Polypeptides exiting the ribosome must fold and assemble in the crowded environment of the cell. Chaperones and other protein homeostasis factors interact with newly translated polypeptides to facilitate...Full Text Available
The human erythrocyte (RBC) Rh blood group system consists of a complex of distinct integral membrane polypeptides with physical properties common to the aminophospholipid transporter responsible for the transbilayer movement of phosphatidylserine (PS) in RBC. To assess the involvement of Rh polypeptides in PS translocation, the aminophospholipid translocase was labeled with a photoactivatable PS analogue, "1"2"5I-azido-PS, and with an inhibitor of PS transport, "1"2"5I-labeled 2-(2-pyridyldithio)ethylamine. The ability of monoclonal Rh antibodies to immunoprecipitate the labeled transporter was determined. Immunoprecipitated Rh polypeptides were found to be labeled with the aminophospholipid translocase markers, suggesting that Rh proteins are involved in the transbilayer movement of PS.
With the aim of an experimental check on the validity of the theory of molecular recognition, the authors have carried out the chemical-enzymatic synthesis and cloning of the gene of human calcitonin and also of the genes of antisense polypeptides to human calcitonin and miniproinsulin. It has been shown that recombinant plasmids obtained on the basis of these synthetic genes are capable of ensuring the biosynthesis of the given polypeptides in E. coli cells as hybrid proteins with the IgG-binding domain of staphylococcal protein A.
We have purified and characterized two peptides, named KAaH1 and KAaH2 (AaH polypeptides 1 and 2 active on K+ channels, where AaH stands for Androctonus australis Hector),...Full Text Available
Pituitary Fshb concentrations increase markedly and selectively beginning on Postnatal Day 20 in the male rat. To evaluate the factors potentially responsible for this rise...Full Text Available
Purified beta-toxin from Clostridium perfringens type C was found to be a single polypeptide chain protein with a molecular weight of approximately 30,000. The toxin was heat labile, with 75% of its...Full Text Available
High resolution structural elucidation of macromolecular structure by solid-state nuclear magnetic resonance requires the preparation of uniformly aligned samples that are isotopically labeled. In...Full Text Available
The sucrose derivative 6'-deoxy-6'-(2-hydroxy-4-azido)benzamidosucrose (6'-HABS) was prepared from sucrose (via 6'-deoxy-6'-aminosucrose) and 4-amino-salicylic acid. 6'-HABS is a competitive inhibitor of sucrose influx into protoplasts from developing soybean cotyledons and of sucrose binding to membranes from the bacteria P. saccharophila. The Ki for inhibition in the soybean protoplasts was 75..mu..M. 6'-Deoxy-6'-(2-hydroxy-3-/sup 125/Iodo-4-azido)benzamidosucrose was prepared by lactoperoxidase iodination of 6'-HABS. Upon photolysis in the presence of membranes from P saccharophila, label from the photoprobe is incorporated into a sucrose inducible polypeptide of mass 84 KD in SDS-PAGE. The polypeptide is protected from labeling by the inclusion of sucrose in the photolysis mixture. Photolysis conditions which lead to specific labeling of the sucrose protectable ...
Synthetic polypeptide antigens of L amino acids, although bearing repeating sequences, are thymus-dependent (L-TD), whereas the same polymers composed of D amino acids are thymus-independent (D-TI),...Full Text Available
A genomic clone that specifies a single polypeptide precursor for ricin, a toxic lectin of Ricinus communis (castor bean), was isolated, sequenced and Sl mapped. The gene encodes a 64 kDa precursor...Full Text Available
Werner Syndrome (WS) is an inherited disease characterized by premature onset of aging, increased cancer incidence, and genomic instability. The WS gene encodes a 1,432-amino acid polypeptide (WRN)...Full Text Available
Based on in vitro rat and human hepatocyte uptake studies showing inhibition of warfarin uptake in the presence of the non-specific organic anion transporting polypeptide (OATP)...Full Text Available
Normal reproductive functioning may require secretion of LH independently of FSH. Variation in GnRH pulse frequency and inhibin negative feedback are mechanisms for differential gonadotropin regulation;...Full Text Available
The authors have recently identified a new cytokeratin (CK) polypeptide, CK 20, whose expression is almost entirely confined to the gastric and intestinal epithelium, urothelium, and Merkel cells. Seven...Full Text Available
Integumentary wounds in mammalian fetuses heal without scar; this scarless wound healing is intrinsic to fetal tissues and is notable for absence of the contraction seen in postnatal (adult) wounds....Full Text Available
The acetylcholine receptor from the electric tissue of Torpedo californica is a large, integral membrane protein containing four different types of polypeptide chains. The structure of the purified...Full Text Available
Amino acids labelled with dimethylaminoazobenzenesulphonyl chloride can be separated by reversed-phase high-pressure liquid chromatography and detected in the visible region (436 nm). All 19 naturally...Full Text Available
A nucleoside triphosphate binding site on calf thymus RNA polymerase II was identified by using photoaffinity analogues of adenosine 5'-triphosphate and guanosine 5'-triphosphate. Both radiolabeled 8-azidoadenosine 5'-triphosphate (8-N3ATP) and radiolabeled 8-azidoguanosine 5'-triphosphate (8-N3GTP) bound to a single polypeptide of this enzyme. This polypeptide has a molecular mass of 37 kilodaltons and an isoelectric point of 5.4. Ultraviolet (UV) irradiation was necessary for photolabeling to occur. In addition, no labeling occurred when the probe was prephotolyzed or when the enzyme was inactivated. Furthermore, photolabeling of the enzyme could be decreased by preincubation with natural substrates. To provide evidence that the radiolabeled polypeptide forms a part of the domain of the nucleoside triphosphate binding site, experiments were performed using unlabeled 8-N3ATP. Although ...
In virtually all forms of life on earth, proteins in each cell are made according to a genetic blueprint, in the form of DNA. The translation of copies of this genetic blueprint (in the form of messenger RNA) into polypeptides is performed on the ribosome, a highly complex molecular machine composed of RNAs and proteins. To this end, special adaptor molecules called transfer RNAs are lined up by the ribosome in the sequence dictated by the genetic code, such that the amino acids carried by these molecules can be linked into a polypeptide. Several cofactors are involved in these processes, some of which require energy freed up by GTP hydrolysis. Although the ribosome was discovered more than 50 years ago, its structure has only been solved recently by X-ray crystallography. Another technique, cryo-electron microscopy, is starting to contribute toward our understanding of the ribosome's function, by portraying its conformational changes ...
The gene encoding the human type I pituitary adenylate cyclase activating polypeptide receptor (ADCYAP1R1) was mapped to chromosome 7 by PCR analysis of genomic DNA from a human/rodent somatic cell hybrid mapping panel. This assignment was confirmed and the gene localized to chromosome band 7p14 by fluorescence in situ hybridization. A yeast artificial chromosome containing ADCYAP1R1 was identified in the CEPH {open_quotes}B{close_quotes} Mega-YAC library. This YAC includes two highly polymorphic dinucleotide repeat sequences that will facilitate genetic studies of the contribution of ADCYAP1R1 in disease states of the central nervous and neuroendocrine systems. 13 refs., 1 fig.
BackgroundhTERTC27 is a 27 kDa C-terminal polypeptide of human telomerase reverse transcriptase that has previously been shown to reduce tumorigenicity of HeLa cells and suppress...Full Text Available
The previously described (M. De Kesel, P. Gilot, M.-C. Misonne, M. Coene, and C. Cocito, J. Clin. Microbiol., 31:947-954, 1993) a362 recombinant polypeptide of Mycobacterium paratuberculosis was used...Full Text Available
Synthesis genes encoding the human #alpha#- and #beta#-globin polypeptides have been expressed from a single operon in Escherichia coli. The #alpha#- and #beta#-globin polypeptides associate into soluble tetramers, incorporate heme, and accumulate to >5% of the total cellular protein. Purified recombinant hemoglobin has the correct stoichiometry of #alpha#- and #beta#-globin chains and contains a full complement of heme. Each globin chain also contains an additional methionine as an extension to the amino terminus. The recombinant hemoglobin has a C_4 reversed-phase HPLC profile essentially identical to that of human hemoglobin A_0 and comigrates with hemoglobin A_0 on SDS/PAGE. The visible spectrum and oxygen affinity are similar to that of native human hemoglobin A_0. The authors have also expressed the #alpha#- and #beta#-globin genes separately and found that the expression of the #alpha#-globin gene alone results in a marked decrease in ...
The low in vivo transduction efficiency of recombinant adeno-associated virus (rAAV) and the undesirably strong immunogenicity of adenovirus (rAdv) have limited their clinical utilization in cancer gene therapy. We have previously demonstrated that intratumoral injection of rAAV expressing a C-terminal polypeptide of human telomerase reverse transcriptase (rAAV-hTERTC27) effectively inhibits the growth of glioblastoma xenografts in nude mice. To further improve its efficacy, we combined rAAV-hTERTC27 with rAdv and investigated the efficiency of the cocktail vectors in vivo. At a nontherapeutic dose (1 x 108 plaque-forming units (PFUs)), rAdv-null and rAdv-hTERTC27 were equipotent in enhancing the therapeutic efficacy of rAAV-hTERTC27 (1.5 x 1011?v.g.), and complete tumor regression w...
A photoaffinity derivative of the local anesthetic trimethisoquin, 5-azido-["3H]trimethisoquin (5-A["3H]T) labelled bands of app. mol. wt 50 k and 66 k. To explain the rather paradoxical labelling by 5-A["3H]T of two polypeptide chains instead of one, three possibilities were considered: (i) The site for non-competititve blockers is not carried by the 50 k or 66 k chain; however, these chains lie in the vicinity of the binding site and become preferentially labelled since they present chemical groups with which the nitrene group of 5-A["3H]T reacts. (ii) The 50 k and 66 k chains are different but carry binding sites for non-competitive blockers with similar reactivities. (iii) The 50 k chain labelled by 5-A["3H]T derives from the 66 k chain by proteolysis. These results show that the third alternative is the correct one. Under conditions which limit proteolysis, 5-A["3H]T selectively labels the 66 k polypeptide chain. (Auth.).
The malM locus of Streptococcus pneumoniae was cloned into one of the two PstI sites of the multicopy S. pneumoniae plasmid pMV158. To eliminate chromosomal transformants in the simultaneous selection for tetracycline resistance (coded by pMV158) and maltose utilization, the host cells contained a chromosomal deletion of the mal gene cluster. Two clones were isolated; one with a 3.3 kb insert (pLS70) which behaved like wild type with respect to maltose utilization, and another with a 2.9 kb insert (pLS69) which behaved as though it contained a down promoter mutation. Preliminary mapping of these clones by restriction analysis placed the 0.4kb deletion on a HindIII fragment in the interior of the chromosomal insert. The recombinant plasmids were able to transform over 50% of a recipient population to Mal/sup +/. Enzyme measurements of the clones indicated an overproduction of amylomaltase, constituting up to 10% of the total cellular protein, and supported the theory that the deletion ...
We have constructed a 27-kDa hTERT C-terminal polypeptide (hTERTC27) devoid of domains required for telomerase activity and demonstrated that it is capable of nuclear translocation/telomere-end targeting. Here we showed that expression of a low level of hTERTC27 renders hTERT positive HeLa cells sensitive to H(2)O(2)-induced oxidative stress and subsequent cell senescence. The senescence-associated gene, the cyclin/cdk inhibitor p21(Waf1), was up-regulated. This occurs without changing the expression of endogenous hTERT, causing significant telomere shortening or inhibiting telomerase activity. Results from this study suggest for the first time that in addition to telomerase activity, the C-terminus of hTERT also plays a role in hTERT-mediated cellular resistance to oxidative stress. PMID:12565825
Human BTEB cDNA clones have been isolated, sequenced, and the corresponding gene has been assigned to human chromosome 9, region q13, by fluorescent in situ hybridization and DNA blot analysis using DNAs from hybrid cell clones containing a single human chromosome. The cDNA clone encodes a polypeptide of 244 amino acids whose sequence shows a high sequence similarity with the rat BTEB (98% amino acid identity).
IntroductionBreast cancer is the most diagnosed and second leading cause of cancer deaths in the U.S. female population. An estimated 5 to 10 percent of all breast cancers are inherited, caused by mutations in the breast cancer susceptibility genes (BRCA1/2). As many as 90% of all mutations are nonsense mutations, causing a truncated polypeptide product. A popular and low cost method of mutation detection has been the protein truncation test (PTT), where target regions of BRCA1/2 are PCR amplified, transcribed/translated in a cell-free protein synthesis system and analyzed for truncated polypeptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and autoradiography. We previously reported a novel High Throughput Solid-Phase PTT (HTS-PTT) based on an enzyme-linked immunosorbent assay (ELISA) format that eliminates the need for radioactivity, SDS-PAGE and subjective interpretation of the results. Here, we report the next ...
Withania somnifera (L.) Dunal (Family, Solanaceae), commonly known as Ashwagandha is one of the most valuable medicinal plants synthesizing large number of pharmacologically active secondary metabolites known as withanolides. Though the plant has been well characterized in terms of phytochemical profiles as well as pharmaceutical activities, not much is known about the genes responsible for biosynthesis of these compounds. In this study, we have characterized a gene encoding farnesyl diphosphate synthase (FPPS; EC 2.5.1.10), a key enzyme in the pathway of biosynthesis of isoprenoids, from W. somnifera. The full-length cDNA of Withania somnifera FPPS (WsFPPS) of 1,253?bps encodes a polypeptide of 343 amino acids. The amino acid sequence homology and phylogenetic analysis suggest that WsFPPS...
The integral membrane protein synaptophysin is one of the most abundant polypeptide components of synaptic vesicles. It is not essential for neurotransmission despite its abundance but is believed to modulate the efficiency of the synaptic vesicle cycle. Detailed behavioral analyses were therefore performed on synaptophysin knockout mice to test whether synaptophysin affects higher brain functions. We find that these animals are more exploratory than their wild type counterparts examining novel objects more closely and intensely in an enriched open field arena. We also detect impairments in learning and memory, most notably reduced object novelty recognition and reduced spatial learning. These deficits are unlikely caused by impaired vision, since all electroretinographic parameters measur...
Abstract NorUDCA (24 norursodeoxycholic acid), the C23 homolog of ursodeoxycholic acid (UDCA), showed remarkable therapeutic effects in cholestatic Mdr2 (Abcb4) (multidrug resistance protein 2/ATP binding cassette b4) knockout mice with sclerosing/fibrosing cholangitis. In contrast to UDCA, norUDCA is inefficiently conjugated in human and rodent liver, and conjugation has been discussed as a key step for the anticholestatic action of UDCA in cholestasis. We compared the choleretic, anticholestatic, and antiapoptotic properties of unconjugated and taurine conjugated UDCA (C24) and norUDCA (C23) in isolated perfused rat liver (IPRL) and in natrium/taurocholate cotransporting polypeptide (Ntcp) transfected human hepatoma (HepG2) cells. Taurolithocholic acid (TLCA) was used to induce a predomi...
The authors report an effort to determine the basis for the altered migration of seven inherited albumin variants detected by one-dimensional electrophoresis in population surveys involving tribal Amerindians and Japanese children. An amino acid substitution has thus far been determined for four of the variants. The randomness in the albumin polypeptide of these and the other sixteen independently ascertained amino acid substitutions of albumin and proalbumin thus far established was analyzed; the clustering of eight of these at two positions in the six-amino acid propeptide sequence seems noteworthy. By comparison with other proteins studied by electrophoresis, albumin exhibits average variability. It is a paradox that individuals who, for genetic reasons, lack albumin exhibit no obvious ill effects; yet, electrophoretic variants of albumin are no more numerous than are variants of proteins, the absence of which results in severe disease.
Glioblastoma multiforme is the most aggressive form of human brain tumor, which has no effective cure. Previously, we have demonstrated that overexpression of the C-terminal fragment of the human telomerase reverse transcriptase (hTERTC27) inhibits the growth and tumorigenicity of human cervical cancer HeLa cells. In this study, the therapeutic effect and molecular mechanisms of hTERTC27-mediated cancer gene therapy were further explored in vivo in established human glioblastoma xenografts in nude mice. We showed that intratumoral injection of adeno-associated virus carrying hTERTC27 (rAAV-hTERTC27) is highly effective in reducing the growth of the subcutaneously transplanted glioblastoma tumors. Histological analyses showed that rAAV-hTERTC27 treatment leads to profound necrosis, apoptosi...
Four trypsin inhibitor homologs, the first known from Dendroaspis angusticeps venom, were characterized using a combination of gel filtration, cation exchange, reverse-phase liquid chromatography, Edman degradation and mass spectrometry. The four toxins comprise two 57 residue and two 59 residue isoforms. The long toxins possess a Lys-Gln N-terminal extension lacked by the short toxins. The only other structural difference is an Arg/His replacement at position 55. The long Arg55 variant is identical to trypsin inhibitor E from the venom of Dendroaspis polylepis. The name epsilon-dendrotoxin is suggested so as to follow the nomenclature of Benishin, C.G., Sorensen, R.G., Brown, W.E., Krueger, B.K., Blaustein, M.P., 1988. Four polypeptide components of green mamba venom selectively block certain potassium channels in rat brain synaptosomes. Mol. Pharmacol. 34, 152-159. Among snake venom protease inhibitors, the epsilon-dendrotoxins are structurally most like the ...
PACAP (pituitary adenylate cyclase activating polypeptide) is widely distributed neuropeptide acting via three subtypes of receptors, PAC(1), VPAC(1) and VPAC(2). Here we examined the localisation and nature of PACAP-immunoreactive nerves in the rat thyroid and parathyroid glands and defined the distribution of PAC(1), VPAC(1) and VPAC(2) receptor mRNA's. In the parathyroid gland a large number of nerve fibres displaying PACAP-immunoreactivity were distributed beneath the capsule, around blood vessels and close to glandular cells. Most of the PACAP-nerves were sensory, since they co-stored CGRP (calcitonin-gene-related peptide) and were sensitive to capsaicin-treatment. mRNA's for PAC(1) and VPAC(2) receptors occurred in the parathyroid gland, mainly located in the glandular cells. In the thyroid gland PACAP-immunoreactive nerve fibres were associated with blood vessels, thyroid follicles and parafollicular C-cells. A high degree of co-existence between PACAP and ...
The COOH-terminus of telomerase reverse transcriptase (hTERT) has been shown to participatein the nuclear translocation of TERT. Here, we constructed plasmids expressing the COOH-terminal M(r) 27,000 polypeptide of hTERT (hTERTC27) withthe telomerase RNA-binding domains and the reverse transcriptase domains deleted. We showed that ectopic overexpression of this polypeptide caused a defect in telomere maintenance in hTERT-positive HeLa cells, which led to senescence-like growth arrest and apoptosis. The hTERTC27 appears to work by inducing telomere dysfunction, exemplified by significantly increased anaphase chromosome end-to-end fusion events in transfected cells. Significantly, it had no effect on the cellular telomerase enzymatic activity or telomere length. The in vivo effect was further demonstrated as HeLa cells stably expressing hTERTC27 have significantly lower growth rate and reduced tumorigenicity in nude mice xenografts. Results from ...
The low in vivo transduction efficiency of recombinant adeno-associated virus (rAAV) and the undesirably strong immunogenicity of adenovirus (rAdv) have limited their clinical utilization in cancer gene therapy. We have previously demonstrated that intratumoral injection of rAAV expressing a C-terminal polypeptide of human telomerase reverse transcriptase (rAAV-hTERTC27) effectively inhibits the growth of glioblastoma xenografts in nude mice. To further improve its efficacy, we combined rAAV-hTERTC27 with rAdv and investigated the efficiency of the cocktail vectors in vivo. At a nontherapeutic dose (1 x 10(8) plaque-forming units (PFUs)), rAdv-null and rAdv-hTERTC27 were equipotent in enhancing the therapeutic efficacy of rAAV-hTERTC27 (1.5 x 10(11) v.g.), and complete tumor regression was achieved in 25% of the treated animals. Importantly, the combination of rAAV-hTERTC27 and a therapeutic dose (2.5 x 10(9) PFU) of rAdv-hTERTC27 significantly augmented the ...
We cloned and characterized horse preproendothelin-2 (PPET-2) cDNA from intestinal tissue. The cDNA encoded 178 amino acids of the PPET-2 polypeptide, in which a 21-amino-acid mature endothelin-2 peptide and a 16-amino acid endothelin-2-like peptide were found. For the open reading frame the correspondence of horse PPET-2 cDNA with those of the ferret, human, dog, mouse and rat was 85.1%, 84.9%, 82.1%, 77.8% and 77.2%, respectively. Analysis of the organ distribution of PPET-2 mRNA by reverse transcription-polymerase chain reaction demonstrated that the kidney, stomach and small intestine are major sites of expression of the PPET-2 gene. Surprisingly, the mRNA is not detected in the large intestine, where high expression is demonstrated in the mouse and rat. This difference may result from the underlying functional differences of the large intestine between a herbivore (horse) and an omnivore (mouse and rat). PMID:15838341
Polypeptides, copolymers of #alpha#-amino acids and #alpha#-hydroxy acids, could prove to be a valuable new class of synthetic biodegradable polymers. In this paper. steps in synthesis of poly (dl-lactide-co-3, 6-dimethylmorpholine-2,5-dione) from dl-lactide and dl-3,6-dimethylmorpholine-2,5-dione was explained. dl-Lactide was synthesized from lactic acid. In the reaction of 2-bromopropionyl chloride and dl-alanine, N-(2-bromopropionyl)-dl-alanine was prepared and this material was converted to its salt and finally this salt was converted to 3,6-dimethylmorpholine-2,5-dione in a sublime r. These two monomers, that is d l-lactide and dl-3,6-dimethylmorpholine-2,5-dione was polymerized by ring-opening polymerization. F T-IR, "1H NMR, "1"3C NMR Spectra were used for structure elucidation of all intermediate compounds and final product.
In drug development, Caco-2 cells are often employed to study the influence of membrane transporters on drug permeability. The aim of the current study was to characterize permeability and kinetic parameters of selected organic anionic compounds in Caco-2 cells, and to investigate whether the Caco-2 cell line may be used as an overall model to predict interactions on multiple membrane transporters in the intestine. Taurocholic acid (TCA) and estrone-3-sulfate (E(1) S) were used as model substrates. Possible inhibitors studied were TCA, E(1) S, taurolithocholic acid, fluvastatin, and glipizide. The effects of these compounds on initial uptake, apparent permeability, and intracellular end-point accumulations of the probe substrates were studied. Both interactions on apical and basolateral influx transporters were observed. These interactions were proposed to be mediated mainly by the apical sodium-dependent bile acid transporter and the organic solute transporter ?/?, and to less extent ...
Tissue factor pathway inhibitor (TFPI), a protease inhibitor that circulates in association with plasma lipoproteins (VLDL, LDL and HDL), helps to regulate the extrinsic blood coagulation cascade. The authors have cloned a 125-kb genomic region containing the entire human TFPI gene on six overlapping cosmids and prepared a restriction map of this contig to clarify gene structure. More than half (45 kb) of the 85-kb gene is occupied with 5[prime] noncoding elements: coding begins at exon 3. A HindIII RFLP identified with one cosmid was genotyped in the CEPH panel of 559 reference families. Linkage analysis using markers on human chromosome 2 located the TFPI gene on 2q, 36 cM proximal to D2S43(pYNZ15) and 13 cM distal to the crystalline [gamma]-polypeptide locus CRYGP1(p5G1). 31 refs., 3 figs., 3 tabs.
Chemical analyses were done on the abnormal hemoglobins of the five (101 x SEC)F_1 offspring of X- irradiated adult SEC mice to determine which hemoglobin genes were expressed in each hemoglobin variant. Three offspring of irradiated SEC males did not express either of the two kinds of #alpha#-chains normally found in all SEC mice. The deficient #alpha#-chain synthesis caused these mice to exhibit an #alpha#-thalassemia similar to human #alpha#-thalassemia. Scanning electron microscopy was used to show that many erythrocytes of mice with #alpha#-thalassemia have bizarre shapes; e.g. many erythrocytes appeared flattened or had thorny projections (acanthocytes). One mutant with a tandem duplication of a segment of chromosome 7 (site of locus determining #beta#-chain structure) produced twice as much SEC as 101 #beta#-chain polypeptides. One mutant that probably arose by non-disjunction of chromosome 7's in its unirradiated 101 mother and loss of chromosome 7 from the ...
A radioimmunoassay is described for the molluscan neuropeptide, Phe-Met-Arg-Phe-NH"2(FMRFamide). The antibody used is C-terminal-specific and shows slight but significant (1-2%) cross-reactivity with chicken pancreatic polypeptide (APP). The assay has been used to identify in rat brain extracts a pair of molecules that may represent mammalian counterparts of FMRFamide. Their concentrations were highest in spinal cord and hypothalamus (>10 pmol.g"-_1) and lowest in cerebellum and striatum (<3.5 pmol.g"-_1). The two immunoreactive peptides were separated on CM ion-exchange chromatography where they appeared to be less basic than FMRFamide. On Sephadex G50 gel filtration one eluted in a similar position to FMRFamide and the other slightly earlier suggesting it may be of higher molecular weight. The rat immunoreactive components do not correspond to previously described neuropeptides or hormones, and may be members of a new group of mammalian neuropeptides with ...
The time of appearance of newly synthesized rRNAs and ribosomal proteins (r-proteins) in the ribosomes of pea cotyledons (Pisum sativum L.) during germination was investigated. The ribosomal fraction was isolated and analyzed according to the method of germination of the embryo in the presence of labeled precursors or after pulse labeling of the embryos at different stages of germination. For the identification of newly synthesized rRNAs in the ribosomes we estimated the relative stability of labeled RNAs to the action of RNase, the sedimentation rate, the ability to be methylated in vivo in the presence of (/sup 14/C)CH/sub 3/-methionine, and the localization in the subunits of dissociated ribosomes. The presence of newly synthesized r-proteins in the ribosomes was judged on the basis of the electrophoretic similarity in SDS-disc electrophoresis of labeled polypeptides of purified ribosome preparations and of genuine r-proteins, as well as according to the ...
Based on studies on the genetic and molecular basis of Shigella flexneri invasive properties, we have constructed and evaluated a double mutant of S. flexneri serotype 5 for utilization as a live attenuated oral vaccine against shigellosis. The first mutation, icsA, blocks intracellular spread of bacteria as well as cell-to-cell infection. It affects the capacity of the invasive pathogen to form large abscesses in epithelia. The second mutation, iuc, eliminates production of the siderophore aerobactin thus impairing growth of the bacterium within tissues. This double mutant, SC5700 appeared safe when administered intragastrically to macaque monkeys as three doses (5 x 10(10) c.f.u. each) at weekly intervals. Protection against a challenge by the wild type isolate (M90T) was observed 4 weeks after the last vaccine inoculation. Duration of carriage was considerably reduced as compared to the control group in which all animals had developed severe dysentery. Seroconversion against ...
The PMS2 gene encodes a protein that is involved in DNA mismatch repair and is mutated in a subset of patients with hereditary nonpolyposis colon cancer (HNPCC). The previously published PMS2 cDNA sequence lack an upstream in-frame stop codon preceding the presumptive initiating methionine. To evaluate the 5` terminus of the PMS2 coding region further, we isolated additional cDNA clones, RT-PCR products, and the corresponding 5` genomic segment of the PMS2 locus. The PMS2 gene transcripts were found to have heterogeneous but colinear 5` termini, one of which contained an in-frame termination codon preceding the initiating methionine. In addition, a novel gene encoding a 34.5-kDa polypeptide was found to initiate transcriptionally within PMS2 from the opposite strand. 23 refs., 5 figs., 2 tabs.
The 2- and 8-azido trimer 5'-triphosphate photoprobes of 2-5A have been enzymatically synthesized from [#gamma#-"3"2P]2-azidoATP and [#alpha#-"3"2P]8-azidoAPT by 2-5A synthetase from rabbit reticulocyte lysates. Identification and structural determination of the 2- and 8-azido adenylate trimer 5'-triphosphates were accomplished by enzymatic hydrolyses with T2 RNase, snake venom phosphodiesterase, and bacterial alkaline phosphatase. Hydrolysis products were identified by HPLC and PEI-cellulose TLC analyses. The 8-azido photoprobe of 2-5A displaces p_3A_4["3"2P]pCp from RNase L with affinity equivalent to p_3A_3. The 8-azido photoprobe also activates RNase L to hydrolyze poly(U)["3"2P]pCp 50% at 7 /times/ 10/sup /minus/9/ M in core-cellulose assays. The 2- and 8-azido photoprobes and authentic p_3A_3 activate RNase L to cleave 28S and 18S rRNA to specific cleavage products at 10/sup /minus/9/ M in rRNA cleavage assays. The nucleotide binding site(s) of RNase L and/or other 2-5A binding ...
This report highlights four main points. (1) A residue substitution in phosphoribulokinase of Synechocystis PCC 6803 renders the mutant light-sensitive. The authors isolated a light-sensitive mutant (BRLS) of the photosynthetic cyanobacterium Synechocystis 6803 that does not survive exposure to bright light; 70% of BRLS cells die upon exposure to light of > 3000 lux for 2 hr. (2) Excitation energy transfer from phycocyanin to chlorophyll in an apcA-defective mutant of Synechocystis sp. PCC 6803. A greenish mutant of the normally bule-green cyanobacterium Synechocystis sp. PC 6803, designated UV6p, was isolated and characterized. UV6p possesses functional photosystems I and II but lacks normal light harvesting phycobilisomes because allophycocyanin is absent and core-specific linker proteins are almost entirely absent. (3) Deletion of the psbG1 gene of the cyanobacterium Synechocystis sp. PCC 6803 leads to the activation of the cryptic psbG2 gene. The genes psbG1 and psbG2 in ...
The murine 3T3-L1 fibroblast under appropriate incubation conditions differentiates into an adipocyte phenotype. This 3T3-L1 adipocyte exhibits many of the morphologic, biochemical, and insulin-responsive features of the normal rodent adipocyte. Using quantitative electron microscopic (EM) autoradiography we find that, when /sup 125/I-insulin is incubated with 3T3-L1 adipocytes, the ligand at early times of incubation localizes to the plasma membrane of the cell preferentially to microvilli and coated pits. When the incubation is continued at 37 degrees C, /sup 125/I-insulin is internalized by the cells and preferential binding to the villous surface is lost. With the internalization of the ligand, two intracellular structures become labeled, as determined by the method of hypothetical grain analysis. These include large clear, presumably endocytotic, vesicles and multivesicular bodies. Over the first hour of incubation the labeling of these structures increases in parallel, but in the ...
Acanthamoeba castellanii myosins IA and IB demonstrate the catalytic properties of a myosin and can support analogues of contractile and motile activity in vitro, but their single, low molecular weight heavy chains, roughly globular shapes, and inabilities to self-assemble into filaments make them structurally atypical myosins. The authors present the complete amino acid sequence of the 128-kDa myosin IB heavy chain, which they deduced from the nucleotide sequence of the gene and which reveals that the polypeptide is a fusion of myosin-like and non-myosin-like sequences. Specifically, the amino-terminal approx. 76 kDa of amino acid sequence is highly similar to the globular head sequences of conventional myosins. By contrast, the remaining approx. 51 kDa of sequence shows no similarity to any portion of conventional myosin sequences, contains regions that are rich in glycine, proline, and alanine residues, and lacks the distinctive sequence characteristics of an ...
Acanthamoeba castellanii myosins IA and IB demonstrate the catalytic properties of a myosin and can support analogues of contractile and motile activity in vitro, but their single, low molecular weight heavy chains, roughly globular shapes, and inabilities to self-assemble into filaments make them structurally atypical myosins. The authors present the complete amino acid sequence of the 128-kDa myosin IB heavy chain, which they deduced from the nucleotide sequence of the gene and which reveals that the polypeptide is a fusion of myosin-like and non-myosin-like sequences. Specifically, the amino-terminal #approx# 76 kDa of amino acid sequence is highly similar to the globular head sequences of conventional myosins. By contrast, the remaining #approx# 51 kDa of sequence shows no similarity to any portion of conventional myosin sequences, contains regions that are rich in glycine, proline, and alanine residues, and lacks the distinctive sequence characteristics of an ...
Large rigid-body domain movements are critical to GroEL-mediated protein folding, especially apical domain elevation and twist associated with the formation of a folding chamber upon binding ATP and co-chaperonin GroES. Here, we have modeled the anisotropic displacements of GroEL domains from various crystallized states, unliganded GroEL, ATP?S-bound, ADP-AlFx/GroES-bound, and ADP/GroES bound, using translation-libration-screw (TLS) analysis. Remarkably, the TLS results show that the inherent motions of unliganded GroEL, a polypeptide-accepting state, are biased along the transition pathway that leads to the folding-active state. In the ADP-AlFx/GroES-bound folding-active state the dynamic modes of the apical domains become reoriented and coupled to the motions of bound GroES. The ADP/GroES complex exhibits these same motions, but they are increased in magnitude, potentially reflecting the decreased stability of the complex after nucleotide hydrolysis. Our results ...
The purpose was to develop a simplified and reliable method of separating free from antibody-bound ligand using a precipitating antibody linked to a cellulose derivative. Dose-response curves and control sera were set up in parallel for various pituitary and placental polypeptides, steroid hormones, insulin, glucagon, triiodothyronine, thyroxine, angiotensin I, calcitonin, gastrin, cyclic AMP, and digoxin. After first-antibody reactions had reached equilibrium, free and bound ligand were separated using a double-antibody solid-phase system in parallel with conventional methods, including dextran-coated charcoal, double-antibody precipitation, single-antibody solid phase, organic solvents, salt precipitation, and anion-exchange resins. The effect of variations in temperature, incubation time, protein content, pH, and amount of separating material added were studied. The results showed that separation was complete within 1 hr for small ligand molecules and within 2 ...
The purpose was to develop a simplified and reliable method of separating free from antibody-bound ligand using a precipitating antibody linked to a cellulose derivative. Dose-response curves and control sera were set up in parallel for various pituitary and placental polypeptides, steroid hormones, insulin, glucagon, triiodothyronine, thyroxine, angiotensin I, calcitonin, gastrin, cyclic AMP, and digoxin. After first-antibody reactions had reached equilibrium, free and bound ligand were separated using a double-antibody solid-phase system in parallel with conventional methods, including dextran-coated charcoal, double-antibody precipitation, single-antibody solid phase, organic solvents, salt precipitation, and anion-exchange resins. The effect of variations in temperature, incubation time, protein content, pH, and amount of separating material added were studied. The results showed that separation was complete within 1 hr for small ligand molecules and within 2 ...
Aminophenpyramine, a derivative of mepyramine (pyrilamine), a typical antagonists of histamine at its H_1 receptor was synthesized and converted into ["1"2"5I]iodoazidophenpyramine, a potential photoaffinity probe for the H_1 receptor. In the dark, reversible binding of this probe to cerebellar membranes occurred with a K/sub d/ of 1.2 x 10"-"1"1 M and a B/sub max/ of 240 fmol/mg of protein and was inhibited by various H_1-receptor antagonists with the expected potencies. These features establish the compound as one of the most potent H_1-receptor antagonists known so far. Upon IV irradiation, 5% of the bound radioactivity was covalently incorporated into cerebellar membrane polypeptides as shown by standard NaDodSO_4/PAGE. Two bands of 47 and 56 kDa were consistently labeled, labeling being prevented by various H_1-receptor antagonists with the expected potencies and stereoselectivity. In the presence of protease inhibitors, labeling of the 56-kDa peptide ...
Glioblastoma multiforme is the most aggressive form of human brain tumor, which has no effective cure. Previously, we have demonstrated that overexpression of the C-terminal fragment of the human telomerase reverse transcriptase (hTERTC27) inhibits the growth and tumorigenicity of human cervical cancer HeLa cells. In this study, the therapeutic effect and molecular mechanisms of hTERTC27-mediated cancer gene therapy were further explored in vivo in established human glioblastoma xenografts in nude mice. We showed that intratumoral injection of adeno-associated virus carrying hTERTC27 (rAAV-hTERTC27) is highly effective in reducing the growth of the subcutaneously transplanted glioblastoma tumors. Histological analyses showed that rAAV-hTERTC27 treatment leads to profound necrosis, apoptosis, infiltration of polymorphonuclear neutrophils and reduced microvessel density in the tumor samples. To study the molecular mechanism of rAAV-hTERTC27-mediated antitumor effects, we analyzed the ...
pT181 is a naturally-occurring 4437 basepair (bp) plasmid isolated from Staphylococcus aureus which encodes inducible resistance to tetracycline (Tc). The DNA sequence data has identified three open reading frames (ORFs). The largest ORF B, has been found to be responsible for the Tc resistance phenotype of pT181. Since most Tc resistance systems appear to be regulated by an effector protein and a repressor protein, several Bal 31 deletion mutants of pT181 were constructed and analyzed in an effort to identify the elements involved in Tc resistance. Two transcomplementing groups of mutants were identified within the tet gene. The mechanism of Tc resistance was studied by assaying the accumulation of (7-/sup 3/H) Tc by Tc sensitive cells, and uninduced and induced pT181-containing cells. A sharp decrease in accumulation of the drug after an initial increase was observed in Tc induced pT181-containing cells. In vivo labeling of Bacillus subtilis minicells containing pT181 was performed ...