Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, 92697-3900, USA.
Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA.
Angew Chem Int Ed Engl. 2018 Mar 19;57(13):3411-3414. doi: 10.1002/anie.201800189. Epub 2018 Mar 1.
Binding and activation of CO by nitrogenase is a topic of interest because CO is isoelectronic to N , the physiological substrate of this enzyme. The catalytic relevance of one- and multi-CO-bound states (the lo-CO and hi-CO states) of V-nitrogenase to C-C coupling and N reduction was examined. 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 N 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.
氮酶与 CO 的结合和激活是一个研究热点，因为 CO 与氮酶的生理底物 N 等电子。研究了 V 氮酶中单 CO 和多 CO 结合态（低 CO 和高 CO 态）对 C-C 偶联和 N 还原的催化相关性。酶学和光谱学研究表明，高 CO 态中的多个 CO 部分不能像它们那样结合，表明 C-C 偶联需要进一步激活和/或还原结合的 CO 实体。此外，这些研究揭示了 N 还原活性降低与低 CO 态中结合 CO 部分的比例增加之间的有趣相关性，这表明在低 CO 态中单 CO 桥联的 belt Fe 原子与催化活性相关。总的来说，这些结果为通过进一步探索 V 氮酶的低 CO 构象的应用来深入了解氮酶催化反应提供了有用的框架。
