Evidence for a multigene family involved in bile acid 7-dehydroxylation in Eubacterium sp. strain VPI 12708.
Eubacterium sp. strain VPI 12708 is a human intestinal isolate which has an inducible bile acid 7-dehydroxylation activity. At least two cholic acid-induced polypeptides, with molecular masses of 27,000 and 45,000 daltons, respectively, coelute with bile acid 7-dehydroxylation activity. The 45,000-dalton polypeptide appears to be encoded by a cholic acid-induced mRNA species of greater than 6 kilobases, which suggests that the gene coding for this polypeptide is part of a larger operon. A gene has been cloned which flanks the gene encoding the 45,000-dalton polypeptide, in the upstream (5') direction. This gene appears to encode a second 27,000-dalton polypeptide. The gene bears striking homology at both the nucleotide (80%) and deduced amino acid sequence (89%) levels with the gene which encodes the 27,000-dalton polypeptide that has been shown previously to be involved in the bile acid 7-dehydroxylation reaction sequence. The implications of this homology and the possible function(s) of the two homologous genes in bile acid 7-dehydroxylation are discussed. Evidence is presented which suggests that the two homologous genes involved in bile acid 7-dehydroxylation may be part of a larger multigene family in Eubacterium sp. strain VPI 12708.
White
W B
WB
Department of Microbiology and Immunology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0678.
Franklund
C V
CV
Coleman
J P
JP
Hylemon
P B
PB
D000595:Amino Acid Sequence; D001483:Base Sequence; D001647:Bile Acids and Salts / Q000378:metabolism*; D015139:Blotting, Southern; D004269:DNA, Bacterial / Q000235:genetics; D005051:Eubacterium / Q000235:genetics* / Q000378:metabolism; D005798:Genes, Bacterial; D006913:Hydroxysteroid Dehydrogenases; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family; D010088:Oxidoreductases; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013250:Steroid Hydroxylases / Q000235:genetics*; D014158:Transcription, Genetic
D001647:Bile Acids and Salts; D004269:DNA, Bacterial; D010088:Oxidoreductases; D006913:Hydroxysteroid Dehydrogenases; C025376:7 alpha-hydroxysteroid dehydrogenase; D013250:Steroid Hydroxylases