Evaluation of the Catalytic Relevance of the CO-bound States of V-Nitrogenase

Angewandte Chemie - International Edition

5 years ago

Evaluation of the Catalytic Relevance of the CO-bound States of V-Nitrogenase

Caleb Hiller, David Britt, Yilin Hu, Jarett Wilcoxen, Chi Chung Lee

Binding and activation of CO by nitrogenase is a topic of interest because CO is isoelectronic to N2, the physiological substrate of this enzyme. Here we examine the catalytic relevance of one- and multi-CO-bound states (i.e., the lo- and hi-CO states) of V-nitrogenase to C-C coupling and N2 reduction. Enzymatic and spectroscopic studies demonstrate that the multiple CO moieties in the hi-CO state cannot be coupled as they are, suggesting that C-C coupling requires further activation and/or reduction of the bound CO entity. Moreover, these studies reveal an interesting correlation between decreased activity of N2 reduction and increased population of the lo-CO state, pointing to the catalytic relevance of the 'belt Fe' atoms that are bridged by the single CO moiety in the lo-CO state. Together, these results provide a useful framework for gaining insights into the nitrogenase-catalyzed reaction via further exploration of the utility of the lo-CO conformation of V-nitrogenase.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/anie.201800189