Involvement of the yciW gene in l-cysteine and l-methionine metabolism in Escherichia coli

We here analyzed a sulfur index of Escherichia coli using LC-MS/MS combined with thiol-specific derivatization by monobromobimane. The obtained sulfur index was then applied to evaluate the l-cysteine producer. E. coli cells overexpressing the yciW gene, a novel Cys regulon, accumulated l-homocysteine, suggesting that YciW is involved in l-methionine biosynthesis.