Abstract

Molybdenum is found in the active site of enzymes usually coordinated by one or two pyranopterin molecules. Here, we mimic an enzyme with a mononuclear molybdenum-bis pyranopterin center by incorporating molybdenum in rubredoxin. In the molybdenum-substituted rubredoxin, the metal ion is coordinated by four sulfurs from conserved cysteine residues of the apo-rubredoxin and two other exogenous ligands, oxygen and thiol, forming a Mo-(VI)-(S-Cys)(4)(O)(X) complex, where X represents -OH or -SR. The rubredoxin molybdenum center is stabilized in a Mo(VI) oxidation state, but can be reduced to Mo(IV) via Mo(V) by dithionite, being a suitable model for the spectroscopic properties of resting and reduced forms of molybdenum-bis pyranopterin-containing enzymes. Preliminary experiments indicate that the molybdenum site built in rubredoxin can promote oxo transfer reactions, as exemplified with the oxidation of arsenite to arsenate.

Original languageEnglish
Pages (from-to)821-829
Number of pages9
JournalJournal Of Biological Inorganic Chemistry
Volume20
Issue number5
DOIs
Publication statusPublished - Jul 2015

Keywords

  • Metal-substituted rubredoxin
  • Models of molybdenum-containing enzymes
  • Resonance Raman
  • F-19-NMR
  • DMSO reductase family
  • RESONANCE RAMAN CHARACTERIZATION
  • NICKEL-SUBSTITUTED RUBREDOXIN
  • PERIPLASMIC NITRATE REDUCTASE
  • NONHEME IRON PROTEIN
  • DESULFOVIBRIO-GIGAS
  • SULFITE OXIDASE
  • ARSENITE OXIDASE
  • CLOSTRIDIUM-PASTEURIANUM
  • ALCALIGENES-FAECALIS
  • OXIDATION-REDUCTION

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