Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.2.1.22 (cystathionine beta-synthase)
965 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An O-acetylserine sulfhydrylase (OASS) from the hyperthermophilic archaeon Aeropyrum pernix K1, which shares the pyridoxal 5'-phosphate binding motif with both OASS and cystathionine beta-synthase (CBS), was cloned and expressed by using Escherichia coli Rosetta(DE3). The purified protein was a dimer and contained pyridoxal 5'-phosphate. It was shown to be an enzyme with CBS activity as well as OASS activity in vitro. The enzyme retained 90% of its activity after a 6-h incubation at 100 degrees C. In the O-acetyl-L-serine sulfhydrylation reaction, it had a pH optimum of 6.7, apparent K(m) values for O-acetyl-L-serine and sulfide of 28 and below 0.2 mM, respectively, and a rate constant of 202 s(-1). In the L-cystathionine synthetic reaction, it showed a broad pH optimum in the range of 8.1 to 8.8, apparent K(m) values for L-serine and L-homocysteine of 8 and 0.51 mM, respectively, and a rate constant of 0.7 s(-1). A. pernix OASS has a high activity in the L-cysteine desulfurization reaction, which produces sulfide and S-(2,3-hydroxy-4-thiobutyl)-L-cysteine from L-cysteine and dithiothreitol.
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PMID:Characterization of a novel thermostable O-acetylserine sulfhydrylase from Aeropyrum pernix K1. 1264 99

The identification, isolation and characterization of a new Aspergillus nidulans positive-acting gene metR, which encodes a transcriptional activator of sulphur metabolism, is reported. metR mutants are tight auxotrophs requiring methionine or homocysteine for growth. Mutations in the metR gene are epistatic to mutations in the negative-acting sulphur regulatory scon genes. The metR coding sequence is interrupted by a single intron of 492 bp which is unusually long for fungi. Aspergillus nidulans METR is a member of bZIP family of DNA-binding proteins. The bZIP domains of METR and the Neurospora crassa CYS3 transcriptional activator of sulphur genes are highly similar. Although Neurospora cys-3 gene does not substitute for the metR function, a chimeric metR gene with a cys-3 bZIP domain is able to transform the DeltametR mutant to methionine prototrophy. This indicates that METR recognizes the same regulatory sequence as CYS3. The metR gene is not essential, as deletion mutants are viable and have similar phenotype as point mutants. In contrast to the Neurospora cys-3, transcription of the metR gene was found to be regulated neither by METR protein nor by sulphur source. Transcription of metR gene is derepressed in the sconB2 mutant. Transcription of genes encoding sulphate permease, homocysteine synthase, cysteine synthase, ATP-sulphurylase, and sulphur controller--sconB is strongly regulated by the metR gene product and depends on the character of the metR mutation and sulphur supplementation.
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PMID:The Aspergillus nidulans metR gene encodes a bZIP protein which activates transcription of sulphur metabolism genes. 1289 30

In this study, the phosphoproteome of Corynebacterium glutamicum, an industrially important soil bacterium of the Corynebacterium/Mycobacterium/Nocardia (CMN) group of Gram-positive bacteria, was investigated by two different detection methods: first, by in vivo radio-labeling using [(33)P]-phosphoric acid with subsequent autoradiography and second, by immunostaining with phosphoamino acid-specific monoclonal antibodies. After two-dimensional gel electrophoresis (2-DE), around 60 [(33)P]-labeled protein spots were visualized and around 90 antibody-decorated protein spots detected; 31 of the protein spots were detected with both methods. By peptide mass fingerprinting, 41 different proteins were identified, namely 5-enolpyruvylshikimate 3-phosphate synthase, aconitase, acyl-CoA carboxylase, acyl-CoA synthetase, ATP (synthase alpha- and beta-chain), carbamoyl-phosphate synthase, citrate synthase, cysteine synthase, DnaK, the elongation factors G, P, Ts and Tu, enolase, fructose bisphosphate aldolase, fumarase, Gap dehydrogenase, glutamine synthetase I, glycine hydroxymethyltransferase, GroEL2, GTPase, heat-inducible transcriptional repressor DnaJ2, inorganic pyrophosphatase, isocitrate dehydrogenase, ketol-acid reductoisomerase, lactate dehydrogenase, leucine-tRNA ligase, lipoamide dehydrogenase, methionine synthase, O-acetylhomoserine sulfhydrylase, pyruvate carboxylase, pyruvate kinase, pyruvate oxidase, ribosomal protein S1, RNA polymerase (beta-subunit), succinyl-CoA:CoA transferase, transketolase and UDP-N-acetylmuramoyl-L-alanine ligase, besides a hypothetical 35k protein and a hypothetical glucose kinase. Both detection techniques were used to create a phosphoproteome map. Additionally, the influence of nitrogen deprivation on the phosphoproteome of C. glutamicum was investigated.
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PMID:Towards a phosphoproteome map of Corynebacterium glutamicum. 1292 88

Variations in proteome profiles of Escherichia coli in response to the overproduction of human leptin, a serine-rich (11.6% of total amino acids) protein, were examined by two-dimensional gel electrophoresis. The levels of heat shock proteins increased, while those of protein elongation factors, 30S ribosomal protein, and some enzymes involved in amino acid biosynthesis decreased, after leptin overproduction. Most notably, the levels of enzymes involved in the biosynthesis of serine family amino acids significantly decreased. Based on this information, we designed a strategy to enhance the leptin productivity by manipulating the cysK gene, encoding cysteine synthase A. By coexpression of the cysK gene, we were able to increase the cell growth rate by approximately twofold. Also, the specific leptin productivity could be increased by fourfold. In addition, we found that cysK coexpression can improve the production of another serine-rich protein, interleukin-12 beta chain, suggesting that this strategy may be useful for the production of other serine-rich proteins as well. The approach taken in this study should be useful in designing a strategy for improving recombinant protein production.
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PMID:Engineering Escherichia coli for increased productivity of serine-rich proteins based on proteome profiling. 1453 24

cDNAs expressed preferentially in an Al-tolerant microorganism were isolated by subtraction hybridization with cDNAs of Al-sensitive Penicillium chrysogenum IFO4626 as driver cDNA and cDNAs of the Al-tolerant mutant derived from the wild cells by UV irradiation as tester cDNA. Northern blot analysis revealed that mRNA levels of six genes were increased significantly in the Al-tolerant mutant after exposure to Al stress when compared with the wild cells. Two genes accumulated in both the presence and absence of Al stress and four genes were induced by Al stress in the Al-tolerant mutant. cDNA fragments were amplified by rapid amplification of cDNA ends and sequenced to obtain full-length cDNAs of the six genes. Two genes were novel or predicted ones and the others showed significant homology to known genes, ADP/ATP translocase, enolase, cysteine synthase, and glucoamylase, which are induced by environmental stresses in prokaryotic and eukaryotic cells. These enzyme activities increased in the Al-tolerant mutant when compared to those in the wild cells, showing that not only the levels of gene expression but also the levels of enzyme activities increased in the Al-tolerant mutant.
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PMID:Cloning and characterization of preferentially expressed genes in an aluminum-tolerant mutant derived from Penicillium chrysogenum IFO4626. 1473 76

We have characterized the iron-sulfur (Fe-S) cluster formation in an anaerobic amitochondrial protozoan parasite, Entamoeba histolytica, in which Fe-S proteins play an important role in energy metabolism and electron transfer. A genomewide search showed that E. histolytica apparently possesses a simplified and non-redundant NIF (nitrogen fixation)-like system for the Fe-S cluster formation, composed of only a catalytic component, NifS, and a scaffold component, NifU. Amino acid alignment and phylogenetic analyses revealed that both amebic NifS and NifU (EhNifS and EhNifU, respectively) showed a close kinship to orthologs from epsilon-proteobacteria, suggesting that both of these genes were likely transferred by lateral gene transfer from an ancestor of epsilon-proteobacteria to E. histolytica. The EhNifS protein expressed in E. coli was present as a homodimer, showing cysteine desulfurase activity with a very basic optimum pH compared with NifS from other organisms. Eh-NifU protein existed as a tetramer and contained one stable [2Fe-2S]2+ cluster per monomer, revealed by spectroscopic and iron analyses. Fractionation of the whole parasite lysate by anion exchange chromatography revealed three major cysteine desulfurase activities, one of which corresponded to the EhNifS protein, verified by immunoblot analysis using the specific EhNifS antibody; the other two peaks corresponded to methionine gamma-lyase and cysteine synthase. Finally, ectopic expression of the EhNifS and EhNifU genes successfully complemented, under anaerobic but not aerobic conditions, the growth defect of an Escherichia coli strain, in which both the isc and suf operons were deleted, suggesting that EhNifS and EhNifU are necessary and sufficient for Fe-S clusters of non-nitrogenase Fe-S proteins to form under anaerobic conditions. This is the first demonstration of the presence and biological significance of the NIF-like system in eukaryotes.
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PMID:An intestinal parasitic protist, Entamoeba histolytica, possesses a non-redundant nitrogen fixation-like system for iron-sulfur cluster assembly under anaerobic conditions. 1475 65

The gram-positive human pathogen Staphylococcus aureus is often isolated with media containing potassium tellurite, to which it has a higher level of resistance than Escherichia coli. The S. aureus cysM gene was isolated in a screen for genes that would increase the level of tellurite resistance of E. coli DH5alpha. The protein encoded by S. aureus cysM is sequentially and functionally homologous to the O-acetylserine (thiol)-lyase B family of cysteine synthase proteins. An S. aureus cysM knockout mutant grows poorly in cysteine-limiting conditions, and analysis of the thiol content in cell extracts showed that the cysM mutant produced significantly less cysteine than wild-type S. aureus SH1000. S. aureus SH1000 cannot use sulfate, sulfite, or sulfonates as the source of sulfur in cysteine biosynthesis, which is explained by the absence of genes required for the uptake and reduction of these compounds in the S. aureus genome. S. aureus SH1000, however, can utilize thiosulfate, sulfide, or glutathione as the sole source of sulfur. Mutation of cysM caused increased sensitivity of S. aureus to tellurite, hydrogen peroxide, acid, and diamide and also significantly reduced the ability of S. aureus to recover from starvation in amino acid- or phosphate-limiting conditions, indicating a role for cysteine in the S. aureus stress response and survival mechanisms.
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PMID:Role of a cysteine synthase in Staphylococcus aureus. 1499 87

Cysteine synthase [O-acetyl-L-serine(thiol)lyase] catalyzes the final step for L-cysteine biosynthesis in plants. The tolerance of transgenic tobacco plants over-expressing cysteine synthase cDNA in cytosol (3F), chloroplasts (4F) and in both organelles (F1) was investigated towards heavy metals such as Cd, Se, Ni, Pb and Cu. The transgenic plants were significantly more tolerant than wild-type plants in agar medium containing Cd, Se and Ni. The F1 transgenic plants had a higher resistance than other transgenic lines towards these metals and could enhance accumulation of Cd in shoot. These results suggest that the transgenic plants over-expressing cysteine synthase both in cytosol and chloroplasts can be applicable to phyto-remediation of Cd from contaminated soils.
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PMID:Heavy metal tolerance of transgenic tobacco plants over-expressing cysteine synthase. 1500 Apr 84

Cadmium (Cd(2+)) is one of well-known toxic heavy metal ions. To gain a global understanding how Cd(2+) affects cells at the molecular level, we systematically studied the cellular response of the fission yeast Schizosaccharomyces pombe to Cd(2+) using our integrated proteomic strategy of amino acid-coded mass tagging (AACT) and liquid chromatography-tandem mass spectrometry. Our proteome-wide investigation unequivocally identified 1133 S. pombe proteins. Of which, the AACT-based quantitative analysis revealed 106 up-regulated and 55 down-regulated proteins on the Cd(2+) exposure. The most prevalent functional class in the up-regulated proteins, approximately 28% of our profile, was the proteins involved in protein biosynthesis, showing a time-dependent biphasic expression pattern characteristic with rapid initial induction and later repression. Most significantly, 27 proteins functionally classified as cell rescue and defense were up-regulated for oxygen and radical detoxification, heat shock response, and other stress response. Furthermore, the large precursor sequence coverage of our AACT approach allowed us to unequivocally identify and quantitate different isozymes for glutathione S-transferase, which have close similarity in their amino acid sequence. Our quantitative dataset also showed that 80% of the up-regulated proteins found in the S. pombe response were different from those in the Saccharomyces cerevisiae response. The function of some of the key identifications was validated through biochemical assays. It is very interesting that the induction of cysteine synthase expression was not observed in our study, although it has been proven as a critical enzyme to supply free cysteines for the enhancing synthesis of Cd(2+)-sequestering molecules such as glutathione and phytochelatins in plants and some yeasts. Our quantitative proteomic result instead suggested that, as an alternative mechanism for the detoxification of Cd(2+), S. pombe produced significantly higher level of inorganic sulfide to immobilize cellular Cd(2+) as a form of CdS nanocrystallites capped with glutathione and/or phytochelatins.
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PMID:Proteomic study for the cellular responses to Cd2+ in Schizosaccharomyces pombe through amino acid-coded mass tagging and liquid chromatography tandem mass spectrometry. 1500 6

Propionibacterium freudenreichii subsp. shermanii is known to prevent mutations caused by various agents such as N-methyl-N'-nitro-N-nitrosoguanidine, 9-aminoacridine, 4-nitro-quinoline-1-oxide and by UV radiation in both prokaryotic and eukaryotic cells. It was also shown to prevent or repair damage caused by H(2)O(2) or UV radiation in Salmonella typhimurium and Escherichia coli, a characteristic previously designated as reactivative effect. In order to characterise this effect at the molecular level, we have purified the active component from a P. freudenreichii cell-free extract using a combination of ammonium sulfate precipitation, anion-exchange and size-exclusion chromatography. The isolated 35 kDa protein was then identified using both N-terminal and internal peptide sequencing as a cysteine synthase. The latter was localised in the P. freudenreichii proteomic map. It is constitutively expressed but also clearly induced during adaptation to detergent and heat, but not acid, stresses. The biological meaning of cysteine synthase in the context of adaptation to oxidative and non-oxidative stresses is discussed.
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PMID:Anti-stress activity of Propionibacterium freudenreichii : identification of a reactivative protein. 1503 64


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