title: Pulsed EPR studies of a bacterial sulfite-oxidizing enzyme with pH-invariant hyperfine interactions from exchangeable protons.
abstract: Variable-frequency pulsed electron paramagnetic resonance studies of the molybdenum(V) center of sulfite dehydrogenase (SDH) clearly show couplings from nearby exchangeable protons that are assigned to a Mo(V)OH(n) group. The hyperfine parameters for these exchangeable protons of SDH are the same at both low and high pH and similar to those for the high-pH forms of sulfite oxidases (SOs) from eukaryotes. The SDH proton parameters are distinctly different from the low-pH forms of chicken and human SO.
authors.affiliation: Department of Chemistry, University of Arizona, Tucson, Arizona 85721-0041, USA.
authors.forename: Arnold M
authors.initials: AM
authors.lastname: Raitsimring
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kappler
authors.forename: Changjian
authors.initials: C
authors.lastname: Feng
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Astashkin
authors.forename: John H
authors.initials: JH
authors.lastname: Enemark
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000201:enzymology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism; D001419:Bacteria / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D002645:Chickens; D017666:Deuterium Oxide; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011522:Protons; D050902:Sulfite Dehydrogenase / Q000737:chemistry* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D011522:Protons; D050902:Sulfite Dehydrogenase; D017666:Deuterium Oxide