Abstract:
Baeyer-Villiger monooxygenase from
Pseudomonas aeruginosa (
PaBVMO) selectively inserts an oxygen atom into the unconventional side of the carbonyl group of 10-carbonyl stearic acid to produce octyl sebacate, which can be used for synthesizing material monomers sebacic acid and 8-hydroxyoctanoic acid. To break through the dual bottleneck of low catalytic efficiency and significant substrate inhibition of
PaBVMO under high substrate concentrations in sebacic acid biosynthesis, this study proposed a semi-rational remodeling strategy for the enzyme's substrate channel. Through the analysis of enzyme-substrate binding free energy and substrate force, the key gating loop structure of the substrate channel was resolved. Based on this strategy, the optimal mutant
PaBVMO
G398A was obtained. It exhibited a catalytic turnover number (TON) of 3.45×10
4, which was 5.3 times higher than that of the parent, and 0.7 times higher than that of the parental enzyme. Meanwhile, the inactivation half-life was prolonged from 1.87 h to 6.14 h, and the stability is significantly enhanced. Gaussian-accelerated molecular dynamics (GaMD) simulations further revealed the synergistic mechanism of G398A mutation inducing the rearrangement of the active pocket of
PaBVMO
G398A. This rearrangement effectively alleviated substrate inhibition by 10-carbonyl stearic acid, enhanced affinity for FAD and improved.