Amini Samira, Oppelt Kerstin, Blacque Olivier, Agrachev Mikhail, Jeschke Gunnar, Zelder Felix
Department of Chemistry, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
Institute of Molecular Physical Science, ETH Zurich Vladimir-Prelog-Weg 2 CH-8093 Zurich Switzerland.
Chem Sci. 2025 Jan 20;16(10):4290-4294. doi: 10.1039/d4sc08416k. eCollection 2025 Mar 5.
Cofactor F430 is a nickel-containing hydrocorphinato complex that plays important roles in the enzymatic formation and oxidation of methane. In methanotrophic bacteria, F430-dependent methyl-coenzyme M reductase (MCR) catalyses the endergonic conversion of the heterodisulfide adduct of coenzymes M and B with methane to methyl-coenzyme M and coenzyme B. In a radical mechanism, the Ni(i)-induced formation of a transient thiyl radical of coenzyme B from the heterodisulfide has been proposed. Herein, we introduce a new semi-artificial Ni-complex derived from vitamin B as functional model of F430. We demonstrate with electrochemical studies that the low valent Ni(i) complex cleaves the biomimetic model compound diphenyl disulfide into approx. 0.5 equivalents of thiophenol and a transient thiophenyl radical at a potential of -1.65 V Fc/Fc. Thiyl radicals are trapped in solution with phenylacetylene as thiophenyl-substituted olefins, but also lead to degradation of the Ni-complex.
辅因子F430是一种含镍的氢化卟啉配合物，在甲烷的酶促形成和氧化过程中发挥着重要作用。在甲烷营养型细菌中，依赖F430的甲基辅酶M还原酶（MCR）催化辅酶M和B的异二硫键加合物与甲烷的吸能转化，生成甲基辅酶M和辅酶B。在一个自由基机制中，有人提出Ni(i)诱导辅酶B的异二硫键形成一个瞬时硫自由基。在此，我们介绍一种源自维生素B的新型半人工镍配合物，作为F430的功能模型。我们通过电化学研究表明，低价态的Ni(i)配合物在-1.65 V（Fc/Fc）的电位下将仿生模型化合物二苯基二硫醚裂解为约0.5当量的苯硫酚和一个瞬时苯硫基自由基。硫自由基在溶液中被苯乙炔捕获，生成苯硫基取代的烯烃，但同时也会导致镍配合物的降解。
