FIGURE 1.

The successive reactions catalyzed by HsaC and HsaD in the catabolism of cholesterol by M. tuberculosis and alternate substrates of HsaD. DSHA is referred to as 4,5–9,10-diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-diene-4-oic acid in the steroid literature. However, the carbon atoms are numbered here according to its IUPAC name, 2-hydroxy-5-methyl-8-(7a-methyl-1,5-dioxooctahydro-1H-inden-4-yl)-6-oxoocta-2,4-dienoic acid, to be consistent with the numbering in HOPDA and HOPODA. In this study, DSHA, HOPDA, and HOPODA were generated by ring cleavage of DHSA, 2,3-dihydroxybiphenyl, and DHDS, respectively.