sulfate-reducing bacteria

Proceedings of the National Academy of Sciences

Significance This paper describes a pathway for anaerobic bacterial metabolism of taurine (2-aminoethanesulfonate), an abundant substrate in the human intestinal microbiota, by the intestinal bacterium and opportunistic pathogen, Bilophila wadsworthia . This metabolism converts taurine to the toxic metabolite hydrogen sulfide (H 2 S), an activity associated with inflammatory bowel disease and colorectal cancer. A critical enzyme in this pathway is isethionate sulfite-lyase, a member of the glycyl radical enzyme family. This enzyme catalyzes a novel, radical-based C-S bond-cleavage reaction to convert isethionate (2-hydroxyethanesulfonate) to sulfite and acetaldehyde. This discovery improves our understanding of H 2 S production in the human body and may also offer new approaches for controlling intestinal H 2 S production and B. wadsworthia infections.

A glycyl radical enzyme enables hydrogen sulfide production by the human intestinal bacteriumBilophila wadsworthia