Unexpected Reactions of α,β‐Unsaturated Fatty Acids Provide Insight into the Mechanisms of CYP152 Peroxygenases
Yuanyuan Jiang, Wei Peng, Zhong Li, Cai You, Yue Zhao, Dandan Tang, Binju Wang, Shengying Li
Abstract
Abstract CYP152 peroxygenases catalyze decarboxylation and hydroxylation of fatty acids using H 2 O 2 as cofactor. To understand the molecular basis for the chemo‐ and regioselectivity of these unique P450 enzymes, we analyze the activities of three CYP152 peroxygenases (OleT JE , P450 SPα , P450 BSβ ) towards cis‐ and trans‐dodecenoic acids as substrate probes. The unexpected 6S‐hydroxylation of the trans‐isomer and 4R‐hydroxylation of the cis‐isomer by OleT JE , and molecular docking results suggest that the unprecedented selectivity is due to OleT JE ’s preference of C2−C3 cis‐configuration. In addition to the common epoxide products, undecanal is the unexpected major product of P450 SPα and P450 BSβ regardless of the cis/trans‐configuration of substrates. The combined H 2 18 O 2 tracing experiments, MD simulations, and QM/MM calculations unravel an unusual mechanism for Compound I‐mediated aldehyde formation in which the active site water derived from H 2 O 2 activation is involved in the generation of a four‐membered ring lactone intermediate. These findings provide new insights into the unusual mechanisms of CYP152 peroxygenases.