Issue 5, 2023

Can the E1 state in nitrogenase tell if there is an activation process prior to catalysis?

Abstract

Model calculations have been performed for the singly reduced ground state of Mo-nitrogenase, usually termed E1. Contradictory conclusions have been reached in two recent experimental studies. In a study based on EPR, it was concluded that there is a bridging hydride in E1, while in an X-ray study it was concluded that there is no hydride in E1. Therefore, the EPR study implies that there is an oxidation of the cofactor going from E0 to E1, the X-ray study implies a reduction. DFT methods have here been used, which have previously been benchmarked on a set of redox enzymes that led to the conclusion that the accuracy is about 3 kcal mol−1 in all cases, even for redox transitions. The methodology should therefore be adequate for resolving the question of the hydride presence in E1. As a comparison, calculations are performed on both Mo- and V-nitrogenase with the same conclusion. The conclusion from the calculations has far reaching consequences for the mechanism of nitrogenase.

Graphical abstract: Can the E1 state in nitrogenase tell if there is an activation process prior to catalysis?

Supplementary files

Article information

Article type
Paper
Submitted
05 Dec 2022
Accepted
12 Jan 2023
First published
12 Jan 2023
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2023,25, 3702-3706

Can the E1 state in nitrogenase tell if there is an activation process prior to catalysis?

P. E. M. Siegbahn, Phys. Chem. Chem. Phys., 2023, 25, 3702 DOI: 10.1039/D2CP05642A

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