Mechanism for the hydrolysis of a sulfur-sulfur bond based on the crystal structure of the thiosulfohydrolase SoxB.
Sauvé V., Roversi P., Leath KJ., Garman EF., Antrobus R., Lea SM., Berks BC.
SoxB is an essential component of the bacterial Sox sulfur oxidation pathway. SoxB contains a di-manganese(II) site and is proposed to catalyze the release of sulfate from a protein-bound cysteine S-thiosulfonate. A direct assay for SoxB activity is described. The structure of recombinant Thermus thermophilus SoxB was determined by x-ray crystallography to a resolution of 1.5 A. Structures were also determined for SoxB in complex with the substrate analogue thiosulfate and in complex with the product sulfate. A mechanistic model for SoxB is proposed based on these structures.