Molecular cloning, characterization, and comparison of four bile salt hydrolase-related enzymes from lactobacillus plantarum gd2 of human origin

A bile salt hydrolase (bsh) enzyme deconjugate taurine and glycine-linked bile salts. Because of the strong implications between deconjugation of tauro- or gluco-conjugated salts and its positive or negative health consequences, the characterization of the bsh enzymes is important. bshs from different lactobacilli species, even strains, exhibit higher variation in sequence, kinetic properties, and substrate specificity. In the present study four bsh related genes from Lactobacillus plantarum GD2 strain were cloned and expressed in Escherichia coli BLR (DE3) strain. Amino acid residues of recombinant bshs were analyzed and their deconjugation abilities were tested with six human conjugated bile salts. Results indicated that the genetic distance among four related bsh genes in Lb. plantarum is far from each other and bsh2-4 enzymes share significant sequence homology specifically with penicillin V acylase (PVA) family members. Biochemical and the in silico analysis suggest that the bsh1 enzyme is a member of the bsh family while bsh2-4 enzymes are members of the PVA family.