Altering the regioselectivity of the subterminal fatty acid hydroxylase P450 BM-3 towards γ- and δ-positions

Abstract

Cytochrome P450 BM-3 monooxygenase from Bacillus megaterium (CYP102A1) catalyzes the subterminal hydroxylation of fatty acids with a chain length of 12–22 carbons. Wild-type P450 BM-3 oxidizes saturated fatty acids at subterminal positions producing a mixture of ω-1, ω-2 and ω-3 hydroxylated products. Using a rational site-directed mutagenesis approach, three new elements have been introduced into the substrate binding pocket of the monooxygenase, which greatly changed the product pattern of lauric acid hydroxylation. Particularly, substitutions at positions S72, V78 and I263 had an effect on the enzyme regioselectivity. The P450 BM-3 mutants V78A F87A I263G and S72Y V78A F87A were able to oxidize lauric acid not only at δ-position (14% and 16%, respectively), but also produced γ- and β-hydroxylated products. δ-Hydroxy lauric and γ-hydroxy lauric acid are important synthons for the production of the corresponding lactones.