Involved in an anaerobic respiration pathway that converts the sulfonate taurine (2-aminoethanesulfonate) to ammonia, acetate and sulfide. Catalyzes activation of the isethionate sulfite-lyase IslA under anaerobic conditions by generation of an organic free radical on a glycine residue, via a homolytic cleavage of S-adenosyl-L-methionine (SAM). glycyl-[protein] + reduced [flavodoxin] + S-adenosyl-L-methionine = 5'-deoxyadenosine + glycin-2-yl radical-[protein] + H(+) + L-methionine + semiquinone [flavodoxin] Binds 3 [4Fe-4S] clusters. One cluster is coordinated with 3 cysteines and an exchangeable S-adenosyl-L-methionine. Organosulfur degradation; alkanesulfonate degradation. Monomer. Highly up-regulated in the presence of taurine or isethionate. Taurine is an abundant dietary and host-derived molecule whose metabolism to hydrogen sulfide (H2S) by members of the human gut microbiota has many prominent connections to host health and disease. The human gut bacterium and opportunistic pathogen Bilophila wadsworthia produces H2S when respiring sulfite (HSO3-) released from organosulfonate substrates such as taurine and isethionate. Belongs to the organic radical-activating enzymes family.