Disease relevance of cysB

• The amino-terminal structure and the essential functional region of the cysB gene product of Escherichia coli K-12 were analyzed by the method of gene fusion [1].
• Purification of the cysB protein from Salmonella typhimurium [2].
• The cysB gene of Klebsiella aerogenes has been cloned, sequenced and shown to complement the cysteine auxotrophic phenotype of Escherichia coli cysB mutants [3].
• A gene cluster containing homologues of the genes cysB, cysJI and cysH was found in the genome of the sulphur-oxidizing purple bacterium Thiocapsa roseopersicina [4].

High impact information on cysB

• DNA sequences of the cysB regions of Salmonella typhimurium and Escherichia coli [5].
• 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 [5].
• Although O-acetyl-L-serine is believed to bind to cysB protein to form a complex that stimulates transcription of genes of the cysteine regulon, we were unable to demonstrate such an interaction using methods that would have detected binding with a Kd of less than 0.1 mM [2].
• Most genes required for cysteine biosynthesis in Salmonella typhimurium and Escherichia coli are positively regulated by cysB, which encodes a transcriptional activator belonging to the LysR family of regulatory proteins [6].
• Inducer stimulates CysB protein binding to sites involved in positive regulation, and inhibits binding to the negatively autoregulated cysB promoter [6].

Biological context of cysB

• Based on the differential gene expression, it was also discovered that sulfur metabolism (through cysB) affects biofilm formation (in the absence of ursolic acid) [7].
• The DNA sequence identity for the cysB coding region in the two species is 80.5% [5].
• The deviation of these sequences from the consensus sequence TTGACA may reflect the fact that cysK is subject to positive control and requires the cysB regulatory protein for expression [8].
• Further characterization of this plasmid showed that it contained cysB, the structural gene for the positive regulator for most cys operon genes [9].
• In vitro transcription runoff studies with DNA template from the S. typhimurium cysJIH promoter region showed synthesis of a product originating at the major in vivo start site, which was dependent on the presence of purified cysB protein and either O-acetyl-L-serine or N-acetyl-L-serine [10].

Associations of cysB with chemical compounds

• The second AR system required the addition of arginine during pH 2.5 acid challenge, the structural gene for arginine decarboxylase (adiA), and the regulator cysB, confirming earlier reports [11].
• Assays of transport systems and enzymes concerned with glucitol and alanine utilization showed that these activities were depressed in cysB mutants relative to isogenic wild-type strains, and cysteine or djenkolate present in the growth media partially restored these activities [12].
• Mutations in the cysB or ybiK genes led to severe growth inhibition when cells were given glutathione as the sole sulfur source [13].
• Operon fusions of the lacZ gene to two different genes of the cysteine regulon controlled by the cysB regulatory protein were isolated [14].

Other interactions of cysB

• The cbl (cysB-like) gene has been identified in Escherichia coli [15].
• The arginine decarboxylase system (including adi and its regulators cysB and adiY) was responsible for arginine-dependent acid resistance [16].

Analytical, diagnostic and therapeutic context of cysB

• Following random and site-directed mutagenesis of the cysB gene, 20 CysB variants were isolated [17].

References