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)

The cyanobacteria produce multi-L-arginyl-poly (aspartic acid), a high molecular weight (Mr=25 000-125 000) branched polypeptide consisting of a poly(aspartic acid) core with L-arginyl residues peptide bonded to each free carboxyl group of the poly(aspartic acid). An enzyme which will elongate Arg-poly(Asp) has been isolated and purified 92-fold from the filamentous cyanobacterium Anabaena cylindrica. The enzyme incorporates arginine and aspartic acid into Arg-poly(Asp) in a reaction which requires ATP, KCl, MgCl2, and a sulfhydryl reagent. The enzymatic incorporation of arginine is dependent upon the presence of L-aspartic acid but not visa versa, a finding which suggests the order of amino acid addition to the branched polypeptide-aspartic acid is added to the core followed by the attachment of an arginine branch. The elongation of Arg-poly(Asp) in-vitro is insensitive to the addition of protein synthesis inhibitors and to the addition of nucleases. These findings support the notion previosly suggested from in-vivo studies that Arg-poly(Asp) is synthesized via a non-ribosomal route and also demonstrate that amino-acetylated transfer-RNAs play no part in at least one step of the biosynthetic mechanism.
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PMID:The biosynthesis of multi-L-arginyl-poly(L-aspartic acid) in the filamentous cyanobacterium Anabaena cylindrica. 0 11

A central eight-stranded beta-pleated sheet is the main feature of the polypeptide backbone folding in dihydrofolate reductase. The innermost four strands and two bridging helices are geometrically similar to but are connected in a different way from those in the dinucleotide binding domains found in nicotinamide-adenine dinucleotide-linked dehydrogenases. Methotrexate is bound in a 15-angstrom-deep cavity with the pteridine ring buried in a primarily hydrophobic pocket, although a strong interaction occurs between the side chain of aspartic acid 27 and N(1), N(8), and the 2-amino group of methotrexate.
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PMID:Dihydrofolate reductase: x-ray structure of the binary complex with methotrexate. 1 20

An NADH-dependent glutamate synthase has been purified 500-fold from the plant cytoplasm fraction of Lupinus angustifolius nodules. It consists of a single polypeptide chain, Mr 235000. The optimum pH is 8.5, at which Km values for 2-oxoglutarate, glutamine and NADH are 39 micrometer, 400 micrometer and 1.3 micrometer respectively. The catalytic centre activity is of the order of 70 s-1 and is independent of pH between 6.5 and 9.5. Glutamate synthase is inhibited by glutamic acid, oxaloacetic acid, aspartic acid and asparagine, all competitive with 2-oxoglutarate; and by NAD+, which is competitive with NADH. There is evidence of two flavine prosthetic groups per enzyme molecule.
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PMID:Enzymes of nitrogen metabolism in legume nodules. Purification and properties of NADH-dependent glutamate synthase from lupin nodules. 2 90

Natural-abundance 13C NMR spectra (at 15.04 MHz) of the polypeptide cardiac stimulant Anthopleurin-A are presented. The spectra contain many resolved one- and two-carbon resonances from carbonyl and aromatic carbons and a few resolved resonances from aliphatic carbons. Most of these have been assigned to individual carbons in the protein. The effect of pH on the 13C spectrum has been investigated. In conjunction with the resonance assignments, this yields estimates for the pK alpha values of the COOH-terminal and NH2-terminal residues, the side chain carboxylate of 1 of the 2 aspartic acid residues, and the imidazolium groups of the 2 histidine residues. The effects of the lanthanides La3+ and Gd3+ on the spectrum have also been studied. The results suggest that there are at least two binding sites, and further studies will be required to characterize these before they can be utilized as an aid in structural mapping. Finally, the results are discussed in relation to a postulated model for the mode of action of Anthopleurin-A.
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PMID:Natural abundance carbon-13 nuclear magnetic resonance study of anthopleurin-A, a cardiac stimulant from the sea anemone Anthopleura xanthogrammica. 3 35

Protein IX from adenovirus type 2 was purified by two methods, one from groups of nine hexons obtained by disrupting purified virus by heating in the presence of deoxycholate, and the other by a previously published method. The purified protein was used to obtain a monospecific antiserum. Protein IX was found to possess both sub-group- and type-specific antigenic determinants which were apparently accessible within the groups of nine hexons. Approximately 15 molecules of IX were found per group of nine hexons and from considerations of symmetry it seemed possible that IX was located at the 'corner to edge' contacts between hexons in the icosahedron. The protein in infected cells was found to possess approximately neutral charge as determined by immunoelectrophoresis. This was consistent with the amino acid composition, which showed it to be rich in serine, alanine and leucine with approximately half of its glutamic and aspartic acid residues amidified, and the isoelectric point of 6.0, as determined by two dimensional gel analysis. No free N-terminal amino acid was detectable. It is suggested that a unique tryptophan residue is located at around position 70 from the blocked N-terminus, on the basis of chemical cleavage by BNPS-skatole. Based on one tryptophan residue a total of 107 amino acids and a mol. wt. of 11200 was deduced. Analysis of 35S-methionine-labelled infected cell extracts in a two-dimensional gel system showed that the synthesis of polypeptide IX could be detected early in infection, i.e. in the presence of an inhibitor of DNA synthesis.
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PMID:Characterization of adenovirus protein IX. 9 18

The amino acid sequence of staphylococcal protease has been determined by analysis of tryptic peptides obtained from cyanogen bromide fragments. Selected peptides obtained from digests with staphylococcal protease, thermolysin, and chymotrypsin provided the information necessary to align the tryptic peptides and the cyanogen bromide fragments. The protease is a single polypeptide chain of some 250 amino acids and is devoid of sulfhydryl groups. The COOH-terminal tryptic peptide of of the protease molecule contains some 43 residues, most of which are aspartic acids, asparagines, and prolines. The amino acid sequence of this peptide was not determined. The primary structure near the active serine residue indicates that staphylococcal protease is related to the pancreatic serine proteases. However, it has little or no additional sequence homologies with these enzymes except for the regions near histidine-50 and aspartic acid - 91. These regions have striking similarities with the corresponding regions of protease B and the trypsin-like enzyme of Streptomyces griseus.
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PMID:The primary structure of staphylococcal protease. 9 22

The amino acids in 9 cyanogen bromide peptides have been placed in sequence starting from the NH2 terminus. The peptides account for residues 1 to 377 of the whole protein and include the largest (CNBr7, 119 residues) and the smallest (CNBr1, 2 residues) of the cyanogen bromide peptides. This region contains only 3 of the 20 lysine residues in the polypeptide chain. A high proportion of charged groups are present (28 of 66 arginine, 28 of 60 glutamic acid, and 24 of 65 aspartic acid residues).
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PMID:Amino acid sequence of beta-galactosidase. VIII. Sequence of the NH2-terminal segment, CNBr peptides 1 to 9, residues 1 to 377. 9 95

A polypeptide with a molecular weight of 8 500 (HP 8 500) was isolated from the mitochondrial membrane of the nuclear mutant cni-1 of Neurospora crassa. This mutant is characterized by a cyanide-insensitive respiration and by a deficiency in the cytochromes aa3 and b. The polypeptide is synthesized on mitochondrial ribosomes. It has an extremely hydrophobic character; it is insoluble in aqueous media in the absence of sodium dodecylsulfate and is soluble in acid chloroform/methanol. It lacks histidine. The polar amino acids lysine, arginine, aspartic acid, glutamic acid, serine and threonine make up only 25% of the total amino acids on a mole-percent basis. The N-terminal amino acid is tyrosine. The possible function of this polypeptide in the mitochondrial membrane is discussed.
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PMID:Isolation and characterization of a mitochondrially synthesized polypeptide from Neurospora crassa cni-1 mutant. 12 27

The elution profile of aspartyl transfer RNA (aspartyl-tRNA) from reversed phase 5 chromatography for tRNA from a spectrum of animal tissues and tumors and human tumors has been examined. It was found that SV40-induced hamster tumors, BHK21/cl 13 cells in culture, certain carcinogen-induced tumors in the Ehrlich ascites tumor, and a number of human carcinomas and adenocarcinomas contained a distinct increase (3- to 20-fold) in the percentage of a late-eluting aspartyl-tRNA over that found in nonmalignant tissues, other animal tumors, and in human melanomas and sarcomas. The ability of the late-eluting aspartyl-tRNAAspIV to bind to ribosomes in the presence of the codons for aspartic acid was compared to that of aspartyl-tRNAAspIII and was found to be approximately the same. Also, the ability of each of the 4 isoaccepting species of aspartyl-tRNA to engage in ribosomal incorporation of aspartic acid into a polypeptide was determined. All 4 isoacceptors function equally well in the amino acid incorporation.
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PMID:The distribution and properties of aspartyl transfer RNA in human and animal tumors. 16 64

The serum high density lipoproteins (HDL) of normolipemic dogs (beagles) were isolated in the density range of p 1.063 to 1.21 g/ml, and characterized in terms of composition and physical properties (flotation and diffusion coefficients, partial specific volume, molecular weight, electrophoretic mobility, ultraviolet absorption, and circular dichroism). The results indicated that canine HDL is a relatively homogeneous class with a molecular weight of about 230 000 and general properties similar to those reported for human HDL. After delipidation, the resulting apolipoprotein, apo-HDL, was fractionated by Sephadex G-200 column chromatography in urea or guanidine hydrochloride solutions. About 90% of the apo-HDL consisted of a protein with a molecular weight of about 28 000, similar in amino acid composition to human apolipoprotein A-I and having the same NH2 terminus (aspartic acid) and COOH terminus (glutamine) and no carbohydrates. Two other proteins were isolated, one having an apparent mol wt of 55 000 and representing, at least in part, an aggregate of apolipoprotein A-I and the other component with a mol wt of 8000, not yet characterized. The results indicate that canine HDL, as an intact complex, has general physical properties that lie between those reported for human HDL2 and HDL3, and that it differs compositionally from the human products mainly in its predominant content of apo-A-I. These findings together with evidence for the relatively homogeneous nature of the canine HDL provide new prospects for unraveling the relationship between polypeptide composition and HDL structure.
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PMID:Isolation and characterization of a dog serum lipoprotein having apolipoprotein A-I as its predominant protein constituent. 17 60


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