hydrolysates (UAH) and extruded amaranth hydrolysates (EAH) and to determine the effect of the hydrolysis time on the profile of peptides produced. Amaranth grain was extruded in a single screw extruder at 125 °C of extrusion temperature and 130 rpm of screw speed. Unprocessed and extruded amaranth flour were hydrolyzed with pepsin/pancreatin enzymes following a kinetic at 10, 25, 60, 90, 120 and 180 min for each enzyme. After 180 min of pepsin hydrolysis, aliquots were taken at each time during pancreatin hydrolysis to characterize the hydrolysates by MALDI-TOF/MS-MS. Molecular masses (MM) (527, 567, 802, 984, 1295, 1545, 2034 and 2064 Da) of peptides appeared consistently during hydrolysis, showing high intensity at 10 min (2064 Da), 120 min (802 Da) and 180 min (567 Da) in UAH. EAH showed high intensity at 10 min (2034 Da) and 120 min (984, 1295 and 1545 Da). Extrusion produced more peptides with MM lower than 1000 Da immediately after 10 min of hydrolysis. Hydrolysis time impacted on the peptide profile, as longer the time lower the MM in both amaranth hydrolysates. Sequences obtained were analyzed for their biological activity at BIOPEP, showing important inhibitory activities related to chronic diseases. These peptides could be used as a food ingredient/supplement in a healthy diet to prevent the risk to develop chronic diseases. PMID:25894223

  2. First isolation of a novel thermostable antifungal peptide secreted by Aspergillus clavatus.

    Science.gov (United States)

    Skouri-Gargouri, Houda; Gargouri, Ali

    2008-11-01

    A novel antifungal peptide produced by an indigenous fungal strain (VR) of Aspergillus clavatus was purified. The antifungal peptide was enriched in the supernatant after heat treatment at 70 degrees C. The thermostable character was exploited in the first purification step, as purified peptide was obtained after ultrafiltration and reverse phase-HPLC on C18 column application. The purified peptide named "AcAFP" for A. clavatus antifungal peptide, has molecular mass of 5773Da determined by MALDI-ToF spectrometry. The N-terminal sequence showed a notable identity to the limited family of antifungal peptides produced by ascomycetes fungi. The AcAFP activity remains intact even after heat treatment at 100 degrees C for 1h confirming its thermostability. It exhibits a strong inhibitory activity against mycelial growth of several serious human and plant pathogenic fungi: Fusariuym oxysporum, Fusarium solani, Aspergillus niger, Botrytis cinerea, Alternaria solani, whereas AcAFP did not affect yeast and bacterial growth. PMID:18687373

  3. Natriuretic peptides in relation to the cardiac innervation and conduction system.

    Science.gov (United States)

    Hansson, Magnus

    2002-09-01

    During the past two decades, the heart has been known to undergo endocrine action, harbouring peptides with hormonal activities. These, termed "atrial natriuretic peptide (ANP)," "brain natriuretic peptide (BNP)," and "C-type natriuretic peptide (CNP)," are polypeptides mainly produced in the cardiac myocardium, where they are released into the circulation, producing profound hypotensive effects due to their diuretic, natriuretic, and vascular dilatory properties. It is, furthermore, well established that cardiac disorders such as congestive heart failure and different forms of cardiomyopathy are combined with increased expression of ANP and BNP, leading to elevated levels of these peptides in the plasma. Besides the occurrence of natriuretic peptides (NPs) in the ordinary myocardium, the presence of ANP in the cardiac conduction system has been described. There is also evidence of ANP gene expression in nervous tissue such as the nodose ganglion and the superior cervical ganglion of the rat, ganglia known to be involved in the neuronal regulation of the heart. Furthermore, in the mammalian heart, ANP appears to affect the cardiac autonomic nervous system by sympathoinhibitory and vagoexcitatory actions. This article provides an overview of the relationship between the cardiac conduction system, the cardiac innervation and NPs in the mammalian heart and provides data for the concept that ANP is also involved in neuronal cardiac regulation. PMID:12226807

  4. Characterization of Peptides Found in Unprocessed and Extruded Amaranth (Amaranthus hypochondriacus Pepsin/Pancreatin Hydrolysates

    Directory of Open Access Journals (Sweden)

    Alvaro Montoya-Rodríguez

    2015-04-01

    Full Text Available The objectives of this study were to characterize peptides found in unprocessed amaranth hydrolysates (UAH and extruded amaranth hydrolysates (EAH and to determine the effect of the hydrolysis time on the profile of peptides produced. Amaranth grain was extruded in a single screw extruder at 125 °C of extrusion temperature and 130 rpm of screw speed. Unprocessed and extruded amaranth flour were hydrolyzed with pepsin/pancreatin enzymes following a kinetic at 10, 25, 60, 90, 120 and 180 min for each enzyme. After 180 min of pepsin hydrolysis, aliquots were taken at each time during pancreatin hydrolysis to characterize the hydrolysates by MALDI-TOF/MS-MS. Molecular masses (MM (527, 567, 802, 984, 1295, 1545, 2034 and 2064 Da of peptides appeared consistently during hydrolysis, showing high intensity at 10 min (2064 Da, 120 min (802 Da and 180 min (567 Da in UAH. EAH showed high intensity at 10 min (2034 Da and 120 min (984, 1295 and 1545 Da. Extrusion produced more peptides with MM lower than 1000 Da immediately after 10 min of hydrolysis. Hydrolysis time impacted on the peptide profile, as longer the time lower the MM in both amaranth hydrolysates. Sequences obtained were analyzed for their biological activity at BIOPEP, showing important inhibitory activities related to chronic diseases. These peptides could be used as a food ingredient/supplement in a healthy diet to prevent the risk to develop chronic diseases.

  5. Brassica juncea Produces a Phytochelatin-Cadmium-Sulfide Complex.

    Science.gov (United States)

    Speiser, D M; Abrahamson, S L; Banuelos, G; Ow, D W

    1992-07-01

    Phytochelatins (PCs) are enzymically synthesized peptides produced in higher plants and some fungi upon exposure to heavy metals. We have examined PC production in the Se-tolerant wild mustard Brassica juncea and found that it produces two types of PC-Cd complexes with the same characteristics as those from fission yeast Schizosaccharomyces pombe, including a high molecular weight PC-Cd-sulfide form. PMID:16669006

  6. Brassica juncea Produces a Phytochelatin-Cadmium-Sulfide Complex 1

    Science.gov (United States)

    Speiser, David M.; Abrahamson, Susan L.; Banuelos, Gary; Ow, David W.

    1992-01-01

    Phytochelatins (PCs) are enzymically synthesized peptides produced in higher plants and some fungi upon exposure to heavy metals. We have examined PC production in the Se-tolerant wild mustard Brassica juncea and found that it produces two types of PC-Cd complexes with the same characteristics as those from fission yeast Schizosaccharomyces pombe, including a high molecular weight PC-Cd-sulfide form. PMID:16669006

  7. Conformational analysis by theoretical calculations of distinctin, an antimicrobial peptide isolated from Phyllomedusa distincta

    International Nuclear Information System (INIS)

    Various studies demonstrate that different frog species produce distinct classes of biologically active peptides. These peptides can act as alternative agents against pathogenic bacteria and fungi by membrane permeability. Although studies have recently demonstrated that this process is utterly related to the secondary structure adopted by the peptide (in this case, the α-helical structure) when in contact with the bacterial membrane, the detailed mechanism is still unknown. In this work we describe a conformational analysis of distinctin, a heterodimeric peptide isolated from the skin of Phyllomedusa distincta, an anuran found in the Brazilian Atlantic Forest. The study yielded a stable geometry with a high content of the α-helical structure both in chains 1 and 2 of distinctin, showing strong interaction between them. (author)

  8. 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.

  9. A novel small antifungal peptide from Bacillus strain B-TL2 isolated from tobacco stems.

    Science.gov (United States)

    Zhang, Beibei; Xie, Chengjian; Yang, Xingyong

    2008-03-01

    A novel small antifungal peptide produced by a Bacillus strain B-TL2 isolated from tobacco stems was purified. The purification procedure consisted of ammonium sulfate precipitation, cation exchange chromatography on CM-Sepharose Fast Flow column and reverse-phase HPLC on SOURCE 5RPC column. After the final isolation step, one peptide with antifungal activity, designated as BTL, was obtained. The molecular mass of the purified BTL was determined as 2500 Da and 2237.7 Da by SDS-PAGE and matrix-assisted laser desorption/ionization time of flight mass spectrometry, respectively. The N-amino acid sequence of BTL was determined to be NH(2)-KQQLATEAESAGPIL, which shows relatively low identity to other antimicrobial peptides from bacteria. The peptide exhibited strong inhibitory activity against mycelial growth of Bipolaris maydis, Alternaria brassicae, Aspergillus niger, Cercospora personata. The purified BTL displayed thermostability, almost retaining 100% activity at 100 degrees C for 15 min. PMID:18241956

  10. A distinct translation initiation mechanism generates cryptic peptides for immune surveillance.

    Directory of Open Access Journals (Sweden)

    Shelley R Starck

    Full Text Available MHC class I molecules present a comprehensive mixture of peptides on the cell surface for immune surveillance. The peptides represent the intracellular protein milieu produced by translation of endogenous mRNAs. Unexpectedly, the peptides are encoded not only in conventional AUG initiated translational reading frames but also in alternative cryptic reading frames. Here, we analyzed how ribosomes recognize and use cryptic initiation codons in the mRNA. We find that translation initiation complexes assemble at non-AUG codons but differ from canonical AUG initiation in response to specific inhibitors acting within the peptidyl transferase and decoding centers of the ribosome. Thus, cryptic translation at non-AUG start codons can utilize a distinct initiation mechanism which could be differentially regulated to provide peptides for immune surveillance.

  11. Peptide-based candidate vaccine against respiratory syncytial virus.

    Science.gov (United States)

    Yusibov, Vidadi; Mett, Vadim; Mett, Valentina; Davidson, Carley; Musiychuk, Konstantin; Gilliam, Suzan; Farese, Ann; Macvittie, Thomas; Mann, Dean

    2005-03-18

    We engineered a 21-mer peptide representing amino acids 170-190 of the respiratory syncytial virus (RSV) G protein as a fusion with the Alfalfa mosaic virus (AlMV) coat protein (CP), produced recombinant AlMV particles presenting this peptide (VMR-RSV) on their surfaces and tested the immunogenicity in vitro in human dendritic cells and in vivo in non-human primates. Significant pathogen-specific immune responses were generated in both systems: (i) human dendritic cells armed with VMR-RSV generated vigorous CD4+ and CD8+ T cell responses; (ii) non-human primates that received these particles responded by mounting strong cellular and humoral immune responses. This approach may validate the use of a novel RSV vaccine delivery vehicle in humans. PMID:15755607

  12. Expression of the mammalian peptide hormone obestatin in Trichoderma reesei.

    Science.gov (United States)

    Sun, Angela; Peterson, Robyn; Te'o, Junior; Nevalainen, Helena

    2016-01-25

    The filamentous fungus Trichoderma reesei is an expression host widely exploited for the production of recombinant proteins. However, its capacity for expressing small peptides (reesei cellobiohydrolase I core (CBHI) or xylanase 2 (XYN2) pro-region as a carrier and the cbh1 promoter for gene expression, in high protein-low protease producing mutant strains T. reesei Rut-C30 and HEPI. The yield of obestatin was improved from about 300 ng/ml to up to 5.5 μg/ml through adaptive laboratory evolution and modifications to the cultivation strategy, which included adjustments of the type and ratio of carbon and nitrogen sources used in the medium. The successful expression of Obe-HFBI demonstrated the potential of T. reesei as an expression host for small peptides and further enhancement of the recombinant yield through modification of culture conditions. PMID:26341165

  13. Synthesis of peptide .alpha.-thioesters

    Science.gov (United States)

    Camarero, Julio A.; Mitchell, Alexander R.; De Yoreo, James J.

    2008-08-19

    Disclosed herein is a new method for the solid phase peptide synthesis (SPPS) of C-terminal peptide .alpha. thioesters using Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazine linker, which is totally stable to conditions required for Fmoc-SPPS. When the peptide synthesis has been completed, activation of the linker is achieved by mild oxidation. The oxidation step converts the acyl-hydrazine group into a highly reactive acyl-diazene intermediate which reacts with an .alpha.-amino acid alkylthioester (H-AA-SR) to yield the corresponding peptide .alpha.-thioester in good yield. A variety of peptide thioesters, cyclic peptides and a fully functional Src homology 3 (SH3) protein domain have been successfully prepared.

  14. Prediction of twin-arginine signal peptides

    DEFF Research Database (Denmark)

    Bendtsen, Jannick Dyrløv; Nielsen, Henrik; Widdick, D.; Palmer, T.; Brunak, Søren

    2005-01-01

    publicly available method, TatP, for prediction of bacterial Tat signal peptides. Results: We have retrieved sequence data for Tat substrates in order to train a computational method for discrimination of Sec and Tat signal peptides. The TatP method is able to positively classify 91% of 35 known Tat signal...... complementary rule based prediction method. Conclusion: The method developed here is able to discriminate Tat signal peptides from cytoplasmic proteins carrying a similar motif, as well as from Sec signal peptides, with high accuracy. The method allows filtering of input sequences based on Perl syntax regular...... expressions, whereas hydrophobicity discrimination of Tat- and Sec- signal peptides is carried out by an artificial neural network. A potential cleavage site of the predicted Tat signal peptide is also reported. The TatP prediction server is available as a public web server at http://www.cbs.dtu.dk/services/TatP/....

  15. Antiviral cationic peptides as a strategy for innovation in global health therapeutics for dengue virus: high yield production of the biologically active recombinant plectasin peptide.

    Science.gov (United States)

    Rothan, Hussin A; Mohamed, Zulqarnain; Suhaeb, Abdulrazzaq M; Rahman, Noorsaadah Abd; Yusof, Rohana

    2013-11-01

    Dengue virus infects millions of people worldwide, and there is no vaccine or anti-dengue therapeutic available. Antimicrobial peptides have been shown to possess effective antiviral activity against various viruses. One of the main limitations of developing these peptides as potent antiviral drugs is the high cost of production. In this study, high yield production of biologically active plectasin peptide was inexpensively achieved by producing tandem plectasin peptides as inclusion bodies in E. coli. Antiviral activity of the recombinant peptide towards dengue serotype-2 NS2B-NS3 protease (DENV2 NS2B-NS3pro) was assessed as a target to inhibit dengue virus replication in Vero cells. Single units of recombinant plectasin were collected after applying consecutive steps of refolding, cleaving by Factor Xa, and nickel column purification to obtain recombinant proteins of high purity. The maximal nontoxic dose (MNTD) of the recombinant peptide against Vero cells was 20 μM (100 μg/mL). The reaction velocity of DENV2 NS2B-NS3pro decreased significantly after increasing concentrations of recombinant plectasin were applied to the reaction mixture. Plectasin peptide noncompetitively inhibited DENV2 NS2B-NS3pro at Ki value of 5.03 ± 0.98 μM. The percentage of viral inhibition was more than 80% at the MNTD value of plectasin. In this study, biologically active recombinant plectasin which was able to inhibit dengue protease and viral replication in Vero cells was successfully produced in E. coli in a time- and cost- effective method. These findings are potentially important in the development of potent therapeutics against dengue infection. PMID:24044366

  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. NisT, the Transporter of the Lantibiotic Nisin, Can Transport Fully Modified, Dehydrated, and Unmodified Prenisin and Fusions of the Leader Peptide with Non-lantibiotic Peptides

    NARCIS (Netherlands)

    Kuipers, Anneke; Boef, Esther de; Rink, Rick; Fekken, Susan; Kluskens, Leon D.; Driessen, Arnold J.M.; Leenhouts, Kees; Kuipers, Oscar P.; Moll, Gert N.

    2004-01-01

    Lantibiotics are lanthionine-containing peptide antibiotics. Nisin, encoded by nisA, is a pentacyclic lantibiotic produced by some Lactococcus lactis strains. Its thioether rings are posttranslationally introduced by a membrane-bound enzyme complex. This complex is composed of three enzymes: NisB, w

  18. Characterization of the substructure and properties of immobilized peptides on silicon surface

    International Nuclear Information System (INIS)

    Research highlights: → Self-assembled monolayers were produced of N-decanoic acid covalently linked to the [1 1 1] surface of a silicon wafer. → The acid terminated monolayers were converted to the N-hydroxy succinimide esters and the biologically active peptide, (A-A-A-A-G-G-ERG-D) was then attached this functionalized surface. → The structure and composition of these films were determined using very high resolution electrical impedance spectroscopy, XPS and FITR. → Attachment of the peptide at pH 7 yielded films that were densely packed with the peptide oriented normal to the surface. Attachment at pH 4 in contrast yieldedless densely packed, thinner, films, suggesting an orientation of the peptides un the plane of the surface. - Abstract: Immobilization of biomaterials onto solid supports is a means of functionalizing materials for applications such as biosensing. Biologically active peptide (A-A-A-A-G-G-G-E-R-G-D) films were attached to N-hydroxy succinimide ester terminated self-assembled monolayers (SAM) which were covalently linked to a smooth silicon surface via Si-C bonds. The peptide films were characterized using electrical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The film structures were determined from examination of the capacitance and conductance dispersions with frequency. Analysis of XPS, EIS and FTIR after immobilization of the peptide film at pH 4 and 7 provided information on the extent of the activation and overall coupling efficiencies of the peptides to the N-hydroxy succinimide ester surface. The resulting film structure was markedly altered by attachment of the peptide at pH 4.

  19. Highly selective enrichment of phosphorylated peptides from peptide mixtures using titanium dioxide microcolumns

    DEFF Research Database (Denmark)

    Larsen, Martin Røssel; Thingholm, Tine E; Jensen, Ole N;

    2005-01-01

    not. Other substituted aromatic carboxylic acids were also capable of specifically reducing binding of nonphosphorylated peptides, whereas phosphoric acid reduced binding of both phosphorylated and nonphosphorylated peptides. A putative mechanism for this intriguing effect is presented....

  20. Antimicrobial Peptides in Toroidal and Cylindrical Pores

    OpenAIRE

    Mihajlovic, Maja; Lazaridis, Themis

    2010-01-01

    Antimicrobial peptides (AMPs) are small, usually cationic peptides, which permeabilize biological membranes. Their mechanism of action is still not well understood. Here we investigate the preference of alamethicin and melittin for pores of different shapes, using molecular dynamics (MD) simulations of the peptides in pre-formed toroidal and cylindrical pores. When an alamethicin hexamer is initially embedded in a cylindrical pore, at the end of the simulation the pore remains cylindrical or ...

  1. Interaction of small peptides with lipid bilayers.

    OpenAIRE

    Damodaran, K. V.; Merz, K M; Gaber, B P

    1995-01-01

    Molecular dynamics simulations of the tripeptide Ala-Phe-Ala-O-tert-butyl interacting with dimyristoylphosphatidylcholine lipid bilayers have been carried out. The lipid and aqueous environments of the peptide, the alkyl chain order, and the lipid and peptide dynamics have been investigated with use of density profiles, radial distribution functions, alkyl chain order parameter profiles, and time correlation functions. It appears that the alkyl chain region accommodates the peptides in the bi...

  2. Self-assembly of tetraphenylalanine peptides

    OpenAIRE

    Mayans Tayadella, Enric; Ballano Ballano, María Gema; Casanovas Salas, Jordi; Díaz Andrade, Angélica María; Pérez Madrigal, Maria del Mar; Estrany Coda, Francesc; Puiggalí Bellalta, Jordi; Cativiela Marín, Carlos A.; Alemán Llansó, Carlos

    2015-01-01

    Three different tetraphenylalanine (FFFF) based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies under a variety of conditions. The FFFF peptide assembles into nanotubes that show more structural imperfections at the surface than those formed by the diphenylalanine (FF) peptide under the same conditions. Periodic DFT calculations (M06L functional) were used to propose a model that consists o...

  3. Salt-resistant short antimicrobial peptides.

    Science.gov (United States)

    Mohanram, Harini; Bhattacharjya, Surajit

    2016-05-01

    Antimicrobial peptides (AMPs) are promising leads for the development of antibiotics against drug resistant bacterial pathogens. However, in vivo applications of AMPs remain obscure due to salt and serum mediated inactivation. The high cost of chemical synthesis of AMPs also impedes potential clinical application. Consequently, short AMPs resistant toward salt and serum inactivation are desirable for the development of peptide antibiotics. In this work, we designed a 12-residue amphipathic helical peptide RR12 (R-R-L-I-R-L-I-L-R-L-L-R-amide) and two Trp containing analogs of RR12 namely RR12Wpolar (R-R-L-I-W-L-I-L-R-L-L-R-amide), and RR12Whydro (R-R-L-I-R-L-W-L-R-L-L-R-amide). Designed peptides demonstrated potent antibacterial activity; MIC ranging from 2 to 8 μM, in the presence of sodium chloride (150 mM and 300 mM). Antibacterial activity of these peptides was also detected in the presence of human serum. Designed peptides, in particular RR12 and RR12Whydro, were only poorly hemolytic. As a mode of action; these peptides demonstrated efficient permeabilization of bacterial cell membrane and lysis of cell structure. We further investigated interactions of the designed peptides with lipopolysaccharide (LPS), the major component of the outer membrane permeability barrier of Gram-negative bacteria. Designed peptides adopted helical conformations in complex with LPS. Binding of peptides with LPS has yielded dissociation the aggregated structures of LPS. Collectively, these designed peptides hold ability to be developed for salt-resistant antimicrobial compounds. Most importantly, current work provides insights for designing salt-resistant antimicrobial peptides. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 345-356, 2016. PMID:26849911

  4. Pulmonary clearance of vasoactive intestinal peptide.

    OpenAIRE

    Barrowcliffe, M P; Morice, A; Jones, J G; Sever, P S

    1986-01-01

    Vasoactive intestinal peptide causes bronchodilatation when given intravenously but is less effective in both animals and man when given by inhalation. This difference may be due to poor transit of the peptide across the bronchial epithelium. To test this hypothesis pulmonary clearance of radiolabelled vasoactive intestinal peptide was measured in Sprague Dawley rats and compared with that of pertechnetate (TcO4-) and diethylene triamine pentaacetate (DTPA). Despite a molecular weight (MW) of...

  5. Genome-based peptide fingerprint scanning

    OpenAIRE

    Giddings, Michael C.; Shah, Atul A.; Gesteland, Ray; Moore, Barry

    2002-01-01

    We have implemented a method that identifies the genomic origins of sample proteins by scanning their peptide-mass fingerprint against the theoretical translation and proteolytic digest of an entire genome. Unlike previously reported techniques, this method requires no predefined ORF or protein annotations. Fixed-size windows along the genome sequence are scored by an equation accounting for the number of matching peptides, the number of missed enzymatic cleavages in each peptide, the number ...

  6. Membrane Perturbation Induced by Interfacially Adsorbed Peptides

    OpenAIRE

    Zemel, Assaf; Ben-Shaul, Avinoam; May, Sylvio

    2004-01-01

    The structural and energetic characteristics of the interaction between interfacially adsorbed (partially inserted) α-helical, amphipathic peptides and the lipid bilayer substrate are studied using a molecular level theory of lipid chain packing in membranes. The peptides are modeled as “amphipathic cylinders” characterized by a well-defined polar angle. Assuming two-dimensional nematic order of the adsorbed peptides, the membrane perturbation free energy is evaluated using a cell-like model;...

  7. The Function and Development of Soybean Peptides

    Institute of Scientific and Technical Information of China (English)

    Yang Caiyan; Song Junmei

    2009-01-01

    Soybean peptides are small molecules hydrolyzed soy protein,from three to six amino acid composition of the peptide mixture,in 1000Da molecular weight below.Because it has a lot of good physical and chemical properties and physiological functions,in many areas has been widely used.This paper reviews the soybean peptide physical and chemical characteristics,physiological functions,technology and applications in the food industry.

  8. Antimicrobial peptides in human skin disease

    OpenAIRE

    Kenshi, Yamasaki; Richard, L. Gallo

    2007-01-01

    The skin continuously encounters microbial pathogens. To defend against this, cells of the epidermis and dermis have evolved several innate strategies to prevent infection. Antimicrobial peptides are one of the primary mechanisms used by the skin in the early stages of immune defense. In general, antimicrobial peptides have broad antibacterial activity against gram-positive and negative bacteria and also show antifungal and antiviral activity. The antimicrobial activity of most peptides occur...

  9. Mechanism of papain-catalyzed synthesis of oligo-tyrosine peptides.

    Science.gov (United States)

    Mitsuhashi, Jun; Nakayama, Tsutomu; Narai-Kanayama, Asako

    2015-01-01

    Di-, tri-, and tetra-tyrosine peptides with angiotensin I-converting enzyme inhibitory activity were synthesized by papain-catalyzed polymerization of L-tyrosine ethyl ester in aqueous media at 30 °C. Varying the reaction pH from 6.0 to 7.5 and the initial concentration of the ester substrate from 25 to 100 mM, the highest yield of oligo-tyrosine peptides (79% on a substrate basis) was produced at pH 6.5 and 75 mM, respectively. In the reaction initiated with 100 mM of the substrate, approx. 50% yield of insoluble, highly polymerized peptides accumulated. At less than 15 mM, the reaction proceeded poorly; however, from 30 mM to 120 mM a dose-dependent increase in the consumption rate of the substrate was observed with a sigmoidal curve. Meanwhile, each of the tri- and tetra-tyrosine peptides, even at approx. 5mM, was consumed effectively by papain but was not elongated to insoluble polymers. For deacylation of the acyl-papain intermediate through which a new peptide bond is made, L-tyrosine ethyl ester, even at 5mM, showed higher nucleophilic activity than di- and tri-tyrosine. These results indicate that the mechanism through which papain polymerizes L-tyrosine ethyl ester is as follows: the first interaction between papain and the ester substrate is a rate-limiting step; oligo-tyrosine peptides produced early in the reaction period are preferentially used as acyl donors, while the initial ester substrate strongly contributes as a nucleophile to the elongation of the peptide product; and the balance between hydrolytic fragmentation and further elongation of oligo-tyrosine peptides is dependent on the surrounding concentration of the ester substrate. PMID:26047910

  10. Isolation and characterization of the lantibiotic salivaricin A and its structural gene salA from Streptococcus salivarius 20P3.

    Science.gov (United States)

    Ross, K F; Ronson, C W; Tagg, J R

    1993-01-01

    A bacteriocin-like inhibitory substance, salivaricin A, was purified from cultures of Streptococcus salivarius 20P3 and was shown by ion spray mass spectrometry to have a molecular mass of 2,315 +/- 1.1 Da. Amino acid composition analysis demonstrated the presence of lanthionine, indicating that salivaricin A may be a member of the lantibiotic class of antibiotic substances. The sequence of eight amino acids at the N terminus of the molecule was determined by Edman degradation, and mixed oligonucleotide probes based on part of this sequence (GSGWIA) were used to detect the salivaricin A structural gene. A 6.2-kb EcoRI fragment of chromosomal DNA from strain 20P3 that hybridized with the probes was cloned, and the hybridizing region was further localized to a 379-bp DraI-AluI fragment. Analysis of the nucleotide sequence of this fragment indicated that salivaricin A is synthesized as a 51-amino-acid prepeptide that is posttranslationally modified and cleaved to give a biologically active 22-residue peptide containing one lanthionine and two beta-methyllanthionine residues. The secondary structure of presalivaricin A was predicted to be similar to that of type A lantibiotics, with a hydrophilic alpha-helical leader sequence and a propeptide region with potential for beta-turn formation and a lack of alpha-helicity. The sequence around the cleavage site of presalivaricin A differed from that of other type A lantibiotics but was similar to that of several bacteriocin-like inhibitory substances produced by lactic acid bacteria. Images PMID:8357242

  11. Peptide Nucleic Acids Complexes of Two Peptide Nucleic Acid Strands and One

    DEFF Research Database (Denmark)

    1999-01-01

    Peptide nucleic acids and analogues of peptide nucleic acids are used to form duplex, triplex, and other structures with nucleic acids and to modify nucleic acids. The peptide nucleic acids and analogues thereof also are used to modulate protein activity through, for example, transcription arrest...

  12. Mechanism and kinetics of peptide partitioning into membranes from all-atom simulations of thermostable peptides

    OpenAIRE

    Ulmschneider, Martin B.; Doux, Jacques P F; Killian, J. Antoinette; Smith, Jeremy C.; Ulmschneider, Jakob P.

    2010-01-01

    Partitioning properties of transmembrane (TM) polypeptide segments directly determine membrane protein folding, stability, and function, and their understanding is vital for rational design of membrane active peptides. However, direct determination of water-to-bilayer transfer of TM peptides has proved difficult. Experimentally, sufficiently hydrophobic peptides tend to aggregate, while atomistic computer simulations at physiological temperatures cannot yet reach the long time scales required...

  13. Synthetic peptide vaccines: palmitoylation of peptide antigens by a thioester bond increases immunogenicity

    DEFF Research Database (Denmark)

    Beekman, N.J.C.M.; Schaaper, W.M.M.; Tesser, G.I.;

    1997-01-01

    amide bond. It was found that these S-palmitoylated peptides were much more immunogenic than N-palmitoylated peptides and at least similar to KLH-conjugated peptides with respect to appearance and magnitude of induced antibodies (canine parvovirus) or immunocastration effect (gonadotropin...

  14. Atrial natriuretic peptides in plasma

    DEFF Research Database (Denmark)

    Goetze, Jens P; Holst Hansen, Lasse; Terzic, Dijana;

    2015-01-01

    Measurement of cardiac natriuretic peptides in plasma has gained a diagnostic role in the assessment of heart failure. Plasma measurement is though hampered by the marked instability of the hormones, which has led to the development of analyses that target N-terminal fragments from the prohormone....... These fragments are stable in plasma and represent surrogate markers of the actual natriuretic hormone. Post-translational processing of the precursors, however, is revealing itself to be a complex event with new information still being reported on proteolysis, covalent modifications, and amino acid...

  15. Glucagon-like peptide-1

    DEFF Research Database (Denmark)

    Deacon, C F; Holst, Jens Juul; Carr, R D

    1999-01-01

    Type 2 diabetes mellitus is a metabolic disease resulting in raised blood sugar which, if not satisfactorily controlled, can cause severe and often debilitating complications. Unfortunately, for many patients, the existing therapies do not give adequate control. Glucagon-like peptide-1 (GLP-1) is...... an incretin hormone which has a spectrum of activities which oppose the symptoms of diabetes. Of particular significance is the fact that these actions are glucose-dependent, meaning that the risk of severe hypoglycemia is practically eliminated. The recent elucidation of the key role of dipeptidyl...

  16. PGx: Putting Peptides to BED.

    Science.gov (United States)

    Askenazi, Manor; Ruggles, Kelly V; Fenyö, David

    2016-03-01

    Every molecular player in the cast of biology's central dogma is being sequenced and quantified with increasing ease and coverage. To bring the resulting genomic, transcriptomic, and proteomic data sets into coherence, tools must be developed that do not constrain data acquisition and analytics in any way but rather provide simple links across previously acquired data sets with minimal preprocessing and hassle. Here we present such a tool: PGx, which supports proteogenomic integration of mass spectrometry proteomics data with next-generation sequencing by mapping identified peptides onto their putative genomic coordinates. PMID:26638927

  17. Designer lipid-like peptides: a class of detergents for studying functional olfactory receptors using commercial cell-free systems.

    Directory of Open Access Journals (Sweden)

    Karolina Corin

    Full Text Available A crucial bottleneck in membrane protein studies, particularly G-protein coupled receptors, is the notorious difficulty of finding an optimal detergent that can solubilize them and maintain their stability and function. Here we report rapid production of 12 unique mammalian olfactory receptors using short designer lipid-like peptides as detergents. The peptides were able to solubilize and stabilize each receptor. Circular dichroism showed that the purified olfactory receptors had alpha-helical secondary structures. Microscale thermophoresis suggested that the receptors were functional and bound their odorants. Blot intensity measurements indicated that milligram quantities of each olfactory receptor could be produced with at least one peptide detergent. The peptide detergents' capability was comparable to that of the detergent Brij-35. The ability of 10 peptide detergents to functionally solubilize 12 olfactory receptors demonstrates their usefulness as a new class of detergents for olfactory receptors, and possibly other G-protein coupled receptors and membrane proteins.

  18. Natriuretic peptides and their therapeutic potential.

    Science.gov (United States)

    Cho, Y; Somer, B G; Amatya, A

    1999-01-01

    Natriuretic peptides are a group of naturally occurring substances that act in the body to oppose the activity of the renin-angiotensin system. There are three major natriuretic peptides: atrial natriuretic peptide (ANP), which is synthesized in the atria; brain natriuretic peptide (BNP), which is synthesized in the ventricles; and C-type natriuretic peptide (CNP), which is synthesized in the brain. Both ANP and BNP are released in response to atrial and ventricular stretch, respectively, and will cause vasorelaxation, inhibition of aldosterone secretion in the adrenal cortex, and inhibition of renin secretion in the kidney. Both ANP and BNP will cause natriuresis and a reduction in intravascular volume, effects amplified by antagonism of antidiuretic hormone (ADH). The physiologic effects of CNP are different from those of ANP and BNP. CNP has a hypotensive effect, but no significant diuretic or natriuretic actions. Three natriuretic peptide receptors (NPRs) have been described that have different binding capacities for ANP, BNP, and CNP. Removal of the natriuretic peptides from the circulation is affected mainly by binding to clearance receptors and enzymatic degradation in the circulation. Increased blood levels of natriuretic peptides have been found in certain disease states, suggesting a role in the pathophysiology of those diseases, including congestive heart failure (CHF), systemic hypertension, and acute myocardial infarction. The natriuretic peptides also serve as disease markers and indicators of prognosis in various cardiovascular conditions. The natriuretic peptides have been used in the treatment of disease, with the most experience with intravenous BNP in the treatment of CHF. Another pharmacologic approach being used is the inhibition of natriuretic peptide metabolism by neutral endopeptidase (NEP) inhibitor drugs. The NEP inhibitors are currently being investigated as treatments for CHF and systemic hypertension. PMID:11720638

  19. Activation of the insulin receptor (IR) by insulin and a synthetic peptide has different effects on gene expression in IR-transfected L6 myoblasts

    DEFF Research Database (Denmark)

    Jensen, M.; Palsgaard, J.; Borup, R.;

    2008-01-01

    Single-chain peptides have been recently produced that display either mimetic or antagonistic properties against the insulin and IGF-1 (insulin-like growth factor 1) receptors. We have shown previously that the insulin mimetic peptide S597 leads to significant differences in receptor activation and...

  20. Efficient expression of isotopically labeled peptides for high resolution NMR studies: Application to the Cdc42/Rac binding domains of virulent kinases in Candida albicans

    International Nuclear Information System (INIS)

    The production of bioactive peptides and small protein fragments is commonly achieved via solid-phase chemical synthesis. However, such techniques become unviable and prohibitively expensive when the peptides are large (e.g., >30 amino acids) or when isotope labeling is required for NMR studies. Expression and purification of large quantities of unfolded peptides in E. coli have also proved to be difficult even when the desired peptides are carried by fusion proteins such as GST. We have developed a peptide expression system that utilizes a novel fusion protein (SFC120) which is highly expressed and directs the peptides to inclusion bodies, thereby minimizing in-cell proteolysis whilst maintaining high yields of peptide expression. The expressed peptides can be liberated from the carrier protein by CNBr cleavage at engineered methionine sites or through proteolysis by specific proteases for peptides containing methionine residues. In the present systems, we use CNBr, due to the absence of methionine residues in the target peptides, although other cleavage sites can be easily inserted. We report the production of six unfolded protein fragments of different composition and lengths (19 to 48 residues) derived from the virulent effector kinases, Cla4 and Ste20 of Candida albicans. All six peptides were produced with high yields of purified material (30-40 mg/l in LB, 15-20 mg/l in M9 medium), pointing to the general applicability of this expression system for peptide production. The enrichment of these peptides with 15N, 15N/13C and even 15N/13C/2H isotopes is presented allowing speedy assignment of poorly-resolved resonances of flexible peptides

  1. Effects of treatment with leptin-like peptides on factors related to body fat control in Wistar rats fed a high-fat diet*

    Directory of Open Access Journals (Sweden)

    Elpidia Poveda

    2011-04-01

    Full Text Available Introduction: The results of administering recombinant leptin, as well as the 116-130 peptide of mouse leptin in ob/ob mice have shown the probability of discovering more efficient leptin-based therapeutic methods to treat obesity. Objective: To demonstrate in Wistar rats fed with high-fat diet if the administration of synthetic peptides corresponding to the 116-130 peptide of mouse leptin (SR 116, its human homologue peptide (SH 95: sequence 95-109 from the 1AX8 protein and five modified peptides (P80 to P84 similar to these two peptides, produces effects related to regulation of body fat. Materials and methods: Nine-week old Wistar rats were fed a high-fat diet for fifteen weeks. On the fifteenth week, and for five consecutive days, they were treated with the peptides to be evaluated. During the days of treatment, body weight and food intake were evaluated. After the last peptide administration, lipid profile, glycerol in the cellular medium, and DNA fragmentation in adipocytes were analyzed. Results: The results revealed that: the SR116 peptide affects the regulation of adiposity in rats fed a high-fat diet. The SH 95 is the human peptide with biological activity similar to SR 116 to lower weight, lessen food intake, and increase free glycerol in the cellular medium. The P80 and P81 peptides had a similar effect on SR 116 and SH 95 regarding body weight and food intake. The SR 116, SH 95 and three of the modified peptides (P80, P81, and P82 caused DNA fragmentation. Conclusion: The results suggest that peptides analogous to leptin are potentially viable to achieve effects of adiposity reduction in Wistar rats with obesity associated to high-fat diet; more research is rendered to explain the differences among peptides and the biological action mechanisms.

  2. Effects of treatment with leptin-like peptides on factors related to body fat control in Wistar rats fed a high-fat diet

    Directory of Open Access Journals (Sweden)

    Elpidia Poveda

    2011-03-01

    Full Text Available Introduction: The results of administering recombinant leptin, as well as the 116-130 peptide of mouse leptin in ob/ob mice have shown the probability of discovering more efficient leptin-based therapeutic methods to treat obesity.Objective: To demonstrate in Wistar rats fed with high-fat diet if the administration of synthetic peptides corresponding to the 116-130 peptide of mouse leptin (SR 116, its human homologue peptide (SH 95: sequence 95-109 from the 1AX8 protein and five modified peptides (P80 to P84 similar to these two peptides, produces effects related to regulation of body fat.Materials and methods: Nine-week old Wistar rats were fed a high-fat diet for fifteen weeks. On the fifteenth week, and for five consecutive days, they were treated with the peptides to be evaluated. During the days of treatment, body weight and food intake were evaluated. After the last peptide administration, lipid profile, glycerol in the cellular medium, and DNA fragmentation in adipocytes were analyzed.Results: The results revealed that: the SR116 peptide affects the regulation of adiposity in rats fed a high-fat diet. The SH 95 is the human peptide with biological activity similar to SR 116 to lower weight, lessen food intake, and increase free glycerol in the cellular medium. The P80 and P81 peptides had a similar effect on SR 116 and SH 95 regarding body weight and food intake. The SR 116, SH 95 and three of the modified peptides (P80, P81, and P82 caused DNA fragmentation.Conclusion: The results suggest that peptides analogous to leptin are potentially viable to achieve effects of adiposity reduction in Wistar rats with obesity associated to high-fat diet; more research is rendered to explain the differences among peptides and the biological action mechanisms.

  3. Driving engineering of novel antimicrobial peptides from simulations of peptide-micelle interactions

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Langham, Allison A; Kaznessis, Yiannis N

    2006-01-01

    Simulations of antimicrobial peptides in membrane mimics can provide the high resolution, atomistic picture that is necessary to decipher which sequence and structure components are responsible for activity and toxicity. With such detailed insight, engineering new sequences that are active but non...... peptides and their interaction with membrane mimics. In this article, we discuss the promise and the challenges of widely used models and detail our recent work on peptide-micelle simulations as an attractive alternative to peptide-bilayer simulations. We detail our results with two large structural...... classes of peptides, helical and beta-sheet and demonstrate how simulations can assist in engineering of novel antimicrobials with therapeutic potential....

  4. Determination of peptide content of DOTA-peptides by metal titration and UPLC

    International Nuclear Information System (INIS)

    Radiolabelled DOTA-peptides are in use for Peptide Receptor Radionuclide Scintigraphy (PRS) and Therapy (PRRT), e.g with 177Lu-DOTA-TATE or 90Y-DOTATOC. Labelling conditions are frequently critical. Therefore, the ingredients of the reaction, e.g. radiometal (90Y and 177Lu) and DOTA-peptide should be pure and the content known. Quality control of DOTA-peptide, can be performed with various methods, most commonly by UV. There are numerous conditions in which this is hampered, e.g. impurities may also have UV-absorption. The aim of the study was to quantify content and purity of DOTA-peptide

  5. Antioxidant activity of yoghurt peptides: Part 2 – Characterisationof peptide fractions

    DEFF Research Database (Denmark)

    Farvin, Sabeena; Baron, Caroline; Nielsen, Nina Skall; Otte, Jeanette; Jacobsen, Charlotte

    2010-01-01

    The aim of the present study was to elucidate previous findings showing that peptide fractions isolated from yoghurt had antioxidant effects. Therefore, peptides and free amino acids released during fermentation of milk were characterised. Yoghurt samples were stripped from sugars and lactic acid...... all the peptides identified contained at least one proline residue. Some of the identified peptides included the hydrophobic amino acid residues Val or Leu at the N-terminus and Pro, His or Tyr in the amino acid sequence, which is characteristic of antioxidant peptides. In addition, the yoghurt...

  6. Trandermal Peptides for Large Molecule Delivery

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ A research team, led by Prof. WEN Longping from the University of Science and Technology of China under CAS,has successfully screened out a trandermal peptide, using biotechnology. The new peptide is able to deliver insulin into human body through skin, rendering an immediate therapeutic effect. The finding was published in the March 27 issue of the journal Natural Biotechnology.

  7. 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...

  8. 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…

  9. Engineered Adhesion Peptides for Improved Silicon Adsorption.

    Science.gov (United States)

    Ramakrishnan, Sathish Kumar; Jebors, Said; Martin, Marta; Cloitre, Thierry; Agarwal, Vivechana; Mehdi, Ahmad; Martinez, Jean; Subra, Gilles; Gergely, Csilla

    2015-11-01

    Engineering peptides that present selective recognition and high affinity for a material is a major challenge for assembly-driven elaboration of complex systems with wide applications in the field of biomaterials, hard-tissue regeneration, and functional materials for therapeutics. Peptide-material interactions are of vital importance in natural processes but less exploited for the design of novel systems for practical applications because of our poor understanding of mechanisms underlying these interactions. Here, we present an approach based on the synthesis of several truncated peptides issued from a silicon-specific peptide recovered via phage display technology. We use the photonic response provided by porous silicon microcavities to evaluate the binding efficiency of 14 different peptide derivatives. We identify and engineer a short peptide sequence (SLVSHMQT), revealing the highest affinity for p(+)-Si. The molecular recognition behavior of the obtained peptide fragment can be revealed through mutations allowing identification of the preferential affinity of certain amino acids toward silicon. These results constitute an advance in both the engineering of peptides that reveal recognition properties for silicon and the understanding of biomolecule-material interactions. PMID:26440047

  10. Milk proteins as precursors of bioactive peptides

    Directory of Open Access Journals (Sweden)

    Marta Dziuba

    2009-03-01

    Full Text Available Milk proteins, a source of bioactive peptides, are the subject of numerous research studies aiming to, among others, evaluate their properties as precursors of biologically active peptides. Physiologically active peptides released from their precursors may interact with selected receptors and affect the overall condition and health of humans. By relying on the BIOPEP database of proteins and bioactive peptides, developed by the Department of Food Biochemistry at the University of Warmia and Mazury in Olsztyn (www.uwm.edu.pl/biochemia, the profiles of potential activity of milk proteins were determined and the function of those proteins as bioactive peptide precursors was evaluated based on a quantitative criterion, i.e. the occurrence frequency of bioactive fragments (A. The study revealed that milk proteins are mainly a source of peptides with the following types of activity: antihypertensive (Amax = 0.225, immunomodulating (0.024, smooth muscle contracting (0.011, antioxidative (0.029, dipeptidyl peptidase IV inhibitors (0.148, opioid (0.073, opioid antagonistic (0.053, bonding and transporting metals and metal ions (0.024, antibacterial and antiviral (0.024, and antithrombotic (0.029. The enzymes capable of releasing bioactive peptides from precursor proteins were determined for every type of activity. The results of the experiment indicate that milk proteins such as lactoferrin, α-lactalbumin, β-casein and κ-casein hydrolysed by trypsin can be a relatively abundant source of biologically active peptides.

  11. 肽类肠内营养制剂的益处%Benefits of peptide-based enteral nutrition

    Institute of Scientific and Technical Information of China (English)

    PamelaR.Poberts

    2001-01-01

    Theories of protein digestion have classically asserted thatproteins are completely hydrolyzed to free amino acids within the intestine before absorption occurs.Further,it has been taught that only free amino acids enter the circulation.However,current evidence indicates that hydrolyzed protein fragments(i.e.peptides)also cross the small intestine and reach peripheral tissue via the systemic circulation,Nitrogen sources for enteral nutrition are free amino acids,peptides,or intact proteins.Current experimental evidence indicates that diets which possess the capability of producing luminal peptides are superior to diets lacking this capacity.The parent protein used for enteral nutrition generates specific peptides which may dictate a variety of metabolic responses. Many small peptides derived from the diet possess bioligic activity and may also play a role in regulating physiologic processes.Dietary peptides can have specific actions either locally,on the gastrointestinal tract,or at more distant sites.These peptides may alter cellular metabolism and may act as vasoregulators,growth factors,releasing hormones,,or neurotransmitters.The concept of dietary bioactive peptides offers an explanation for varying effects of diet on physiologic responses.These concepts have spurred research efforts into the possibility of enteral administration of biogenic amines.

  12. An overview of antifungal peptides derived from insect.

    Science.gov (United States)

    Faruck, Mohammad Omer; Yusof, Faridah; Chowdhury, Silvia

    2016-06-01

    Fungi are not classified as plants or animals. They resemble plants in many ways but do not produce chlorophyll or make their own food photosynthetically like plants. Fungi are useful for the production of beer, bread, medicine, etc. More complex than viruses or bacteria; fungi can be destructive human pathogens responsible for various diseases in humans. Most people have a strong natural immunity against fungal infection. However, fungi can cause diseases when this immunity breaks down. In the last few years, fungal infection has increased strikingly and has been accompanied by a rise in the number of deaths of cancer patients, transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients owing to fungal infections. The growth rate of fungi is very slow and quite difficult to identify. A series of molecules with antifungal activity against different strains of fungi have been found in insects, which can be of great importance to tackle human diseases. Insects secrete such compounds, which can be peptides, as a part of their immune defense reactions. Active antifungal peptides developed by insects to rapidly eliminate infectious pathogens are considered a component of the defense munitions. This review focuses on naturally occurring antifungal peptides from insects and their challenges to be used as armaments against human diseases. PMID:26093218

  13. Intracellular Action of a Secreted Peptide Required for Fungal Virulence.

    Science.gov (United States)

    Homer, Christina M; Summers, Diana K; Goranov, Alexi I; Clarke, Starlynn C; Wiesner, Darin L; Diedrich, Jolene K; Moresco, James J; Toffaletti, Dena; Upadhya, Rajendra; Caradonna, Ippolito; Petnic, Sarah; Pessino, Veronica; Cuomo, Christina A; Lodge, Jennifer K; Perfect, John; Yates, John R; Nielsen, Kirsten; Craik, Charles S; Madhani, Hiten D

    2016-06-01

    Quorum sensing (QS) is a bacterial communication mechanism in which secreted signaling molecules impact population function and gene expression. QS-like phenomena have been reported in eukaryotes with largely unknown contributing molecules, functions, and mechanisms. We identify Qsp1, a secreted peptide, as a central signaling molecule that regulates virulence in the fungal pathogen Cryptococcus neoformans. QSP1 is a direct target of three transcription factors required for virulence, and qsp1Δ mutants exhibit attenuated infection, slowed tissue accumulation, and greater control by primary macrophages. Qsp1 mediates autoregulatory signaling that modulates secreted protease activity and promotes cell wall function at high cell densities. Peptide production requires release from a secreted precursor, proQsp1, by a cell-associated protease, Pqp1. Qsp1 sensing requires an oligopeptide transporter, Opt1, and remarkably, cytoplasmic expression of mature Qsp1 complements multiple phenotypes of qsp1Δ. Thus, C. neoformans produces an autoregulatory peptide that matures extracellularly but functions intracellularly to regulate virulence. PMID:27212659

  14. Epithelial Antimicrobial Peptides: Guardian of the Oral Cavity

    Directory of Open Access Journals (Sweden)

    Mayank Hans

    2014-01-01

    Full Text Available Gingival epithelium provides first line of defence from the microorganisms present in dental plaque. It not only provides a mechanical barrier but also has an active immune function too. Gingival epithelial cells participate in innate immunity by producing a range of antimicrobial peptides to protect the host against oral pathogens. These epithelial antimicrobial peptides (EAPs include the β-defensin family, cathelicidin (LL-37, calprotectin, and adrenomedullin. While some are constitutively expressed in gingival epithelial cells, others are induced upon exposure to microbial insults. It is likely that these EAPs have a role in determining the initiation and progression of oral diseases. EAPs are broad spectrum antimicrobials with a different but overlapping range of activity. Apart from antimicrobial activity, they participate in several other crucial roles in host tissues. Some of these, for instance, β-defensins, are chemotactic to immune cells. Others, such as calprotectin are important for wound healing and cell proliferation. Adrenomedullin, a multifunctional peptide, has its biological action in a wide range of tissues. Not only is it a potent vasodilator but also it has several endocrine effects. Knowing in detail the various bioactions of these EAPs may provide us with useful information regarding their utility as therapeutic agents.

  15. Designing peptidic inhibitors of serum amyloid A aggregation process.

    Science.gov (United States)

    Sosnowska, Marta; Skibiszewska, Sandra; Kamińska, Emilia; Wieczerzak, Ewa; Jankowska, Elżbieta

    2016-04-01

    Amyloid A amyloidosis is a life-threatening complication of a wide range of chronic inflammatory, infectious and neoplastic diseases, and the most common form of systemic amyloidosis worldwide. It is characterized by extracellular tissue deposition of fibrils that are composed of fragments of serum amyloid A protein (SAA), a major acute-phase reactant protein, produced predominantly by hepatocytes. Currently, there are no approved therapeutic agents directed against the formation of fibrillar SAA assemblies. We attempted to develop peptidic inhibitors based on their similarity and complementarity to the regions critical for SAA self-association, which they should interact with and block their assembly into amyloid fibrils. Inh1 and inh4 which are comprised of the residues from the amyloidogenic region of SAA1.1 protein and Aβ peptide, respectively, were found by us as capable to significantly suppress aggregation of the SAA1-12 peptide. It was chosen as an aggregation model that mimicks the amyloidogenic nucleus of SAA protein. We suppose that aromatic interactions may be responsible for inhibitory activity of both compounds. We also recognized that aromatic residues are involved in self-association of SAA1-12. PMID:26759015

  16. Peptide nanospheres self-assembled from a modified β-annulus peptide of Sesbania mosaic virus.

    Science.gov (United States)

    Matsuura, Kazunori; Mizuguchi, Yusaku; Kimizuka, Nobuo

    2016-11-01

    A novel β-annulus peptide of Sesbania mosaic virus bearing an FKFE sequence at the C terminus was synthesized, and its self-assembling behavior in water was investigated. Dynamic light scattering and transmission electron microscopy showed that the β-annulus peptide bearing an FKFE sequence self-assembled into approximately 30 nm nanospheres in water at pH 3.8, whereas the β-annulus peptide without the FKFE sequence afforded only irregular aggregates. The peptide nanospheres possessed a definite critical aggregation concentration (CAC = 26 μM), above which the size of nanospheres were nearly unaffected by the peptide concentration. The formation of peptide nanospheres was significantly affected by pH; the peptide did not form any assemblies at pH 2.2, whereas larger aggregates were formed at pH 6.4-11.6. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 470-475, 2016. PMID:26573103

  17. Interpreting peptide mass spectra by VEMS

    DEFF Research Database (Denmark)

    Mathiesen, Rune; Lundsgaard, M.; Welinder, Karen G.;

    2003-01-01

    Most existing Mass Spectra (MS) analysis programs are automatic and provide limited opportunity for editing during the interpretation. Furthermore, they rely entirely on publicly available databases for interpretation. VEMS (Virtual Expert Mass Spectrometrist) is a program for interactive analysis...... of peptide MS/MS spectra imported in text file format. Peaks are annotated, the monoisotopic peaks retained, and the b-and y-ion series identified in an interactive manner. The called peptide sequence is searched against a local protein database for sequence identity and peptide mass. The report...... compares the calculated and the experimental mass spectrum of the called peptide. The program package includes four accessory programs. VEMStrans creates protein databases in FASTA format from EST or cDNA sequence files. VEMSdata creates a virtual peptide database from FASTA files. VEMSdist displays the...

  18. Intracellular signalling by C-peptide.

    Science.gov (United States)

    Hills, Claire E; Brunskill, Nigel J

    2008-01-01

    C-peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C-peptide when administered to individuals with type I diabetes. Data indicate that C-peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G-protein coupled. Binding of C-peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI-3-kinase activity, stimulation of the Na(+)/K(+) ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C-peptide may serve as a potential therapeutic agent for the treatment or prevention of long-term complications associated with diabetes. PMID:18382618

  19. Intracellular Signalling by C-Peptide

    Directory of Open Access Journals (Sweden)

    Claire E. Hills

    2008-01-01

    Full Text Available C-peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C-peptide when administered to individuals with type I diabetes. Data indicate that C-peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G-protein coupled. Binding of C-peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI-3-kinase activity, stimulation of the Na+/K+ ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C-peptide may serve as a potential therapeutic agent for the treatment or prevention of long-term complications associated with diabetes.

  20. Insights into How Cyclic Peptides Switch Conformations.

    Science.gov (United States)

    McHugh, Sean M; Rogers, Julia R; Yu, Hongtao; Lin, Yu-Shan

    2016-05-10

    Cyclic peptides have recently emerged as promising modulators of protein-protein interactions. However, it is currently highly difficult to predict the structures of cyclic peptides owing to their rugged conformational free energy landscape, which prevents sampling of all thermodynamically relevant conformations. In this article, we first investigate how a relatively flexible cyclic hexapeptide switches conformations. It is found that, although the circular geometry of small cyclic peptides of size 6-8 may require rare, coherent dihedral changes to sample a new conformation, the changes are rather local, involving simultaneous changes of ϕi and ψi or ψi and ϕi+1. The understanding of how these cyclic peptides switch conformations enables the use of metadynamics simulations with reaction coordinates specifically targeting such coupled two-dihedral changes to effectively sample cyclic peptide conformational space. PMID:27031286

  1. Radiolabeled peptides: experimental and clinical applications

    International Nuclear Information System (INIS)

    Radiolabeled receptor specific biomolecules hold unlimited potential in nuclear medicine. During the past few years much attention has been drawn to the development radiolabeled peptides for a variety of diagnostic applications, as well as for therapy of malignant tumors. Although only one peptide, In-111-DTPA-(D)-Phe1-octreotide, is available commercially for oncologic imaging, many more have been examined in humans with hematological disorders, and the early results appear to be promising. Impetus generated by these results have prompted investigators to label peptides with such radionuclides as Tc-99m, I-123, F-18, Cu-64, and Y-90. This review is intended to highlight the qualities of peptides, summarize the clinical results, and address some important issues associated with radiolabeling of highly potent peptides. While doing so, various methods of radiolabeling have been described, and their strengths and weaknesses have also been discussed. (author)

  2. Peptide-Lipid Interactions: Experiments and Applications

    Directory of Open Access Journals (Sweden)

    Massimiliano Galdiero

    2013-09-01

    Full Text Available The interactions between peptides and lipids are of fundamental importance in the functioning of numerous membrane-mediated cellular processes including antimicrobial peptide action, hormone-receptor interactions, drug bioavailability across the blood-brain barrier and viral fusion processes. Moreover, a major goal of modern biotechnology is obtaining new potent pharmaceutical agents whose biological action is dependent on the binding of peptides to lipid-bilayers. Several issues need to be addressed such as secondary structure, orientation, oligomerization and localization inside the membrane. At the same time, the structural effects which the peptides cause on the lipid bilayer are important for the interactions and need to be elucidated. The structural characterization of membrane active peptides in membranes is a harsh experimental challenge. It is in fact accepted that no single experimental technique can give a complete structural picture of the interaction, but rather a combination of different techniques is necessary.

  3. Improved machine learning method for analysis of gas phase chemistry of peptides

    Directory of Open Access Journals (Sweden)

    Ahn Natalie

    2008-12-01

    Full Text Available Abstract Background Accurate peptide identification is important to high-throughput proteomics analyses that use mass spectrometry. Search programs compare fragmentation spectra (MS/MS of peptides from complex digests with theoretically derived spectra from a database of protein sequences. Improved discrimination is achieved with theoretical spectra that are based on simulating gas phase chemistry of the peptides, but the limited understanding of those processes affects the accuracy of predictions from theoretical spectra. Results We employed a robust data mining strategy using new feature annotation functions of MAE software, which revealed under-prediction of the frequency of occurrence in fragmentation of the second peptide bond. We applied methods of exploratory data analysis to pre-process the information in the MS/MS spectra, including data normalization and attribute selection, to reduce the attributes to a smaller, less correlated set for machine learning studies. We then compared our rule building machine learning program, DataSqueezer, with commonly used association rules and decision tree algorithms. All used machine learning algorithms produced similar results that were consistent with expected properties for a second gas phase mechanism at the second peptide bond. Conclusion The results provide compelling evidence that we have identified underlying chemical properties in the data that suggest the existence of an additional gas phase mechanism for the second peptide bond. Thus, the methods described in this study provide a valuable approach for analyses of this kind in the future.

  4. Chitosan-Poly (I:C-PADRE Based Nanoparticles as Delivery Vehicles for Synthetic Peptide Vaccines

    Directory of Open Access Journals (Sweden)

    Jorge F. Correia-Pinto

    2015-09-01

    Full Text Available The safety and precision of peptide antigens has prompted the search for adjuvants capable of increasing the immune response against these intrinsically poorly immunogenic antigens. The integration of both immunostimulants and peptide antigens within nanometric delivery systems for their co-delivery to immune cells is a promising vaccination strategy. With this in mind, the potential synergistic effect of the immunostimulant poly (I:C (pIC and a T-Helper peptide (PADRE, integrated into a chitosan (CS based nanostructure, was explored. The value of this nanostructured combination of materials was assessed for a peptide antigen (1338aa derived from the HPV-16 L2 protein. These nanoparticles, produced by ionic gelation technique, exhibited a nanometric size (<300 nm, a high positive surface charge (>40 mV and high pIC association efficiency (>96%. They also showed capacity for the association of both the 1338aa and PADRE peptides. The influence of the presence of pIC and PADRE in the nanocomposition, as well as that of the peptide presentation form (encapsulated versus surface adsorbed on the antibody induction was evaluated in a preliminary in vivo study. The data obtained highlights the possibility to engineer nanoparticles through the rational combination of a number of adjuvant molecules together with the antigen.

  5. Novel Bifunctional Natriuretic Peptides as Potential Therapeutics*

    Science.gov (United States)

    Dickey, Deborah M.; Burnett, John C.; Potter, Lincoln R.

    2008-01-01

    Synthetic atrial natriuretic peptide (carperitide) and B-type natriuretic peptide (BNP; nesiritide) are used to treat congestive heart failure. However, despite beneficial cardiac unloading properties, reductions in renal perfusion pressures limit their clinical effectiveness. Recently, CD-NP, a chimeric peptide composed of C-type natriuretic peptide (CNP) fused to the C-terminal tail of Dendroaspis natriuretic peptide (DNP), was shown to be more glomerular filtration rate-enhancing than BNP in dogs. However, the molecular basis for the increased responsiveness was not determined. Here, we show that the DNP tail has a striking effect on CNP, converting it from a non-agonist to a partial agonist of natriuretic peptide receptor (NPR)-A while maintaining the ability to activate NPR-B. This effect is specific for human receptors because CD-NP was only a slightly better activator of rat NPR-A due to the promiscuous nature of CNP in this species. Interesting, the DNP tail alone had no effect on any NPR even though it is effective in vivo. To further increase the potency of CD-NP for NPR-A, we converted two different triplet sequences within the CNP ring to their corresponding residues in BNP. Both variants demonstrated increased affinity and full agonist activity for NPR-A, whereas one was as potent as any NPR-A activator known. In contrast to a previous report, we found that DNP binds the natriuretic peptide clearance receptor (NPR-C). However, none of the chimeric peptides bound NPR-C with significantly higher affinity than endogenous ligands. We suggest that bifunctional chimeric peptides represent a new generation of natriuretic peptide therapeutics. PMID:18940797

  6. Novel bifunctional natriuretic peptides as potential therapeutics.

    Science.gov (United States)

    Dickey, Deborah M; Burnett, John C; Potter, Lincoln R

    2008-12-12

    Synthetic atrial natriuretic peptide (carperitide) and B-type natriuretic peptide (BNP; nesiritide) are used to treat congestive heart failure. However, despite beneficial cardiac unloading properties, reductions in renal perfusion pressures limit their clinical effectiveness. Recently, CD-NP, a chimeric peptide composed of C-type natriuretic peptide (CNP) fused to the C-terminal tail of Dendroaspis natriuretic peptide (DNP), was shown to be more glomerular filtration rate-enhancing than BNP in dogs. However, the molecular basis for the increased responsiveness was not determined. Here, we show that the DNP tail has a striking effect on CNP, converting it from a non-agonist to a partial agonist of natriuretic peptide receptor (NPR)-A while maintaining the ability to activate NPR-B. This effect is specific for human receptors because CD-NP was only a slightly better activator of rat NPR-A due to the promiscuous nature of CNP in this species. Interesting, the DNP tail alone had no effect on any NPR even though it is effective in vivo. To further increase the potency of CD-NP for NPR-A, we converted two different triplet sequences within the CNP ring to their corresponding residues in BNP. Both variants demonstrated increased affinity and full agonist activity for NPR-A, whereas one was as potent as any NPR-A activator known. In contrast to a previous report, we found that DNP binds the natriuretic peptide clearance receptor (NPR-C). However, none of the chimeric peptides bound NPR-C with significantly higher affinity than endogenous ligands. We suggest that bifunctional chimeric peptides represent a new generation of natriuretic peptide therapeutics. PMID:18940797

  7. Modelling water molecules inside cyclic peptide nanotubes

    Science.gov (United States)

    Tiangtrong, Prangsai; Thamwattana, Ngamta; Baowan, Duangkamon

    2016-03-01

    Cyclic peptide nanotubes occur during the self-assembly process of cyclic peptides. Due to the ease of synthesis and ability to control the properties of outer surface and inner diameter by manipulating the functional side chains and the number of amino acids, cyclic peptide nanotubes have attracted much interest from many research areas. A potential application of peptide nanotubes is their use as artificial transmembrane channels for transporting ions, biomolecules and waters into cells. Here, we use the Lennard-Jones potential and a continuum approach to study the interaction of a water molecule in a cyclo[(- D-Ala- L-Ala)_4-] peptide nanotube. Assuming that each unit of a nanotube comprises an inner and an outer tube and that a water molecule is made up of a sphere of two hydrogen atoms uniformly distributed over its surface and a single oxygen atom at the centre, we determine analytically the interaction energy of the water molecule and the peptide nanotube. Using this energy, we find that, independent of the number of peptide units, the water molecule will be accepted inside the nanotube. Once inside the nanotube, we show that a water molecule prefers to be off-axis, closer to the surface of the inner nanotube. Furthermore, our study of two water molecules inside the peptide nanotube supports the finding that water molecules form an array of a 1-2-1-2 file inside peptide nanotubes. The theoretical study presented here can facilitate thorough understanding of the behaviour of water molecules inside peptide nanotubes for applications, such as artificial transmembrane channels.

  8. Molecular Cloning and Sequence Analysis of the cDNAs Encoding Toxin-Like Peptides from the Venom Glands of Tarantula Grammostola rosea

    Directory of Open Access Journals (Sweden)

    Tadashi Kimura

    2012-01-01

    Full Text Available Tarantula venom glands produce a large variety of bioactive peptides. Here we present the identification of venom components obtained by sequencing clones isolated from a cDNA library prepared from the venom glands of the Chilean common tarantula, Grammostola rosea. The cDNA sequences of about 1500 clones out of 4000 clones were analyzed after selection using several criteria. Forty-eight novel toxin-like peptides (GTx1 to GTx7, and GTx-TCTP and GTx-CRISP were predicted from the nucleotide sequences. Among these peptides, twenty-four toxins are ICK motif peptides, eleven peptides are MIT1-like peptides, and seven are ESTX-like peptides. Peptides similar to JZTX-64, aptotoxin, CRISP, or TCTP are also obtained. GTx3 series possess a cysteine framework that is conserved among vertebrate MIT1, Bv8, prokineticins, and invertebrate astakines. GTx-CRISP is the first CRISP-like protein identified from the arthropod venom. Real-time PCR revealed that the transcripts for TCTP-like peptide are expressed in both the pereopodal muscle and the venom gland. Furthermore, a unique peptide GTx7-1, whose signal and prepro sequences are essentially identical to those of HaTx1, was obtained.

  9. Angiotensin-I-converting enzyme-inhibitory peptides in commercial Wisconsin Cheddar cheeses of different ages.

    Science.gov (United States)

    Lu, Y; Govindasamy-Lucey, S; Lucey, J A

    2016-01-01

    Bioactive peptides, including angiotensin-I-converting enzyme-inhibitory (ACEI) peptides, were investigated in commercially produced Wisconsin Cheddar cheeses that ranged in age from ≤ 6d to more than 2 yr. The ACEI activity of cheese was determined in water-soluble extracts (WSE) that were fractionated for components with molecular weight (MW) ≤ 3,000 Da, and peptides identified using HPLC and tandem mass spectrometry. The number of types of bioactive peptides increased with an increase in ripening time. Six of the identified ACEI peptides, Ile-Pro-Pro (IPP), Val-Pro-Pro (VPP), Glu-Lys-Asp-Glu-Arg-Phe (EKDERF), Val-Arg-Tyr-Leu (VRYL), Tyr-Pro-Phe-Pro-Gly-Pro-Ile-Pro-Asn (YPFPGPIPN), and Phe-Phe-Val-Ala-Pro (FFVAP), with known high ACEI activity (low IC50 values, the concentration needed to inhibit ACE to 50% of its original activity) were synthesized and used to quantify the amounts of these peptides in various cheese extracts. The concentrations of these 6 ACEI peptides increased up to a certain stage of ripening. The maximum contents of IPP, VPP, and EKDERF were 2.8, 7.4, and 5.3mg/100 g of cheese, respectively, and these levels were found in a 1-yr-old Cheddar cheese sample. The maximum content of VRYL (7.5mg/100 g of cheese) was found in a 2-yr-old Cheddar cheese sample, whereas the maximum content of YPFPGPIPN (6.8 mg/100 g of cheese) was found in a 6-mo-old Cheddar cheese sample. Trace amounts of FFVAP were found in these cheeses. Aged Cheddar cheese was found to be a rich source of ACEI peptides even though large differences exist between cheeses from different manufacturers. PMID:26506550

  10. Insights into the Role of Biomineralizing Peptide Surfactants on Making Nanoemulsion-Templated Silica Nanocapsules.

    Science.gov (United States)

    Hui, Yue; Wibowo, David; Zhao, Chun-Xia

    2016-01-26

    We recently developed a novel approach for making oil-core silica-shell nanocapsules using designed bifunctional peptides (also called biomineralizing peptide surfactants) having both surface activity and biomineralization activity. Using the bifunctional peptides, oil-in-water nanoemulsion templates can be readily prepared, followed by the silicification directed exclusively onto the oil droplet surfaces and thus the formation of the silica shell. To explore their roles in the synthesis of silica nanocapsules, two bifunctional peptides, AM1 and SurSi, were systematically studied and compared. Peptide AM1, which was designed as a stimuli-responsive surfactant, demonstrated quick adsorption kinetics with a rapid decrease in the oil-water interfacial tension, thus resulting in the formation of nanoemulsions with a droplet size as small as 38 nm. Additionally, the nanoemulsions showed good stability over 4 weeks because of the formation of a histidine-Zn(2+) interfacial network. In comparison, the SurSi peptide that was designed by modularizing an AM1-like surface-active module with a highly cationic biosilicification-active module was unable to effectively reduce the oil-water interfacial tension because of its high molecular charge at neutral pH. The slow adsorption resulted in the formation of less stable nanoemulsions with a larger size (60 nm) than that of AM1. Besides, both AM1 and SurSi were found to be able to induce biomimetic silica formation. SurSi produced well-dispersed and uniform silica nanospheres in the bulk solution, whereas AM1 generated only irregular silica aggregates. Consequently, well-defined silica nanocapsules were synthesized using SurSi nanoemulsion templates, whereas silica aggregates instead of nanocapsules predominated when templating AM1 nanoemulsions. This finding indicated that the capability of peptide surfactants to form isolated silica nanospheres might play a role in the successful fabrication of silica nanocapsules. This

  11. Molecular cloning and expression of gene fragments from corynebacteriophage beta encoding enzymatically active peptides of diphtheria toxin.

    OpenAIRE

    Tweten, R K; Collier, R J

    1983-01-01

    Two restriction fragments from corynebacteriophage beta vir tox+ that encode peptides similar to diphtheria toxin fragment A and the chain termination fragment, CRM45, have been cloned into Escherichia coli in plasmid pBR322. Clones containing the recombinant plasmids produced gene products that were active in catalyzing the ADP ribosylation of elongation factor 2 and were reactive with diphtheria toxin antiserum. Toxin-related peptides were found primarily in the periplasmic compartment and ...

  12. Sec-Mediated Transport of Posttranslationally Dehydrated Peptides in Lactococcus lactis

    NARCIS (Netherlands)

    Kuipers, Anneke; Wierenga, Jenny; Rink, Rick; Kluskens, Leon D.; Driessen, Arnold J.M.; Kuipers, Oscar P.; Moll, Gert N.

    2006-01-01

    Nisin is a lanthionine-containing antimicrobial peptide produced by Lactococcus lactis. Its (methyl)lanthionines are introduced by two posttranslational enzymatic steps involving the dehydratase NisB, which dehydrates serine and threonine residues, and the cyclase NisC, which couples these dehydrate

  13. Identification of a β-glucosidase from the Mucor circinelloides genome by peptide pattern recognition

    DEFF Research Database (Denmark)

    Yuhong, Huang; Busk, Peter Kamp; Grell, Morten Nedergaard;

    2014-01-01

    Mucor circinelloides produces plant cell wall degrading enzymes that allow it to grow on complex polysaccharides. Although the genome of M. circinelloides has been sequenced, only few plant cell wall degrading enzymes are annotated in this species. We applied peptide pattern recognition, which is a...

  14. Tandem heterocyclization domains in a nonribosomal peptide synthetase essential for siderophore biosynthesis in Vibrio anguillarum

    NARCIS (Netherlands)

    Di Lorenzo, M.; Stork, M.; Naka, H.; Tolmasky, M.E.; Crosa, J.H.

    2008-01-01

    Anguibactin, the siderophore produced by Vibrio anguillarum 775, is synthesized via a nonribosomal peptide synthetase (NRPS) mechanism. Most of the genes required for anguibactin biosynthesis are harbored by the pJM1 plasmid. Complete sequencing of this plasmid identified an orf encoding a 108 kDa p

  15. Boosting Farm Produce Supply

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the wake of escalating inflation,securing farm produce supply and stablizing grain prices could help to alleviate economic pressure The Chinese Government has pledged to secure a stable supply of farm produce.According to a document released after the annual Central Rural Work Conference held on December 22-23 in Beijing,preventing short supplies of farm produce and avoiding"ex-

  16. The novel amyloid-beta peptide aptamer inhibits intracellular amyloid-beta peptide toxicity

    Institute of Scientific and Technical Information of China (English)

    Xu Wang; Yi Yang; Mingyue Jia; Chi Ma; Mingyu Wang; Lihe Che; Yu Yang; Jiang Wu

    2013-01-01

    Amyloid β peptide binding alcohol dehydrogenase (ABAD) decoy peptide (DP) can competitively antagonize binding of amyloid β peptide to ABAD and inhibit the cytotoxic effects of amyloid β peptide. Based on peptide aptamers, the present study inserted ABAD-DP into the disulfide bond of human thioredoxin (TRX) using molecular cloning technique to construct a fusion gene that can express the TRX1-ABAD-DP-TRX2 aptamer. Moreover, adeno-associated virus was used to allow its stable expression. Immunofluorescent staining revealed the co-expression of the transduced fusion gene TRX1-ABAD-DP-TRX2 and amyloid β peptide in NIH-3T3 cells, indicating that the TRX1-ABAD-DP-TRX2 aptamer can bind amyloid β peptide within cells. In addition, cell morphology and MTT results suggested that TRX1-ABAD-DP-TRX2 attenuated amyloid β peptide-induced SH-SY5Y cell injury and improved cell viability. These findings confirmed the possibility of constructing TRX-based peptide aptamer using ABAD-DP. Moreover, TRX1-ABAD-DP-TRX2 inhibited the cytotoxic effect of amyloid β peptide.

  17. Interactions of Bio-Inspired Membranes with Peptides and Peptide-Mimetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Michael Sebastiano

    2015-08-01

    Full Text Available Via Dissipative Particle Dynamics (DPD and implicit solvent coarse-grained (CG Molecular Dynamics (MD we examine the interaction of an amphiphilic cell-penetrating peptide PMLKE and its synthetic counterpart with a bio-inspired membrane. We use the DPD technique to investigate the interaction of peptide-mimetic nanoparticles, or nanopins, with a three-component membrane. The CG MD approach is used to investigate the interaction of a cell-penetrating peptide PMLKE with single-component membrane. We observe the spontaneous binding and subsequent insertion of peptide and nanopin in the membrane by using CG MD and DPD approaches, respectively. In addition, we find that the insertion of peptide and nanopins is mainly driven by the favorable enthalpic interactions between the hydrophobic components of the peptide, or nanopin, and the membrane. Our study provides insights into the mechanism underlying the interactions of amphiphilic peptide and peptide-mimetic nanoparticles with a membrane. The result of this study can be used to guide the functional integration of peptide and peptide-mimetic nanoparticles with a cell membrane.

  18. Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides

    Energy Technology Data Exchange (ETDEWEB)

    Vegt, Erik; Eek, Annemarie; Oyen, Wim J.G.; Gotthardt, Martin; Boerman, Otto C. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine (444), PO Box 9101, Nijmegen (Netherlands); Jong, Marion de [Erasmus Medical Centre, Department of Nuclear Medicine, Rotterdam (Netherlands)

    2010-02-15

    In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of {sup 111}In-albumin, {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide was determined. FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of {sup 111}In-albumin, {sup 111}In-exendin and {sup 111}In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide 6), was selected for in vivo testing. In rats, 5 mg of peptide 6 very efficiently inhibited the renal uptake of {sup 111}In-minigastrin, by 88%. Uptake of {sup 111}In-exendin and {sup 111}In-octreotide was reduced by 26 and 33%, respectively. The albumin-derived peptide 6 efficiently inhibited the renal reabsorption of {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide and is a promising candidate for kidney protection in PRRT. (orig.)

  19. Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides

    International Nuclear Information System (INIS)

    In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of 111In-albumin, 111In-minigastrin, 111In-exendin and 111In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of 111In-minigastrin, 111In-exendin and 111In-octreotide was determined. FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of 111In-albumin, 111In-exendin and 111In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide 6), was selected for in vivo testing. In rats, 5 mg of peptide 6 very efficiently inhibited the renal uptake of 111In-minigastrin, by 88%. Uptake of 111In-exendin and 111In-octreotide was reduced by 26 and 33%, respectively. The albumin-derived peptide 6 efficiently inhibited the renal reabsorption of 111In-minigastrin, 111In-exendin and 111In-octreotide and is a promising candidate for kidney protection in PRRT. (orig.)

  20. rapmad: Robust analysis of peptide microarray data

    Directory of Open Access Journals (Sweden)

    Rothermel Andrée

    2011-08-01

    Full Text Available Abstract Background Peptide microarrays offer an enormous potential as a screening tool for peptidomics experiments and have recently seen an increased field of application ranging from immunological studies to systems biology. By allowing the parallel analysis of thousands of peptides in a single run they are suitable for high-throughput settings. Since data characteristics of peptide microarrays differ from DNA oligonucleotide microarrays, computational methods need to be tailored to these specifications to allow a robust and automated data analysis. While follow-up experiments can ensure the specificity of results, sensitivity cannot be recovered in later steps. Providing sensitivity is thus a primary goal of data analysis procedures. To this end we created rapmad (Robust Alignment of Peptide MicroArray Data, a novel computational tool implemented in R. Results We evaluated rapmad in antibody reactivity experiments for several thousand peptide spots and compared it to two existing algorithms for the analysis of peptide microarrays. rapmad displays competitive and superior behavior to existing software solutions. Particularly, it shows substantially improved sensitivity for low intensity settings without sacrificing specificity. It thereby contributes to increasing the effectiveness of high throughput screening experiments. Conclusions rapmad allows the robust and sensitive, automated analysis of high-throughput peptide array data. The rapmad R-package as well as the data sets are available from http://www.tron-mz.de/compmed.

  1. Conus Peptides A Rich Pharmaceutical Treasure

    Institute of Scientific and Technical Information of China (English)

    Cheng-Zhong WANG; Cheng-Wu CHI

    2004-01-01

    Marine predatory cone snails (genus Conus) with over 500 species represent what is arguably the largest single genus of marine animals alive today. All Conus are venomous and utilize a complex mixture of Conus peptides to capture their preys and for other biological purposes. Each component of Conus peptides selectively targets a specific subtype of ion channels, neurotransmitter receptors or transporters.Owing to their diversity, more than 50,000 distinct active peptides are theoretically estimated in Conus venoms. These diversified toxins are generally categorized into several superfamilies and/or families based on their characteristic arrangements of cysteine residues and pharmacological actions. Some mechanisms underlying the remarkable diversity of Conus peptides have been postulated: the distinctive gene structure, gene duplication and/or allelic selection, genus speciation, and sophisticated expression pattern and posttranslational modification of these peptides. Due to their highly pharmacological potency and target selectivity, Conus peptides have attracted extensive attention with their potentials to be developed as new research tools in neuroscience field and as novel medications in clinic for pain, epilepsy and other neuropathic disorders. Several instructive lessons for our drug development could be also learnt from these neuropharmacological "expertises". Conus peptides comprise a rich resource for neuropharmacologists, and most of them await to be explored.

  2. C-Peptide and its intracellular signaling.

    Science.gov (United States)

    Hills, Claire E; Brunskill, Nigel J

    2009-01-01

    Although long believed to be inert, C-peptide has now been shown to have definite biological effects both in vitro and in vivo in diabetic animals and in patients with type 1 diabetes. These effects point to a protective action of C-peptide against the development of diabetic microvascular complications. Underpinning these observations is undisputed evidence of C-peptide binding to a variety of cell types at physiologically relevant concentrations, and the downstream stimulation of multiple cell signaling pathways and gene transcription via the activation of numerous transcription factors. These pathways affect such fundamental cellular processes as re-absorptive and/or secretory phenotype, migration, growth, and survival. Whilst the receptor remains to be identified, experimental data points strongly to the existence of a specific G-protein-coupled receptor for C-peptide. Of the cell types studied so far, kidney tubular cells express the highest number of C-peptide binding sites. Accordingly, C-peptide exerts major effects on the function of these cells, and in the context of diabetic nephropathy appears to antagonise the pathophysiological effects of major disease mediators such as TGFbeta1 and TNFalpha. Therefore, based on its cellular activity profile C-peptide appears well positioned for development as a therapeutic tool to treat microvascular complications in type 1 diabetes. PMID:20039003

  3. Novel pH-Sensitive Cyclic Peptides.

    Science.gov (United States)

    Weerakkody, Dhammika; Moshnikova, Anna; El-Sayed, Naglaa Salem; Adochite, Ramona-Cosmina; Slaybaugh, Gregory; Golijanin, Jovana; Tiwari, Rakesh K; Andreev, Oleg A; Parang, Keykavous; Reshetnyak, Yana K

    2016-01-01

    A series of cyclic peptides containing a number of tryptophan (W) and glutamic acid (E) residues were synthesized and evaluated as pH-sensitive agents for targeting of acidic tissue and pH-dependent cytoplasmic delivery of molecules. Biophysical studies revealed the molecular mechanism of peptides action and localization within the lipid bilayer of the membrane at high and low pHs. The symmetric, c[(WE)4WC], and asymmetric, c[E4W5C], cyclic peptides translocated amanitin, a polar cargo molecule of similar size, across the lipid bilayer and induced cell death in a pH- and concentration-dependent manner. Fluorescently-labelled peptides were evaluated for targeting of acidic 4T1 mammary tumors in mice. The highest tumor to muscle ratio (5.6) was established for asymmetric cyclic peptide, c[E4W5C], at 24 hours after intravenous administration. pH-insensitive cyclic peptide c[R4W5C], where glutamic acid residues (E) were replaced by positively charged arginine residues (R), did not exhibit tumor targeting. We have introduced a novel class of cyclic peptides, which can be utilized as a new pH-sensitive tool in investigation or targeting of acidic tissue. PMID:27515582

  4. Untapped Resources: Biotechnological Potential of Peptides and Secondary Metabolites in Archaea

    Science.gov (United States)

    Charlesworth, James C.; Burns, Brendan P.

    2015-01-01

    Archaea are an understudied domain of life often found in “extreme” environments in terms of temperature, salinity, and a range of other factors. Archaeal proteins, such as a wide range of enzymes, have adapted to function under these extreme conditions, providing biotechnology with interesting activities to exploit. In addition to producing structural and enzymatic proteins, archaea also produce a range of small peptide molecules (such as archaeocins) and other novel secondary metabolites such as those putatively involved in cell communication (acyl homoserine lactones), which can be exploited for biotechnological purposes. Due to the wide array of metabolites produced there is a great deal of biotechnological potential from antimicrobials such as diketopiperazines and archaeocins, as well as roles in the cosmetics and food industry. In this review we will discuss the diversity of small molecules, both peptide and nonpeptide, produced by archaea and their potential biotechnological applications. PMID:26504428

  5. Natriuretic peptides in cardiometabolic regulation and disease

    DEFF Research Database (Denmark)

    Zois, Nora E; Bartels, Emil D; Hunter, Ingrid; Kousholt, Birgitte S; Olsen, Lars Henning; Goetze, Jens P

    2014-01-01

    decade. Dysregulation of the natriuretic peptide system has been associated with obesity, glucose intolerance, type 2 diabetes mellitus, and essential hypertension. Moreover, the natriuretic peptides have been implicated in the protection against atherosclerosis, thrombosis, and myocardial ischaemia. All......In the 30 years since the identification of the natriuretic peptides, their involvement in regulating fluid and blood pressure has become firmly established. Data indicating a role for these hormones in lifestyle-related metabolic and cardiovascular disorders have also accumulated over the past...... role in lifestyle-related metabolic and cardiovascular disorders....

  6. Imaging tumors with peptide-based radioligands

    Energy Technology Data Exchange (ETDEWEB)

    Behr, T. M.; Gotthardt, M.; Barth, A.; Behe, M. [Philipps-University of Marburg, Dept. of Nuclear Medicine, Marburg (Germany)

    2001-06-01

    Regulatory peptides are small, readily diffusable and potent natural substances with a wide spectrum of receptor-mediated actions in humans. High affinity receptors for these peptides are (over)-expressed in many neoplasms, and these receptors may represent, therefore, new molecular targets for cancer diagnosis and therapy. This review aims to give an overview of the peptide-based radiopharmaceuticals which are presently already commercially available or which are in advanced stages of their clinical testing so that their broader availability is anticipated soon. Physiologically, these peptides bind to and act through G protein-coupled receptors in the cell membrane. Historically, somatostatin analogs are the first class of receptor binding peptides having gained clinical application. In {sup 111}In-DTPA-(D-Phe{sup 1})-octreotide is the first and only radio peptide which has obtained regulatory approval in Europe and the United States to date. Extensive clinical studies involving several thousands of patients have shown that the major clinical application of somatostatin receptor scintigraphy is the detection and the staging of gastroenteropancreatic neuroendocrine tumors (carcinoids). In these tumors, octreotide scintigraphy is superior to any other staging method. However, its sensitivity and accuracy in other, more frequent neoplasms is limited. Radiolabeled vasoactive intestinal peptide (VIP) has been shown to visualize the majority of gastrointestinal adenocarcinomas, as well as some neuroendocrine tumors, including insulinomas (the latter being often missed by somatostatin receptor scintigraphy). Due to the outstanding diagnostic accuracy of the pentagastrin test in detecting the presence, persistence, or recurrence of medullary thyroid cancer (MTC), it was postulated the expression of the corresponding (i.e. cholecystokinin (CCK-)-B) receptor type in human MTC. This receptor is also widely expressed on human small-cell lung. Indeed, {sup 111}In-labeled DTPA

  7. Biologically produced sulfur

    NARCIS (Netherlands)

    Kleinjan, W.E.; Keizer, de A.; Janssen, A.J.H.

    2003-01-01

    Sulfur compound oxidizing bacteria produce sulfur as an intermediate in the oxidation of hydrogen sulfide to sulfate. Sulfur produced by these microorganisms can be stored in sulfur globules, located either inside or outside the cell. Excreted sulfur globules are colloidal particles which are stabil

  8. 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

  9. Exploiting Protected Maleimides to Modify Oligonucleotides, Peptides and Peptide Nucleic Acids

    Directory of Open Access Journals (Sweden)

    Clément Paris

    2015-04-01

    Full Text Available This manuscript reviews the possibilities offered by 2,5-dimethylfuran-protected maleimides. Suitably derivatized building blocks incorporating the exo Diels-Alder cycloadduct can be introduced at any position of oligonucleotides, peptide nucleic acids, peptides and peptoids, making use of standard solid-phase procedures. Maleimide deprotection takes place upon heating, which can be followed by either Michael-type or Diels-Alder click conjugation reactions. However, the one-pot procedure in which maleimide deprotection and conjugation are simultaneously carried out provides the target conjugate more quickly and, more importantly, in better yield. This procedure is compatible with conjugates involving oligonucleotides, peptides and peptide nucleic acids. A variety of cyclic peptides and oligonucleotides can be obtained from peptide and oligonucleotide precursors incorporating protected maleimides and thiols.

  10. Combined Statistical Analyses of Peptide Intensities and Peptide Occurrences Improves Identification of Significant Peptides from MS-based Proteomics Data

    Energy Technology Data Exchange (ETDEWEB)

    Webb-Robertson, Bobbie-Jo M.; McCue, Lee Ann; Waters, Katrina M.; Matzke, Melissa M.; Jacobs, Jon M.; Metz, Thomas O.; Varnum, Susan M.; Pounds, Joel G.

    2010-11-01

    Liquid chromatography-mass spectrometry-based (LC-MS) proteomics uses peak intensities of proteolytic peptides to infer the differential abundance of peptides/proteins. However, substantial run-to-run variability in peptide intensities and observations (presence/absence) of peptides makes data analysis quite challenging. The missing abundance values in LC-MS proteomics data are difficult to address with traditional imputation-based approaches because the mechanisms by which data are missing are unknown a priori. Data can be missing due to random mechanisms such as experimental error, or non-random mechanisms such as a true biological effect. We present a statistical approach that uses a test of independence known as a G-test to test the null hypothesis of independence between the number of missing values and the experimental groups. We pair the G-test results evaluating independence of missing data (IMD) with a standard analysis of variance (ANOVA) that uses only means and variances computed from the observed data. Each peptide is therefore represented by two statistical confidence metrics, one for qualitative differential observation and one for quantitative differential intensity. We use two simulated and two real LC-MS datasets to demonstrate the robustness and sensitivity of the ANOVA-IMD approach for assigning confidence to peptides with significant differential abundance among experimental groups.

  11. Peptide Internalization Enabled by Folding: Triple Helical Cell-Penetrating Peptides

    OpenAIRE

    Shinde, Aparna; Feher, Katie M.; Hu, Chloe; Slowinska, Katarzyna

    2014-01-01

    Cell-Penetrating Peptides (CPPs) are known as efficient transporters of molecular cargo across cellular membranes. Their properties make them ideal candidates for in vivo applications. However, challenges in development of effective CPPs still exist: CPPs are often fast degraded by proteases and large concentration of CPPs required for cargo transporting can cause cytotoxicity. It was previously shown that restricting peptide flexibility can improve peptide stability against enzymatic degrada...

  12. A Peptide & Peptide Nucleic Acid Synthesis Technology for Transporter Molecules and Theranostics - The SPPS

    OpenAIRE

    Pipkorn, Ruediger; Braun, Klaus; Wiessler, Manfred; Waldeck, Waldemar; Schrenk, Hans-Hermann; Koch, Mario; Semmler, Wolfhard; Komljenovic, Dorde

    2014-01-01

    Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and functi...

  13. Effect of peptide secondary structure on peptide amphiphile supramolecular structure and interactions

    OpenAIRE

    Missirlis, Dimitris; Chworos, Arkadiusz; Fu, Caroline J; Khant, Htet A.; Krogstad, Daniel V.; Tirrell, Matthew

    2011-01-01

    Bottom-up fabrication of self-assembled nanomaterials requires control over forces and interactions between building blocks. We here report on the formation and architecture of supramolecular structures constructed from two different peptide amphiphiles. Inclusion of four alanines between a 16-mer peptide and a 16-carbon long aliphatic tail resulted in a secondary structure shift of the peptide headgroups from alpha helices to beta sheets. A concomitant shift in self-assembled morphology from...

  14. A statistical approach to determining responses to individual peptides from pooled-peptide ELISpot data.

    Science.gov (United States)

    Ström, Peter; Støer, Nathalie; Borthwick, Nicola; Dong, Tao; Hanke, Tomáš; Reilly, Marie

    2016-08-01

    To investigate in detail the effect of infection or vaccination on the human immune system, ELISpot assays are used to simultaneously test the immune response to a large number of peptides of interest. Scientists commonly use "peptide pools", where, instead of an individual peptide, a test well contains a group of peptides. Since the response from a well may be due to any or many of the peptides in the pool, pooled assays usually need to be followed by confirmatory assays of a number of individual peptides. We present a statistical method that enables estimation of individual peptide responses from pool responses using the Expectation Maximization (EM) algorithm for "incomplete data". We demonstrate the accuracy and precision of these estimates in simulation studies of ELISpot plates with 90 pools of 6 or 7 peptides arranged in three dimensions and three Mock wells for the estimation of background. In analysis of real pooled data from 6 subjects in a HIV-1 vaccine trial, where 199 peptides were arranged in 80 pools if size 9 or 10, our estimates were in very good agreement with the results from individual-peptide confirmatory assays. Compared to the classical approach, we could identify almost all the same peptides with high or moderate response, with less than half the number of confirmatory tests. Our method facilitates efficient use of the information available in pooled ELISpot data to avoid or reduce the need for confirmatory testing. We provide an easy-to-use free online application for implementing the method, where on uploading two spreadsheets with the pool design and pool responses, the user obtains the estimates of the individual peptide responses. PMID:27196788

  15. Increased plasma levels and blunted effects of brain natriuretic peptide in rats with congestive heart failure.

    Science.gov (United States)

    Hoffman, A; Grossman, E; Keiser, H R

    1991-07-01

    The hemodynamic and renal effects of brain natriuretic peptide (BNP) were studied in conscious rats with experimental congestive heart failure (CHF) produced by an aortocaval fistula. The peptide had potent hypotensive, diuretic, and natriuretic effects in control rats, all of which were abolished in CHF. Plasma levels of BNP increased time-dependently during the development of CHF, and were more than four-fold higher in sodium retaining rats than in control rats. The data suggest that BNP secretion from the atria is increased in CHF, and that resistance to BNP, in addition to the relative resistance to atrial natriuretic factor, may contribute to sodium retention in CHF. PMID:1831369

  16. Various mechanisms in cyclopeptide production from precursors synthesized independently of non-ribosomal peptide synthetases

    Institute of Scientific and Technical Information of China (English)

    Wenyan Xu; Liling Li; Liangcheng Du; Ninghua Tan

    2011-01-01

    An increasing number of cyclopeptides have been discovered as products of ribosomal synthetic pathway.The biosynthetic study of these cyclopeptides has revealed interesting new mechanisms for cyclization.This review highlighted the recent discoveries in cyclization mechanisms for cyclopeptides synthesized independently of non-ribosomal peptide synthetases,including endopeptidase-catalyzed cyclization,intein-mediated cyclization,and peptide synthetase-catalyzed cyclization.This information may help to design hybrid ribosomal and non-ribosomal biosynthetic systems to produce novel cyclopeptides with various bioactivities.

  17. Radioimmunological determination of procollagen (type III) and procollagen peptide (type III)

    International Nuclear Information System (INIS)

    The detection of antigens circulating in the blood enables the early recognition of fibrotic processes e.g. liver cirrhosis and hepatitis. One thus uses an anti procollagen (type III) labelled with iodine 125 by the chloramine-T method, or an anti-procollagen peptide (type III) serum which is brought together with a sample of unknown contents. The separation of the antigen-antibody complex is carried out by means of a highly specific antiserum. The procollagen peptide (type III) is produced from calf skin of a foetus or from human aszites fluid. (DG)

  18. A peptide-gated ion channel from the freshwater polyp Hydra

    DEFF Research Database (Denmark)

    Golubovic, Andjelko; Kuhn, Anne; Williamson, Michael;

    2007-01-01

    regarded as a curiosity, and it was not known whether peptide-gated ionotropic receptors are also present in other animal groups. Nervous systems first evolved in cnidarians, which extensively use neuropeptides. Here we report cloning from the freshwater cnidarian Hydra of a novel ion channel (Hydra sodium...... channel, HyNaC) that is directly gated by the neuropeptides Hydra-RFamides I and II and is related to FaNaC. The cells expressing HyNaC localize to the base of the tentacles, adjacent to the neurons producing the Hydra-RFamides, suggesting that the peptides are the natural ligands for this channel. Our...

  19. Plants producing biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Papavinasam, S. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Lab

    2009-08-15

    Biofuels are currently produced primarily from five plants, namely corn, canola, sugar cane, palm oil, jatropha. However, research and development efforts are underway around the world produce biofuels from other sources, particularly from algae. This paper described the characteristics of the top 5 plants and their role in the production of biofuels. Countries where these plants are cultivated were also summarized. The article indicated that producing ethanol from corn, is not very efficient since growing corn requires more fertilizer and pesticides than most other crops, plus the corn kernels have to undergo energy-intensive distillation and chemical extraction processes. China is the world's largest producer of rapeseed oil, with an annual production of 12 million tons. The countries of the European Union collectively produce another 16 million tons, of which nearly 4 million tons were used in 2006 to produce biodiesel. Brazil is the world's largest producer of sugar cane, and accounts for about 45 per cent of global ethanol production. Malaysia and Indonesia are the key players in the palm oil market, accounting for 85 per cent of global production. India has identified more than 11 million hectares that would be suitable for growing jatropha, whose seeds contain up to 40 per cent oil that can be burned in a conventional diesel engine after extraction. 1 tab.

  20. Determination of peptide content and purity of DOTA-peptides by metal ion titration and UPLC. An alternative method to monitor quality of DOTA-peptides

    International Nuclear Information System (INIS)

    PRRT requires high specific activities, thus at low molar ratio between DOTA-peptide and radioactivity. Therefore, the ingredients of the reaction, including (radio)metals and DOTA-peptide must be pure and the content known. Our aim was to quantify content and purity of DOTA-peptide by a base-to-base separation of DOTA-peptide and metal-DOTA-peptide by UPLC and UV-detection. Quantification of these peaks reveals an accurate and sensitive method to quantify purity and content of DOTA-peptides. Moreover, this technique enables monitoring of the (radio)labeling process and co-introduction of impurities, including metal ions. (author)

  1. From a pro-apoptotic peptide to a lytic peptide: One single residue mutation.

    Science.gov (United States)

    Zhou, Xi-Rui; Zhang, Qiang; Tian, Xi-Bo; Cao, Yi-Meng; Liu, Zhu-Qing; Fan, Ruru; Ding, Xiu-Fang; Zhu, Zhentai; Chen, Long; Luo, Shi-Zhong

    2016-08-01

    Further discovery and design of new anticancer peptides are important for the development of anticancer therapeutics, and study on the detailed acting mechanism and structure-function relationship of peptides is critical for anticancer peptide design and application. In this study, a novel anticancer peptide ZXR-1 (FKIGGFIKKLWRSKLA) derived from a known anticancer peptide mauriporin was developed, and a mutant ZXR-2 (FKIGGFIKKLWRSLLA) with only one residue difference at the 14th position (Lys→Leu) was also engineered. Replacement of the lysine with leucine made ZXR-2 more potent than ZXR-1 in general. Even with only one residue mutation, the two peptides displayed distinct anticancer modes of action. ZXR-1 could translocate into cells, target on the mitochondria and induce cell apoptosis, while ZXR-2 directly targeted on the cell membranes and caused membrane lysis. The variance in their acting mechanisms might be due to the different amphipathicity and positive charge distribution. In addition, the two Ile-Leu pairs (3-10 and 7-14) in ZXR-2 might also play a role in improving its cytotoxicity. Further study on the structure-function relationship of the two peptides may be beneficial for the design of novel anticancer peptides and peptide based therapeutics. PMID:27207743

  2. Peptide binding specificity of the chaperone calreticulin

    DEFF Research Database (Denmark)

    Sandhu, N.; Duus, K.; Jorgensen, C.S.;

    2007-01-01

    Calreticulin is a molecular chaperone with specificity for polypeptides and N-linked monoglucosylated glycans. In order to determine the specificity of polypeptide binding, the interaction of calreticulin with polypeptides was investigated using synthetic peptides of different length and composit...

  3. Charge Transport Phenomena in Peptide Molecular Junctions

    International Nuclear Information System (INIS)

    Inelastic electron tunneling spectroscopy (IETS) is a valuable in situ spectroscopic analysis technique that provides a direct portrait of the electron transport properties of a molecular species. In the past, IETS has been applied to small molecules. Using self-assembled nano electronic junctions, IETS was performed for the first time on a large polypeptide protein peptide in the phosphorylated and native form, yielding interpretable spectra. A reproducible 10-fold shift of the I/V characteristics of the peptide was observed upon phosphorylation. Phosphorylation can be utilized as a site-specific modification to alter peptide structure and thereby influence electron transport in peptide molecular junctions. It is envisioned that kinases and phosphatases may be used to create tunable systems for molecular electronics applications, such as biosensors and memory devices.

  4. Charge Transport Phenomena in Peptide Molecular Junctions

    Directory of Open Access Journals (Sweden)

    Alessandra Luchini

    2008-01-01

    Full Text Available Inelastic electron tunneling spectroscopy (IETS is a valuable in situ spectroscopic analysis technique that provides a direct portrait of the electron transport properties of a molecular species. In the past, IETS has been applied to small molecules. Using self-assembled nanoelectronic junctions, IETS was performed for the first time on a large polypeptide protein peptide in the phosphorylated and native form, yielding interpretable spectra. A reproducible 10-fold shift of the I/V characteristics of the peptide was observed upon phosphorylation. Phosphorylation can be utilized as a site-specific modification to alter peptide structure and thereby influence electron transport in peptide molecular junctions. It is envisioned that kinases and phosphatases may be used to create tunable systems for molecular electronics applications, such as biosensors and memory devices.

  5. METHOD OF PRODUCING NEUTRONS

    Science.gov (United States)

    Imhoff, D.H.; Harker, W.H.

    1964-01-14

    This patent relates to a method of producing neutrons in which there is produced a heated plasma containing heavy hydrogen isotope ions wherein heated ions are injected and confined in an elongated axially symmetric magnetic field having at least one magnetic field gradient region. In accordance with the method herein, the amplitude of the field and gradients are varied at an oscillatory periodic frequency to effect confinement by providing proper ratios of rotational to axial velocity components in the motion of said particles. The energetic neutrons may then be used as in a blanket zone containing a moderator and a source fissionable material to produce heat and thermal neutron fissionable materials. (AEC)

  6. A genome-wide analysis of nonribosomal peptide synthetase gene clusters and their peptides in a Planktothrix rubescens strain

    Directory of Open Access Journals (Sweden)

    Nederbragt Alexander J

    2009-08-01

    Full Text Available Abstract Background Cyanobacteria often produce several different oligopeptides, with unknown biological functions, by nonribosomal peptide synthetases (NRPS. Although some cyanobacterial NRPS gene cluster types are well described, the entire NRPS genomic content within a single cyanobacterial strain has never been investigated. Here we have combined a genome-wide analysis using massive parallel pyrosequencing ("454" and mass spectrometry screening of oligopeptides produced in the strain Planktothrix rubescens NIVA CYA 98 in order to identify all putative gene clusters for oligopeptides. Results Thirteen types of oligopeptides were uncovered by mass spectrometry (MS analyses. Microcystin, cyanopeptolin and aeruginosin synthetases, highly similar to already characterized NRPS, were present in the genome. Two novel NRPS gene clusters were associated with production of anabaenopeptins and microginins, respectively. Sequence-depth of the genome and real-time PCR data revealed three copies of the microginin gene cluster. Since NRPS gene cluster candidates for microviridin and oscillatorin synthesis could not be found, putative (gene encoded precursor peptide sequences to microviridin and oscillatorin were found in the genes mdnA and oscA, respectively. The genes flanking the microviridin and oscillatorin precursor genes encode putative modifying enzymes of the precursor oligopeptides. We therefore propose ribosomal pathways involving modifications and cyclisation for microviridin and oscillatorin. The microviridin, anabaenopeptin and cyanopeptolin gene clusters are situated in close proximity to each other, constituting an oligopeptide island. Conclusion Altogether seven nonribosomal peptide synthetase (NRPS gene clusters and two gene clusters putatively encoding ribosomal oligopeptide biosynthetic pathways were revealed. Our results demonstrate that whole genome shotgun sequencing combined with MS-directed determination of oligopeptides successfully

  7. Gene Transfer with Poly-Melittin Peptides

    OpenAIRE

    Chen, Chang-Po; Kim, Ji-Seon; Steenblock, Erin; Liu, Dijie; Rice, Kevin G.

    2006-01-01

    The 26 amino acid hemolytic melittin peptide was converted into a gene transfer peptide that binds to DNA and polymerized through disulfide bond formation. Melittin analogues were synthesized by addition of one to four Lys repeats at either the C or N-subterminal end along with terminal Cys residues. Melittin analogues were able to bind and polymerize on plasmids resulting in the formation of DNA condensates. In the absence of DNA, melittin analogues retained their red blood cell hemolytic po...

  8. Neuroprotective peptides related to Alzheimer's disease

    Czech Academy of Sciences Publication Activity Database

    Slaninová, Jiřina; Borovičková, Lenka; Bláha, I.; Hlaváček, Jan; Krejčová, G.; Patočka, J.

    Patras : Typorama, 2005 - (Cordopatis, P.; Manessi-Zoupa, E.; Pairas, G.), 147-154 ISBN 960-7620-31-3. [Hellenic Forum on Bioactive Peptides /4./. Patras (GR), 22.04.2004-24.04.2004] R&D Projects: GA ČR(CZ) GA305/03/1100 Institutional research plan: CEZ:AV0Z40550506 Keywords : peptides * Alzheimer's disease * humanin Subject RIV: CE - Biochemistry

  9. 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 ...

  10. Lucifensin, a peptide behind the maggot therapy

    Czech Academy of Sciences Publication Activity Database

    Čeřovský, Václav

    Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 22-26 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506 Keywords : lucifensin * maggot therapy * antimicrobial activity * peptide synthesis * disulfide bridge Subject RIV: CC - Organic Chemistry

  11. Dietary fiber, gut peptides, and adipocytokines

    OpenAIRE

    Sánchez, David; Miguel, Marta; Aleixandre, Amaya

    2012-01-01

    The consumption of dietary fiber (DF) has increased since it was related to the prevention of a range of illnesses and pathological conditions. DF can modify some gut hormones that regulate satiety and energy intake, thus also affecting lipid metabolism and energy expenditure. Among these gut hormones are ghrelin, glucagon-like peptide 1, peptide YY, and cholecystokinin. Adipose tissue is known to express and secrete a variety of products known as >adipocytokines,> which are also affected by ...

  12. From antimicrobial to anticancer peptides. A review.

    OpenAIRE

    Diana eGaspar; A. Salomé eVeiga; Miguel A.R.B. eCastanho

    2013-01-01

    Antimicrobial peptides (AMPs) are part of the innate immune defense mechanism of many organisms. Although AMPs have been essentially studied and developed as potential alternatives for fighting infectious diseases, their use as anticancer peptides (ACPs) in cancer therapy either alone or in combination with other conventional drugs has been regarded as a therapeutic strategy to explore. As human cancer remains a cause of high morbidity and mortality worldwide, an urgent need of new, selective...

  13. Chemical Pyrophosphorylation of Functionally Diverse Peptides

    OpenAIRE

    Marmelstein, Alan M.; Yates, Lisa M.; Conway, John H.; Fiedler, Dorothea

    2013-01-01

    A highly selective and convenient method for the synthesis of pyrophosphopeptides in solution is reported. The remarkable compatibility with functional groups (alcohol, thiol, amine, carboxylic acid) in the peptide substrates suggests that the intrinsic nucleophilicity of the phosphoserine residue is much higher than previously appreciated. Because the methodology operates in polar solvents, including water, a broad range of pyrophosphopeptides can be accessed. We envision these peptides will...

  14. Tryptophan rotamer distributions in amphipathic peptides at a lipid surface.

    OpenAIRE

    Clayton, A H; Sawyer, W. H.

    1999-01-01

    The fluorescence decay of tryptophan is a sensitive indicator of its local environment within a peptide or protein. We describe the use of frequency domain fluorescence spectroscopy to determine the conformational and environmental changes associated with the interaction of single tryptophan amphipathic peptides with a phospholipid surface. The five 18-residue peptides studied are based on a class A amphipathic peptide known to associate with lipid bilayers. The peptides contain a single tryp...

  15. Stereo-separations of Peptides by Capillary Electrophoresis and Chromatography

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Afzal Hussain, Iqbal Hussain, Mohamed F. Al-Ajmi & Imran Ali ### Abstract Small peptides (di-, tri-, tetra- penta- hexa etc. and peptides) control many chemical and biological processes. The biological importance of stereomers of peptides is of great value. The stereo-separations of peptides are gaining importance in biological and medicinal sciences and pharmaceutical industries. There is a great need of experimental protocols of stereo-separations of peptides. The vario...

  16. Constructing bioactive peptides with pH-dependent activities

    OpenAIRE

    Tu, Zhigang; Volk, Melanie; Shah, Khushali; Clerkin, Kevin; Liang, Jun F.

    2009-01-01

    Many bioactive peptides are featured by their arginine and lysine rich contents. In this study, lysine and arginine residues in lytic peptides were selectively replaced by histidines. Although resulted histidine-containing lytic peptides had decreased activity, they did show pH-dependent cytotoxicity. The activity of the constructed histidine-containing lytic peptides increased 2 ~ 8 times as the solution pH changed from of 7.4 to 5.5. More importantly, these histidine-containing peptides mai...

  17. Design, synthesis and analysis of novel SMAC-based peptides

    Czech Academy of Sciences Publication Activity Database

    Georgieva, M.; Dzimbova, T.; Sázelová, Petra; Detcheva, R.; Kašička, Václav; Pajpanova, T.

    Sofia: Bulgarian Peptide Society, 2015 - (Naydenova, E.; Pajpanova, T.; Danalev, D.), s. 178-179 ISBN 978-619-90427-2-4. [Peptides 2014. European Peptide Symposium /33./. Sofia (BG), 31.08.2014-05.09.2014] Institutional support: RVO:61388963 Keywords : peptides * analysis * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation http://bulpepsoc.info/wp-content/uploads/2015/06/PEPTIDES-2014-electronic-version.pdf

  18. Membrane manufacture for peptide separations

    KAUST Repository

    Kim, DooLi

    2016-06-07

    Nanostructured polymeric membranes are key tools in biomedical applications such as hemodialysis, protein separations, in the food industry, and drinking water supply from seawater. Despite of the success in different separation processes, membrane manufacture itself is at risk, since the most used solvents are about to be banned in many countries due to environmental and health issues. We propose for the first time the preparation of polyethersulfone membranes based on dissolution in the ionic liquid 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DEP). We obtained a series of membranes tailored for separation of solutes with molecular weight of 30, 5, 1.3, and 1.25 kg mol-1 with respective water permeances of 140, 65, 30 and 20 Lm-2h-1bar-1. We demonstrate their superior efficiency in the separation of complex mixtures of peptides with molecular weights in the range of 800 to 3500 gmol-1. Furthermore, the thermodynamics and kinetics of phase separation leading to the pore formation in the membranes were investigated. The rheology of the solutions and the morphology of the prepared membranes were examed and compared to those of polyethersulfone in organic solvents currently used for membrane manufacture.

  19. Agricultural Producer Certificates

    Data.gov (United States)

    Montgomery County of Maryland — A Certified Agricultural Producer, or representative thereof, is an individual who wishes to sell regionally-grown products in the public right-of-way. A Certified...

  20. Protective Effect of Wheat Peptides Against Small Intestinal Damage Induced by Non-Steroidal Anti-Inlfammatory Drugs in Rats

    Institute of Scientific and Technical Information of China (English)

    YIN Hong; PAN Xing-chang; WANG Shao-kang; YANG Li-gang; SUN Gui-ju

    2014-01-01

    Non-steroidal anti-inlfammatory drugs (NSAIDs) were able to produce tissue damage and oxidative stress in animal models of small intestinal damage. In this study, the putative protective effect of wheat peptides was evaluated in a NSAID-induced small intestinal damage model in rats, different doses of wheat peptides or distilled water were administered daily by intragastric administration for 30 d until small intestinal damage was caused. Before sacriifcing, NSAIDs (aspirin and indomethacin) or physiological saline were infused into the digestive tract twice. Wheat peptides administration reduced edema and small intestinal damage, and signiifcantly decreased the level of tumor necrosis factor (TNF)-α in mucous membrane of small intestine. Oxidative stress was signiifcantly increased after NSAID infusion and was reduced by wheat peptides. Wheat peptides increased glutathione peroxidase(GSH-Px) activity in mucous membrane of small intestine. µ-Opioid receptor mRNA expression decreased more signiifcantly in wheat peptides treated rats than in the model control group. Overall, the results suggest that non-steroidal anti-inlfammatory drugs induced small intestinal damage in rats and wheat peptides administration may be an effective tool for protecting small intestinal tissue against NSAID-induced small intestinal damage and oxidative stress.

  1. Confinement-dependent friction in peptide bundles.

    Science.gov (United States)

    Erbaş, Aykut; Netz, Roland R

    2013-03-19

    Friction within globular proteins or between adhering macromolecules crucially determines the kinetics of protein folding, the formation, and the relaxation of self-assembled molecular systems. One fundamental question is how these friction effects depend on the local environment and in particular on the presence of water. In this model study, we use fully atomistic MD simulations with explicit water to obtain friction forces as a single polyglycine peptide chain is pulled out of a bundle of k adhering parallel polyglycine peptide chains. The whole system is periodically replicated along the peptide axes, so a stationary state at prescribed mean sliding velocity V is achieved. The aggregation number is varied between k = 2 (two peptide chains adhering to each other with plenty of water present at the adhesion sites) and k = 7 (one peptide chain pulled out from a close-packed cylindrical array of six neighboring peptide chains with no water inside the bundle). The friction coefficient per hydrogen bond, extrapolated to the viscous limit of vanishing pulling velocity V → 0, exhibits an increase by five orders of magnitude when going from k = 2 to k = 7. This dramatic confinement-induced friction enhancement we argue to be due to a combination of water depletion and increased hydrogen-bond cooperativity. PMID:23528088

  2. Biomathematical description of synthetic peptide libraries.

    Directory of Open Access Journals (Sweden)

    Timo Sieber

    Full Text Available Libraries of randomised peptides displayed on phages or viral particles are essential tools in a wide spectrum of applications. However, there is only limited understanding of a library's fundamental dynamics and the influences of encoding schemes and sizes on their quality. Numeric properties of libraries, such as the expected number of different peptides and the library's coverage, have long been in use as measures of a library's quality. Here, we present a graphical framework of these measures together with a library's relative efficiency to help to describe libraries in enough detail for researchers to plan new experiments in a more informed manner. In particular, these values allow us to answer-in a probabilistic fashion-the question of whether a specific library does indeed contain one of the "best" possible peptides. The framework is implemented in a web-interface based on two packages, discreteRV and peptider, to the statistical software environment R. We further provide a user-friendly web-interface called PeLiCa (Peptide Library Calculator, http://www.pelica.org, allowing scientists to plan and analyse their peptide libraries.

  3. Biomathematical Description of Synthetic Peptide Libraries

    Science.gov (United States)

    Trepel, Martin

    2015-01-01

    Libraries of randomised peptides displayed on phages or viral particles are essential tools in a wide spectrum of applications. However, there is only limited understanding of a library's fundamental dynamics and the influences of encoding schemes and sizes on their quality. Numeric properties of libraries, such as the expected number of different peptides and the library's coverage, have long been in use as measures of a library's quality. Here, we present a graphical framework of these measures together with a library's relative efficiency to help to describe libraries in enough detail for researchers to plan new experiments in a more informed manner. In particular, these values allow us to answer-in a probabilistic fashion-the question of whether a specific library does indeed contain one of the "best" possible peptides. The framework is implemented in a web-interface based on two packages, discreteRV and peptider, to the statistical software environment R. We further provide a user-friendly web-interface called PeLiCa (Peptide Library Calculator, http://www.pelica.org), allowing scientists to plan and analyse their peptide libraries. PMID:26042419

  4. Neutron diffraction studies of viral fusion peptides

    Science.gov (United States)

    Bradshaw, Jeremy P.; J. M. Darkes, Malcolm; Katsaras, John; Epand, Richard M.

    2000-03-01

    Membrane fusion plays a vital role in a large and diverse number of essential biological processes. Despite this fact, the precise molecular events that occur during fusion are still not known. We are currently engaged on a study of membrane fusion as mediated by viral fusion peptides. These peptides are the N-terminal regions of certain viral envelope proteins that mediate the process of fusion between the viral envelope and the membranes of the host cell during the infection process. As part of this study, we have carried out neutron diffraction measurements at the ILL, BeNSC and Chalk River, on a range of viral fusion peptides. The peptides, from simian immunodeficiency virus (SIV), influenza A and feline leukaemia virus (FeLV), were incorporated into stacked phospholipid bilayers. Some of the peptides had been specifically deuterated at key amino acids. Lamellar diffraction data were collected and analysed to yield information on the peptide conformation, location and orientation relative to the bilayer.

  5. III. Organometallic and Bioorganometallic Chemistry - Ferrocene Peptides

    Directory of Open Access Journals (Sweden)

    Kovačević, M.

    2012-02-01

    Full Text Available This paper is devoted to the bioconjugates of ferrocene with naturally occuring amino acids/peptides - mostly dealing with authors' results accompanied, to a lesser degree, by the relevant literature data. Chapter 2 deals with natural peptides and peptidomimetics, mainly focusing on α-helix and β pleated sheet (as the most important elements of peptide secondary and tertiary structure, and artificial β-sheets nucleated by non-amino acid turn inducers. Chapter 3 describes peptides generated from ferrocenecarboxylic acid and ferroceneamine, as well as with the bioconjugates of heteroannulary substituted ferrocene-1,1'-dicarboxylic acid (Fcd and ferrocene-1,1'-diamine (Fcda. Chapter 4 elaborates authors' papers about peptides based on 1'-aminoferrocene-1-carboxylic acid (Fca. Chapter 5 is devoted to the new monosubstituted Fcd and Fcda conjugates with amino acids, while Chapter 6 describes our publications in the field of very topical peptidomimetics - ferrocene ureidopeptides and β peptides. Conformational analysis of the newly prepared ferrocene bioconjugates in solution and solid state was performed by means of spectroscopic methods (CD, IR, 1D- NMR, 2D-NMR, v. r. NMR, and temperature and concentration dependent NMR and DFT calculations.

  6. Production of angiotensin-I-converting enzyme inhibitory peptides from β-lactoglobulin- and casein-derived peptides: an integrative approach.

    Science.gov (United States)

    Welderufael, Fisseha T; Gibson, Trevor; Jauregi, Paula

    2012-01-01

    Angiotensin I-converting enzyme (ACE) inhibition is one of the mechanisms by which reduction in blood pressure is exerted. Whey proteins are a rich source of ACE inhibitory peptides and have shown a blood pressure reduction effect i.e. antihypertensive activity. The aim of this work was to develop a simplified process using a combination of adsorption and microfiltration steps for the production of hydrolysates from whey with high ACE inhibitory activity and potency; the latter was measured as the IC50, which is the peptide concentration required to reduce ACE activity by half. This process integrates the selective separation of β-lactoglobulin- and casein-derived peptides (CDP) from rennet whey and their hydrolysis, which results in partially pure, less complex hydrolysates with high bioactive potency. Hydrolysis was carried out with protease N "Amano" in a thermostatically controlled membrane reactor operated in a batch mode. By applying the integrative approach it was possible to produce from the same feedstock two different hydrolysates that exhibited high ACE inhibition. One hydrolysate was mainly composed of casein-derived peptides with IC50=285 μg/mL. In this hydrolysate we identified the well-known potent ACE-inhibitor and antihypertensive tripeptide Ile-Pro-Pro (IPP) and another novel octapeptide Gln-Asp-Lys-Thr-Glu-Ile-Pro-Thr (QDKTEIPT). The second hydrolysate was mainly composed of β-lactoglobulin derived peptides with IC50=28 μg/mL. This hydrolysate contained a tetrapeptide (Ile-Ile-Ala-Glu) IIAE as one of the two major peptides. A further advantage to this process is that enzyme activity was substantially increased as enzyme product inhibition was reduced. PMID:22467199

  7. Enterohepatic circulation of bacterial chemotactic peptide in rats with experimental colitis

    International Nuclear Information System (INIS)

    The association of hepatobiliary disorders with colonic inflammation is well recognized. Although the pathophysiology is obscure, increased permeation of toxic bacterial products across the inflamed gut to the portal circulation might be one mechanism. Potentially toxic metabolites include N-formylated chemotactic peptides that are produced by several species of intestinal bacteria and can be detected in colonic fluid in vivo. To investigate the metabolic fate of one of these low molecular weight proinflammatory peptides, N-formyl L-methionine L-leucine 125I-L-tyrosine was introduced into colon loops of healthy rats (n = 10) and rats with experimental colitis (n = 15) induced by rectal instillation of 15% (vol/vol) acetic acid. Gut, liver, and blood radioactivity were monitored by external gamma-counting and radioactivity in bile was measured by biliary catheter drainage into a well counter. Bile was processed by high-performance liquid chromatography to determine the amount of intact, bioactive peptide excreted over 3 h. After colonic instillation of 1 nmol of peptide, the mean (+/- SEM) biliary excretion of intact peptide was 6.4 +/- 2.0 pmol in normal rats and 49.0 +/- 20 pmol in rats with colitis (p less than 0.01). An enterohepatic circulation of synthetic N-formyl L-methionine L-leucine L-tyrosine has been demonstrated in the rat. Experimental colitis was associated with an eightfold increase in biliary excretion of this proinflammatory bacterial peptide. Proinflammatory bacterial peptides synthesized by colonic bacteria could be important in the pathophysiology of colon inflammation and its frequently associated hepatobiliary complications

  8. PEP-on-DEP: A competitive peptide-based disposable electrochemical aptasensor for renin diagnostics.

    Science.gov (United States)

    Biyani, Manish; Kawai, Keiko; Kitamura, Koichiro; Chikae, Miyuki; Biyani, Madhu; Ushijima, Hiromi; Tamiya, Eiichi; Yoneda, Takashi; Takamura, Yuzuru

    2016-10-15

    Antibody-based immunosensors are relatively less accessible to a wide variety of unreachable targets, such as low-molecular-weight biomarkers that represent a rich untapped source of disease-specific diagnostic information. Here, we present a peptide aptamer-based electrochemical sensor technology called 'PEP-on-DEP' to detect less accessible target molecules, such as renin, and to improve the quality of life. Peptide-based aptamers represent a relatively smart class of affinity binders and show great promise in biosensor development. Renin is involved in the regulation of arterial blood pressure and is an emerging biomarker protein for predicting cardiovascular risk and prognosis. To our knowledge, no studies have described aptamer molecules that can be used as new potent probes for renin. Here, we describe a portable electrochemical biosensor platform based on the newly identified peptide aptamer molecules for renin. We constructed a randomized octapeptide library pool with diversified sequences and selected renin specific peptide aptamers using cDNA display technology. We identified a few peptide aptamer sequences with a KD in the µM binding affinity range for renin. Next, we grafted the selected peptide aptamers onto gold nanoparticles and detected renin in a one-step competitive assay using our originally developed DEP (Disposable Electrochemical Printed) chip and a USB powered portable potentiostat system. We successfully detected renin in as little as 300ngmL(-1) using the PEP-on-DEP method. Thus, the generation and characterization of novel probes for unreachable target molecules by merging a newly identified peptide aptamer with electrochemical transduction allowed for the development of a more practical biosensor that, in principle, can be adapted to develop a portable, low-cost and mass-producible biosensor for point-of-care applications. PMID:26746799

  9. Silver adducts of four-branched histidine rich peptides exhibit synergistic antifungal activity.

    Science.gov (United States)

    Leng, Qixin; Woodle, Martin C; Liu, Yijia; Mixson, A James

    2016-09-01

    Previously, a four branched histidine-lysine rich peptide, H3K4b, was shown to demonstrate selective antifungal activity with minimal antibacterial activity. Due to the potential breakdown from proteases, H3K4b was further evaluated in the current study by varying the D- and l-amino acid content in its branches. Whereas analogues of H3K4b that selectively replaced l-amino acids (H3k4b, h3K4b) had improved antifungal activity, the all d-amino acid analogue, h3k4b, had reduced activity, suggesting that partial breakdown of the peptide may be necessary. Moreover, because histidines form coordination bonds with the silver ion, we examined whether silver adducts can be formed with these branched histidine-lysine peptides, which may improve antifungal activity. For Candida albicans, the silver adduct of h3K4b or H3k4b reduced the MIC compared to peptide and silver ions alone by 4- and 5-fold, respectively. For Aspergillus fumigatus, the silver adducts showed even greater enhancement of activity. Although the silver adducts of H3k4b or h3K4b showed synergistic activity, the silver adduct with the all l-amino acid H3K4b surprisingly showed the greatest synergistic and growth inhibition of A. fumigatus: the silver adduct of H3K4b reduced the MIC compared to the peptide and silver ions alone by 30- and 26-fold, respectively. Consistent with these antifungal efficacy results, marked increases in free oxygen radicals were produced with the H3K4b and silver combination. These studies suggest that there is a balance between stability and breakdown for optimal antifungal activity of the peptide alone and for the peptide-silver adduct. PMID:27387239

  10. Multivalent antiviral XTEN-peptide conjugates with long in vivo half-life and enhanced solubility.

    Science.gov (United States)

    Ding, Sheng; Song, Michael; Sim, Bee-Cheng; Gu, Chen; Podust, Vladimir N; Wang, Chia-Wei; McLaughlin, Bryant; Shah, Trishul P; Lax, Rodney; Gast, Rainer; Sharan, Rahul; Vasek, Arthur; Hartman, M Amanda; Deniston, Colin; Srinivas, Prathna; Schellenberger, Volker

    2014-07-16

    XTENs are unstructured, nonrepetitive protein polymers designed to prolong the in vivo half-life of pharmaceuticals by introducing a bulking effect similar to that of poly(ethylene glycol). While XTEN can be expressed as a recombinant fusion protein with bioactive proteins and peptides, therapeutic molecules of interest can also be chemically conjugated to XTEN. Such an approach permits precise control over the positioning, spacing, and valency of bioactive moieties along the length of XTEN. We have demonstrated the attachment of T-20, an anti-retroviral peptide indicated for the treatment of HIV-1 patients with multidrug resistance, to XTEN. By reacting maleimide-functionalized T-20 with cysteine-containing XTENs and varying the number and positioning of cysteines in the XTENs, a library of different peptide-polymer combinations were produced. The T-20-XTEN conjugates were tested using an in vitro antiviral assay and were found to be effective in inhibiting HIV-1 entry and preventing cell death, with the copy number and spacing of the T-20 peptides influencing antiviral activity. The peptide-XTEN conjugates were also discovered to have enhanced solubilities in comparison with the native T-20 peptide. The pharmacokinetic profile of the most active T-20-XTEN conjugate was measured in rats, and it was found to exhibit an elimination half-life of 55.7 ± 17.7 h, almost 20 times longer than the reported half-life for T-20 dosed in rats. As the conjugation of T-20 to XTEN greatly improved the in vivo half-life and solubility of the peptide, the XTEN platform has been demonstrated to be a versatile tool for improving the properties of drugs and enabling the development of a class of next-generation therapeutics. PMID:24932887

  11. Mechanisms of the antifungal action of marine metagenome-derived peptide, MMGP1, against Candida albicans.

    Directory of Open Access Journals (Sweden)

    Muthuirulan Pushpanathan

    Full Text Available BACKGROUND: Development of resistant variants to existing antifungal drugs continues to be the serious problem in Candida albicans-induced fungal pathogenesis, which has a considerable impact on animal and human health. Identification and characterization of newer drugs against C. albicans is, therefore, essential. MMGP1 is a direct cell-penetrating peptide recently identified from marine metagenome, which was found to possess potent antifungal activity against C. albicans. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigated the mechanism of antifungal action of MMGP1 against C. albicans. Agarose gel shift assay found the peptide to be having a remarkable DNA-binding ability. The modification of the absorption spectra and fluorescence quenching of the tryptophyl residue correspond to the stacking between indole ring and nucleotide bases. The formation of peptide-DNA complexes was confirmed by fluorescence quenching of SYTO 9 probe. The interaction of peptide with plasmid DNA afforded protection of DNA from enzymatic degradation by DNase I. In vitro transcription of mouse β-actin gene in the presence of peptide led to a decrease in the level of mRNA synthesis. The C. albicans treated with MMGP1 showed strong inhibition of biosynthetic incorporation of uridine analog 5-ethynyluridine (EU into nascent RNA, suggesting the peptide's role in the inhibition of macromolecular synthesis. Furthermore, the peptide also induces endogenous accumulation of reactive oxygen species (ROS in C. albicans. MMGP1 supplemented with glutathione showed an increased viability of C. albicans cells. The hyper-produced ROS by MMGP1 leads to increased levels of protein carbonyls and thiobarbituric acid reactive substances and it also causes dissipation of mitochondrial membrane potential and DNA fragmentation in C. albicans cells. CONCLUSION: And Significance: Therefore, the antifungal activity of MMGP1 could be attributed to its binding with DNA, causing

  12. Pore Forming Properties of Cecropin-Melittin Hybrid Peptide in a Natural Membrane

    Directory of Open Access Journals (Sweden)

    Giorgio Rispoli

    2009-12-01

    Full Text Available The pore forming properties of synthetic cecropin-melittin hybrid peptide (Acetyl-KWKLFKKIGAVLKVL-CONH2; CM15 were investigated by using photoreceptor rod outer segments (OS isolated from frog retinae obtained by using the whole-cell configuration of the patch-clamp technique. CM15 was applied (and removed to (from the OS in ~50 ms with a computer-controlled microperfusion system. Once the main OS endogenous conductance was blocked with light, the OS membrane resistance was ≥1 GΩ, allowing high resolution, low-noise recordings. Different to alamethicines, CM15 produced voltage-independent membrane permeabilisation, repetitive peptide application caused a progressive permeabilisation increase, and no single-channel events were detected at low peptide concentrations. Collectively, these results indicate a toroidal mechanism of pore formation by CM15.

  13. 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.

  14. Synthetic Peptides as Structural Maquettes of Angiotensin-I Converting Enzyme Catalytic Sites

    Directory of Open Access Journals (Sweden)

    Zinovia Spyranti

    2010-01-01

    Full Text Available The rational design of synthetic peptides is proposed as an efficient strategy for the structural investigation of crucial protein domains difficult to be produced. Only after half a century since the function of ACE was first reported, was its crystal structure solved. The main obstacle to be overcome for the determination of the high resolution structure was the crystallization of the highly hydrophobic transmembrane domain. Following our previous work, synthetic peptides and Zinc(II metal ions are used to build structural maquettes of the two Zn-catalytic active sites of the ACE somatic isoform. Structural investigations of the synthetic peptides, representing the two different somatic isoform active sites, through circular dichroism and NMR experiments are reported.

  15. Fragmentation of phosphorylated and singly charged peptide ions via interaction with metastable atoms.

    Science.gov (United States)

    Berkout, Vadym D; Doroshenko, Vladimir M

    2008-12-01

    Fragmentation of phosphorylated peptide ions via interaction with electronically excited metastable argon atoms was studied in a linear trap - time-of-flight mass spectrometer. Doubly charged ions of phosphorylated peptides from an Enolase digest were produced by electrospray ionization and subjected to a metastable atom beam in the linear trap. The metastable argon atoms were generated using a glow-discharge source. An intensive series of c- and z- ions were observed in all cases, with the phosphorylation group intact. The formation of molecular radical cations with reduced charge indicated that an electron transfer from a highly excited metastable state of argon to the peptide cation occurred. Additionally, singly charged Bradykinin, Substance P and Fibrinopeptide A molecular ions were fragmented via interaction with electronically excited metastable helium atoms. The fragmentation mechanism was different in this case and involved Penning ionization. PMID:19956340

  16. Catalysis of peptide bond formation by histidyl-histidine in a fluctuating clay environment

    Science.gov (United States)

    White, D. H.; Erickson, J. C.

    1980-01-01

    The condensation of glycine to form oligoglycines during wet-dry fluctuations on clay surfaces was enhanced up to threefold or greater by small amounts of histidyl-histidine. In addition, higher relative yields of the longer oligomers were produced. Other specific dipeptides tested gave no enhancement, and imidazole, histidine, and N-acetylhistidine gave only slight enhancements. Histidyl-histidine apparently acts as a true catalyst (in the sense of repeatedly catalyzing the reaction), since up to 52 nmol of additional glycine were incorporated into oligoglycine for each nmol of catalyst added. This is the first known instance of a peptide or similar molecule demonstrating a catalytic turnover number greater than unity in a prebiotic oligomer synthesis reaction, and suggests that histidyl-histidine is a model for a primitive prebiotic proto-enzyme. Catalysis of peptide bond synthesis by a molecule which is itself a peptide implies that related systems may be capable of exhibiting autocatalytic growth.

  17. ANNEXIN A1 N-TERMINAL DERIVED PEPTIDE AC2-26 EXERTS CHEMOKINETIC EFFECTS ON HUMAN NEUTROPHILS

    Directory of Open Access Journals (Sweden)

    MauroPerretti

    2012-02-01

    Full Text Available It is postulated that peptides derived from the N-terminal region of Annexin A1, a glucocorticoid-regulated 37-kDa protein, could act as biomimetics of the parent protein. However, recent evidence, amongst which the ability to interact with distinct receptors other then that described for Annexin A1, suggest that these peptides might fulfil other functions at variance to those reported for the parent protein. Here we tested the ability of peptide Ac2-26 to induce chemotaxis of human neutrophils, showing that this peptide can elicit responses comparable to those produced by the canonical activator formyl-Met-Leu-Phe (or FMLP. However, whilst disruption of the chemical gradient abolished the FMLP response, addition of peptide Ac2-26 in the top well of the chemotaxis chamber did not affect (10 µM or augmented (at 30 µM the neutrophil locomotion to the bottom well, as elicited by 10 µM peptide Ac2-26. Intriguingly, the sole addition of peptide Ac2-26 in the top wells produced a marked migration of neutrophils. A similar behaviour was observed when human primary monocytes were used. Thus, peptide Ac2-26 is a genuine chemokinetic agent towards human blood leukocytes. Neutralization strategies indicated that engagement of either the GPCR termed FPR1 or its cognate receptor FPR2/ALX was sufficient to sustain peptide Ac2-26 induced neutrophil migration. Similarly, application of pharmacological inhibitors showed that cell locomotion to peptide Ac2-26 was mediated primarily by the ERK, but not the JNK and p38 pathways. In conclusion, we report here novel in vitro properties for peptide Ac2-26, promoting neutrophil and monocyte chemokinesis, a process that may contribute to accelerate the resolution phase of inflammation. Here we postulate that the generation Annexin A1 N-terminal peptides at the site of inflammation may expedite the egress of migrated leukocytes thus promoting the return to homeostasis.

  18. Interaction of antimicrobial peptides with lipid membranes

    International Nuclear Information System (INIS)

    This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low temperatures that upon heating transform into a highly curved inverse hexagonal phase. Insertion of the peptide induced inverse bicontinuous cubic phases which are an ideal compromise between the curvature stress and the packing frustration. Melittin usually induced a mixture of two cubic phases, Im3m and Pn3m, with a ratio of lattice parameters close to 1.279, related to the underlying minimal surfaces. They formed during the lamellar to hexagonal phase transition and persisted during cooling till the onset of the gel phase. The phases formed at different lipid-to-peptide ratios had very similar lattice parameters. Epitaxial relationships existed between coexisting cubic phases and hexagonal or lamellar phases due to confinement of all phases to an onion vesicle, a vesicle with several layers consisting of different lipid phases. Alamethicin induced the same cubic phases, although their formation and lattice parameters were dependent on the peptide concentration. The cubic phases formed during heating from the lamellar phase and their onset

  19. Interaction of antimicrobial peptides with lipid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hanulova, Maria

    2008-12-15

    This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low temperatures that upon heating transform into a highly curved inverse hexagonal phase. Insertion of the peptide induced inverse bicontinuous cubic phases which are an ideal compromise between the curvature stress and the packing frustration. Melittin usually induced a mixture of two cubic phases, Im3m and Pn3m, with a ratio of lattice parameters close to 1.279, related to the underlying minimal surfaces. They formed during the lamellar to hexagonal phase transition and persisted during cooling till the onset of the gel phase. The phases formed at different lipid-to-peptide ratios had very similar lattice parameters. Epitaxial relationships existed between coexisting cubic phases and hexagonal or lamellar phases due to confinement of all phases to an onion vesicle, a vesicle with several layers consisting of different lipid phases. Alamethicin induced the same cubic phases, although their formation and lattice parameters were dependent on the peptide concentration. The cubic phases formed during heating from the lamellar phase and their onset

  20. A Facile Route to Tailoring Peptide-Stabilized Gold Nanoparticles Using Glutathione as a Synthon

    Directory of Open Access Journals (Sweden)

    Rosina Ho Wu

    2014-05-01

    Full Text Available The preparation of gold nanoparticles (AuNPs of high purity and stability remains a major challenge for biological applications. This paper reports a simple synthetic strategy to prepare water-soluble peptide-stabilized AuNPs. Reduced glutathione, a natural tripeptide, was used as a synthon for the growth of two peptide chains directly on the AuNP surface. Both nonpolar (tryptophan and methionine and polar basic (histidine and dansylated arginine amino acids were conjugated to the GSH-capped AuNPs. Ultracentrifugation concentrators with polyethersulfone (PES membranes were used to purify precursor materials in each stage of the multi-step synthesis to minimize side reactions. Thin layer chromatography, transmission electron microscopy, UV-Visible, 1H-NMR, and fluorescence spectroscopies demonstrated that ultracentrifugation produces high purity AuNPs, with narrow polydispersity, and minimal aggregation. More importantly, it allows for more control over the composition of the final ligand structure. Studies under conditions of varying pH and ionic strength revealed that peptide length, charge, and hydrophobicity influence the stability as well as solubility of the peptide-capped AuNPs. The synthetic and purification strategies used provide a facile route for developing a library of tailored biocompatible peptide-stabilized AuNPs for biomedical applications.

  1. Characterization of bioactive RGD peptide immobilized onto poly(acrylic acid) thin films by plasma polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hyun Suk; Ko, Yeong Mu; Shim, Jae Won [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, Gwangju (Korea, Republic of); Lim, Yun Kyong; Kook, Joong-Ki [Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Cho, Dong-Lyun [School of Applied Chemical Engineering and Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju (Korea, Republic of); Kim, Byung Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, Gwangju (Korea, Republic of)

    2010-11-01

    Plasma surface modification can be used to improve the surface properties of commercial pure Ti by creating functional groups to produce bioactive materials with different surface topography. In this study, a titanium surface was modified with acrylic acid (AA) using a plasma treatment and immobilized with bioactive arginine-glycine-aspartic acid (RGD) peptide, which may accelerate the tissue integration of bone implants. Both terminals containing the -NH{sub 2} of RGD peptide sequence and -COOH of poly(acrylic acid) (PAA) thin film were combined with a covalent bond in the presence of 1-ethyl-3-3-dimethylaminopropyl carbodiimide (EDC). The chemical structure and morphology of AA film and RGD immobilized surface were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All chemical analysis showed full coverage of the Ti substrate with the PAA thin film containing COOH groups and the RGD peptide. The MC3T3-E1 cells were cultured on each specimen, and the cell alkaline phosphatase (ALP) activity were examined. The surface-immobilized RGD peptide has a significantly increased the ALP activity of MC3T3-E1 cells. These results suggest that the RGD peptide immobilization on the titanium surface has an effect on osteoblastic differentiation of MC3T3-E1 cells and potential use in osteo-conductive bone implants.

  2. Characterization of bioactive RGD peptide immobilized onto poly(acrylic acid) thin films by plasma polymerization

    International Nuclear Information System (INIS)

    Plasma surface modification can be used to improve the surface properties of commercial pure Ti by creating functional groups to produce bioactive materials with different surface topography. In this study, a titanium surface was modified with acrylic acid (AA) using a plasma treatment and immobilized with bioactive arginine-glycine-aspartic acid (RGD) peptide, which may accelerate the tissue integration of bone implants. Both terminals containing the -NH2 of RGD peptide sequence and -COOH of poly(acrylic acid) (PAA) thin film were combined with a covalent bond in the presence of 1-ethyl-3-3-dimethylaminopropyl carbodiimide (EDC). The chemical structure and morphology of AA film and RGD immobilized surface were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All chemical analysis showed full coverage of the Ti substrate with the PAA thin film containing COOH groups and the RGD peptide. The MC3T3-E1 cells were cultured on each specimen, and the cell alkaline phosphatase (ALP) activity were examined. The surface-immobilized RGD peptide has a significantly increased the ALP activity of MC3T3-E1 cells. These results suggest that the RGD peptide immobilization on the titanium surface has an effect on osteoblastic differentiation of MC3T3-E1 cells and potential use in osteo-conductive bone implants.

  3. Short Peptides Enhance Single Cell Adhesion and Viability onMicroarrays

    Energy Technology Data Exchange (ETDEWEB)

    Veiseh, Mandana; Veiseh, Omid; Martin, Michael C.; Asphahani,Fareid; Zhang, Miqin

    2007-01-19

    Single cell patterning holds important implications forbiology, biochemistry, biotechnology, medicine, and bioinformatics. Thechallenge for single cell patterning is to produce small islands hostingonly single cells and retaining their viability for a prolonged period oftime. This study demonstrated a surface engineering approach that uses acovalently bound short peptide as a mediator to pattern cells withimproved single cell adhesion and prolonged cellular viabilityon goldpatterned SiO2 substrates. The underlying hypothesis is that celladhesion is regulated bythe type, availability, and stability ofeffective cell adhesion peptides, and thus covalently bound shortpeptides would promote cell spreading and, thus, single cell adhesion andviability. The effectiveness of this approach and the underlyingmechanism for the increased probability of single cell adhesion andprolonged cell viability by short peptides were studied by comparingcellular behavior of human umbilical cord vein endothelial cells on threemodelsurfaces whose gold electrodes were immobilized with fibronectin,physically adsorbed Arg-Glu-Asp-Val-Tyr, and covalently boundLys-Arg-Glu-Asp-Val-Tyr, respectively. The surface chemistry and bindingproperties were characterized by reflectance Fourier transform infraredspectroscopy. Both short peptides were superior to fibronectin inproducing adhesion of only single cells, whereas the covalently boundpeptide also reduced apoptosis and necrosisof adhered cells. Controllingcell spreading by peptide binding domains to regulate apoptosis andviability represents a fundamental mechanism in cell-materialsinteraction and provides an effective strategy in engineering arrays ofsingle cells.

  4. A phage display-selected peptide inhibitor of Agrobacterium vitis polygalacturonase.

    Science.gov (United States)

    Warren, Jeremy G; Kasun, George W; Leonard, Takara; Kirkpatrick, Bruce C

    2016-05-01

    Agrobacterium vitis, the causal agent of crown gall of grapevine, is a threat to viticulture worldwide. A major virulence factor of this pathogen is polygalacturonase, an enzyme that degrades pectin components of the xylem cell wall. A single gene encodes for the polygalacturonase gene. Disruption of the polygalacturonase gene results in a mutant that is less pathogenic and produces significantly fewer root lesions on grapevines. Thus, the identification of peptides or proteins that could inhibit the activity of polygalacturonase could be part of a strategy for the protection of plants against this pathogen. A phage-displayed combinatorial peptide library was used to isolate peptides with a high binding affinity to A. vitis polygalacturonase. These peptides showed sequence similarity to regions of Oryza sativa (EMS66324, Japonica) and Triticum urartu (NP_001054402, wild wheat) polygalacturonase-inhibiting proteins (PGIPs). Furthermore, these panning experiments identified a peptide, SVTIHHLGGGS, which was able to reduce A. vitis polygalacturonase activity by 35% in vitro. Truncation studies showed that the IHHL motif alone is sufficient to inhibit A. vitis polygalacturonase activity. PMID:26177065

  5. Refining comparative proteomics by spectral counting to account for shared peptides and multiple search engines.

    Science.gov (United States)

    Chen, Yao-Yi; Dasari, Surendra; Ma, Ze-Qiang; Vega-Montoto, Lorenzo J; Li, Ming; Tabb, David L

    2012-09-01

    Spectral counting has become a widely used approach for measuring and comparing protein abundance in label-free shotgun proteomics. However, when analyzing complex samples, the ambiguity of matching between peptides and proteins greatly affects the assessment of peptide and protein inventories, differentiation, and quantification. Meanwhile, the configuration of database searching algorithms that assign peptides to MS/MS spectra may produce different results in comparative proteomic analysis. Here, we present three strategies to improve comparative proteomics through spectral counting. We show that comparing spectral counts for peptide groups rather than for protein groups forestalls problems introduced by shared peptides. We demonstrate the advantage and flexibility of this new method in two datasets. We present four models to combine four popular search engines that lead to significant gains in spectral counting differentiation. Among these models, we demonstrate a powerful vote counting model that scales well for multiple search engines. We also show that semi-tryptic searching outperforms tryptic searching for comparative proteomics. Overall, these techniques considerably improve protein differentiation on the basis of spectral count tables. PMID:22552787

  6. Characterization of model peptide adducts with reactive metabolites of naphthalene by mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Nathalie T Pham

    Full Text Available Naphthalene is a volatile polycyclic aromatic hydrocarbon generated during combustion and is a ubiquitous chemical in the environment. Short term exposures of rodents to air concentrations less than the current OSHA standard yielded necrotic lesions in the airways and nasal epithelium of the mouse, and in the nasal epithelium of the rat. The cytotoxic effects of naphthalene have been correlated with the formation of covalent protein adducts after the generation of reactive metabolites, but there is little information about the specific sites of adduction or on the amino acid targets of these metabolites. To better understand the chemical species produced when naphthalene metabolites react with proteins and peptides, we studied the formation and structure of the resulting adducts from the incubation of model peptides with naphthalene epoxide, naphthalene diol epoxide, 1,2-naphthoquinone, and 1,4-naphthoquinone using high resolution mass spectrometry. Identification of the binding sites, relative rates of depletion of the unadducted peptide, and selectivity of binding to amino acid residues were determined. Adduction occurred on the cysteine, lysine, and histidine residues, and on the N-terminus. Monoadduct formation occurred in 39 of the 48 reactions. In reactions with the naphthoquinones, diadducts were observed, and in one case, a triadduct was detected. The results from this model peptide study will assist in data interpretation from ongoing work to detect peptide adducts in vivo as markers of biologic effect.

  7. Characterization of bioactive RGD peptide immobilized onto poly(acrylic acid) thin films by plasma polymerization

    Science.gov (United States)

    Seo, Hyun Suk; Ko, Yeong Mu; Shim, Jae Won; Lim, Yun Kyong; Kook, Joong-Ki; Cho, Dong-Lyun; Kim, Byung Hoon

    2010-11-01

    Plasma surface modification can be used to improve the surface properties of commercial pure Ti by creating functional groups to produce bioactive materials with different surface topography. In this study, a titanium surface was modified with acrylic acid (AA) using a plasma treatment and immobilized with bioactive arginine-glycine-aspartic acid (RGD) peptide, which may accelerate the tissue integration of bone implants. Both terminals containing the -NH2 of RGD peptide sequence and -COOH of poly(acrylic acid) (PAA) thin film were combined with a covalent bond in the presence of 1-ethyl-3-3-dimethylaminopropyl carbodiimide (EDC). The chemical structure and morphology of AA film and RGD immobilized surface were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All chemical analysis showed full coverage of the Ti substrate with the PAA thin film containing COOH groups and the RGD peptide. The MC3T3-E1 cells were cultured on each specimen, and the cell alkaline phosphatase (ALP) activity were examined. The surface-immobilized RGD peptide has a significantly increased the ALP activity of MC3T3-E1 cells. These results suggest that the RGD peptide immobilization on the titanium surface has an effect on osteoblastic differentiation of MC3T3-E1 cells and potential use in osteo-conductive bone implants.

  8. Electrophoretic Transport of Na(+) and K(+) Ions Within Cyclic Peptide Nanotubes.

    Science.gov (United States)

    Carvajal-Diaz, Jennifer A; Cagin, Tahir

    2016-08-18

    One of the most important applications of cyclic peptide nanotubes (CPNTs) is their potential to be used as artificial ion channels. Natural ion channels are large and complex membrane proteins, which are very expensive, difficult to isolate, and sensible to denaturation; for this reason, artificial ion channels are an important alternative, as they can be produced by simple and inexpensive synthetic chemistry paths, allowing manipulation of properties and enhancement of ion selectivity properties. Artificial ion channels can be used as component in molecular sensors and novel therapeutic agents. Here, the electrophoretic transport of Na(+) and K(+) ions within cyclic peptide nanotubes is investigated by using molecular dynamic simulations. The effect of electric field in the stability of peptide nanotubes was studied by calculating the root mean square deviation curves. Results show that the stability for CPNTs decreases for higher electric fields. Selective transport of cations within the hydrophilic tubes was observed and the negative Cl(-) ions did not enter the peptide nanotubes during the simulation. Radial distribution functions were calculated to describe structural properties and coordination numbers and changes in the first and second hydration shell were observed for the transport of Na(+) and K(+) inside of cyclic peptide nanotubes. However, no effect on coordination number was observed. Diffusion coefficients were calculated from the mean square deviation curves and the Na(+) ion showed higher mobility than the K(+) ion as observed in equivalent experimental studies. The values for diffusion coefficients are comparable with previous calculations in protein channels of equivalent sizes. PMID:27448165

  9. Nanoparticles of cationic chimeric peptide and sodium polyacrylate exhibit striking antinociception activity at lower dose.

    Science.gov (United States)

    Gupta, Kshitij; Singh, Vijay P; Kurupati, Raj K; Mann, Anita; Ganguli, Munia; Gupta, Yogendra K; Singh, Yogendra; Saleem, Kishwar; Pasha, Santosh; Maiti, Souvik

    2009-02-20

    The current study investigates the performance of polyelectrolyte complexes based nanoparticles in improving the antinociceptive activity of cationic chimeric peptide-YFa at lower dose. Size, Zeta potential and morphology of the nanoparticles were determined. Size of the nanoparticles decreases and zeta potential increases with concomitant increase in charge ratio (Z(+/-)). The nanoparticles at Z(+/-)12 are spherical with 70+/-7 nm diameter in AFM and displayed positive surface charge and similar sizes (83+/-8 nm) by Zetasizer. The nanoparticles of Z(+/-) 12 are used in this study. Cytotoxicity by MTT assay on three different mammalian cell lines (liver, neuronal and kidney) revealed lower toxicity of nanoparticles. Hematological parameters were also not affected by nanoparticles compared to normal counts of water treated control group. Nanoparticles containing 10 mg/kg YFa produced increased antinociception, approximately 36%, in tail-flick latency test in mice, whereas the neat peptide at the same concentration did not show any antinociception activity. This enhancement in activity is attributed to the nanoparticle associated protection of peptide from proteolytic degradation. In vitro peptide release study in plasma also supported the antinociception profile of nanoparticles. Thus, our results suggest of a potential nanoparticle delivery system for cationic peptide drug candidates for improving their stability and bioavailability. PMID:19014986

  10. Structures of two distinct conformations of holo-non-ribosomal peptide synthetases.

    Science.gov (United States)

    Drake, Eric J; Miller, Bradley R; Shi, Ce; Tarrasch, Jeffrey T; Sundlov, Jesse A; Allen, C Leigh; Skiniotis, Georgios; Aldrich, Courtney C; Gulick, Andrew M

    2016-01-14

    Many important natural products are produced by multidomain non-ribosomal peptide synthetases (NRPSs). During synthesis, intermediates are covalently bound to integrated carrier domains and transported to neighbouring catalytic domains in an assembly line fashion. Understanding the structural basis for catalysis with non-ribosomal peptide synthetases will facilitate bioengineering to create novel products. Here we describe the structures of two different holo-non-ribosomal peptide synthetase modules, each revealing a distinct step in the catalytic cycle. One structure depicts the carrier domain cofactor bound to the peptide bond-forming condensation domain, whereas a second structure captures the installation of the amino acid onto the cofactor within the adenylation domain. These structures demonstrate that a conformational change within the adenylation domain guides transfer of intermediates between domains. Furthermore, one structure shows that the condensation and adenylation domains simultaneously adopt their catalytic conformations, increasing the overall efficiency in a revised structural cycle. These structures and the single-particle electron microscopy analysis demonstrate a highly dynamic domain architecture and provide the foundation for understanding the structural mechanisms that could enable engineering of novel non-ribosomal peptide synthetases. PMID:26762461

  11. Truncated Glucagon-like Peptide-1 and Exendin-4 α-Conotoxin pl14a Peptide Chimeras Maintain Potency and α-Helicity and Reveal Interactions Vital for cAMP Signaling in Vitro.

    Science.gov (United States)

    Swedberg, Joakim E; Schroeder, Christina I; Mitchell, Justin M; Fairlie, David P; Edmonds, David J; Griffith, David A; Ruggeri, Roger B; Derksen, David R; Loria, Paula M; Price, David A; Liras, Spiros; Craik, David J

    2016-07-22

    Glucagon-like peptide-1 (GLP-1) signaling through the glucagon-like peptide 1 receptor (GLP-1R) is a key regulator of normal glucose metabolism, and exogenous GLP-1R agonist therapy is a promising avenue for the treatment of type 2 diabetes mellitus. To date, the development of therapeutic GLP-1R agonists has focused on producing drugs with an extended serum half-life. This has been achieved by engineering synthetic analogs of GLP-1 or the more stable exogenous GLP-1R agonist exendin-4 (Ex-4). These synthetic peptide hormones share the overall structure of GLP-1 and Ex-4, with a C-terminal helical segment and a flexible N-terminal tail. Although numerous studies have investigated the molecular determinants underpinning GLP-1 and Ex-4 binding and signaling through the GLP-1R, these have primarily focused on the length and composition of the N-terminal tail or on how to modulate the helicity of the full-length peptides. Here, we investigate the effect of C-terminal truncation in GLP-1 and Ex-4 on the cAMP pathway. To ensure helical C-terminal regions in the truncated peptides, we produced a series of chimeric peptides combining the N-terminal portion of GLP-1 or Ex-4 and the C-terminal segment of the helix-promoting peptide α-conotoxin pl14a. The helicity and structures of the chimeric peptides were confirmed using circular dichroism and NMR, respectively. We found no direct correlation between the fractional helicity and potency in signaling via the cAMP pathway. Rather, the most important feature for efficient receptor binding and signaling was the C-terminal helical segment (residues 22-27) directing the binding of Phe(22) into a hydrophobic pocket on the GLP-1R. PMID:27226591

  12. Peptide-membrane interactions of arginine-tryptophan peptides probed using quartz crystal microbalance with dissipation monitoring.

    KAUST Repository

    Rydberg, Hanna A

    2014-04-18

    Membrane-active peptides include peptides that can cross cellular membranes and deliver macromolecular cargo as well as peptides that inhibit bacterial growth. Some of these peptides can act as both transporters and antibacterial agents. It is desirable to combine the knowledge from these two different fields of membrane-active peptides into design of new peptides with tailored actions, as transporters of cargo or as antibacterial substances, targeting specific membranes. We have previously shown that the position of the amino acid tryptophan in the peptide sequence of three arginine-tryptophan peptides affects their uptake and intracellular localization in live mammalian cells, as well as their ability to inhibit bacterial growth. Here, we use quartz crystal microbalance with dissipation monitoring to assess the induced changes caused by binding of the three peptides to supported model membranes composed of POPC, POPC/POPG, POPC/POPG/cholesterol or POPC/lactosyl PE. Our results indicate that the tryptophan position in the peptide sequence affects the way these peptides interact with the different model membranes and that the presence of cholesterol in particular seems to affect the membrane interaction of the peptide with an even distribution of tryptophans in the peptide sequence. These results give mechanistic insight into the function of these peptides and may aid in the design of membrane-active peptides with specified cellular targets and actions.

  13. Growth-Blocking Peptides As Nutrition-Sensitive Signals for Insulin Secretion and Body Size Regulation.

    Science.gov (United States)

    Koyama, Takashi; Mirth, Christen K

    2016-02-01

    In Drosophila, the fat body, functionally equivalent to the mammalian liver and adipocytes, plays a central role in regulating systemic growth in response to nutrition. The fat body senses intracellular amino acids through Target of Rapamycin (TOR) signaling, and produces an unidentified humoral factor(s) to regulate insulin-like peptide (ILP) synthesis and/or secretion in the insulin-producing cells. Here, we find that two peptides, Growth-Blocking Peptide (GBP1) and CG11395 (GBP2), are produced in the fat body in response to amino acids and TOR signaling. Reducing the expression of GBP1 and GBP2 (GBPs) specifically in the fat body results in smaller body size due to reduced growth rate. In addition, we found that GBPs stimulate ILP secretion from the insulin-producing cells, either directly or indirectly, thereby increasing insulin and insulin-like growth factor signaling activity throughout the body. Our findings fill an important gap in our understanding of how the fat body transmits nutritional information to the insulin producing cells to control body size. PMID:26928023

  14. New dendrimer - Peptide host - Guest complexes: Towards dendrimers as peptide carriers

    DEFF Research Database (Denmark)

    Boas, Ulrik; Sontjens, S.H.M.; Jensen, Knud Jørgen; Christensen, J.B.; Meijer, E.W.

    2002-01-01

    Adamantyl urea and adamantyl thiourea modified poly(propylene imine) dendrimers act as hosts for N-terminal tert-butoxycarbonyl (Boc)-protected peptides and form chloroform-soluble complexes. investigations with NMR spectroscopy show that the peptide is bound to the dendrimer by ionic interactions...

  15. 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].

  16. Peptide-MHC class I stability is a stronger predictor of CTL immunogenicity than peptide affinity

    DEFF Research Database (Denmark)

    Harndahl, Mikkel Nors; Rasmussen, Michael; Nielsen, Morten;

    2012-01-01

    Peptide-MHC class I stability is a stronger predictor of CTL immunogenicity than peptide affinity Mikkel Harndahla, Michael Rasmussena, Morten Nielsenb, Soren Buusa,∗ a Laboratory of Experimental Immunology, Faculty of Health Sciences, University of Copenhagen, Denmark b Center for Biological Seq...... al., 2007. J. Immunol. 178, 7890–7901. doi:10.1016/j.molimm.2012.02.025...

  17. Peptide biomarkers as evidence of perchlorate biodegradation.

    Science.gov (United States)

    Bansal, Reema; Crawford, Ronald L; Paszczynski, Andrzej J

    2011-02-01

    Perchlorate is a known health hazard for humans, fish, and other species. Therefore, it is important to assess the response of an ecosystem exposed to perchlorate contamination. The data reported here show that a liquid chromatography-mass spectrometry-based proteomics approach for the detection of perchlorate-reducing enzymes can be used to measure the ability of microorganisms to degrade perchlorate, including determining the current perchlorate degradation status. Signature peptides derived from chlorite dismutase (CD) and perchlorate reductase can be used as biomarkers of perchlorate presence and biodegradation. Four peptides each derived from CD and perchlorate reductase subunit A (PcrA) and seven peptides derived from perchlorate reductase subunit B (PcrB) were identified as signature biomarkers for perchlorate degradation, as these sequences are conserved in the majority of the pure and mixed perchlorate-degrading microbial cultures examined. However, chlorite dismutase signature biomarker peptides from Dechloromonas agitata CKB were found to be different from those in other cultures used and should also be included with selected CD biomarkers. The combination of these peptides derived from the two enzymes represents a promising perchlorate presence/biodegradation biomarker system. The biomarker peptides were detected at perchlorate concentrations as low as 0.1 mM and at different time points both in pure cultures and within perchlorate-reducing environmental enrichment consortia. The peptide biomarkers were also detected in the simultaneous presence of perchlorate and an alternate electron acceptor, nitrate. We believe that this technique can be useful for monitoring bioremediation processes for other anthropogenic environmental contaminants with known metabolic pathways. PMID:21115710

  18. Clinical relevance of intestinal peptide uptake

    Institute of Scientific and Technical Information of China (English)

    Hugh; James; Freeman

    2015-01-01

    AIM: To determine available information on an independent peptide transporter 1(Pep T1) and its potential relevance to treatment, this evaluation was completed.METHODS: Fully published English language literature articles sourced through Pub Med related to protein digestion and absorption, specifically human peptide and amino acid transport, were accessed and reviewed.Papers from 1970 to the present, with particular emphasis on the past decade, were examined. In addition,abstracted information translated to English in Pub Med was also included. Finally, studies and reviews relevant to nutrient or drug uptake, particularly in human intestine were included for evaluation. This work represents a summary of all of these studies with particular reference to peptide transporter mediated assimilation of nutrients and pharmacologically active medications.RESULTS: Assimilation of dietary protein in humans involves gastric and pancreatic enzyme hydrolysis to luminal oligopeptides and free amino acids. During the ensuing intestinal phase, these hydrolytic products are transported into the epithelial cell and, eventually, the portal vein. A critical component of this process is the uptake of intact di-peptides and tri-peptides by an independent Pep T1. A number of "peptide-mimetic" pharmaceutical agents may also be transported through this carrier, important for uptake of different antibiotics, antiviral agents and angiotensin-converting enzyme inhibitors. In addition, specific peptide products of intestinal bacteria may also be transported by Pep T1, with initiation and persistence of an immune response including increased cytokine production and associated intestinal inflammatory changes. Interestingly, these inflammatory changes may also be attenuated with orallyadministered anti-inflammatory tripeptides administered as site-specific nanoparticles and taken up by this Pep T1 transport protein. CONCLUSION: Further evaluation of the role of this transporter in treatment of

  19. Toward the assessment of food toxicity for celiac patients: characterization of monoclonal antibodies to a main immunogenic gluten peptide.

    Directory of Open Access Journals (Sweden)

    Belén Morón

    Full Text Available BACKGROUND AND AIMS: Celiac disease is a permanent intolerance to gluten prolamins from wheat, barley, rye and, in some patients, oats. Partially digested gluten peptides produced in the digestive tract cause inflammation of the small intestine. High throughput, immune-based assays using monoclonal antibodies specific for these immunotoxic peptides would facilitate their detection in food and enable monitoring of their enzymatic detoxification. Two monoclonal antibodies, G12 and A1, were developed against a highly immunotoxic 33-mer peptide. The potential of each antibody for quantifying food toxicity for celiac patients was studied. METHODS: Epitope preferences of G12 and A1 antibodies were determined by ELISA with gluten-derived peptide variants of recombinant, synthetic or enzymatic origin. RESULTS: The recognition sequences of G12 and A1 antibodies were hexameric and heptameric epitopes, respectively. Although G12 affinity for the 33-mer was superior to A1, the sensitivity for gluten detection was higher for A1. This observation correlated to the higher number of A1 epitopes found in prolamins than G12 epitopes. Activation of T cell from gluten digested by glutenases decreased equivalently to the detection of intact peptides by A1 antibody. Peptide recognition of A1 included gliadin peptides involved in the both the adaptive and innate immunological response in celiac disease. CONCLUSIONS: The sensitivity and epitope preferences of the A1 antibody resulted to be useful to detect gluten relevant peptides to infer the potential toxicity of food for celiac patients as well as to monitor peptide modifications by transglutaminase 2 or glutenases.

  20. Coupling to the surface of liposomes alters the immunogenicity of hepatitis C virus-derived peptides and confers sterile immunity.

    Science.gov (United States)

    Takagi, Akira; Kobayashi, Nobuharu; Taneichi, Maiko; Uchida, Tetsuya; Akatsuka, Toshitaka

    2013-01-01

    We have previously demonstrated that antigens chemically coupled to the surface of liposomes consisting of unsaturated fatty acids were cross-presented by antigen presenting cells to cytotoxic T lymphocytes (CTLs). Liposomal form of immunodominant CTL epitope peptides derived from lymphocytic choriomeningitis virus exhibited highly efficient antiviral CTL responses in immunized mice. In this study, we coupled 15 highly conserved immunodominant CTL epitope peptides derived from hepatitis C virus (HCV) to the surface of liposomes. We also emulsified the peptides in incomplete Freund's adjuvant, and compared the immune responses of the two methods of presenting the peptides by cytotoxicity induction and interferon-gamma (IFN-γ) production by CD8(+) T cells of the immunized mice. We noticed significant variations of the immunogenicity of each peptide between the two antigen delivery systems. In addition, the immunogenicity profiles of the peptides were also different from those observed in the mice infected with recombinant adenoviruses expressing HCV proteins as previously reported. Induction of anti-viral immunity by liposomal peptides was tested by the challenge experiments using recombinant vaccinia viruses expressing corresponding HCV epitopes. One D(b)-restricted and three HLA-A(*)0201-restricted HCV CTL epitope peptides on the surface of liposomes were found to confer complete protection to immunized mice with establishment of long-term memory. Interestingly, their protective efficacy seemed to correlate with the induction of IFN-γ producing cells rather than the cytotoxicity induction suggesting that the immunized mice were protected through non-cytolytic mechanisms. Thus, these liposomal peptides might be useful as HCV vaccines not only for prevention but also for therapeutic use. PMID:23159619

  1. Immunoregulatory activities of human immunodeficiency virus (HIV) proteins: Effect of HIV recombinant and synthetic peptides on immunoglobulin synthesis and proliferative responses by normal lymphocytes

    International Nuclear Information System (INIS)

    Recombinant and synthetic peptides corresponding to envelope proteins of the human immunodeficiency virus (HIV) were examined for their effects on the activities of lymphocytes from normal donors in vitro. Although lymphocytes cultured with env-gag peptides produced significant amounts of IgG, addition of env-gag peptides to a pokeweed mitogen-induced B-cell activation system resulted in suppression of immunoglobulin synthesis by normal lymphocytes. Recombinant antigens, env-gag and env-80 dihydrofolate reductase (DHFR), produced a substantial proliferative response by peripheral blood mononuclear cells (PBMC) as determined by [3H]thymidine incorporation. PBMC precultured with HIV synthetic peptide env 578-608 also manifested significant proliferative responses as compared to control cultures. CD3+ lymphocytes precultured with recombinant HIV antigens, env-gag and env-80 DHFR, and synthetic HIV peptide, env 487-511, showed moderate but significant proliferative responses. Both recombinant antigens and synthetic peptides also produced a dose-dependent stimulatory effect on proliferation by CD3- lymphocytes. These studies demonstrate that recombinant and synthetic peptides of the HIV genome express immunoregulatory T- and B-cell epitopes. Identification of unique HIV epitopes with immunogenic and immunoregulatory activities is necessary for the development of an effective vaccine against HIV infection

  2. Urinary Peptide Levels in Patients with Chronic Renal Failure

    Directory of Open Access Journals (Sweden)

    Mungli Prakash

    2010-10-01

    Full Text Available Introduction: Peptide levels in urine are found to be decreased in renal failure. In the current study urinary peptide levels were determined in chronic renal failure (CRF patients. Method: 86 CRF patients and 80 healthy controls were selected for the study. Urinary proteins and peptide levels were determined by spectrophotometer based Lowry and Bradford methods. Urinary creatinine levels were determined by clinical chemistry analyzer. Results: There was significant decrease in urinary peptide levels in CRF patients and Urinary % peptides were significantly decreased in CRF patients as compared to healthy controls. Urinary % peptides correlated negatively with proteinuria. Conclusion: we have found decrease in urinary peptides and % urinary peptides in CRF patients and possibly measurement of % urinary peptides may possibly serve as better indicator in early detection of impairment in renal function.

  3. Selection of Genetic engineering peptide ligands for TNF receptor imaging

    International Nuclear Information System (INIS)

    Objective: To screen the peptide ligands of TNF receptor from phage 6-mer peptide library with the purpose of developing new peptides radiopharmaceuticals for TNF receptor imaging. Methods: The soluble protein of TNF receptor I (sTNFR I) was used to screen the TNF-specific epitopes from phage 6-mer peptide library. After four rounds of affinity screening, the peptides displayed on the selected phage were directly subjected to ELISA to determine their immunological activity to sTNFR. The amino acid sequences of the peptides with highest immunological activity were deduced through DNA sequencing. And their conserved sequences were further determined. Results: Peptides sequences mimicking TNF-specific epitopes were obtained. Conclusion: The short peptides sequences mimicking TNF -specific epitopes were successfully acquired. The method which was established in the present study may provide a feasible way in peptides radiopharmaceuticals development for TNF receptor imaging. (authors)

  4. Peptide pool immunization and CD8+ T cell reactivity

    DEFF Research Database (Denmark)

    Rasmussen, Susanne B; Harndahl, Mikkel N; Buus, Anette Stryhn;

    2013-01-01

    peptide in the Elispot culture. Immunization with a mixture of the VSV-peptide and a "normal" peptide also resulted in IFNγ spot formation without addition of peptide to the assay culture. Peptide-tetramer staining of CD8(+) T cells from mice immunized with a mixture of VSV-peptide and "normal" peptide......Mice were immunized twice with a pool of five peptides selected among twenty 8-9-mer peptides for their ability to form stable complexes at 37°C with recombinant H-2K(b) (half-lives 10-15h). Vaccine-induced immunity of splenic CD8(+) T cells was studied in a 24h IFNγ Elispot assay. Surprisingly...... peptides induced normal peptide immunity i.e. the specific T cell reactivity in the Elispot culture was strictly dependent on exposure to the immunizing peptide ex vivo. However, immunization with two of the peptides, a VSV- and a Mycobacterium-derived peptide, resulted in IFNγ spot formation without...

  5. Producing CD-ROMs.

    Science.gov (United States)

    Hyams, Peter, Ed.

    1992-01-01

    This issue presents 11 articles that address issues relating to the production of CD-ROMs. Highlights include current uses of CD-ROM; standards; steps involved in producing CD-ROMs, including data capture, conversion, and tagging, product design, and indexing; authoring; selecting indexing and retrieval software; costs; multimedia CD-ROMs; and…

  6. Producing superhydrophobic roof tiles

    Science.gov (United States)

    Carrascosa, Luis A. M.; Facio, Dario S.; Mosquera, Maria J.

    2016-03-01

    Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for producing superhydrophobic surfaces on building materials is developed and their effectiveness and their durability on clay roof tiles are evaluated. Specifically, an organic-inorganic hybrid gel containing silica nanoparticles is produced. The nanoparticles create a densely packed coating on the roof tile surface in which air is trapped. This roughness produces a Cassie-Baxter regime, promoting superhydrophobicity. A surfactant, n-octylamine, was also added to the starting sol to catalyze the sol-gel process and to coarsen the pore structure of the gel network, preventing cracking. The application of ultrasound obviates the need to use volatile organic compounds in the synthesis, thereby making a ‘green’ product. It was also demonstrated that a co-condensation process effective between the organic and inorganic species is crucial to obtain durable and effective coatings. After an aging test, high hydrophobicity was maintained and water absorption was completely prevented for the roof tile samples under study. However, a transition from a Cassie-Baxter to a Wenzel state regime was observed as a consequence of the increase in the distance between the roughness pitches produced by the aging of the coating.

  7. Adenoviral Producer Cells

    Directory of Open Access Journals (Sweden)

    Imre Kovesdi

    2010-08-01

    Full Text Available Adenovirus (Ad vectors, in particular those of the serotype 5, are highly attractive for a wide range of gene therapy, vaccine and virotherapy applications (as discussed in further detail in this issue. Wild type Ad5 virus can replicate in numerous tissue types but to use Ad vectors for therapeutic purposes the viral genome requires modification. In particular, if the viral genome is modified in such a way that the viral life cycle is interfered with, a specific producer cell line is required to provide trans-complementation to overcome the modification and allow viral production. This can occur in two ways; use of a producer cell line that contains specific adenoviral sequences incorporated into the cell genome to trans-complement, or use of a producer cell line that naturally complements for the modified Ad vector genome. This review concentrates on producer cell lines that complement non-replicating adenoviral vectors, starting with the historical HEK293 cell line developed in 1977 for first generation Ad vectors. In addition the problem of replication-competent adenovirus (RCA contamination in viral preparations from HEK293 cells is addressed leading to the development of alternate cell lines. Furthermore novel cell lines for more complex Ad vectors and alternate serotype Ad vectors are discussed.

  8. Top Hispanic Degree Producers

    Science.gov (United States)

    Diverse: Issues in Higher Education, 2012

    2012-01-01

    This article presents a list of the top 100 producers of associate, bachelor's and graduate degrees awarded to minority students based on research conducted by Dr. Victor M.H. Borden, professor of educational leadership and policy students at the Indiana University Bloomington. For the year 2012, the listings focus on Hispanic students. Data for…

  9. Peptide inhibition of human cytomegalovirus infection

    Directory of Open Access Journals (Sweden)

    Morris Cindy A

    2011-02-01

    Full Text Available Abstract Background Human cytomegalovirus (HCMV is the most prevalent congenital viral infection in the United States and Europe causing significant morbidity and mortality to both mother and child. HCMV is also an opportunistic pathogen in immunocompromised individuals, including human immunodeficiency virus (HIV- infected patients with AIDS, and solid organ and allogeneic stem cell transplantation recipients. Current treatments for HCMV-associated diseases are insufficient due to the emergence of drug-induced resistance and cytotoxicity, necessitating novel approaches to limit HCMV infection. The aim of this study was to develop therapeutic peptides targeting glycoprotein B (gB, a major glycoprotein of HCMV that is highly conserved across the Herpesviridae family, that specifically inhibit fusion of the viral envelope with the host cell membrane preventing HCMV entry and infection. Results Using the Wimley-White Interfacial Hydrophobicity Scale (WWIHS, several regions within gB were identified that display a high potential to interact with lipid bilayers of cell membranes and hydrophobic surfaces within proteins. The ability of synthetic peptides analogous to WWIHS-positive sequences of HCMV gB to inhibit viral infectivity was evaluated. Human foreskin fibroblasts (HFF were infected with the Towne-GFP strain of HCMV (0.5 MOI, preincubated with peptides at a range of concentrations (78 nm to 100 μM, and GFP-positive cells were visualized 48 hours post-infection by fluorescence microscopy and analyzed quantitatively by flow cytometry. Peptides that inhibited HCMV infection demonstrated different inhibitory concentration curves indicating that each peptide possesses distinct biophysical properties. Peptide 174-200 showed 80% inhibition of viral infection at a concentration of 100 μM, and 51% and 62% inhibition at concentrations of 5 μM and 2.5 μM, respectively. Peptide 233-263 inhibited infection by 97% and 92% at concentrations of 100

  10. Computational Studies of Difference in Binding Modes of Peptide and Non-Peptide Inhibitors to MDM2/MDMX Based on Molecular Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Yuxin Zhang

    2012-02-01

    Full Text Available Inhibition of p53-MDM2/MDMX interaction is considered to be a promising strategy for anticancer drug design to activate wild-type p53 in tumors. We carry out molecular dynamics (MD simulations to study the binding mechanisms of peptide and non-peptide inhibitors to MDM2/MDMX. The rank of binding free energies calculated by molecular mechanics generalized Born surface area (MM-GBSA method agrees with one of the experimental values. The results suggest that van der Waals energy drives two kinds of inhibitors to MDM2/MDMX. We also find that the peptide inhibitors can produce more interaction contacts with MDM2/MDMX than the non-peptide inhibitors. Binding mode predictions based on the inhibitor-residue interactions show that the π–π, CH–π and CH–CH interactions dominated by shape complimentarity, govern the binding of the inhibitors in the hydrophobic cleft of MDM2/MDMX. Our studies confirm the residue Tyr99 in MDMX can generate a steric clash with the inhibitors due to energy and structure. This finding may theoretically provide help to develop potent dual-specific or MDMX inhibitors.

  11. The Equilibrium Thermodynamics of Various Peptide Sequences

    Science.gov (United States)

    Yaşar, Fatih

    The equilibrium thermodynamic properties of two peptide sequences of β-casein in the α-helix regions were studied by three-dimensional molecular modeling in vacuum. All the three-dimensional conformations of each peptide sequences were obtained by multicanonical simulations using ECEPP/2 force field and each simulation was started from completely random initial conformation. No a-priori information about ground-state is used in the simulations. In the present study, we calculated the average values of total energy, specific heat, fourth-order cumulant for two peptide sequences of β-casein as a function of temperature. We observed that the specific heat shows two peaks as a function of temperature for both peptides. Because our sequences have highly helical structure and two peaks in the specific heat, we have also studied the helix-coil transitions to determine these peaks. Our data indeed show these peptides have highly helical structure and better agreement with the results of spectroscopic techniques and other prediction methods.

  12. Biosynthetic engineering of nonribosomal peptide synthetases.

    Science.gov (United States)

    Kries, Hajo

    2016-09-01

    From the evolutionary melting pot of natural product synthetase genes, microorganisms elicit antibiotics, communication tools, and iron scavengers. Chemical biologists manipulate these genes to recreate similarly diverse and potent biological activities not on evolutionary time scales but within months. Enzyme engineering has progressed considerably in recent years and offers new screening, modelling, and design tools for natural product designers. Here, recent advances in enzyme engineering and their application to nonribosomal peptide synthetases are reviewed. Among the nonribosomal peptides that have been subjected to biosynthetic engineering are the antibiotics daptomycin, calcium-dependent antibiotic, and gramicidin S. With these peptides, incorporation of unnatural building blocks and modulation of bioactivities via various structural modifications have been successfully demonstrated. Natural product engineering on the biosynthetic level is not a reliable method yet. However, progress in the understanding and manipulation of biosynthetic pathways may enable the routine production of optimized peptide drugs in the near future. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:27465074

  13. 7 CFR 1250.305 - Egg producer or producer.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Egg producer or producer. 1250.305 Section 1250.305... Research and Promotion Order Definitions § 1250.305 Egg producer or producer. Egg producer or producer... laying hens is in some other party to the contract. In the event the party to an oral contract...

  14. A mutant L-asparaginase II signal peptide improves the secretion of recombinant cyclodextrin glucanotransferase and the viability of Escherichia coli.

    Science.gov (United States)

    Ismail, Noor Faizah; Hamdan, Salehhuddin; Mahadi, Nor Muhammad; Murad, Abdul Munir Abdul; Rabu, Amir; Bakar, Farah Diba Abu; Klappa, Peter; Illias, Rosli Md

    2011-05-01

    L-Asparaginase II signal peptide was used for the secretion of recombinant cyclodextrin glucanotransferase (CGTase) into the periplasmic space of E. coli. Despite its predominant localisation in the periplasm, CGTase activity was also detected in the extracellular medium, followed by cell lysis. Five mutant signal peptides were constructed to improve the periplasmic levels of CGTase. N1R3 is a mutated signal peptide with the number of positively charged amino acid residues in the n-region increased to a net charge of +5. This mutant peptide produced a 1.7-fold enhancement of CGTase activity in the periplasm and significantly decreased cell lysis to 7.8% of the wild-type level. The formation of intracellular inclusion bodies was also reduced when this mutated signal peptide was used as judged by SDS-PAGE. Therefore, these results provide evidence of a cost-effective means of expression of recombinant proteins in E. coli. PMID:21234789

  15. A phage display delected 7-mer peptide inhibitor of the tannerella forsythia metalloprotease-like enzyme karilysin can be truncated to ser-trp-phe-pro

    DEFF Research Database (Denmark)

    Skottrup, Peter Durand; Sørensen, Grete; Ksiazek, Miroslaw; Potempa, Jan; Riise, Erik Skjold

    2012-01-01

    Tannerella forsythia is a gram-negative bacteria, which is strongly associated with the development of periodontal disease. Karilysin is a newly identified metalloprotease-like enzyme, that is secreted from T. forsythia. Karilysin modulates the host immune response and is therefore considered a...... Maltose Binding protein (MBP) was produced with peptide15 fused to the N-terminus of MBP. The peptide15-MBP was expressed in E. coli and the purified fusion-protein was used to verify Kly18 specific binding. Chemically synthesised peptide15 (SWFPLRSGGG) could inhibit the enzymatic activity of both Kly18...... and intact Karilysin (Kly48). Furthermore, peptide15 could slow down the autoprocessing of intact Kly48 to Kly18. The WFP motif was important for inhibition and a truncation study further demonstrated that the N-terminal serine was also essential for Kly18 inhibition. The SWFP peptide had a Ki value...

  16. Inhibition of LtxA toxicity by blocking cholesterol binding with peptides.

    Science.gov (United States)

    Brown, A C; Koufos, E; Balashova, N V; Boesze-Battaglia, K; Lally, E T

    2016-02-01

    The leukotoxin (LtxA) produced by Aggregatibacter actinomycetemcomitans kills host immune cells, allowing the bacterium to establish an ecological niche in the upper aerodigestive tract of its human host. The interaction of LtxA with human immune cells is both complex and multifaceted, involving membrane lipids as well as cell-surface proteins. In the initial encounter with the host cell, LtxA associates with lymphocyte function-associated antigen-1, a cell surface adhesion glycoprotein. However, we have also demonstrated that the toxin associates strongly with the plasma membrane lipids, specifically cholesterol. This association with cholesterol is regulated by a cholesterol recognition amino acid consensus (CRAC) motif, with a sequence of (334) LEEYSKR(340), in the N-terminal region of the toxin. Here, we have demonstrated that removal of cholesterol from the plasma membrane or mutation of the LtxA CRAC motif inhibits the activity of the toxin in THP-1 cells. To inhibit LtxA activity, we designed a short peptide corresponding to the CRAC(336) motif of LtxA (CRAC(336WT)). This peptide binds to cholesterol and thereby inhibits the toxicity of LtxA in THP-1 cells. Previously, we showed that this peptide inhibits LtxA toxicity against Jn.9 (Jurkat) cells, indicating that peptides derived from the cholesterol-binding site of LtxA may have a potential clinical applicability in controlling infections of repeats-in-toxin-producing organisms. PMID:26352738

  17. Peptide friction in water nanofilm on mica surface

    Institute of Scientific and Technical Information of China (English)

    Zhou Bo; Xiu Peng; Wang Chun-Lei; Fang Hai-Ping

    2012-01-01

    Peptide frictions in water nanofilms of various thicknesses on a mica surface are studied via molecular dynamics simulations.We find that the forced lateral motion of the peptide exhibits stick-slip behaviour at low water coverage;in contrast,the smooth gliding motion is observed at higher water coverage.The adsorbed peptide can form direct peptide-surface hydrogen bonds as well as indirect peptide-water-surface hydrogen bonds with the substrate. We propose that the stick-slip phenomenon is attributed to the overall effects of direct and indirect hydrogen bonds formed between the surface and the peptide.

  18. Glucagonlike Peptide 2 Analogue Teduglutide

    Science.gov (United States)

    Chaturvedi, Lakshmi S.; Basson, Marc D.

    2015-01-01

    IMPORTANCE Short bowel syndrome occurs when a shortened intestine cannot absorb sufficient nutrients or fluids. Teduglutide is a recombinant analogue of human glucagonlike peptide 2 that reduces dependence on parenteral nutrition in patients with short bowel syndrome by promoting enterocytic proliferation, increasing the absorptive surface area. However, enterocyte function depends not only on the number of cells that are present but also on differentiated features that facilitate nutrient absorption and digestion. OBJECTIVE To test the hypothesis that teduglutide impairs human intestinal epithelial differentiation. DESIGN AND SETTING We investigated the effects of teduglutide in the modulation of proliferation and differentiation in human Caco-2 intestinal epithelial cells at a basic science laboratory. This was an in vitro study using Caco-2 cells, a human-derived intestinal epithelial cell line commonly used to model enterocytic biology. EXPOSURE Cells were exposed to teduglutide or vehicle control. MAINOUTCOMESAND MEASURES We analyzed the cell cycle by bromodeoxyuridine incorporation or propidium iodide staining and flow cytometry and measured cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. We used quantitative reverse transcription–polymerase chain reaction to assay the expression of the enterocytic differentiation markers villin, sucrase-isomaltase, glucose transporter 2 (GLUT2), and dipeptidyl peptidase 4 (DPP-4), as well as that of the putative differentiation signals schlafen 12 (SLFN12) and caudal-related homeobox intestine-specific transcription factor (Cdx2). Villin promoter activity was measured by a luciferase-based assay. RESULTS The MTS assay demonstrated that teduglutide increased cell numbers by a mean (SD) of 10% (2%) over untreated controls at a maximal 500nM (n = 6, P < .05). Teduglutide increased bromodeoxyuridine-positive cells vs untreated controls by a mean (SD

  19. Cell-free synthesis of isotopically labelled peptide ligands for the functional characterization of G protein-coupled receptors.

    Science.gov (United States)

    Joedicke, Lisa; Trenker, Raphael; Langer, Julian D; Michel, Hartmut; Preu, Julia

    2016-01-01

    Cell-free systems exploit the transcription and translation machinery of cells from different origins to produce proteins in a defined chemical environment. Due to its open nature, cell-free protein production is a versatile tool to introduce specific labels such as heavy isotopes, non-natural amino acids and tags into the protein while avoiding cell toxicity. In particular, radiolabelled peptides and proteins are valuable tools for the functional characterization of protein-protein interactions and for studying binding kinetics. In this study we evaluated cell-free protein production for the generation of radiolabelled ligands for G protein-coupled receptors (GPCRs). These receptors are seven-transmembrane-domain receptors activated by a plethora of extracellular stimuli including peptide ligands. Many GPCR peptide ligands contain disulphide bonds and are thus inherently difficult to produce in bacterial expression hosts or in Escherichia coli-based cell-free systems. Here, we established an adapted E. coli-based cell-free translation system for the production of disulphide bond-containing GPCR peptide ligands and specifically introduce tritium labels for detection. The bacterial oxidoreductase DsbA is used as a chaperone to favour the formation of disulphide bonds and to enhance the yield of correctly folded proteins and peptides. We demonstrate the correct folding and formation of disulphide bonds and show high-affinity ligand binding of the produced radio peptide ligands to the respective receptors. Thus, our system allows the fast, cost-effective and reliable synthesis of custom GPCR peptide ligands for functional and structural studies. PMID:27047736

  20. Angiotensin I-Converting Enzyme Inhibitory Peptides of Chia (Salvia hispanica) Produced by Enzymatic Hydrolysis

    OpenAIRE

    Maira Rubi Segura Campos; Fanny Peralta González; Luis Chel Guerrero; David Betancur Ancona

    2013-01-01

    Synthetic angiotensin I-converting enzyme (ACE-I) inhibitors can have undesirable side effects, while natural inhibitors have no side effects and are potential nutraceuticals. A protein-rich fraction from chia (Salvia hispanica L.) seed was hydrolyzed with an Alcalase-Flavourzyme sequential system and the hydrolysate ultrafiltered through four molecular weight cut-off membranes (1 kDa, 3 kDa, 5 kDa, and 10 kDa). ACE-I inhibitory activity was quantified in the hydrolysate and ultrafiltered fra...

  1. Adsorption of peptides produced by cyanobacterium Microcystis aeruginosa onto granular activated carbon

    Czech Academy of Sciences Publication Activity Database

    Kopecká, Ivana; Pivokonský, Martin; Pivokonská, Lenka; Hnaťuková, Petra; Šafaříková, Jana

    2014-01-01

    Roč. 69, April (2014), s. 595-608. ISSN 0008-6223 R&D Projects: GA ČR GAP105/11/0247 Institutional support: RVO:67985874 Keywords : Microcystis aeruginosa * granular activated carbon * celllular organic matter (COM) Subject RIV: BK - Fluid Dynamics Impact factor: 6.196, year: 2014 http://www.sciencedirect.com/science/article/pii/S000862231301227X

  2. A subdomain swap strategy for reengineering nonribosomal peptides.

    Science.gov (United States)

    Kries, Hajo; Niquille, David L; Hilvert, Donald

    2015-05-21

    Nonribosomal peptide synthetases (NRPSs) protect microorganisms from environmental threats by producing diverse siderophores, antibiotics, and other peptide natural products. Their modular molecular structure is also attractive from the standpoint of biosynthetic engineering. Here we evaluate a methodology for swapping module specificities of these mega-enzymes that takes advantage of flavodoxin-like subdomains involved in substrate recognition. Nine subdomains encoding diverse specificities were transplanted into the Phe-specific GrsA initiation module of gramicidin S synthetase. All chimeras could be purified as soluble protein. One construct based on a Val-specific subdomain showed sizable adenylation activity and functioned as a Val-Pro diketopiperazine synthetase upon addition of the proline-specific GrsB1 module. These results suggest that subdomain swapping could be a viable alternative to previous NRPS design approaches targeting binding pockets, domains, or entire modules. The short length of the swapped sequence stretch may facilitate straightforward exploitation of the wealth of existing NRPS modules for combinatorial biosynthesis. PMID:26000750

  3. Release of peptides from Fibrinogen in vitro and in vivo

    International Nuclear Information System (INIS)

    The dissertation deals experimentally with the following problem fields: The attempt was made to obtain extremely pure, native peptides from fibrinogen with micropreparation with the help of high-pressure liquid chromatography (HPLC); a HPLC-pure antigen which could be labelled (DAT-FPA) was also to be produced and a HPLC-purified, labelled antigen (J 125 DAT-FPA) for the radioimmunoassay was to be prepared. By applying HPLC-purified FPA-material to immunise rabbits, a highly specific antibody against FPA was obtained, and the radioimmunoassay was decisively improved. Furthermore, a method with a high recovery rate specific for the A-peptides could be found. A procedure was developed which is able to separate the modifications from the plasma from one another and to prove them specifically in ng-quantities. This is the first time that the sensitive method of high-pressure liquid chromatography is used to observe the effects of the snake venom enzymes on fibrinogen over a period of 20 hrs. The kinetics of intravenously administered J 123 DAT-FPA and, in comparison, J 123 FPB β 15-42 in vivo in rabbits with the help of a scintiscanning method, was investigated and the distribution in the organism and the ways of elimination were determined. (orig./MG)

  4. Effect of Professional Exercises on Brain Natriuretic Peptide

    Directory of Open Access Journals (Sweden)

    MA Babaee Beigi

    2009-12-01

    Full Text Available Background: Brain natriuretic peptide (BNP reflects myocardial wall stress. BNP activities are similar to those of atrial natriuretic peptide, including diuresis, natriuresis, hypotension and smooth muscle relaxation as well as ability to inhibit the rennin aldosterone system. It is mainly produced and released into the circulation by the ventricle in response to increased ventricular wall pressure or stretching. Therefore, BNP can be served as a marker of left ventricular dysfunction. The aim of this study was to investigate effect of various professional exercises on plasma BNP levels.Methods: We enrolled 20 consecutive healthy professional athletic males from different sporting disciplines including 5 football players, 5 volleyball players, 5 bodybuilders and 5 water- polo players. Plasma BNP samples were taken immediately before and 1 hour after exercise.Results: Plasma BNP level was significantly increased after exercise (30.01 ± 23.46 vs. 16.72 ± 10.86 pg/ml; P= 0.042. The highest increase in BNP level was found among volleyball players (mean values: 19.12 to 43.38 pg/ml; 126.3% increase after volleyball compared to other exercises. Conclusion: Exercise can increase plasma BNP levels, particularly among volleyball players.

  5. Insect antimicrobial peptides act synergistically to inhibit a trypanosome parasite.

    Science.gov (United States)

    Marxer, Monika; Vollenweider, Vera; Schmid-Hempel, Paul

    2016-05-26

    The innate immune system provides protection from infection by producing essential effector molecules, such as antimicrobial peptides (AMPs) that possess broad-spectrum activity. This is also the case for bumblebees, Bombus terrestris, when infected by the trypanosome, Crithidia bombi Furthermore, the expressed mixture of AMPs varies with host genetic background and infecting parasite strain (genotype). Here, we used the fact that clones of C. bombi can be cultivated and kept as strains in medium to test the effect of various combinations of AMPs on the growth rate of the parasite. In particular, we used pairwise combinations and a range of physiological concentrations of three AMPs, namely Abaecin, Defensin and Hymenoptaecin, synthetized from the respective genomic sequences. We found that these AMPs indeed suppress the growth of eight different strains of C. bombi, and that combinations of AMPs were typically more effective than the use of a single AMP alone. Furthermore, the most effective combinations were rarely those consisting of maximum concentrations. In addition, the AMP combination treatments revealed parasite strain specificity, such that strains varied in their sensitivity towards the same mixtures. Hence, variable expression of AMPs could be an alternative strategy to combat highly variable infections.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160603

  6. Anisotropic membrane curvature sensing by antibacterial peptides

    CERN Document Server

    Gómez-Llobregat, Jordi; Lindén, Martin

    2014-01-01

    Many proteins and peptides have an intrinsic capacity to sense and induce membrane curvature, and play crucial roles for organizing and remodeling cell membranes. However, the molecular driving forces behind these processes are not well understood. Here, we describe a new approach to study curvature sensing, by simulating the direction-dependent interactions of single molecules with a buckled lipid bilayer. We analyze three antimicrobial peptides, a class of membrane-associated molecules that specifically target and destabilize bacterial membranes, and find qualitatively different sensing characteristics that would be difficult to resolve with other methods. These findings provide new insights into the microscopic mechanisms of antimicrobial peptides, which might aid the development of new antibiotics. Our approach is generally applicable to a wide range of curvature sensing molecules, and our results provide strong motivation to develop new experimental methods to track position and orientation of membrane p...

  7. Anisotropic Membrane Curvature Sensing by Amphipathic Peptides.

    Science.gov (United States)

    Gómez-Llobregat, Jordi; Elías-Wolff, Federico; Lindén, Martin

    2016-01-01

    Many proteins and peptides have an intrinsic capacity to sense and induce membrane curvature, and play crucial roles for organizing and remodeling cell membranes. However, the molecular driving forces behind these processes are not well understood. Here, we describe an approach to study curvature sensing by simulating the interactions of single molecules with a buckled lipid bilayer. We analyze three amphipathic antimicrobial peptides, a class of membrane-associated molecules that specifically target and destabilize bacterial membranes, and find qualitatively different sensing characteristics that would be difficult to resolve with other methods. Our findings provide evidence for direction-dependent curvature sensing mechanisms in amphipathic peptides and challenge existing theories of hydrophobic insertion. The buckling approach is generally applicable to a wide range of curvature-sensing molecules, and our results provide strong motivation to develop new experimental methods to track position and orientation of membrane proteins. PMID:26745422

  8. Antimicrobial peptides in innate immune responses

    DEFF Research Database (Denmark)

    Sorensen, O.E.; Borregaard, N.; Cole, A.M.

    2008-01-01

    novo synthesis or by proteolytic cleavage from antimicrobially inactive proproteins. Studies of human diseases and animal studies have given important clues to the in vivo role of AMPs. It is now evident that dysregulation of the generation of AMPs in innate immune responses plays a role in certain......Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de...... diseases like Crohn's disease and atopic dermatitis. AMPs are attractive candidates for development of novel antibiotics due to their in vivo activity profile and some peptides may serve as templates for further drug development Udgivelsesdato: 2008...

  9. Peptide Based Radiopharmaceuticals: Specific Construct Approach

    Energy Technology Data Exchange (ETDEWEB)

    Som, P; Rhodes, B A; Sharma, S S

    1997-10-21

    The objective of this project was to develop receptor based peptides for diagnostic imaging and therapy. A series of peptides related to cell adhesion molecules (CAM) and immune regulation were designed for radiolabeling with 99mTc and evaluated in animal models as potential diagnostic imaging agents for various disease conditions such as thrombus (clot), acute kidney failure, and inflection/inflammation imaging. The peptides for this project were designed by the industrial partner, Palatin Technologies, (formerly Rhomed, Inc.) using various peptide design approaches including a newly developed rational computer assisted drug design (CADD) approach termed MIDAS (Metal ion Induced Distinctive Array of Structures). In this approach, the biological function domain and the 99mTc complexing domain are fused together so that structurally these domains are indistinguishable. This approach allows construction of conformationally rigid metallo-peptide molecules (similar to cyclic peptides) that are metabolically stable in-vivo. All the newly designed peptides were screened in various in vitro receptor binding and functional assays to identify a lead compound. The lead compounds were formulated in a one-step 99mTc labeling kit form which were studied by BNL for detailed in-vivo imaging using various animals models of human disease. Two main peptides usingMIDAS approach evolved and were investigated: RGD peptide for acute renal failure and an immunomodulatory peptide derived from tuftsin (RMT-1) for infection/inflammation imaging. Various RGD based metallopeptides were designed, synthesized and assayed for their efficacy in inhibiting ADP-induced human platelet aggregation. Most of these peptides displayed biological activity in the 1-100 µM range. Based on previous work by others, RGD-I and RGD-II were evaluated in animal models of acute renal failure. These earlier studies showed that after acute ischemic injury the renal cortex displays

  10. Metal Ion Controlled Polymorphism of a Peptide

    DEFF Research Database (Denmark)

    Hemmingsen, Lars Bo Stegeager; Jancso, Attila; Szunyogh, Daniel; Larsen, Flemming Hofmann; Thulstrup, Peter Waaben; Christensen, Niels Johan; Gyurcsik, Bela

    2011-01-01

    In this work a metal ion binding model dodecapeptide was investigated in terms of its capacity to adopt different structures depending on the metal ion to peptide stoichiometry. The dodecapeptide is much simpler than real proteins, yet displays sufficient complexity to model the effect of metal...... ions on fully or partially unstructured proteins, or the effect of metal ions on protein aggregation. Metal ions may be employed to fold (or misfold) individual peptides in a controlled manner depending on the potential metal ion coordinating amino acid side chains (Cys, His, Asp, Glu, …) in the...... peptide, and the ligand and structural preferences of the metal ion (in our studies Zn2+, Cd2+, Hg2+, Cu+/2+). Simultaneously, new species such as metal ion bridged ternary complexes or even oligomers may be formed. In recent previous studies we have observed similar polymorphism of zinc finger model...

  11. Peptides as catalysts in the RNA world

    DEFF Research Database (Denmark)

    Wieczorek, Rafal; Dörr, Mark; Luisi, Pier Luigi;

    the RNA world concept. Contrary to RNA building blocks, amino acids form quite easily in simulated prebiotic reactions. Also, many prebiotic scenarios for condensation of amino acids into peptides have been proposed and successfully demonstrated experimentally (Rode 1999). We also have growing body of...... experimental evidence showing various catalytic activities associated with short chain peptides, some of them as small as dipeptides. One such peptide, composed of only two amino acid residues; serine and histidine, was reported to exhibit broad hydrolytic activities. The dipeptide SerHis can catalyze the...... hydrolysis of esters, proteins and nucleic acids (Li et al. 2000). The direction of the catalysis either toward hydrolysis or condensation is determined by thermodynamic constraints. In an aqueous medium (a general requirement for prebiotically compatible reactions), hydrolysis is thermodynamically favored...

  12. Design and Application of Antimicrobial Peptide Conjugates.

    Science.gov (United States)

    Reinhardt, Andre; Neundorf, Ines

    2016-01-01

    Antimicrobial peptides (AMPs) are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT) or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry. PMID:27187357

  13. Silica precipitation with synthetic silaffin peptides.

    Science.gov (United States)

    Wieneke, Ralph; Bernecker, Anja; Riedel, Radostan; Sumper, Manfred; Steinem, Claudia; Geyer, Armin

    2011-08-01

    Silaffins are highly charged proteins which are one of the major contributing compounds that are thought to be responsible for the formation of the hierarchically structured silica-based cell walls of diatoms. Here we describe the synthesis of an oligo-propyleneamine substituted lysine derivative and its incorporation into the KXXK peptide motif occurring repeatedly in silaffins. N(ε)-alkylation of lysine was achieved by a Mitsunobu reaction to obtain a protected lysine derivative which is convenient for solid phase peptide synthesis. Quantitative silica precipitation experiments together with structural information about the precipitated silica structures gained by scanning electron microscopy revealed a dependence of the amount and form of the silica precipitates on the peptide structure. PMID:21674108

  14. Design and Application of Antimicrobial Peptide Conjugates

    Directory of Open Access Journals (Sweden)

    Andre Reinhardt

    2016-05-01

    Full Text Available Antimicrobial peptides (AMPs are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry.

  15. Synthesis and evaluation of amphiphilic peptides as nanostructures and drug delivery tools

    Science.gov (United States)

    Sayeh, Naser Ali

    Intracellular delivery of cell-impermeable compounds in a variety cells using delivery systems have been extensively studied in recent years. Obtaining desirable cellular uptake levels often requires the administration of high quantities of drugs to achieve the expected intracellular biological effect. Thus, improving the translocation process across the plasma membrane will significantly reduce the quantity of required administered drug and consequently minimize the side effects in most of the cases. Efficient delivery of these molecules to the cells and tissues is a difficult challenge. Compounds with low cellular permeability are commonly considered to be of limited therapeutic value. Over the past few decades, several biomedical carriers, such as polymers, nanospheres, nanocapsules, liposomes, micelles, peptides and dendrimers have been widely used to deliver therapeutic and diagnostic agents to the cells. Biomaterials generated from nano-scale compounds have shown some promising data for delivery of many compounds in a number of diseases, such as viral infections, cancer, and genetic disorders. Although much progress has been achieved in this field, many challenges still remain, such as toxicity and limited stability. Liposomes suffer from poor stability in the bloodstream and leakage during storage. They tend to aggregate and fuse with or leak entrapped drugs, especially highly hydrophilic small molecules. For solid lipid nanoparticles (SLNs), drug expulsion after polymorphic transition during storage, inadequate loading capacity, and relatively high water content of the dispersions have been observed. Poly(lactic-coglycolic acid (PLGA) degrades in the body producing its original monomers of lactic acid and glycolic acid, which are the by-products of various metabolic pathways. However, this acidic microenvironment that occurs during degradation could negatively affect the stability of the loaded compound. Dendrimers can carry drugs as complexes or as

  16. Diagnostic and immunoprophylactic applications of synthetic peptides in veterinary microbiology

    Directory of Open Access Journals (Sweden)

    Saravanan Paramasivam

    2009-10-01

    Full Text Available Chemically synthesized peptides are considered as potential reagents for various applications in biological sciences. They mimic naturally occurring peptides or segments of proteins and have emerged as diagnostic reagents and safe immunogens in animal science. Carefully selected peptides resembling authentic epitopes serve as synthetic antigens in diagnostic tests. Synthetic peptide-based vaccines can elicit antibodies against animal pathogens. The early use of synthetic peptides as a vaccine for foot-and-mouth disease stimulated interest in the development of peptide-based diagnostics and immunoprophylactics. The development of a peptide vaccine for canine parvovirus confirmed the usefulness of peptides as immunoprophylactics. Recently, the advent of the technology for the development of multiple antigenic peptides (MAPs has provided a well-defined method for the production of highly immunogenic peptides and anti-peptide antibodies. Antibodies raised against major epitopes can be used in the detection of the native antigen (virus in the enzyme-linked immunosorbent assay (ELISA and other tests, vindicating the usefulness of peptides for safe, chemically defined, non-infectious diagnostics and immunoprophylactics. This article focuses on the methods for selecting and preparing peptides for the predicted epitopes, their characterization and use, and the application of MAPs.

  17. Interactions at the Peptide/Silicon Surfaces: Evidence of Peptide Multilayer Assembly.

    Science.gov (United States)

    Pápa, Zsuzsanna; Ramakrishnan, Sathish Kumar; Martin, Marta; Cloitre, Thierry; Zimányi, László; Márquez, Jessica; Budai, Judit; Tóth, Zsolt; Gergely, Csilla

    2016-07-19

    Selective deposition of peptides from liquid solutions to n- and p-doped silicon has been demonstrated. The selectivity is governed by peptide/silicon adhesion differences. A noninvasive, fast characterization of the obtained peptide layers is required to promote their application for interfacing silicon-based devices with biological material. In this study we show that spectroscopic ellipsometry-a method increasingly used for the investigation of biointerfaces-can provide essential information about the amount of adsorbed peptide material and the degree of coverage on silicon surfaces. We observed the formation of peptide multilayers for a strongly binding adhesion peptide on p-doped silicon. Application of the patterned layer ellipsometric evaluation method combined with Sellmeier dispersion led to physically consistent results, which describe well the optical properties of peptide layers in the visible spectral range. This evaluation allowed the estimation of surface coverage, which is an important indicator of adsorption quality. The ellipsometric findings were well supported by atomic force microscopy results. PMID:27315212

  18. Identification of the agr Peptide of Listeria monocytogenes

    Science.gov (United States)

    Zetzmann, Marion; Sánchez-Kopper, Andrés; Waidmann, Mark S.; Blombach, Bastian; Riedel, Christian U.

    2016-01-01

    Listeria monocytogenes (Lm) is an important food-borne human pathogen that is able to strive under a wide range of environmental conditions. Its accessory gene regulator (agr) system was shown to impact on biofilm formation and virulence and has been proposed as one of the regulatory mechanisms involved in adaptation to these changing environments. The Lm agr operon is homologous to the Staphylococcus aureus system, which includes an agrD-encoded autoinducing peptide that stimulates expression of the agr genes via the AgrCA two-component system and is required for regulation of target genes. The aim of the present study was to identify the native autoinducing peptide (AIP) of Lm using a luciferase reporter system in wildtype and agrD deficient strains, rational design of synthetic peptides and mass spectrometry. Upon deletion of agrD, luciferase reporter activity driven by the PII promoter of the agr operon was completely abolished and this defect was restored by co-cultivation of the agrD-negative reporter strain with a producer strain. Based on the sequence and structures of known AIPs of other organisms, a set of potential Lm AIPs was designed and tested for PII-activation. This led to the identification of a cyclic pentapeptide that was able to induce PII-driven luciferase reporter activity and restore defective invasion of the agrD deletion mutant into Caco-2 cells. Analysis of supernatants of a recombinant Escherichia coli strain expressing AgrBD identified a peptide identical in mass and charge to the cyclic pentapeptide. The Lm agr system is specific for this pentapeptide since the AIP of Lactobacillus plantarum, which also is a pentapeptide yet with different amino acid sequence, did not induce PII activity. In summary, the presented results provide further evidence for the hypothesis that the agrD gene of Lm encodes a secreted AIP responsible for autoregulation of the agr system of Lm. Additionally, the structure of the native Lm AIP was identified.

  19. Aerosolized Medications for Gene and Peptide Therapy.

    Science.gov (United States)

    Laube, Beth L

    2015-06-01

    Inhalation therapy has matured to include drugs that: (1) deliver nucleic acids that either lead to the restoration of a gene construct or protein coding sequence in a population of cells or suppress or disrupt production of an abnormal gene product (gene therapy); (2) deliver peptides that target lung diseases such as asthma, sarcoidosis, pulmonary hypertension, and cystic fibrosis; and (3) deliver peptides to treat diseases outside the lung whose target is the systemic circulation (systemic drug delivery). These newer applications for aerosol therapy are the focus of this paper, and I discuss the status of each and the challenges that remain to their successful development. Drugs that are highlighted include: small interfering ribonucleic acid to treat lung cancer and Mycobacterium tuberculosis; vectors carrying the normal alpha-1 antitrypsin gene to treat alpha-1 antitrypsin deficiency; vectors carrying the normal cystic fibrosis transmembrane conductance regulator gene to treat cystic fibrosis; vasoactive intestinal peptide to treat asthma, pulmonary hypertension, and sarcoidosis; glutathione to treat cystic fibrosis; granulocyte-macrophage colony-stimulating factor to treat pulmonary alveolar proteinosis; calcitonin for postmenopausal osteoporosis; and insulin to treat diabetes. The success of these new aerosol applications will depend on many factors, such as: (1) developing gene therapy formulations that are safe for acute and chronic administrations to the lung, (2) improving the delivery of the genetic material beyond the airway mucus barrier and cell membrane and transferring the material to the cell cytoplasm or the cell nucleus, (3) developing aerosol devices that efficiently deliver genetic material and peptides to their lung targets over a short period of time, (4) developing devices that increase aerosol delivery to the lungs of infants, (5) optimizing the bioavailability of systemically delivered peptides, and (6) developing peptide formulations for

  20. Selection of trkB-binding peptides from a phage-displayed random peptide library

    Institute of Scientific and Technical Information of China (English)

    马仲才; 吴晓兰; 曹明媚; 潘卫; 朱分禄; 陈景山; 戚中田

    2003-01-01

    Brain-derived neurotrophic factor (BDNF) shows potential in the treatment of neurodegenerative diseases, but the therapeutic application of BDNF has been greatly limited because it is too large in molecular size to permeate blood-brain barrier. To develop low-molecular-weight BDNF-like peptides, we selected a phage-displayed random peptide library using trkB expressed on NIH 3T3 cells as target in the study. With the strategy of peptide library incubation with NIH 3T3 cells and competitive elution with 1 υg/mL of BDNF in the last round of selection, the specific phages able to bind to the natural conformation of trkB and antagonize BDNF binding to trkB were enriched effectively. Five trkB-binding peptides were obtained, in which a core sequence of CRA/TXφXXφXXC (X represents the random amino acids, φ represents T, L or I) was identified. The BDNF-like activity of these five peptides displayed on phages was not observed, though all of them antagonized the activity of BDNF in a dose-dependent manner. Similar results were obtained with the synthetic peptide of C1 clone, indicating that the 5 phage-derived peptides were trkB antagonists. These low-molecular-weight antagonists of trkB may be of potential application in the treatment of neuroblastoma and chronic pain. Meanwhile, the obtained core sequence also could be used as the base to construct the secondary phage-displayed peptide library for further development of small peptides mimicking BDNF activity.