title: Constitutive mutation of cysJIH operon in a cysB deletion strain of Salmonella typhimurium.
abstract: In a cysB deletion strain a new mutation, denoted cys-2332 was isolated, which causes the constitutive expression of the cysJIH operon. cys-2332 is closely linked to cysJIH and presumably is located in the initiator region of this operon, rendering its expression independent of the cysB gene product and the internal inducer O-acetyl-L-serine. The presence of sulfite reductase (encoded by cysI and cysJ) activity in a cysB- cys-2332 double mutant indicates that cysG, which is not linked to cysJIH but is required for the synthesis of the sulfite reductase co-factor siroheme, is not controlled by cysB.
mesh_terms: D002874:Chromosome Mapping; D003545:Cysteine / Q000235:genetics*; D003547:Cysteine Synthase / Q000378:metabolism; D009154:Mutation; D009876:Operon; D010088:Oxidoreductases / Q000378:metabolism; D010724:Phosphoadenosine Phosphosulfate; D012486:Salmonella typhimurium / Q000201:enzymology / Q000235:genetics*
chemical_list: D010724:Phosphoadenosine Phosphosulfate; D010088:Oxidoreductases; D003547:Cysteine Synthase; D003545:Cysteine