Complex phenotypes of a mutant inactivated for CymR, the global regulator of cysteine metabolism in Bacillus subtilis.

We characterized various phenotypes of a mutant inactivated for CymR, the master regulator of cysteine metabolism in Bacillus subtilis. The deletion of cymR resulted in impaired growth in the presence of cystine and increased sensitivity to hydrogen peroxide-, disulfide-, paraquat- and tellurite-induced stresses. Estimation of metabolite pools suggested that these phenotypes could be the result of profound metabolic changes in the DeltacymR mutant including an increase of the intracellular cysteine pool and hydrogen sulfide formation, as well as a depletion of branched-chain amino acids.