Modified active site coordination in a clinical mutant of sulfite oxidase.
The molybdenum site of the Arginine 160 --> Glutamine clinical mutant of the physiologically vital enzyme sulfite oxidase has been investigated by a combination of X-ray absorption spectroscopy and density functional theory calculations. We conclude that the mutant enzyme has a six-coordinate pseudo-octahedral active site with coordination of Glutamine Oepsilon to molybdenum. This contrasts with the wild-type enzyme which is five-coordinate with approximately square-based pyramidal geometry. This difference in the structure of the molybdenum site explains many of the properties of the mutant enzyme which have previously been reported.
Doonan
Christian J
CJ
Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Wilson
Heather L
HL
Rajagopalan
K V
KV
Garrett
Robert M
RM
Bennett
Brian
B
Prince
Roger C
RC
George
Graham N
GN
D000465:Algorithms; D001120:Arginine / Q000737:chemistry / Q000235:genetics; D001665:Binding Sites; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D005973:Glutamine / Q000031:analogs & derivatives / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008982:Molybdenum / Q000737:chemistry*; D009154:Mutation; D009942:Organometallic Compounds / Q000737:chemistry*; D011487:Protein Conformation; D013057:Spectrum Analysis; D050876:Sulfite Oxidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014965:X-Rays
D009942:Organometallic Compounds; D005973:Glutamine; D008982:Molybdenum; D001120:Arginine; D050876:Sulfite Oxidase