Disease relevance of cysK

• A CuraBLASTN homology search showed that the ORF shared 59% nucleotide identity with the cysK of Bacillus subtilis [1].
• An E. coli auxotroph lacking cysteine synthase loci could be complemented with A. brasilense Sp7 cysK [2].
• Insertional disruption of the cysK gene did not produce a cysteine auxotroph, indicating that gene redundancy in the cysteine biosynthetic or other biosynthetic pathways exists in Azospirillum, as already described in other bacteria [2].
• Introduction of the B. stearothermophilus V cysK gene into a cysK strain of Salmonella typhimurium LT2 resulted in complementation of the mutation as well as transfer of tellurite resistance [3].
• The product of the cysK gene of Bacillus stearothermophilus V mediates potassium tellurite resistance in Escherichia coli [3].

High impact information on cysK

• A third mutant protein, CysB(W166R), was totally inactive at 10 mM MgCl2, but gave constitutive expression of the cysK and cysJIH promoters at 2 mM MgCl2 [4].
• Mutants inactivated for cysK or yrhB grew similarly to the wild-type strain in the presence of methionine [5].
• Using DNA microarrays we found that, in addition to cysH, almost all of the genes required for sulfate assimilation are constitutively expressed in cysK mutants [6].
• 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 [7].
• 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 [7].

Chemical compound and disease context of cysK

• Identification, cloning and characterization of cysK, the gene encoding O-acetylserine (thiol)-lyase from Azospirillum brasilense, which is involved in tellurite resistance [2].

Biological context of cysK

• The 3.0-kb HindIII-EcoRI fragment bearing cysK contained two additional ORFs encoding a putative transcriptional regulator and dUTPase [2].
• After hydrolysis of the purified protein, amino acid sequences of five peptides were obtained, which permitted the cloning and sequencing of the cysK gene [2].
• We show that a null mutation in the cysK gene encoding an O-acetylserine-(thiol)lyase, the enzyme that catalyzes the final step in cysteine biosynthesis, results in constitutive expression of the cysH operon [6].

Associations of cysK with chemical compounds

• Surprisingly, wild-type CysB was also constitutive for the cysK promoter at 2 mM mgCl2 but not at 10 mM MgCl2; it required inducer for cysJIH promoter activation at both concentrations [4].

References