Improving the Oxygenation Performance of a Cyanobacterial Lipoxygenase by Oxygen Channel Engineering

Lipoxygenase catalyzes the dioxygenation of unsaturated fatty acids, which represents a sustainable pathway for producing bioderived fine chemicals. Herein, structure-guided engineering of the oxygen tunnel of a well-expressed 13-(S)-lipoxygenase from cyanobacteria was performed, resulting in a mutant A324G/S392G which showed 3 to 5-fold increases in activity toward a panel of unsaturated fatty acids. Molecular dynamics simulations elucidated the molecular basis for A324 and S392 as activity determining residues in the oxygen tunnel. The practicability of the mutant was demonstrated by the biosynthesis of hydroperoxy fatty acid 13S-HPOD with a high space time yield (STY) of 2.28 kg L-1 d(-1). Our results also demonstrate a good example for engineering biocatalysts that require gaseous molecules as cosubstrate.

Automated summary

In this study, structure-guided engineering was performed on a lipoxygenase enzyme, resulting in a mutant with increased activity towards unsaturated fatty acids. The mutant successfully synthesized a high-yield hydroperoxy fatty acid, demonstrating the practicability of engineered biocatalysts, especially those that require gaseous molecules as cosubstrates.