Catalyzes the meta-cleavage of 3,4-dihydroxy-9,10-seconandrost-1,3,5(10)-triene-9,17-dione (3,4-DHSA) to produce 4,5-9,10-diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-diene-4-oic acid (4,9-DSHA). 3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione + O2 = (1E,2Z)-3-hydroxy-5,9,17-trioxo-4,5:9,10-disecoandrosta-1(10),2-dien-4-oate + H(+) Binds 1 Fe(2+) ion per subunit. Steroid metabolism; cholesterol metabolism. Homodimer, but may form a homooctamer. Induced by KstR. Cells lacking this gene completely fail to grow on cholesterol due the blockage of the catabolic pathway and develop a pink color consistent with the accumulation of toxic catechols. Mice intravenously infected with the mutant survive substantially longer than those infected with the wild-type. Cholesterol metabolism contributes to the survival of M.tuberculosis in the host by helping the bacterial multiplication during earlier stages of infection and to the dissemination of the pathogen in the host. Belongs to the extradiol ring-cleavage dioxygenase family.