Crystal structure of 3-hydroxybenzoate 6-hydroxylase uncovers lipid-assisted flavoprotein strategy for regioselective aromatic hydroxylation

Abstract

Background: 3-Hydroxybenzoate 6-hydroxylase (3HB6H) is a flavoprotein monooxygenase involved in the catabolism of aromatic compounds in soil microorganisms. Results: The enzyme crystal structure features natively bound phospholipids and a Tyr-His pair for substrate binding and catalysis. Conclusion: 3HB6H has a peculiar substrate-binding site that uses a bound lipid to help to discriminate between ortho- and para-hydroxylation. Significance: 3HB6H structure uncovers new flavoprotein strategy for regioselective aromatic hydroxylation. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.