Interaction of product analogues with the active site of Rhodobacter sphaeroides dimethyl sulfoxide reductase

Abstract

We report a structural characterization using X-ray absorption spectroscopy of Rhodobacter sphaeroides dimethylsulfoxide (DMSO) reductase reduced with trimethylarsine, and show that this is structurally analogous to the physiologically relevant dimethylsulfide-reduced DMSO reductase. Our data unambiguously indicate that these species should be regarded as formal MoIV species, and indicate a classical coordination complex of trimethylarsine oxide, with no special structural distortions. The similarity of the trimethylarsine and dimethylsulfide complexes suggests in turn that the dimethylsulfide reduced enzyme possesses a classical coordination of DMSO with no special elongation of the S—O bond, as previously suggested.