Barchenko Maxim, Malcomson Thomas, de Visser Sam P, O'Malley Patrick J
Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, U.K.
Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
Inorg Chem. 2023 Oct 9;62(40):16401-16411. doi: 10.1021/acs.inorgchem.3c02072. Epub 2023 Sep 27.
[MFeS] cubanes have for some time been of interest for their ability to mimic the electronic and geometric structure of the active site of nitrogenase, the enzyme responsible for fixing N to NH. Nitrogenase naturally occurs in three forms, with the major difference being that the metal ion present in the cofactor active site is either molybdenum (FeMoco), vanadium (FeVco), or iron. The molybdenum and vanadium versions of these cofactors are more closely studied, owing to their larger abundance and rate of catalysis. In this study, we compare free energy profiles and electronic properties of the Mo/V cubanes at various stages during the reduction of NH to NH. Our findings highlight the differences in how the complexes facilitate the reaction, in particular, vanadium's comparatively weaker ability to interact with the Fe/S network and stabilize reducing electrons prior to N-N bond cleavage, which may have implications when considering the lower efficiency of the vanadium-dependent nitrogenase.
一段时间以来，[MFeS] 立方烷因其能够模拟固氮酶活性位点的电子和几何结构而备受关注，固氮酶是一种负责将N固定为NH的酶。固氮酶天然存在三种形式，主要区别在于辅因子活性位点中存在的金属离子要么是钼（FeMoco）、钒（FeVco），要么是铁。由于这些辅因子中钼和钒的版本丰度更高且催化速率更快，因此对它们的研究更为深入。在本研究中，我们比较了在将NH还原为NH的不同阶段，钼/钒立方烷的自由能分布和电子性质。我们的研究结果突出了这些配合物促进反应方式的差异，特别是钒与Fe/S网络相互作用以及在N-N键断裂之前稳定还原电子的能力相对较弱，这在考虑依赖钒的固氮酶效率较低时可能具有重要意义。
