Laboratory of Chemical Biology and State Key Laboratory of Natural Medicines, China Pharmaceutical University, 639 Longmian Avenue, Nanjing, Jiangsu Province, 211198, P. R. China.
National Center for Protein Science and Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 333 Haike Road, Shanghai, 201210, P. R. China.
Chembiochem. 2020 Aug 17;21(16):2297-2305. doi: 10.1002/cbic.202000071. Epub 2020 Apr 30.
Like a vast number of enzymes in nature, bacterial cytochrome P450 monooxygenases require an activated form of flavin as a cofactor for catalytic activity. Riboflavin is the precursor of FAD and FMN that serves as indispensable cofactor for flavoenzymes. In contrast to previous notions, herein we describe the identification of an electron-transfer process that is directly mediated by riboflavin for N-dealkylation by bacterial P450 monooxygenases. The electron relay from NADPH to riboflavin and then via activated oxygen to heme was proposed based on a combination of X-ray crystallography, molecular modeling and molecular dynamics simulation, site-directed mutagenesis and biochemical analysis of representative bacterial P450 monooxygenases. This study provides new insights into the electron transfer mechanism in bacterial P450 enzyme catalysis and likely in yeasts, fungi, plants and mammals.
与自然界中大量的酶一样，细菌细胞色素 P450 单加氧酶需要黄素的激活形式作为催化活性的辅助因子。核黄素是 FAD 和 FMN 的前体，它们是黄素酶不可缺少的辅助因子。与先前的观点不同，本文描述了一种电子传递过程的鉴定，该过程直接由核黄素介导，用于细菌 P450 单加氧酶的 N-脱烷基化。根据 X 射线晶体学、分子建模和分子动力学模拟、定点突变和代表性细菌 P450 单加氧酶的生化分析的组合，提出了从 NADPH 到核黄素，然后通过活性氧到血红素的电子传递。这项研究为细菌 P450 酶催化中的电子转移机制提供了新的见解，可能在酵母、真菌、植物和哺乳动物中也是如此。
