Trapping an intermediate of dinitrogen (N2) reduction on nitrogenase.

ABSTRACT: Nitrogenase reduces dinitrogen (N2) by six electrons and six protons at an active-site metallocluster called FeMo cofactor, to yield two ammonia molecules. Insights into the mechanism of substrate reduction by nitrogenase have come from recent successes in trapping and characterizing intermediates generated during the reduction of protons as well as nitrogenous and alkyne substrates by MoFe proteins with amino acid substitutions. Here, we describe an intermediate generated at a high concentration during reduction of the natural nitrogenase substrate, N2, by wild-type MoFe protein, providing evidence that it contains N2 bound to the active-site FeMo cofactor. When MoFe protein was frozen at 77 K during steady-state turnover with N2, the S = 3/2 EPR signal (g = [4.3, 3.64, 2.00]) arising fro

SUBMITTER: Barney BM 

PROVIDER: S-EPMC2814451 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature