DNA sequences of the cysB regions of Salmonella typhimurium and Escherichia coli

Journal of Biological Chemistry (Impact Factor: 4.57). 06/1987; 262(13):5999-6005.
Source: PubMed


Nucleotide sequences of the cysB region of Salmonella typhimurium and Escherichia coli have been determined and compared. A total of 1759 nucleotides were sequenced in S. typhimurium and 1840 in E. coli. Both contain a 972-nucleotide open reading frame identified as the coding region for the cysB regulatory protein on the basis of sequence homology and by comparison of the deduced amino acid sequences with known physicochemical properties of this protein. The DNA sequence identity for the cysB coding region in the two species is 80.5%. The deduced amino acid sequences are 95% identical. The predicted cysB polypeptide molecular weights are 36,013 for S. typhimurium and 36,150 for E. coli. For both proteins a helix-turn-helix region similar to that found in other DNA-binding proteins is predicted from the deduced amino acid sequence. Sequences upstream to cysB contain open reading frames which represent the carboxyl-terminal end of the topA gene product, DNA topoisomerase I. A pattern of highly conserved nucleotide sequences in the 151 nucleotides immediately preceding the cysB initiator codon in both species suggests that this region may contain multiple signals for the regulation of cysB expression.

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    • "Interaction of CmbR with P metC in L. lactis are dimers (Schell, 1993). The CysB proteins of E. coli and S. enterica serovar Typhimurium are tetramers of identical 36 kDa subunits (Ostrowski et al., 1987). By analogy, it seems likely that CmbR acts as a multimer, possibly as a tetramer. "
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    ABSTRACT: The metC-cysK operon involved in sulphur metabolism in Lactococcus lactis is positively regulated by the LysR-type protein CmbR. Transcription from the metC promoter is activated when concentrations of methionine and cysteine in the growth medium are low. The metC promoter region contains two direct and three inverted repeats. Deletion analysis indicated that direct repeat 2 (DR2) is required for activation of the metC promoter by CmbR. Gel mobility shift assays confirmed that CmbR binds to a 407 bp DNA fragment containing the metC promoter. This binding was stimulated by O-acetyl-L-serine. Competition experiments with deletion variants of the metC promoter showed that CmbR binding only occurred with fragments containing an intact DR2, confirming that DR2 is the CmbR binding site within the metC promoter.
    Microbiology 03/2005; 151(Pt 2):439-46. DOI:10.1099/mic.0.27411-0 · 2.56 Impact Factor
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    • "Plasmids pRS415 lacZYA + promoterless vector used for construction of lacZ operon fusions , Amp R Simons et al . ( 1987 ) pMS421 Low - copy - number cloning vector , Spc R Grana et al . ( 1988 ) pQE70 Expression vector , Amp R Qiagen pREP4 Low - copy plasmid , carries lacI gene , Kan R Qiagen pJOH1 pBR322 carrying WT cysB , Amp R Ostrowski et al . ( 1987 ) pHV3002 pMS421 carrying WT hslJ on 3 ? 7 kb DNA fragment from l265 Lilic et al . ( 2003 )"
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    ABSTRACT: The LysR-type transcriptional regulator (LTTR) CysB is a transcription factor in Escherichia coli cells, where as a homotetramer it binds the target promoter regions and activates the genes involved in sulphur utilization and sulphonate-sulphur metabolism, while negatively autoregulating its own transcription. The hslJ gene was found to be negatively regulated by CysB and directly correlated with novobiocin resistance of the bacterium. cysB mutants showed upregulation of the hslJ : : lacZ gene fusion and exhibited increased novobiocin resistance. In this study the hslJ transcription start point and the corresponding putative sigma(70) promoter were determined. The hslJ promoter region was defined by employing different hslJ-lacZ operon fusions, and transcription of the hslJ gene was shown to be subject to both repression imposed by the CysB regulator and direct or indirect autogenous negative control. These two regulations compete to some extent but they are not mutually exclusive. CysB acts as a direct repressor of hslJ transcription and binds the hslJ promoter region that carries the putative CysB repressor site. This CysB binding, apparently responsible for repression, is enhanced in the presence of the ligand N-acetylserine (NAS), hitherto considered to be a positive cofactor in CysB-mediated gene regulations. Interallelic complementation of characterized CysB mutants I33N and S277Ter partially restored the repression of hslJ transcription and the consequent novobiocin sensitivity, but did not complement the cysteine auxotrophy.
    Microbiology 01/2004; 149(Pt 12):3449-59. DOI:10.1099/mic.0.26609-0 · 2.56 Impact Factor
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    ABSTRACT: anslation assays. Theopenreading frame encoded aprotein ofeither 33or36 kilodaltons whosesequence showssimilarity toNodDregulatory proteins. Thebacterium Rhizobium meliloti formsnitrogen-fixing nodules oncertain membersofthegenera Medicago, Trig- onella, andMelilotus. Thebacteria invade thehostplant through roothairs, stimulate cortical cells todivide, and occupy nodule cells, wheretheplants andbacteria establish ametabolic symbiosis (28). Thisprocess requires bacterial nodulation (nod) genes, including nodA,nodB,andnodC, which arerequired forearly events inthis sequence, andalso
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