Dimethyl sulfoxide reductase active site structure

Dimethyl sulfoxide reductases from both R. sphaeroides and R. capsulatus have been the subject of several x-ray studies [112-115], In addition, extensive resonance Raman (RR) [119,125] and EXAFS studies [126,127] of both oxidized and reduced enzymes have been reported. Despite these studies, there is no single fully accepted picture for the active site of dmso reductase and its transformations during turnover. The following discussion outlines the structural features of the active site and the cofactor that are common to the various analyses as well as the current points of contention. 

Numerous oxo-molybdo-bis(dithiolene) and oxo-tungsto-bis(dithiolene) complexes have been synthesized and characterized as potential structural analogues of the active sites of the dimethyl sulfoxide reductase (DMSOR) and aldehyde oxidoreductase (AOR) families of mononuclear Mo and W enzymes [see Fig. 16 and Chapter 10 in this volume (50)]. The available IR and Raman data for the Mo and W complexes are summarized in Tables VII and VIII,... 

Garton, S. D., Hilton, J., Oku, H., Crouse, B. R., Rajagopalan, K. V., and Johnson, M. K., 1997, Active site structures and catalytic mechanism of Rhodobacter sphaeroides dimethyl sulfoxide reductase as revealed by resonance Raman spectroscopy, J. Am. Chem. Soc. 119 129061112916. 

Strucmres of representative Mo- and W-containing enzymes are presented in Figure 17.7. The structure of the DMSO reductase from Rhodobacter sphaeroides is given in Figure 17.7(c). In the DMSO reductase family, the metal centre is bound to two molecules of the cofactor. DMSO reductase itself catalyses the reduction of dimethyl sulfoxide to dimethylsulhde with incorporation of the oxygen atom of DMSO into water. The active site of the... 

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