QM/MM Study of Partial Dissociation of S2B for the E₂ Intermediate of Nitrogenase.

ABSTRACT: Nitrogenase is the only enzyme that can cleave the triple bond in N₂, making nitrogen available for all lifeforms. Previous computational studies have given widely diverging results regarding the reaction mechanism of the enzyme. For example, some recent studies have suggested that one of the μ₂-bridging sulfide ligands (S2B) may dissociate from one of the Fe ions when protonated in the doubly reduced and protonated E₂ state, whereas other studies indicated that such half-dissociated states are unfavorable. We have examined how the relative energies of 26 structures of the E₂ state depend on details of combined quantum mechanical and molecular mechanical (QM/MM) calculations. We show that the selection of the broken-symmetry state, the basis set,

SUBMITTER: Jiang H 

PROVIDER: S-EPMC9667496 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature