State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P.R. China.
Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
J Phys Chem Lett. 2022 Apr 7;13(13):2871-2877. doi: 10.1021/acs.jpclett.2c00513. Epub 2022 Mar 24.
Electron transfer (ET) is a fundamental process in transition-metal-dependent metalloenzymes. In these enzymes, the spin-spin interactions within the same metal center and/or between different metal sites can play a pivotal role in the catalytic cycle and reactivity. This Perspective highlights that the exchange and/or superexchange interactions can intrinsically modulate the inner-sphere and long-range electron transfer, thus controlling the mechanism and activity of metalloenzymes. For mixed-valence diiron oxygenases, the spin-regulated inner-sphere ET can be dictated by exchange interactions, leading to efficient O-O bond activations. Likewise, the spin-regulated inner-sphere ET can be enhanced by both exchange and superexchange interactions in [Fe4S4]-dependent SAM enzymes, which enable the efficient cleavage of the S─C(γ) or S─C5' bond of SAM. In addition to inner-sphere ET, superexchange interactions may modulate the long-range ET between metalloenzymes. We anticipate that the exchange and superexchange enhanced reactivity could be applicable in other important metalloenzymes, such as Photosystem II and nitrogenases.
电子转移（ET）是依赖于过渡金属的金属酶中的一个基本过程。在这些酶中，同一金属中心内和/或不同金属位点之间的自旋-自旋相互作用可以在催化循环和反应性中发挥关键作用。本观点强调，交换和/或超交换相互作用可以内在地调节内球和远程电子转移，从而控制金属酶的机制和活性。对于混合价态二铁氧还酶，自旋调节的内球 ET 可以由交换相互作用决定，从而导致有效的 O-O 键活化。同样，[Fe4S4] 依赖性 SAM 酶中的交换和超交换相互作用可以增强自旋调节的内球 ET，从而有效地切割 SAM 的 S─C(γ)或 S─C5'键。除了内球 ET 之外，超交换相互作用还可以调节金属酶之间的远程 ET。我们预计，交换和超交换增强的反应性可能适用于其他重要的金属酶，如光系统 II 和氮酶。
