Electronic Structure Description of the cis-MoOS Unit in Models for Molybdenum Hydroxylases

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dc.contributor.authorDoonan, C.
dc.contributor.authorRubie, N.
dc.contributor.authorPeariso, K.
dc.contributor.authorHarris, H.
dc.contributor.authorKnottenbelt, S.
dc.contributor.authorGeorge, G.
dc.contributor.authorYoung, C.
dc.contributor.authorKirk, M.
dc.date.issued2008
dc.descriptionCopyright © 2008 American Chemical Society
dc.description.abstractThe molybdenum hydroxylases catalyze the oxidation of numerous aromatic heterocycles and simple organics and, unlike other hydroxylases, utilize water as the source of oxygen incorporated into the product. The electronic structures of the cis-MoOS units in CoCp2[TpiPrMoVOS(OPh)] and TpiPrMoVIOS(OPh) (TpiPr = hydrotris(3-isopropylpyrazol-1-yl)borate), new models for molybdenum hydroxylases, have been studied in detail using S K-edge X-ray absorption spectroscopy, vibrational spectroscopy, and detailed bonding calculations. The results show a highly delocalized Mo=S pi* LUMO redox orbital that is formally Mo(dxy) with approximately 35% sulfido ligand character. Vibrational spectroscopy has been used to quantitate Mo-Ssulfido bond order changes in the cis-MoOS units as a function of redox state. Results support a redox active molecular orbital that has a profound influence on MoOS bonding through changes to the relative electro/nucleophilicity of the terminal sulfido ligand accompanying oxidation state changes. The bonding description for these model cis-MoOS systems supports enzyme mechanisms that are under orbital control and dominantly influenced by the unique electronic structure of the cis-MoOS site. The electronic structure of the oxidized enzyme site is postulated to play a role in polarizing a substrate carbon center for nucleophilic attack by metal activated water and acting as an electron sink in the two-electron oxidation of substrates.
dc.description.statementofresponsibilityChristian J. Doonan, Nick D. Rubie, Katrina Peariso, Hugh H. Harris, Sushilla Z. Knottenbelt, Graham N. George, Charles G. Young, and Martin L. Kirk
dc.identifier.citationJournal of the American Chemical Society, 2008; 130(1):55-65
dc.identifier.doi10.1021/ja068512m
dc.identifier.issn0002-7863
dc.identifier.issn1520-5126
dc.identifier.orcidHarris, H. [0000-0002-3472-8628]
dc.identifier.urihttp://hdl.handle.net/2440/57820
dc.language.isoen
dc.publisherAmer Chemical Soc
dc.source.urihttps://doi.org/10.1021/ja068512m
dc.subjectMolybdenum
dc.subjectMixed Function Oxygenases
dc.subjectMetalloproteins
dc.subjectSpectrum Analysis
dc.subjectBinding Sites
dc.subjectMolecular Conformation
dc.subjectElectrons
dc.subjectModels, Molecular
dc.titleElectronic Structure Description of the cis-MoOS Unit in Models for Molybdenum Hydroxylases
dc.typeJournal article
pubs.publication-statusPublished

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