A highly conserved mycobacterial cholesterol catabolic pathway.

ABSTRACT: Degradation of the cholesterol side-chain in Mycobacterium tuberculosis is initiated by two cytochromes P450, CYP125A1 and CYP142A1, that sequentially oxidize C26 to the alcohol, aldehyde and acid metabolites. Here we report characterization of the homologous enzymes CYP125A3 and CYP142A2 from Mycobacterium smegmatis mc(2) 155. Heterologously expressed, purified CYP125A3 and CYP142A2 bound cholesterol, 4-cholesten-3-one, and antifungal azole drugs. CYP125A3 or CYP142A2 reconstituted with spinach ferredoxin and ferredoxin reductase efficiently hydroxylated 4-cholesten-3-one to the C-26 alcohol and subsequently to the acid. The X-ray structures of both substrate-free CYP125A3 and CYP142A2 and of cholest-4-en-3-one-bound CYP142A2 reveal significant differences in the substrate binding sites c

SUBMITTER: Garcia-Fernandez E 

PROVIDER: S-EPMC3706556 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature