Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have determined the nucleotide sequence of the polC gene of Bacillus subtilis which codes for DNA polymerase III. Our recent analysis has revealed that the gene comprises 4311 nucleotides, from the start to the stop codon, 306 nucleotides more than we reported earlier. The plasmid reported by us and by N.C. Brown's laboratory contained a sequence at the end of the gene which is not related to the polC region of B. subtilis. We have isolated the rest of the gene, the sequence of which is presented in this paper. The new stop codon is followed by a hyphenated palindromic sequence of 13 nucleotides. The C-terminus of the coding region contains the novel mutation, dnaF, which results in a defect in the initiation of replication due to a change in the codon TCC to TTC (serine to phenylalanine). The hypermutator mutation mut-1 is due to two point mutations in the 3' to 5' exonuclease domain, the proof reading function. The codon changes are GGA to GAA (glycine to glutamic acid) and AGC to AAC (serine to asparagine). The elongation defective mutation, polC26, affecting the catalytic site that adds nucleotides to the growing chain, is due to a change in the codon GTC to GAC (valine to aspartic acid). It is separated from the mutation reported earlier, azp-12, by 306 nucleotides. Knowing the locations of the mutational sites allowed us to deduce the domains of the gene and the enzyme it encodes, and permitted us to present a precise map of the gene at the molecular level.
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PMID:Genetic structure and domains of DNA polymerase III of Bacillus subtilis. 184 Jun 38

Skeletal-muscle sarcoplasmic reticulum (SR) comprises two distinct domains, corresponding to the free membrane of longitudinal SR (LSR) and the junctional membrane region of the terminal cisternae (TC), respectively. The junctional membrane contains the ryanodine receptor (RyR)/Ca(2+)-release channel and additional minor protein components that still require biochemical investigation, in relation to excitation-contraction coupling. Recent findings suggested the involvement in this process of a 170 kDa protein [Kim, Caswell, Talvenheimo & Brandt (1990) Biochemistry 29, 9281-9289], also characterized as a phosphoprotein in junctional TC in independent studies [Chu, Submilla, Inesi, Jay & Campbell (1990) Biochemistry 29, 5899-5905]. We show that this protein is a specific substrate of exogenous cyclic AMP-dependent protein kinase, that it is exposed to the outer surface of intact TC vesicles, and that it co-localizes with the RyR to the junctional membrane. Comparative analysis of LSR and TC subfractions for the 160 kDa glycoprotein sarcalumenin, using Western-blot techniques and specific monoclonal antibodies or concanavalin A as a ligand, revealed that the distribution of this protein within the SR corresponds inversely to both that of the RyR and of the 170 kDa protein. The 170 kDa protein, like sarcalumenin, stains blue with the cationic dye Stains-All and binds 45Ca2+ on blots, but it is uniquely distinguished by its ability to bind 125I-labelled low-density lipoprotein. The similarity of these properties, as well as the pI and solubility properties, to those described for the SR protein, recently purified and cloned and named histidine-rich Ca(2+)-binding protein [HCP; Hofmann, Brown, Lee, Pathak, Anderson & Goldstein (1989) J. Biol. Chem. 264, 8260-8270], makes it very likely that our protein and HCP may indeed be identical. The protein described in the present study differs from sarcalumenin because its migration in SDS/PAGE is accelerated in the presence of Ca2+, a previously reported property of other Ca(2+)-binding proteins [leMaire, Lund, Viel, Champeil & Moller (1989) J. Biol. Chem. 265, 1111-1123], arguing for Ca(2+)-induced protein-conformational changes. Kinase-dependent phosphorylation of our protein is another distinguishing feature, which, although not previously reported for HCP, is consistent with the presence of potential serine/threonine phosphorylation sites in the middle portion of the cloned HCP molecule. The finding that HCP, contrary to early views, selectively binds to the cytoplasmic side of the junctional membrane, together with its newly characterized properties, seem to provide new clues as to a possible role in electromechanical coupling and/or Ca2+ release.
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PMID:Subcellular fractionation to junctional sarcoplasmic reticulum and biochemical characterization of 170 kDa Ca(2+)- and low-density-lipoprotein-binding protein in rabbit skeletal muscle. 187 15

The influenza virus hemagglutinin (HA) temperature-sensitive (ts) mutant, ts61S, contains a nucleotide change in RNA segment 4 which leads to an amino acid change at HA1 residue 110 of serine to proline. When ts61S HA is synthesized and maintained at the nonpermissive temperature (39.5 degrees), the HA is defective in transport in the exocytic pathway and is retained in the endoplasmic reticulum (S. Nakajima, D. J. Brown, M., Ueda, K., Nakajima, A. Suguira, A. K. Pattnaik, and D. P. Nayak, 1986, Virology 154, 279-285). In a comparison of the biochemical properties of ts61S HA and A/WSN/33 HA (wt) expressed at the permissive temperature (33 degrees), we have found that ts61S HA is extensively debilitated. A large proportion of ts61S HA fails to gain reactivity with conformation-specific monoclonal antibodies and does not become resistant to protease digestion. In turn, a large population of the molecules are not transported from the ER to the Golgi apparatus or cell surface with the same kinetics or efficiency as wt HA. These data suggest that the serine to proline change at HA1 residue 110 leads to partial impairment of folding at the permissive temperature with complete impairment at the nonpermissive temperature.
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PMID:Influenza virus ts61S hemagglutinin is significantly defective in polypeptide folding and intracellular transport at the permissive temperature. 192 89

A 1.5-kilobase cDNA clone for human pyruvate dehydrogenase E1 was isolated from a lambda gt11 expression library by screening with polyclonal antiserum to the E1 alpha subunit of the porcine pyruvate dehydrogenase complex, a polyclonal antibody against bovine pyruvate dehydrogenase complex and a synthetic oligonucleotide based on the known amino acid sequence of the amino-terminal of the bovine pyruvate dehydrogenase-E1 alpha subunit. Nucleotide sequence analysis of the cDNA revealed a 5'-untranslated sequence of 72 nucleotides, a translated sequence of 1170 nucleotides, and a 3'-untranslated sequence of 223 nucleotides with a poly(A) tail. The cDNA structure predicts a leader sequence of 29 amino acids and a mature protein of 362 amino acids comprising an amino-terminal peptide identical to that of the bovine E1 alpha subunit and three serine phosphorylation sites whose sequence was also identical to those in the bovine E1 alpha subunit. The translated sequence for the mature protein differs substantially from that described by Dahl et al. (Dahl, H. H., Hunt, S. M., Hutchison, W. M., and Brown, G. K. (1987) J. Biol. Chem. 262, 7398-7403) by virtue of a frameslip between bases 390 and 594. This amended sequence is confirmed by the presence of additional restriction sites for the enzymes NaeI and HaeII at the beginning and end, respectively, of this section. The leader sequence is typical for mitochondrial enzymes being composed of a combination of neutral and basic residues. The amino acid composition is strikingly similar to that of the bovine protein. This cDNA clone hybridizes with a 1.8-kilobase mRNA on a Northern blot analysis of human fibroblasts, and a second minor band of 4.4 kilobases is also detected.
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PMID:Isolation of a full-length complementary DNA coding for human E1 alpha subunit of the pyruvate dehydrogenase complex. 282 59

We have studied function and structure of the low density lipoprotein (LDL) receptors in a monensin-resistant (Monr-31) mutant isolated from Chinese hamster ovary (CHO) cells. To assay the ability of the receptor to bind LDL, we employed three methods, 125I-LDL binding to the cells at 4 degrees C, 125I-LDL binding to the receptor-phospholipid complex (Schneider, W.J., Goldstein, J.L., and Brown, M.S. (1980) J. Biol. Chem. 255, 11442-11447), and ligand blotting (Daniel, T.O., Schneider, W.J., Goldstein, J.L., and Brown, M.S. (1983) J. Biol. Chem. 258, 4606-4611). The LDL receptor number was similar in both CHO and Monr-31, but the binding affinity was reduced in the mutant. The semi-quantitative immunoblotting assay with an antibody directed against the COOH-terminal 14 amino acids and the ligand-blotting assay with LDL also showed that the relative steady-state level of the receptor in Monr-31 was comparable to that in CHO, whereas the binding capacity of the receptor in Monr-31 was lower than that in CHO. The precursor and degradation forms of the LDL receptors produced in the mutant cells were similar in size to those in the parental cells, but the apparent molecular mass of the mature receptor protein in sodium dodecyl sulfate-polyacrylamide gels was reduced about 5000 daltons in the mutant. These results suggest a structural change at the NH2-terminal LDL binding domain. Tests of the effects of tunicamycin, endo-alpha-N-acetylgalactosaminidase (O-glycanase), and sialidase (neuraminidase) on the molecular size of the mature receptors indicated that the reduced size of the receptor in the mutant cells resulted from altered oligosaccharide chain(s) linked to serine/threonine residues in the binding domain. We compared the molecular sizes and binding activity of human LDL receptors in several clones derived from CHO and Monr-31 cells which were transfected with human LDL receptor cDNA. The human LDL receptors produced in the transfected clones of Monr-31 were also smaller in molecular size and lower in binding capacity than those produced in the transfected clones of CHO. These results suggest that both structural and functional alteration of the LDL receptor of Monr-31 is not caused by a mutation in the structural gene of the LDL receptor but by altered processing or maturation of the receptor. The correlation of the decrease in molecular size and reduced binding capacity of the LDL receptor is discussed.
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PMID:Low binding capacity and altered O-linked glycosylation of low density lipoprotein receptor in a monensin-resistant mutant of Chinese hamster ovary cells. 330 76

An inbred rat model of small bowel transplantation was used to study the metabolic consequences of systemic venous drainage of the graft. Lewis rats received either Lewis (isograft) or Lewis X Brown Norway F1 (allograft) small bowel grafts. Venous drainage of the isografts was to either the portal vein or the inferior vena cava. Allograft recipients underwent systemic venous drainage and were treated with a 4-week course of tapering cyclosporine. Ammonia levels in systemically drained isografts (108 +/- 5 microM/100 ml) were more than twice those in portally drained isografts (38 +/- 3, P less than 0.001), while amino acid analysis showed significant elevations in glycine, serine, asparagine, histidine, phenylalanine, and tyrosine. Ammonia levels decreased and amino acid alterations were generally corrected when animals were fed a modified protein diet low in aromatic and high in branched chain amino acids. Recipients of both systemically and portally drained isografts grew normally, while weight gain in allograft recipients was impaired. We conclude that systemic venous drainage of small bowel grafts results in altered ammonia and amino acid levels that resemble those found in models of hepatic encephalopathy; these changes can be significantly ameliorated by dietary modification; and the compromised growth seen in systemically drained allografted animals results from chronic rejection and/or cyclosporine rather than the partial porto-systemic shunt.
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PMID:Metabolic aspects of small bowel transplantation in inbred rats. 349 83

Bovine adrenal cortex contains a high molecular weight casein kinase II-like enzyme (Mr 500,000) that phosphorylates a specific serine residue in the cytoplasmic domain of the low density lipoprotein (LDL) receptor (Kishimoto, A., Brown, M. S., Slaughter, C. A., and Goldstein, J. L. (1987) J Biol. Chem. 262, 1344-1351). In the current paper, we provide evidence to suggest that this 500-kDa kinase can be dissociated into two subunits, a catalytic subunit and an activator subunit, by treatment with 1 M NaCl. The catalytic subunit was purified to homogeneity (greater than 100,000-fold) using affinity chromatography on GTP-agarose plus several other chromatography steps. It had an Mr of 50,000 by gel filtration and 35,000 by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The catalytic subunit phosphorylated casein actively, but it phosphorylated the LDL receptor with only low affinity. The affinity for the LDL receptor was increased 10-fold (saturation at 10 nM LDL receptor) by addition of a second protein that was released from a high molecular weight 500-kDa complex by 1 M NaCl. This activator protein (Mr 120,000 by gel filtration) was extremely heat stable but was destroyed by trypsin. It appeared to be required in stoichiometric amounts with relation to the LDL receptor. It did not increase the ability of the 50-kDa subunit to phosphorylate casein nor did it activate phosphorylation of the LDL receptor or casein by classic casein kinase II. The current data raise the possibility that the specificity of the 500-kDa LDL receptor kinase is attributable to a heat-stable activator subunit that binds to the LDL receptor and thereby renders it a better substrate for the catalytic subunit of the kinase.
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PMID:Purification of catalytic subunit of low density lipoprotein receptor kinase and identification of heat-stable activator protein. 359 14

When slices of adult rabbit articular cartilage were incubated in culture medium, the rate of incorporation of [35S]sulphate or [3H]acetate into glycosaminoglycans increased 4-8 fold during the first 5 days of incubation. Similar changes in biosynthetic activity were observed during culture of adult bovine cartilage. The activation of synthesis was not serum-dependent, but appeared to be a result of the depletion of tissue proteoglycan that occurs under these incubation conditions [Sandy, Brown & Lowther (1978) Biochim. Biophys. Acta 543, 536--544]. Thus, although complete activation was observed in serum-free medium, it was not observed if the cartilage was cultured inside dialysis tubing or in medium containing added proteoglycan subunit. The average molecular size of the proteoglycans synthesized by activated tissue was slightly larger than normal, as determined by chromatography on Sepharose CL-2B, and the average molecular size of the glycosaminoglycans synthesized by activated tissue was markedly increased over the normal. The increase in chain size was accompanied by an increase in the proportion of the chains degraded by chondroitinase ABC; these results are consistent with the preferential synthesis by activated chondrocytes of chondroitin sulphate-rich proteoglycans. The increase in glycosaminoglycan chain size was observed whether the chains were formed on endogenous core protein or on exogenous benzyl-beta-D-zyloside. An approximate 4-fold activation in culture of glycosaminoglycan synthesis on protein core was accompanied by a 1.54-fold increase in the rate of incorporation of [3H]serine into the chondroitin sulphate-linkage region of the proteoglycans. A 2.8-fold activation in culture of glycosaminoglycan synthesis on benzyl-beta-D-zyloside was accompanied by a 1.7-fold increase in the rate of incorporation of [3H]benzyl-beta-D-zyloside into glycosaminoglycans. The activation of glycosaminoglycan synthesis was, however, accompanied by no detectable change in the activity of xylosyltransferase (EC 2.4.2.26) in cell-free extracts. These results are discussed in relation to current ideas on the control of proteoglycan synthesis in cartilage.
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PMID:Control of proteoglycan synthesis. Studies on the activation of synthesis observed during culture of articular cartilages. 677 23

The procoagulant was isolated from the venom of four clinically significant species of brown snake; Pseudonaja affinis, P. inframacula, P. nuchalis, and P. textilis. HPLC elution profiles and PAGE showed a high degree of homology between the procoagulants from the four species. Antiserum from the CSL Ltd (Brown Snake Antivenom) produced a single band against all four procoagulants. The specific activity of the procoagulant varied between species, while inhibitory studies indicated that the procoagulants were serine proteases with a sialic acid component which also contributes to the coagulant action.
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PMID:Comparative study on the procoagulant from the venom of Australian brown snakes (Elapidae; Pseudonaja spp.). 805

Phosphatidyl inositol, phosphatidyl choline, phosphatidyl glycerol, phosphatidyl serine, phosphatidyl ethanolamine, phosphatidic acid and sphingomyelin were all found to be effective at reducing the Ca2+ requirement for m-calpain autolysis. In the absence of phospholipid, pig kidney m-calpain required 1.4 mM Ca2+ for 50% autolysis under the assay conditions used. Phospholipids caused a reduction in this Ca2+ requirement to a value between 0.45 mM Ca2+ for phosphatidyl glycerol and 1.1 mM Ca2+ for phosphatidyl ethanolamine. Previous studies (Crawford, C., Brown, N.R. and Willis, A.C. (1990) Biochem. J. 265, 575-579) have shown that the most probable site for phospholipid interaction in calpain is the N-terminal region between residues 39 to 62 of the small subunit of calpain (G17TAMRILGG). In this study we examine the possible role of this G17TAMRILGG region. Three synthetic peptides corresponding to parts of this sequence were used to examine the phospholipid binding sequence. Analysis of the phospholipid vesicle binding properties of these peptides suggested that both the TAMRIL and polyglycine sequences were required for binding to phosphatidyl inositol vesicles.
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PMID:Investigation of the interaction of m-calpain with phospholipids: calpain-phospholipid interactions. 862 30


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