Structural and Catalytic Characterization of a Fungal Baeyer-Villiger Monooxygenase

摘要: Baeyer-Villiger monooxygenases (BVMOs) are biocatalysts that convert ketones to esters. Due their high regio-, stereo- and enantioselectivity ability catalyse these reactions under mild conditions, they have gained interest as alternatives chemical catalysts. Despite widespread occurrence within the fungal kingdom, most of currently characterized BVMOs from bacterial origin. Here we report catalytic structural characterization BVMOAFL838 Aspergillus flavus. converts linear aryl with regioselectivity. Steady-state kinetics revealed show significant substrate inhibition phenylacetone, which was more pronounced at low pH, enzyme buffer concentrations. Para substitutions on phenyl group significantly improved affinity increased turnover frequencies. preferentially oxidize aliphatic when separated by least two carbons carbonyl group. The X-ray crystal structure, first a BVMO, determined 1.9 A typical overall fold seen in type I BVMOs. active site Arg Asp conserved, found “in” position. Similar phenylacetone monooxygenase (PAMO), residue insert relative cyclohexanone (CHMO) forms bulge site. Approximately half “variable” loop is folded into short α-helix covers part entry channel non-NADPH bound structure. This study adds current efforts rationalize scope through comparative investigation different