Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A strong transcriptional signal previously cloned from the Streptomyces griseus genome in S. lividans was subcloned and its nucleotide sequence was determined. Upstream of the transcriptional start point which was determined by high-resolution S1 nuclease mapping, -35 (5'-TTGCCG-3') and -10 (5'-TAGCGT-3') sequences, separated by 18 nucleotides, were present. By replacing the tet promoter of pBR322 with the Streptomyces promoter, no expression of the tet gene was observed in Escherichia coli cells. The result suggests that notwithstanding a similarity to the E. coli -35 and -10 sequences, the Streptomyces promoter is not functional in E. coli. The strong promoter was inserted in multi-copy and wide host range plasmids pIJ702 and pKS11, resulting in the pSEV series of expression-vectors with several unique restriction endonuclease cleavage sites downstream of the promoter for cloning of foreign genes. The extremely heat-stable malate dehydrogenase of Thermus flavus, when its coding sequence with a ribosome-binding site was located downstream of the strong promoter in pSEV2, was produced in large quantities in S. lividans throughout growth. When an extracellular cellulase from Bacillus subtilis was expressed in a cellulase-negative S. lividans strain, virtually all of the cellulase activity was found in the culture supernatant.
Mol Gen Genet 1987 Dec
PMID:Construction and characterization of multicopy expression-vectors in Streptomyces spp. 312 89

We cloned and characterized a mouse cytosolic malate dehydrogenase (cMDHase) (EC 1.1.1.37) gene, which is about 14 x 10(3) base-pairs long and is interrupted by eight introns. The 5' and 3' flanking regions and the exact sizes and boundaries of the exon blocks, including the transcription-initiation sites, were determined. The 5' end of the gene lacks the TATA and CAAT boxes characteristic of eukaryotic promoters, but contains G + C-rich sequences, one putative binding site for a cellular transcription factor, Sp1, and at least two major transcription-initiation sites. The sequences around the transcription-initiation sites are compatible with the formation of a number of potentially stable stem-loop structures. We compared structural organization of the mouse cMDHase gene with that of the previously characterized mouse mitochondrial MDHase (mMDHase) gene, and found that the conservation of intron positions spreads across much of the two genes. This result suggests that a common ancestral gene for the cytosolic MDHase and the mitochondrial MDHase was broken up by introns, before the divergence. We also compared the nucleotide sequence of the promoter region of the mouse cytosolic MDHase gene with that of the other three mouse genes coding for isoenzymes participating in the malate-aspartate shuttle, i.e. mitochondrial MDHase, cytosolic and mitochondrial aspartate aminotransferases (cAspATase and mAspATase). We found that highly conserved regions are present in the promoter region of the cAspATase gene.
J Mol Biol 1988 Aug 05
PMID:Structural organization of the mouse cytosolic malate dehydrogenase gene: comparison with that of the mouse mitochondrial malate dehydrogenase gene. 317 22

Structural organization of the mouse mitochondrial malate dehydrogenase (EC 1.1.1.37) gene was determined by analyzing a genomic DNA fragment isolated from a cosmid library. The gene is 12,000 base-pairs long and contains nine exons interrupted by eight introns of various sizes. The 5' and 3'-flanking regions, and the exact sizes and boundaries of the exon blocks including the transcription-initiation sites were determined. In the 5'-flanking region, there is neither a TATA box nor a CAAT box. Instead of these sequences, there are six copies of the GGGCGG or CCGCCC sequence, which is a potential binding site for the transcription factor, Sp1. The 5'-flanking region up to about 600 nucleotides is G + C-rich (65%) and contains sequences compatible with the formation of a number of potentially stable stem-loop structures. S1 nuclease mapping and primer extension analysis demonstrated that transcription of the mitochondrial malate dehydrogenase gene initiates at multiple sites. Comparison of the nucleotide sequence of the promoter region of the mitochondrial malate dehydrogenase gene with that of the mitochondrial aspartate aminotransferase gene, revealed that there are several highly conserved regions between these two mitochondrial enzyme genes participating in the malate-aspartate shuttle.
J Mol Biol 1988 Mar 05
PMID:Structural organization of the mouse mitochondrial malate dehydrogenase gene. 337 35

Isolation of electrophoretic mobility shift mutants for a large number of enzyme loci in CHO cells has allowed the identification of many genes which are functionally hemizygous. To gain further insight into the nature of hemizygosity in CHO cells and the mechanisms by which it has arisen, we are attempting to determine whether hemizygous gene loci are clustered in a few localized chromosomal regions in CHO or are more generally distributed throughout the genome. Isozyme analysis of a series of CHO electrophoretic mobility shift mutants for MDH2 (malate dehydrogenase 2, EC 1.1.1.37) revealed that this locus is functionally hemizygous in CHO cells, but the locus could not be mapped by conventional approaches because of the similar electrophoretic mobilities of Chinese hamster and mouse MDH2 isozymes. Construction of intraspecific CHO X CHO hybrids using electrophoretic mobility shift mutants with secondary, selectable drug-resistance markers allowed us to determine that MDH2 is not closely linked to any previously mapped hemizygous marker loci in CHO, but is linked to alleles for two dizygous gene loci, PGM3 and APRT, on CHO chromosome Z7. A possible genetic basis for hemizygosity of the MDH2 locus in CHO cells is discussed.
Somat Cell Mol Genet 1986 Mar
PMID:Functional hemizygosity for the MDH2 locus in Chinese hamster ovary cells. 345 74

The mechanism by which the nephrotoxic S-conjugates S-(1,2-dichlorovinyl)-L-cysteine (DCVC) and S-(1,2-dichlorovinyl)-L-homocysteine (DCVHC) produce toxicity in rat kidney mitochondria was studied by examining their effects on mitochondrial function, structural integrity, and metabolism. Both S-conjugates inhibited succinate-linked state 3 respiration and impaired the ability of mitochondria to retain Ca2+ and to generate a membrane potential; 30-60 min were required for maximal expression of these functional changes. Mitochondrial structure was damaged, as indicated by enhanced polyethylene glycol-induced shrinkage of matrix volume and by leakage of protein and malic dehydrogenase from the matrix; 60-120 min were required for maximal expression of these structural changes. Much shorter incubation times (15-30 min) were required for DCVC and DCVHC to decrease ATP concentrations, to alter the concentrations of several citric acid cycle intermediates, and to inhibit succinate:cytochrome c oxidoreductase and isocitrate dehydrogenase activities. Lipid peroxidation and oxidation of glutathione to glutathione disulfide also occurred. The relative time courses of these pathological changes indicate that the initial effects of DCVC and DCVHC in renal mitochondria are the inhibition of energy metabolism and the oxidation of glutathione. These changes then lead to alterations in mitochondrial function and ultimately to irreversible damage to mitochondrial structure.
Mol Pharmacol 1987 Oct
PMID:Mechanism of S-(1,2-dichlorovinyl)-L-cysteine- and S-(1,2-dichlorovinyl)-L-homocysteine-induced renal mitochondrial toxicity. 367 Feb 84

Data from small-angle X-ray and neutron scattering and ultracentrifugation experiments on solutions of malate dehydrogenase from Halobacterium maris mortui are analysed together to yield a model for the enzyme particle formed by the protein and its interactions with water and salt in the solvent. The halophilic enzyme is stable only in high concentrations of salt and the model has structural features that are absent from non-halophilic malate dehydrogenase. The complementarity of the information derived from the three experimental methods is discussed extensively and quantitatively. It derives from the fact that mass density (ultracentrifugation), electron density (X-rays) and neutron scattering density are independent of each other. Each method gives a different "view" of the same particle, and an analysis of the combined data provided thermodynamic and structural parameters with, apart from the chemical composition of the solutions, only one other assumption: a constant partial specific volume for water equal to 1.00 cm3 g-1. Both the insights gained by this novel approach and its limitations are carefully pointed out. In solvents between 1 M and 5 M-NaCl, the enzyme forms a particle of invariant volume, consisting of a protein dimer (87,000 g mol-1) with which are associated 0.87 g of water and 0.35 g of salt per gram of protein. The partial specific volume of the protein calculated from the combined experimental data is 0.753(+/- 0.030) cm3 g-1, in good agreement with the value calculated from the amino acid composition. The particle has a radius of gyration of 32 A and an equivalent Stokes radius of 43 A. By combining the data from the X-ray and neutron scattering studies, the radii of gyration of the protein moiety alone and of the associated water and salt distribution were calculated. They are 28 A and about 40 A, respectively. The large-angle scattering curves show that the shapes of the particle and of the protein moiety alone are similar. At very low resolution they can be approximated by an ellipsoid of axial ratio 1:1:0.6 (or 1:1:1.5). At higher resolution, it becomes apparent that the particle has a significantly larger interface with solvent than an homogeneous ellipsoid or globular protein. The model has a globular protein core similar to non-halophilic malate dehydrogenase, with about 20% of the protein extending loosely out of the core, forming the large interface with solvent. The main interactions with water and salt take place on this outer part.
J Mol Biol 1986 Jul 05
PMID:Solution structure of halophilic malate dehydrogenase from small-angle neutron and X-ray scattering and ultracentrifugation. 378 99

The glycosomes of in vitro grown procyclic trypomastigote forms of Trypanosoma brucei were purified by three different procedures and the results compared by electron microscopy, enzyme assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Centrifugation on a self-forming Percoll gradient followed by a sucrose gradient centrifugation resulted in the least enriched glycosomal preparation. Centrifugation on a pre-formed Nycodenz gradient gave an improved preparation but the most homogeneous preparation of intact glycosomes was obtained after centrifugation on two successive sucrose gradients. Glycosomes purified by both the Nycodenz and double sucrose gradient procedures appeared larger than in situ glycosomes presumably due to an osmotic effect resulting from disruption of the granular matrix of the organelles. Nevertheless, there appears to be no loss of cisternal contents due to the swelling of the organelles. The glycosomes of the bloodstream form trypomastigotes purified by the same procedures show, however, no sign of swelling. A comparison of glycosomes purified from procyclic trypomastigotes and bloodstream form trypomastigotes prepared by the same double sucrose procedure demonstrated that in the glycosome of procyclic trypomastigotes: activities of hexokinase, phosphoglucose isomerase, phosphofructose kinase, aldolase and phosphoglycerate kinase and diminished by 80-100%; activities of glyceraldehyde-3-phosphate dehydrogenase, triose phosphate isomerase and glycerol-3-phosphate dehydrogenase remain unchanged or are only slightly reduced; there is an appearance of four major new proteins, among which could be phosphoenol pyruvate carboxykinase and malate dehydrogenase. These observations are in basic agreement with those by Hart et al. (Mol. Biochem. Parasitol. 12, 25-35, 1984).
Mol Biochem Parasitol 1986 Dec
PMID:An improved purification of glycosomes from the procyclic trypomastigotes of Trypanosoma brucei. 380 43

Cells of the aerotolerant anaerobe Giardia lamblia respire in the presence of oxygen. Endogenous respiration is stimulated by glucose but not by other carbohydrates and Krebs cycle intermediates. Endogenous and glucose-stimulated respiration are insensitive to cyanide, malonate, and 2,4-dinitrophenol, but are inhibited by atabrin and iodoacetamide. G. lamblia produces ethanol, acetate and CO2 both aerobically and anaerobically either from endogenous reserves or exogenous glucose. Molecular hydrogen is not produced. The following enzyme activities were detected in homogenates: hexokinase, fructose-biphosphate aldolase, pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malate dehydrogenase (decarboxylating), pyruvate synthase, acetyl-CoA synthetase, alcohol dehydrogenase (NADP+), NADH dehydrogenase, NADPH dehydrogenase, NADPH oxidoreductase and superoxide dismutase. The enzymes of energy and carbohydrate metabolism are nonsedimentable (109 000 x g for 30 min). Activities of lactate dehydrogenase, hydrogenase, phosphate acetyltransferase, acetate kinase, citrate synthase, succinate dehydrogenase, fumarate hydratase and catalase were below the limits of detection. The results suggest the occurrence of glycolysis, energy production by substrate level phosphorylation and a flavin, iron-sulfur protein mediated electron transport system as well as the absence of cytochrome mediated oxidative phosphorylation and functional Krebs cycle.
Mol Biochem Parasitol 1980 Mar
PMID:Energy metabolism of the anaerobic protozoon Giardia lamblia. 610 7

Transformation of fibroblasts by several retroviruses that produce transforming gene products associated with protein kinase activity results in the phosphorylation of a normal cellular protein with an Mr of 34,000 (the 34K protein). Evidence is presented here that, as extracted from chicken embryo fibroblasts, this protein exists in two forms that differ both in their elution from hydroxylapatite and in their native molecular weight. The form that eluted from hydroxylapatite at 210 to 295 mM potassium phosphate displayed a native molecular weight of 30,000 to 40,000, whereas the form that eluted at 320 to 440 mM displayed a native molecular weight of 60,000 to 70,000. The latter form copurified with a low-molecular-weight protein with an approximate Mr of 6,000 (6K). Both forms of 34K were completely separable from malate dehydrogenase activity. Phosphorylated 34K, isolated from Rous sarcoma virus-transformed cells, was also present in two forms; hence, in the cell neither form serves as a preferential substrate for pp60v-src. We found that the expression of 34K differed greatly in various avian tissues. In particular, it was present in the highest concentration in cultured fibroblasts and in very low concentration in brain tissue. Its expression in this tissue seems to be controlled at the level of transcription, since 34K mRNA in brain tissue was barely detectable. The expression of 6K was similar to that of 34K.
Mol Cell Biol 1984 Jan
PMID:Biochemical characterization of a 34-kilodalton normal cellular substrate of pp60v-src and an associated 6-kilodalton protein. 632 54

A 36,000-dalton cellular protein (p36) has been identified previously as an abundant substrate for phosphorylation by tyrosine-specific protein kinases. Since several of the responsible kinases are associated with the plasma membrane, we explored the subcellular distribution of p36. Biochemical fractionations located p36 on the plasma membrane of both normal and retrovirus-transformed cells. Approximately half of the p36 was bound to the membrane with the affinity of a peripheral membrane protein; the remainder was even more tightly bound. The distribution of p36 among subcellular fractions and its affinity for the plasma membrane were not affected by tyrosine phosphorylation. We determined that p36 is synthesized in the soluble compartment of the cell and then moves rapidly to the membranous compartment. Immunofluorescence microscopy with antibodies directed against p36 revealed two distinct distributions of the antigen: (i) a sharply demarcated crenelated pattern within or immediately beneath the plasma membrane, which we presume to be a correlary of the distribution of p36 in biochemical fractionations; and (ii) diffuse staining in a cytoplasmic location that could not be attributed to a specific feature of cytoarchitecture and could not be easily reconciled with the results of biochemical fractionations. Efforts to detect the secretion of p36 were unsuccessful. No evidence was obtained for exposure of p36 on the cell surface, and no changes in localization were observed as a consequence of neoplastic transformation. During the course of this study, we had the opportunity to pursue a previous report that p36 is a component of the enzyme malate dehydrogenase (Rubsamen et al., Proc. Natl. Acad. Sci. U.S.A. 79:228-232, 1982). We were unable to substantiate this claim. We conclude that at least a substantial fraction of p36 is located on the cytoplasmic aspect of the plasma membrane, where it could be well situated to serve as a substrate for several identified tyrosine-specific kinases. But the function of p36 and its role, if any, in neoplastic transformation of cells by retroviruses possessing tyrosine-specific kinases remain enigmatic.
Mol Cell Biol 1983 Mar
PMID:Subcellular location of an abundant substrate (p36) for tyrosine-specific protein kinases. 634 13


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>