Comparative assessment of the composition and charge state of nitrogenase FeMo-cofactor.

ABSTRACT: A significant limitation in our understanding of the molecular mechanism of biological nitrogen fixation is the uncertain composition of the FeMo-cofactor (FeMo-co) of nitrogenase. In this study we present a systematic, density functional theory-based evaluation of spin-coupling schemes, iron oxidation states, ligand protonation states, and interstitial ligand composition using a wide range of experimental criteria. The employed functionals and basis sets were validated with molecular orbital information from X-ray absorption spectroscopic data of relevant iron-sulfur clusters. Independently from the employed level of theory, the electronic structure with the greatest number of antiferromagnetic interactions corresponds to the lowest energy state for a given charge and oxidation state dist

SUBMITTER: Harris TV 

PROVIDER: S-EPMC3105220 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature