Tunnel engineering for modulating the substrate preference in cytochrome P450BsβHI
Shuaiqi Meng, Ruipeng An, Zhongyu Li, Ulrich Schwaneberg, Yu Ji, Mehdi D. Davari, Fang Wang, Meng Wang, Meng Qin, Kaili Nie, Luo Liu
Abstract
Abstract An active site is normally located inside enzymes, hence substrates should go through a tunnel to access the active site. Tunnel engineering is a powerful strategy for refining the catalytic properties of enzymes. Here, P450 Bsβ HI (Q85H/V170I) derived from hydroxylase P450 Bsβ from Bacillus subtilis was chosen as the study model, which is reported as a potential decarboxylase. However, this enzyme showed low decarboxylase activity towards long-chain fatty acids. Here, a tunnel engineering campaign was performed for modulating the substrate preference and improving the decarboxylation activity of P450 Bsβ HI. The finally obtained BsβHI-F79A variant had a 15.2-fold improved conversion for palmitic acid; BsβHI-F173V variant had a 3.9-fold improved conversion for pentadecanoic acid. The study demonstrates how the substrate preference can be modulated by tunnel engineering strategy.