Cytochrome P450 enzymes are considered the most versatile biological catalysts in nature. The highly diversified functionalities of this superfamily of hemeproteins are widely associated with steroid biosynthesis, drug metabolism, biosynthesis of natural products, and industrial oxidation reactions. A typical P450 catalytic cycle requires sequential transfer of two electrons from NAD(P)H to the heme-iron reactive center for O2 activation. For the most abundant bacterial Class I P450 systems, this important process is usually mediated by two redox partner proteins including an FAD-containing ferredoxin reductase (FdR) and a small iron-sulfur protein, ferredoxin (Fdx). However, it is often unclear which pair of Fdx and FdR among multiple redox partners are the optimal ones for a specific Class I P450 enzyme. To address this long-standing but underexplored question of both mechanistic and practical significance, herein, we constitute a reaction matrix network with 16 Fdxs, 8 FdRs and 6 P450s (against 7 substrates). By analyzing the reactivity profiles of 896 P450 reactions, together with phylogenetic analysis, redox potential measurements, structural simulation, and Fdx-P450 molecular docking, we provide new insights into the recognition and interactions between bacterial Class I P450 enzymes and redox partners. Based on our results and analysis, several empirical rules are proposed for further examinations: 1) the plastidic-type FdR and the Fe2S2 Fdx are more likely to provide high electron transfer efficiency for a bacterial Class I P450 enzyme; 2) the native redox partners are not necessarily the best choices for a P450 of interest; 3) it is not necessarily better to use the most efficient redox partner for a specific P450 reaction since the undesired over-oxidation could occur; and 4) redox partners could be utilized to generate more oxidative derivatives.

Mechanistic insights into interactions between bacterial class I P450 enzymes and redox partners

2019 Spring National Meeting

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