Issue 2, 2017

Infrared spectroscopy of the nitrogenase MoFe protein under electrochemical control: potential-triggered CO binding

Abstract

We demonstrate electrochemical control of the nitrogenase MoFe protein, in the absence of Fe protein or ATP, using europium(III/II) polyaminocarboxylate complexes as electron transfer mediators. This allows the potential dependence of proton reduction and inhibitor (CO) binding to the active site FeMo-cofactor to be established. Reduction of protons to H2 is catalyzed by the wild type MoFe protein and β-98Tyr→His and β-99Phe→His variants of the MoFe protein at potentials more negative than −800 mV (vs. SHE), with greater electrocatalytic proton reduction rates observed for the variants compared to the wild type protein. Electrocatalytic proton reduction is strongly attenuated by carbon monoxide (CO), and the potential-dependence of CO binding to the FeMo-cofactor is determined by in situ infrared (IR) spectroelectrochemistry. The vibrational wavenumbers for CO coordinated to the FeMo-cofactor are consistent with earlier IR studies on the MoFe protein with Fe protein/ATP as reductant showing that electrochemically generated states of the protein are closely related to states generated with the native Fe protein as electron donor.

Graphical abstract: Infrared spectroscopy of the nitrogenase MoFe protein under electrochemical control: potential-triggered CO binding

Supplementary files

Article information

Article type
Edge Article
Submitted
28 Jun 2016
Accepted
26 Oct 2016
First published
27 Oct 2016
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2017,8, 1500-1505

Author version available

Infrared spectroscopy of the nitrogenase MoFe protein under electrochemical control: potential-triggered CO binding

P. Paengnakorn, P. A. Ash, S. Shaw, K. Danyal, T. Chen, D. R. Dean, L. C. Seefeldt and K. A. Vincent, Chem. Sci., 2017, 8, 1500 DOI: 10.1039/C6SC02860H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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