Spectroscopic Definition of the Cu_Z° Intermediate in Turnover of Nitrous Oxide Reductase and Molecular Insight into the Catalytic Mechanism.

ABSTRACT: Spectroscopic methods and density functional theory (DFT) calculations are used to determine the geometric and electronic structure of Cu_Z°, an intermediate form of the Cu₄S active site of nitrous oxide reductase (N₂OR) that is observed in single turnover of fully reduced N₂OR with N₂O. Electron paramagnetic resonance (EPR), absorption, and magnetic circular dichroism (MCD) spectroscopies show that Cu_Z° is a 1-hole (i.e., 3Cu^ICu^II) state with spin density delocalized evenly over Cu_I and Cu_IV. Resonance Raman spectroscopy shows two Cu-S vibrations at 425 and 413 cm^-1, the latter with a -3 cm^-1 O¹⁸ solvent isotope shift. DFT calculations correlated to

SUBMITTER: Johnston EM 

PROVIDER: S-EPMC5532879 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature