Photoinduced Reductive Elimination of H₂ from the Nitrogenase Dihydride (Janus) State Involves a FeMo-cofactor-H₂ Intermediate.

ABSTRACT: N₂ reduction by nitrogenase involves the accumulation of four reducing equivalents at the active site FeMo-cofactor to form a state with two [Fe-H-Fe] bridging hydrides (denoted E₄(4H), the Janus intermediate), and we recently demonstrated that the enzyme is activated to cleave the N≡N triple bond by the reductive elimination (re) of H₂ from this state. We are exploring a photochemical approach to obtaining atomic-level details of the re activation process. We have shown that, when E₄(4H) at cryogenic temperatures is subjected to 450 nm irradiation in an EPR cavity, it cleanly undergoes photoinduced re of H₂ to give a reactive doubly reduced intermediate, denoted E₄(2H)*, which corresponds to the intermediate that would form

SUBMITTER: Lukoyanov D 

PROVIDER: S-EPMC5444871 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature