Molecular cloning of the cys genes (cysC, cysD, cysH, cysI, cysJ, and cysG) responsible for cysteine biosynthesis in Escherichia coli K-12.

The cysCDHIJ gene region at 59 min and the cysG gene at 74 min on the chromosome of Escherichia coli K-12 were cloned. The ability of these cloned genes to complement mutants was analyzed and their restriction maps were determined. The following results were obtained. First, the cysCDHIJ regulon could be separated into cysCD and cysHIJ regions. Second, the cysG gene was quite different from the cysI and cysJ genes.