title: Molybdenum site structure of MOSC family proteins.
abstract: Mo K-edge X-ray absorption spectroscopy has been used to probe as-isolated structures of the MOSC family proteins pmARC-1 and HMCS-CT. The Mo K-edge near-edge spectrum of HMCS-CT is shifted ~2.5 eV to lower energy compared to the pmARC-1 spectrum, which indicates that as-isolated HMCS-CT is in a more reduced state than pmARC-1. Extended X-ray absorption fine structure analysis indicates significant structural differences between pmARC-1 and HMCS-CT, with the former being a dioxo site and the latter possessing only a single terminal oxo ligand. The number of terminal oxo donors is consistent with pmARC-1 being in the Mo(VI) oxidation state and HMCS-CT in the Mo(IV) state. These structures are in accord with oxygen-atom-transfer reactivity for pmARC-1 and persulfide bond cleavage chemistry for HMCS-CT.
authors.affiliation: Department of Chemistry and Chemical Biology, The University of New Mexico , MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States.
authors.forename: Logan J
authors.initials: LJ
authors.lastname: Giles
authors.forename: Christian
authors.initials: C
authors.lastname: Ruppelt
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Ralf R
authors.initials: RR
authors.lastname: Mendel
authors.forename: Florian
authors.initials: F
authors.lastname: Bittner
authors.forename: Martin L
authors.initials: ML
authors.lastname: Kirk
mesh_terms: D006801:Humans; D008982:Molybdenum / Q000737:chemistry*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry*; D011487:Protein Conformation; D056928:X-Ray Absorption Spectroscopy
chemical_list: D008982:Molybdenum; D010088:Oxidoreductases