Genome mining reveals new bacterial type I Baeyer-Villiger monooxygenases with (bio)synthetic potential

Abstract

Baeyer-Villiger monooxygenases (BVMOs) are oxidorreductases that catalyze the oxidation of ketones in a very selective manner. By genome mining we detected seven putative type I BVMOs in Bradyrhizobium diazoefficiens USDA 110. As we established the phylogenetic relationships among them and with other type I BVMOs, we found out that they belong to different clades of the phylogenetic tree. Thus, we decided to clone and heterologously express five of them. Three of them, each one from a divergent phylogenetic group, were obtained as soluble proteins, allowing us to proceed with their biocatalytic assessment and enzymatic characterization. As to substrate scope and selectivity, we observed a complementary behavior among the three BVMOs. BVMO2 was the more versatile biocatalyst in whole-cell systems while BVMO4 and BVMO5 showed a narrow substrate profile with preference for linear ketones and particular regioselectivity for (±)-cis-bicyclo[3.2.0]hept-2-en-6-one.