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Reversible Dissociation Of Thiolate Ligands From Molybdenum In An Enzyme Of The Dimethyl Sulfoxide Reductase Family, Robert C. Bray, Benjamin Adams, Andrew T. Smith, Brian Bennett, Susan Bailey
Reversible Dissociation Of Thiolate Ligands From Molybdenum In An Enzyme Of The Dimethyl Sulfoxide Reductase Family, Robert C. Bray, Benjamin Adams, Andrew T. Smith, Brian Bennett, Susan Bailey
Physics Faculty Research and Publications
Much is unknown concerning the role of thiolate ligands of molybdenum in molybdopterin enzymes. It has been suggested that thiolate dissociation from molybdenum is part of the catalytic mechanism of bis-molybdopterin enzymes of the dimethyl sulfoxide reductase (DMSOR) family. For DMSOR from Rhodobacter capsulatus, thiolate dissociation has therefore been investigated crystallographically, by UV/visible spectroscopy, and by enzyme assays. When crystallized from sodium citrate, all four thiolates of DMSOR are within bonding distance of Mo, but after extended exposure to Na+-Hepes, a pair of thiolates dissociates, a mixture of structures being indicated after shorter exposures to this buffer. …
Dimethylsulfoxide Reductase: An Enzyme Capable Of Catalysis With Either Molybdenum Or Tungsten At The Active Site, Lisa J. Stewart, Susan Bailey, Brian Bennett, John M. Charnock, C. David Garner, Alan S. Mcalpine
Dimethylsulfoxide Reductase: An Enzyme Capable Of Catalysis With Either Molybdenum Or Tungsten At The Active Site, Lisa J. Stewart, Susan Bailey, Brian Bennett, John M. Charnock, C. David Garner, Alan S. Mcalpine
Physics Faculty Research and Publications
DMSO reductase (DMSOR) from Rhodobacter capsulatus, well-characterised as a molybdoenzyme, will bind tungsten. Protein crystallography has shown that tungsten in W-DMSOR is ligated by the dithiolene group of the two pyranopterins, the oxygen atom of Ser147 plus another oxygen atom, and is located in a very similar site to that of molybdenum in Mo-DMSOR. These conclusions are consistent with W LIII-edge X-ray absorption, EPR and UV/visible spectroscopic data. W-DMSOR is significantly more active than Mo-DMSOR in catalysing the reduction of DMSO but, in contrast to the latter, shows no significant ability to catalyse the oxidation of DMS.