SUBSTRATE SCOPE OF A RHIZOBIAL BAEYER-VILLIGER MONOOXYGENASE EXPRESSED IN Escherichia coli

CECCOLI, ROMINA D.; BIANCHI DARIO A; RIAL, DANIELA V.

San Miguel de Tucuman

Congreso; XII Congreso Argentino de Microbilogía General; 2017

Type I Baeyer-Villiger monooxygenases (BVMOs) are flavoenzymes that depend on FAD and require NADPH as electron donor to catalyze the monooxygenation of a carbonyl substrate in the presence of molecular oxygen. These enzymes oxidize cyclic or linear ketones to produce lactones or esters which are valuable precursors for the synthesis of biologically active compounds and natural products. Due to their strict dependence on NADPH for activity, biotransformations in whole-cell systems represent a valuable experimental strategy for synthetic applications. Our group is interested in expanding the number of biocatalysts for Baeyer-Villiger oxidations. We have identified several putative genes coding for typical type I BVMOs in the genome of Bradyrhizobium diazoefficiens by sequence homology analysis using representative BVMOs as queries. In this study, we selected one of these genes, named bj02 that encodes a protein with the characteristic consensus sequences and dinucleotide-binding motifs of type I BVMOs. We performed a phylogenetic analysis with different recombinant BVMOs to predict the location of the new enzyme in the inferred phylogenetic tree. The gene of interest was cloned and expressed in Escherichia coli. Then, we assessed the substrate preferences of this novel BVMO by whole-cell biotransformations under growing conditions. Several ketones with different structures were tested as substrates. Most of them were converted to their corresponding esters or lactones suggesting potential applications in the future. Funded by ANPCyT, CONICET, UNR.