What Is the Structure of the E₄ Intermediate in Nitrogenase?

ABSTRACT: Nitrogenase is the only enzyme that can cleave the strong triple bond in N₂. The active site contains a complicated MoFe₇S₉C cluster. It is believed that it needs to accept four protons and electrons, forming the E₄ state, before it can bind N₂. However, there is no consensus on the atomic structure of the E₄ state. Experimental studies indicate that it should contain two hydride ions bridging two pairs of Fe ions, and it has been suggested that both hydride ions as well as the two protons bind on the same face of the cluster. On the other hand, density functional theory (DFT) studies have indicated that it is energetically more favorable with either three hydride ions or with a triply protonated carbide ion, depending on th

SUBMITTER: Cao L 

PROVIDER: S-EPMC7343244 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature