The active site of arsenite oxidase from Alcaligenes faecalis

Thomas Conrads, Craig Hemann, Graham N. George*, Ingrid J. Pickering, Roger C. Prince, Russ Hille

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Arsenite oxidase, a member of the DMSO reductase family of molybdenum enzymes, has two molecules of guanosine dinucleotide molybdenum cofactor coordinating the molybdenum at the active site. X-ray absorption spectroscopy indicates that the Mo-S bonds shorten from 2.47 to 2.37 Å upon reduction with the physiological substrate. It also indicates the presence of an oxo ligand at 1.70 Å in both oxidized and reduced forms of the enzyme, together with a short, 1.83 Å, Mo-O bond in the oxidized form that is lost upon reduction. Resonance Raman spectroscopy indicates that the two pterin dithiolene moieties have different aromaticities, with one, the Q-pterin, having a more discrete dithiolate structure while the other, the P-pterin, has considerable π-delocalization. Our results indicate that the structure of arsenite oxidase is intermediate between that seen in other molybdenum enzymes, in which one ligand to the metal is provided by the polypeptide (serine, cysteine, or selenocysteine), and tungsten enzymes that lack a peptide ligand.

Original languageEnglish
Pages (from-to)11276-11277
Number of pages2
JournalJournal of the American Chemical Society
Issue number38
StatePublished - 25 Sep 2002
Externally publishedYes


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