Fig. 1: Amidation and de-amidation reactions of bile acids are associated with bacterial bsh.
From: Bile salt hydrolase catalyses formation of amine-conjugated bile acids
a, Bile acid–CoA:amino acid N-acyltransferase activity with the substrate depicted as a general bile acid structure modified with CoA. b, Deconjugation reaction by bacterial BSH of host-derived GCA or TCA. c, The BSH amino acid N-acyltransferase activity characterized in this study, with the conjugated bile acids GCA and TCA as examples. This activity leads to the biosynthesis of BBAAs. a–c, R1–R3 represent potential sites of backbone hydroxylation; RG/T represents glycine and taurine. d, Correlation between presence or absence of the bsh gene with the ability of various bacterial taxa to produce BBAAs. e, RT-qPCR of B. longum NCTC 11818 supplemented with 200 μM each of CA and DCA. Expression of bsh was compared to vehicle using the 2−∆∆Ct method normalized to the reference gene ldhl, and significance was determined using a two-tailed t-test (P = 0.0026**). Bar plots designate the mean ± s.d., n = 5.
