Active-site dynamics and large-scale domain motions of sulfite oxidase: a molecular dynamics study.
The physiologically vital enzyme sulfite oxidase employs rapid intramolecular electron transfer between a molybdenum ion in the C-terminal domain (the site of sulfite oxidation) and a heme moeity in the N-terminal domain to complete its catalytic cycle. Crystal structures of the enzyme show C- and N-terminal domain orientations that are not consistent with rapid intramolecular electron transfer. Domain motion has been postulated to explain this discrepancy. In the present work we employ molecular dynamics simulations to understand the large-scale domain motions of the enzyme. We observe motion of the N-terminal domain into an orientation similar to that postulated for rapid electron transfer. Our simulations also probe the dynamics of the active site and surrounding residues, adding a further level of structural and thermodynamic detail in understanding sulfite oxidase function.
Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada.
M Jake
MJ
Pushie
Graham N
GN
George
D055162:Biocatalysis; D020134:Catalytic Domain; D004579:Electron Transport; D056004:Molecular Dynamics Simulation; D008982:Molybdenum / Q000737:chemistry; D017434:Protein Structure, Tertiary; D050876:Sulfite Oxidase / Q000737:chemistry*
D008982:Molybdenum; D050876:Sulfite Oxidase