Hexachlorobenzene Catabolism Involves a Nucleophilic Aromatic Substitution and Flavin-N5-Oxide Formation.

HcbA1 is a unique flavoenzyme that catalyzes the first step in the bacterial hexachlorobenzene catabolic pathway. Here we report in vitro reconstitution of the HcbA1-catalyzed reaction. Detailed mechanistic studies provide evidence for nucleophilic aromatic substitution and flavin-N5-oxide formation.