P450-BM3-Catalyzed Sulfoxidation versus Hydroxylation: A Common or Two Different Catalytically Active Species?

作者：Jian‐bo Wang, Qun Huang, Wei Peng, Peng Wu, Da Yu, Bo Chen, Binju Wang, Manfred T. Reetz · 发表于：Journal of the American Chemical Society · 年份：2020 · DOI：10.1021/jacs.9b13061 · 被引用次数：56 · 研究领域：Metal-Catalyzed Oxygenation Mechanisms、Pharmacogenetics and Drug Metabolism、Oxidative Organic Chemistry Reactions

High Resolution Image Download MS PowerPoint Slide While the mechanism of the P450-catalyzed oxidative hydroxylation of organic compounds has been studied in detail for many years, less is known about sulfoxidation. Depending upon the structure of the respective substrate, heme-Fe═O (Cpd I), heme–Fe(III)–OOH (Cpd 0), and heme–Fe(III)–H 2 O 2 (protonated Cpd 0) have been proposed as reactive intermediates. In the present study, we consider the transformation of isosteric substrates via sulfoxidation and oxidative hydroxylation, respectively, catalyzed by regio- and enantioselective mutants of P450-BM3 which were constructed by directed evolution. 1-Thiochromanone and 1-tetralone were used as the isosteric substrates because, unlike previous studies involving fully flexible compounds such as thia-fatty acids and fatty acids, respectively, these compounds are rigid and cannot occur in a multitude of different conformations and binding modes in the large P450-BM3 binding pocket. The experimental results comprising activity and regio- and enantioselectivity, flanked by molecular dynamics computations within a time scale of 300 ns and QM/MM calculations of transition-state energies, unequivocally show that heme-Fe═O (Cpd I) is the common catalytically active intermediate in both sulfoxidation and oxidative hydroxylation.