The Structure of Formaldehyde-Inhibited Xanthine Oxidase Determined by 35 GHz 2H ENDOR Spectroscopy
| Autor: | R. Adam Kinney, Bo Zhang, Rebecca L. McNaughton, Russ Hille, Muralidharan Shanmugam, Brian M. Hoffman |
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| Rok vydání: | 2010 |
| Předmět: |
Xanthine Oxidase
Protein Conformation Chemistry Electron Spin Resonance Spectroscopy Formaldehyde General Chemistry Photochemistry Biochemistry Article Catalysis chemistry.chemical_compound Colloid and Surface Chemistry Protein structure Catalytic Domain Organic chemistry Xanthine oxidase Spectroscopy |
| Zdroj: | Journal of the American Chemical Society. 132:14015-14017 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | The formaldehyde-inhibited Mo(V) state of xanthine oxidase (I) has been studied for four decades, yet it has not proven possible to distinguish unequivocally among the several structures proposed for this form. The uniquely large isotropic hyperfine coupling for (13)C from CH(2)O led to the intriguing suggestion of a direct Mo-C bond for the active site of I. This suggestion was supported by the recent crystal structures of glycol- and glycerol-inhibited forms of aldehyde oxidoreductase, a member of the xanthine oxidase family. (1)H and (2)H ENDOR spectra of I(C(1,2)H(2)O) in H(2)O/D(2)O buffer now have unambiguously revealed that the active-site structure of I contains a CH(2)O adduct of Mo(V) in the form of a four-membered ring with S and O linking the C to Mo and have ruled out a direct Mo-C bond. Density functional theory computations are consistent with this conclusion. We interpret the large (13)C coupling as resulting from a "transannular hyperfine interaction". |
| Databáze: | OpenAIRE |
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