The bile acid-inducible baiB gene from Eubacterium sp. strain VPI 12708 encodes a bile acid-coenzyme A ligase.
The baiB gene from Eubacterium sp. strain VPI 12708 was previously cloned, sequenced, and shown to be part of a large bile acid-inducible operon encoding polypeptides believed to be involved in bile acid 7 alpha-dehydroxylation. In the present study, the baiB gene was subcloned and expressed in Escherichia coli and shown to encode a bile acid-coenzyme A (CoA) ligase. This ligase required a C-24 bile acid with a free carboxyl group, ATP, Mg2+, and CoA for synthesis of the final bile acid-CoA conjugate. Product analysis by reverse-phase high-performance liquid chromatography revealed final reaction products that comigrated with cholyl-CoA and AMP. A putative bile acid-AMP intermediate was detected when CoA was omitted from the reaction mixture. The bile acid-CoA ligase has amino acid sequence similarity to several other polypeptides involved in the ATP-dependent linking of AMP or CoA to cyclic carboxylated compounds. The bile acid-CoA ligation is believed to be the initial step in the bile acid 7 alpha-dehydroxylation pathway in Eubacterium sp. strain VPI 12708.
Mallonee
D H
DH
Department of Microbiology and Immunology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0678.
Adams
J L
JL
Hylemon
P B
PB
D001483:Base Sequence; D001647:Bile Acids and Salts / Q000378:metabolism*; D003001:Cloning, Molecular; D003066:Coenzyme A Ligases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005051:Eubacterium / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment
D001647:Bile Acids and Salts; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D003066:Coenzyme A Ligases; C070656:bile acid-CoA ligase