Open AccessAddressing Serine Lability in a Paramagnetic Dimethyl Sulfoxide Reductase Catalytic Intermediate
Author(s) -
Khadanand Kc,
Jing Yang,
Martin L. Kirk
Publication year - 2021
Publication title -
inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 233
eISSN - 1520-510X
pISSN - 0020-1669
DOI - 10.1021/acs.inorgchem.1c00940
Subject(s) - chemistry , electron paramagnetic resonance , catalytic cycle , lability , extended x ray absorption fine structure , crystallography , paramagnetism , dimethyl sulfoxide , catalysis , ligand (biochemistry) , molybdenum , electron transfer , photochemistry , oxidoreductase , absorption spectroscopy , inorganic chemistry , nuclear magnetic resonance , enzyme , organic chemistry , biochemistry , physics , receptor , quantum mechanics
Two new desoxo molybdenum(V) complexes have been synthesized and characterized as models for the paramagnetic high-g split intermediate observed in the catalytic cycle of dimethyl sulfoxide reductase (DMSOR). Extended X-ray absorption fine structure (EXAFS) and electron paramagnetic resonance (EPR) data are used to provide new insight into the geometric and electronic structures of high-g split and other EPR-active type II/III DMSOR family enzyme forms. The results support a 6-coordinate [(PDT) 2 Mo(OH)(O Ser )] - structure (PDT = pyranopterin dithiolene) for a high- g split with four S donors from two PDT ligands, a coordinated hydroxyl ligand, and a serinate O donor. This geometry orients the redox orbital toward the substrate access channel for the two-electron reduction of substrates.