FIG 4.

Confirmation of enzymatic functions of the putative baiA (DER43_01330) and baiB (DER43_01335) genes in the uncultured Clostridiales bacterium UBA11811. A diagram showing the enzymatic reactions of cholic acid by BaiA and BaiB proteins (A). LC-Q-TOF-MS ion chromatograms showing the production of cholyl-CoA (m/z 1158.4026 of [M+H]⁺, 6.544 min) by BaiB (B) and 3-oxo-cholyl-CoA (m/z 1156.3852 of [M+H]⁺, 6.428 min) by BaiB and BaiA (C) from cholic acid. Cell lysate of E. coli BL21(DE3) harboring the pET28a plasmid without a DNA insert was used as a negative control.