title: Implications for the mechanism of sulfite oxidizing enzymes from pulsed EPR spectroscopy and DFT calculations for "difficult" nuclei.
abstract: The catalytic mechanisms of sulfite oxidizing enzymes (SOEs) have been investigated by multi-frequency pulsed EPR measurements of "difficult" magnetic nuclei (35.37Cl, 33S, 17O) associated with the Mo(v) center. Extensive DFT calculations have been used to relate the experimental magnetic resonance parameters of these nuclei to specific active site structures. This combined spectroscopic and computational approach has provided new insights concerning the structure/function relationships of the active sites of SOEs, including: (i) the exchange of oxo ligands; (ii) the nature of the blocked forms; and (iii) the role of Cl- in low pH forms.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721-0041, USA. jenemark@u.arizona.edu
authors.forename: John H
authors.initials: JH
authors.lastname: Enemark
authors.forename: Arnold M
authors.initials: AM
authors.lastname: Raitsimring
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Astashkin
authors.forename: Eric L
authors.initials: EL
authors.lastname: Klein
mesh_terms: D020134:Catalytic Domain; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D050876:Sulfite Oxidase / Q000737:chemistry*; D013447:Sulfites / Q000378:metabolism*
chemical_list: D013447:Sulfites; D050876:Sulfite Oxidase