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Title: Molybdenum site of sulfite oxidase: A comparison of wild-type and the cysteine 207 to serine mutant using X-ray absorption spectroscopy

Journal Article · · Journal of the American Chemical Society
DOI:https://doi.org/10.1021/ja961218h· OSTI ID:380887
 [1]; ;  [2];  [3]
  1. Stanford Univ., CA (United States)
  2. Duke Univ., Durham, NC (United States)
  3. Exxon Research and Engineering Company, Annandale, NJ (United States)

X-ray absorption spectroscopy at the molybdenum and sulfur K-edges has been used to probe the active site of wild-type and cysteine 207 {yields} serine mutant human sulfite oxidases. We compare the active site structures in the Mo(VI) oxidation states: the wild-type enzyme possesses two Mo=O ligands at 1.71 A and three Mo-S ligands at 2.41 A. The mutant molybdenum site is a novel trioxo site with Mo=O bond lengths of 1.74 A, with two Mn-S ligands at 2.47 A. We conclude that cysteine 207 is a ligand of molybdenum in wild-type human sulfite oxidase, and that, in the mutant, the Mo is ligated to an extra oxo group rather than the hydroxyl of the substituent serine 207. 36 refs., 7 figs., 1 tab.

OSTI ID:
380887
Journal Information:
Journal of the American Chemical Society, Vol. 118, Issue 36; Other Information: PBD: 11 Sep 1996
Country of Publication:
United States
Language:
English