SseA, a 3-mercaptopyruvate sulfurtransferase from escherichia coli : crystallization and preliminary crystallographic data

SseA, the translation product of the Escherichia coli sseA gene, is a 31 kDa protein endowed with 3-mercaptopyruvate:cyanide sulfurtransferase activity in vitro. As such, SseA is the prototype of a sulfurtransferase subfamily distinguished from the better known rhodanese sulfurtransferases, which display thiosulfate:cyanide sulfurtransferase activity. The physiological role of the two homologous enzyme families, whose catalytic activity is centred on a reactive invariant cysteine, is a matter of debate. In this framework, the forthcoming crystal structure analysis of SseA will be based on the tetragonal crystal form (space group P4(1) or P4(3)) reported here, with unit-cell parameters a = b = 150.2, c = 37.9 Angstrom. The in vivo role and substrate specificity of sulfurtransferase enzymes has been greatly debated. SseA, a 3-mecaptopyruvate: cyanide sulfurtransferase from E. coli, has been crystallized in a tetragonal crystal form suitable for X-ray crystallographic investigations.