Rieske non-heme iron oxygenase (RO) family, 2-Halobenzoate 1,2-dioxygenase (HBDO) subfamily, N-terminal Rieske domain of the oxygenase alpha subunit; ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis. HBDO catalyzes the double hydroxylation of 2-halobenzoates with concomitant release of halogenide and carbon dioxide, yielding catechol.