Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A protein designated as BE-20 was purified from cauda epididymal fluid of the rabbit by preparative polyacrylamide gel electrophoresis and HPLC on a mono Q HR5/5 anion exchange column. The purified protein migrated with an estimated Mt of 20,000 when analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The amino acid sequence of the N-terminus of the BE-20 protein was determined. The initial eight amino acid residues were His-Gly-Ala-Asp-Lys-Pro-Gly-Val. The corresponding 23 mer oligonucleotide (5'-CATGGCGCTGACAAGCCTGGGGT-3') was synthesized and used as sense primer with rabbit epididymal mRNA as template in the RT-PCR system. The purified BE-20 cDNA consisted of 499 bp with an open reading frame of 285 bp encoding a deduced polypeptide composed of 95 amino acids. The BE-20 cDNA had 78.5% identity in 479 bp overlap with human epididymis-specific HE4 cDNA. The amino acid sequences of the initial 30 amino acid residues of the N-terminus of the purified protein and the deduced polypeptides were as follows: N-His-Gly-Ala-Asp-Lys-Pro-Gly-Val-Cys-Pro-Gln-Leu-Ser-Ala-Asp-Leu-Asn-Cy s- Thr-Gln-Asp-Cys-Arg-Ala-Asp-Gln-Asp-Cys-Ala-Glu. The deduced polypeptide contained 16 cysteine residues and had partial sequence homology with proteins belonging to the four-disulfide core family of extracellular proteinase inhibitors. The BE-20 protein may play a role in sperm maturation and/or capacitation.
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PMID:Identification of a rabbit epididymal protein gene. 888 63

We use a three-dimensional lattice model of proteins to investigate systematically the global properties of the polypeptide chains that determine the folding to the native conformation starting from an ensemble of denatured conformations. In the coarse-grained description, the polypeptide chain is modeled as a heteropolymer consisting of N beads confined to the vertices of a simple cubic lattice. The interactions between the beads are taken from a random gaussian distribution of energies, with a mean value B0 < 0 that corresponds to the overall average hydrophobic interaction energy. We studied 56 sequences all with a unique ground state (native conformation) covering two values of N (15 and 27) and two values of B0. The smaller value of magnitude of B0 was chosen so that the average fraction of hydrophobic residues corresponds to that found in natural proteins. The higher value of magnitude of B0 was selected with the expectation that only the fully compact conformations would contribute to the thermodynamic behavior. For N = 15 the entire conformation space (compact as well as noncompact structures) can be exhaustively enumerated so that the thermodynamic properties can be exactly computed at all temperatures. The thermodynamic properties for the 27-mer chain were calculated using the slow cooling technique together with standard Monte Carlo simulations. The kinetics of approach to the native state for all the sequences was obtained using Monte Carlo simulations. For all sequences we find that there are two intrinsic characteristic temperatures, namely, T theta and Tf. At the temperature T theta the polypeptide chain makes a transition to a collapsed structure, while at Tf the chain undergoes a transition to the native conformation. We show that foldability of sequences can be characterized entirely in terms of these two temperatures. It is shown that fast folding sequences have small values of sigma = (T theta - Tf)/T theta whereas slow folders have larger values of sigma (the range of sigma is 0 < sigma < 1). The calculated values of the folding times correlate extremely well with sigma. An increase in sigma from 0.1 to 0.7 can result in an increase of 5-6 orders of magnitudes in folding times. In contrast, we demonstrate that there is no useful correlation between folding times and the energy gap between the native conformation and the first excited state at any N for any value of B0. In particular, in the parameter space of the model, many sequences with varying energy gaps, all with roughly the same folding time, can be easily engineered. Folding sequences in this model, therefore, can be classified based solely on the value of sigma. Fast folders have small values of sigma (typically less than about 0.1), moderate folders have values of sigma in the approximate range between 0.1 and 0.6, while for slow folders sigma exceeds 0.6. The precise boundary between these categories depends crucially on N and on the model. The range of sigma for fast folders decreases with the length of the chain. At temperatures close to Tf fast folders reach the native conformation via a native conformation nucleation collapse mechanism without forming any detectable intermediates, whereas only a fraction of molecule phi (T) reaches the native conformation by this process for moderate folders. The remaining fraction reaches the native state via three-stage multipathway process. For slow folders phi (T) is close to zero at all temperatures. The simultaneous requirement of native state stability and kinetic accessibility can be achieved at high enough temperatures for those sequences with small values of sigma. The utility of these results for de novo design of proteins is briefly discussed.
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PMID:Factors governing the foldability of proteins. 899 Apr 96

There is evidence that chronic ethanol treatment (CET) disrupts the biological rhythms of various brain functions and behaviors. Because the suprachiasmatic nucleus (SCN) is widely recognized as the dominant pacemaker of the circadian system, we have examined the effects of CET and withdrawal on the main morphological features and chemoarchitecture of this hypothalamic nucleus. Groups of rats ethanol-treated for 6 and 12 months were compared with withdrawn rats (ethanol-treated for 6 months and then switched to a normal diet for an additional 6 months) and with groups of age-matched control and pair-fed control rats. The volume and the total number of neurons of the SCN were estimated from conventionally stained material, whereas the total number of astrocytes and of neurons containing vasopressin (AVP), vasoactive intestinal polypeptide (VIP), gastrin-releasing peptide (GRP), and somatostatin (SS) were estimated from immunostained sections. The estimates were obtained using unbiased stereological methods, based on Cavalieri's principle and the optical fractionator. The volume of the SCN and the total number of SCN neurons and astrocytes did not vary among groups. We found, however, that CET induced a significant reduction in the total number of AVP-, VIP-, GRP-, and SS-containing neurons. Withdrawal from alcohol did not reduce but rather augmented the loss of VIP- and GRP-immunoreactive neurons. The CET-induced neurochemical alterations seem to result from a decrease in neuropeptide synthesis, as revealed by the reduction in AVP and VIP mRNA levels demonstrated by in situ hybridization with radioactively labeled 48-mer AVP and 30-mer VIP probes. It is thus possible to conclude that the irreversible CET-induced changes in the neurochemistry of the SCN might underpin the disturbances in circadian rhythms observed after long-term alcohol consumption.
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PMID:Chronic alcohol consumption and withdrawal do not induce cell death in the suprachiasmatic nucleus, but lead to irreversible depression of peptide immunoreactivity and mRNA levels. 900 74

A protein designated as BE-20 was purified from cauda epididymal fluid of male rabbits and the amino acid sequence of the N-terminus was determined. A 23-mer oligonucleotide coding the N-terminal eight amino acids of the BE-20 protein was synthesized. The oligonucleotide was used as sense primer with rabbit epididymal mRNA as template in the RT-PCR system. The BE-20 cDNA consisted of 499 bp with an open reading frame of 285 bp encoding a deduced polypeptide composed of 95 amino acids. Digoxigenin-labeled BE-20 cDNA was prepared and used as a hybridization probe to detect the specific mRNA. The probe interacted with a 1.2-kb mRNA prepared from rabbit epididymis; mRNAs prepared from rabbit testis gave negative reaction. Using tissue sections, the BE-20 mRNA was located in the epithelial cells of the cauda epididymis and proximal segment of the ductus deferens by in situ hybridization method. Sections of the corpus and caput epididymis, testis, and liver gave negative reaction. Polyclonal anti-BE-20 antibodies were raised and found to inhibit in vitro the capacity of human sperm to penetrate zona-free hamster ova. The results suggest that BE-20 protein may influence maturation of spermatozoa during its movement through the epididymis and/or the capacity of sperm to fertilize ova.
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PMID:Expression of the BE-20 epididymal protein gene: in situ hybridization. 901 16

sds22 was originally identified in yeast as a regulator of protein phosphatase-1 that is essential for the completion of mitosis. We show here that a structurally related mammalian polypeptide (41.6 kDa) is part of a 260-kDa species of protein phosphatase-1. This holoenzyme, designated PP-1N(sds22), could be immunoprecipitated with sds22 antibodies and was retained by microcystin-Sepharose. PP-1N(sds22) is a latent phosphatase, but its activity could be revealed by the proteolytic destruction of the noncatalytic subunit(s). PP-1N(sds22) accounted for only 5-10% of the total activity of PP-1 in rat liver nuclear extracts. A synthetic 22-mer peptide, corresponding to a leucine-rich repeat of sds22, specifically inhibited the catalytic subunit of PP-1, showing that at least part of the latency stems from the interaction of the sds22 repeat(s) with PP-1C.
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PMID:Identification of sds22 as an inhibitory subunit of protein phosphatase-1 in rat liver nuclei. 903 83

The murine AIDS (MAIDS) is a retrovirus-induced disease that shows severe immunodeficiency with abnormal lymphoproliferation in susceptible strains of mice. To clarify the antigenicity of gag gene products of the LP-BM5 defective virus, which is known as the causative virus of MAIDS, we expressed and purified the gag p12 gene product (P12) by using a baculovirus expression vector system. The P12 protein strongly stimulated the proliferation of normal C57BL/6 (B6) lymph node T-cells in vitro. Furthermore, a 25-mer synthetic polypeptide within the P12 sequence gave rise to the similar or even higher activation of T-cells. The phenotype of responding T-cells was found to be CD8+ CD44low, indicating that naive CD8+ T-cells respond against a peptide encoded within a MAIDS defective virus gag p12 gene. Finally, the expression of T-cell receptor (TcR) V beta on the responding CD8+ T-cells was analyzed. Although CD8+ T-cells with the particular V beta chains were expanded in response to the 25-mer peptide, this polypeptide does not seem to be a superantigen, since this response is MHC class I-restricted and the V beta preference is not striking. The presentation pathway of this highly antigenic polypeptide will be discussed.
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PMID:A polypeptide encoded within the murine AIDS defective virus stimulates primary proliferation of CD8+ T-cells. 914 39

Involvement of mucosal cells in inflammatory bowel disease (IBD) may be a sequenced process and the molecular difference between involved and uninvolved cells might implicate a possible mechanism in the disease process. The aim of this study was to compare gene expression between involved and uninvolved colonic mucosa cells in an individual with ulcerative colitis (UC) and to clone, sequence, and identify those differentially expressed genes, mRNA differential display was used to identify the gene expression in the mucosa of the UC patient. Anchored oligo(dT) primers and random 5' oligonucleotide 10-mer were used to carry out polymerase chain reaction on reverse-transcribed RNA (RT-PCR). The amplified cDNAs were displayed on a standard sequencing gel and comparisons were drawn between each two lanes representing either involved or uninvolved cells from a specific combination of two primers. Wherever differences were noted between lanes, the bands were reamplified using PCR, cloned into specialized vectors for positive selection, and then confirmed by dot blot. The cloned genes were then sequenced and compared with the GenBank database. About 1200 mRNA species were displayed in the sequencing gel. Among them, 106 fragments were differentially expressed between the two groups. Twenty-five of those differentially displayed gene fragments have been isolated, reamplified, and cloned for sequencing and dot blot analysis. Seventeen of the fragments were differentially expressed using the dot blot technique. Among those 25 gene fragments, 14 have homology to known genes and 11 have no match to any reported genes. Those matched known genes included genes for parathyroid tumor, T cell receptor-beta, alpha-nascent polypeptide-associated complex, ovarian cancer, and myeloblast. This is the first study using mRNA differential display to observe differential gene expression between involved and uninvolved mucosa cells in UC and it shows that differential display is a rapid method for characterizing gene changes in vivo in ulcerative colitis. The results from this study may provide useful information and facilitate further gene studies in this disease.
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PMID:mRNA differential display of colonic mucosa cells in ulcerative colitis. 920 57

The aggregation and structural properties of the synthetic C-terminal half [Ala330, Ala350(270-373; 104-mer)] polypeptide from HIV-1 p24gag were studied. In concentrated solutions the synthetic polypeptide aggregated to tetramers which, upon dilution, gave a mixture of monomeric and dimeric and dimeric species. These results correlated well with the in vitro aggregation properties of recombinant p24. The tetrameric form of the synthetic polypeptide had a pI which differed by about four units from that of the mixture of monomeric and dimeric species. CD studies indicated that the latter contained, in aqueous solutions, a compact molecule lacking, however, a defined tertiary structure. Addition of MeOH to aqueous solutions of both tetramer and monomer/dimer mixture induced a more defined structure, which was assigned to that of an alpha + beta protein in agreement with secondary structure predictions. A model of the dimeric form of the 104-mer, which takes into account the results presented here and those from a study on the specificity of a set of anti-104-mer MoAbs, is presented. Finally, the results indicated that the structure of the 104-mer in its dimeric form is similar to that adopted by the same sequence when part of full-length p24.
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PMID:The structural and aggregation properties of the synthetic C-terminal half (104-mer) polypeptide from HIV p24gag resemble those of full-length protein. 923 Apr 82

Peptides derived from endogenous proteins are presented by MHC class I molecules, whereas those derived from exogenous proteins are presented by MHC class II molecules. This strict segregation has been reconsidered in recent reports in which exogenous antigens are shown to be presented by MHC class I molecules in the phagocytic pathway. In this report, the presentation pathway of an exogenously added highly antigenic polypeptide encoded by the murine AIDS (MAIDS) defective virus gag p12 gene is investigated. A 25-mer polypeptide (P12-25) encoded within the gag p12 region of the MAIDS defective virus was found to be effective in stimulating unprimed B6 (H-2b) CD8+ T cells in vitro. The presentation of P12-25 is sensitive to cytochalasin B and D, brefeldin A and gelonin, a ribosome-inactivating protein synthesis inhibitor, but less sensitive or resistant to lactacystin, a highly specific inhibitor of the proteasome. Interestingly, CA-074, a selective inhibitor of cathepsin B, inhibited presentation of the polypeptide, indicating its involvement in the degradation of the P12-25 polypeptide. In fact, when P12-25 was digested with purified cathepsin B in vitro, a highly antigenic 11-mer peptide containing the class I (H-2Db)-binding motif was obtained. Our results favor the phagosome/macropinosome-to-cytosol-to-endoplasmic reticulum (ER)-to-cell surface pathway for exogenous antigens presented by MHC class I molecules. These findings may be relevant to exploiting peptide vaccines that specifically elicit CD8+ T cell immunity in vivo.
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PMID:MHC class I presentation of an exogenous polypeptide antigen encoded by the murine AIDS defective virus. 927 2

A sub-gene encoding the catalytic (acetyltransferase) domain (E2pCD) comprising residues 173-427 of the dihydrolipoyl acetyltransferase (E2p) chain of the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus was expressed in Escherichia coli. The product assembled to form the characteristic icosahedral (60-mer) core structure with full catalytic activity. The Km values for dihydrolipoamide and acetyl-CoA were 1.2 mM and 13 microM, respectively. Dissociation of the icosahedral E2pCD into monomers by exposure to guanidine hydrochloride and the subsequent reassociation by gradual removal of the denaturing agent demonstrated the ability of the polypeptide chain to fold and reassemble in the absence of chaperonins.
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PMID:The catalytic domain of dihydrolipoyl acetyltransferase from the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus. Expression, purification and reversible denaturation. 928 Mar 9


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