QM/MM calculations reveal a bridging hydroxo group in a vanadium nitrogenase crystal structure.

Bardi Benediktsson,Ragnar Bjornsson,Albert Th Thorhallsson

doi:10.1039/c8cc03793k

Bardi Benediktsson, Ragnar Bjornsson + Show 1 more

Open Access

https://doi.org/10.1039/c8cc03793k

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Abstract

A new 1.2 Å crystal structure of vanadium nitrogenase, isolated under turnover conditions, recently revealed a light atom ligand (OH or NH) replacing the bridging S2B sulfide of the FeV cofactor. QM/MM calculations on the new structure now reveal the light-atom ligand to be a bridging hydroxo group, probably derived from water binding to the cofactor.

Highlights

A new 1.2 Å crystal structure of vanadium nitrogenase, isolated under turnover conditions, recently revealed a light atom ligand (OH or NH) replacing the bridging S2B sulfide of the FeV cofactor
quantum mechanics/molecular mechanics (QM/MM) calculations on the new structure reveal the light-atom ligand to be a bridging hydroxo group, probably derived from water binding to the cofactor
The chemistry of the nitrogenases differ, with V nitrogenase requiring more electrons and protons for N2 reduction and more H2 is produced per N2 reacted,[7] as compared to Mo nitrogenase

Summary

Introduction

A new 1.2 Å crystal structure of vanadium nitrogenase, isolated under turnover conditions, recently revealed a light atom ligand (OH or NH) replacing the bridging S2B sulfide of the FeV cofactor. The 1.2 Å crystal structure revealed the same unusual CO32À/NO3À ligand but the S2B bridging sulfide was missing and a lightatom ligand had replaced it (Fig. 1).

Results

Conclusion