Enzymes
| UniProtKB help_outline | 1 proteins |
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- Name help_outline 7α-hydroxy-3-oxochol-4-en-24-oate Identifier CHEBI:87747 Charge -1 Formula C24H35O4 InChIKeyhelp_outline CFLVYJJIZHNITM-NLXMLWGDSA-M SMILEShelp_outline C1[C@@]2([C@]3(CC[C@]4([C@]([C@@]3([C@@H](CC2=CC(C1)=O)O)[H])(CC[C@@]4([C@@H](CCC(=O)[O-])C)[H])[H])C)[H])C 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 3-oxochola-4,6-dien-24-oate Identifier CHEBI:87748 Charge -1 Formula C24H33O3 InChIKeyhelp_outline CREVIXFSUWYGRJ-IHMUCKAYSA-M SMILEShelp_outline C1[C@@]2([C@]3(CC[C@]4([C@]([C@@]3(C=CC2=CC(C1)=O)[H])(CC[C@@]4([C@@H](CCC(=O)[O-])C)[H])[H])C)[H])C 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,048 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:47548 | RHEA:47549 | RHEA:47550 | RHEA:47551 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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| MetaCyc help_outline |
Publications
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Expression and characterization of a C24 bile acid 7 alpha-dehydratase from Eubacterium sp. strain VPI 12708 in Escherichia coli.
Dawson J.A., Mallonee D.H., Bjorkhem I., Hylemon P.B.
The intestinal bacterium Eubacterium sp. strain VPI 12708 has been shown to have a bile acid 7 alpha/7 beta-dehydroxylation pathway. A large bile acid inducible (bai) operon encoding at least 9 open reading frames has been cloned and sequenced from this bacterium. The baiE gene from this operon ha ... >> More
The intestinal bacterium Eubacterium sp. strain VPI 12708 has been shown to have a bile acid 7 alpha/7 beta-dehydroxylation pathway. A large bile acid inducible (bai) operon encoding at least 9 open reading frames has been cloned and sequenced from this bacterium. The baiE gene from this operon has been subcloned and expressed in E. coli and found to encode a bile acid 7 alpha-dehydratase (BA7 alpha D). The purified BA7 alpha D was shown to have a calculated subunit mass of 19 kD and a relative native molecular weight of 36,000. The Km and Vmax for 7 alpha, 12 alpha-dihydroxy-3-oxo-4-cholenoic acid was 0.16 mM and 0.48 nmol/min per mg protein, respectively. Of the substrates tested, the BA7 alpha D used only 7 alpha, 12 alpha-dihydroxy-3-oxo-4-cholenoic acid and 7 alpha-hydroxy-3-oxo-4-cholenoic acid as substrates. A molecular modeling program (SYBYL) was used to calculate the energy differences between the various intermediates in the 7 alpha-dehydroxylation pathway. A marked energy difference (-9.4 kcal/mol) was observed between 7 alpha, 12 alpha-dihydroxy-3-oxo-4-cholenoic acid and 12 alpha-hydroxy-3-oxo-4,6-choldienoic acid, possibly accounting for the apparent irreversibility of the bile acid 7 alpha-dehydratase reaction under our experimental conditions. No significant amino acid sequence homologies were found between BA7 alpha D and other proteins in the data base; however, BA7 alpha D does contain a lipocalin signature sequence, possibly indicating a bile acid binding domain. The bile acid 7 alpha-dehydratase appears to be a unique enzyme in the bacterial bile acid 7 alpha-dehydroxylation pathway. << Less
J. Lipid Res. 37:1258-1267(1996) [PubMed] [EuropePMC]
This publication is cited by 2 other entries.
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Structure and functional characterization of a bile acid 7alpha dehydratase BaiE in secondary bile acid synthesis.
Bhowmik S., Chiu H.P., Jones D.H., Chiu H.J., Miller M.D., Xu Q., Farr C.L., Ridlon J.M., Wells J.E., Elsliger M.A., Wilson I.A., Hylemon P.B., Lesley S.A.
Conversion of the primary bile acids cholic acid (CA) and chenodeoxycholic acid (CDCA) to the secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA) is performed by a few species of intestinal bacteria in the genus Clostridium through a multistep biochemical pathway that removes a ... >> More
Conversion of the primary bile acids cholic acid (CA) and chenodeoxycholic acid (CDCA) to the secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA) is performed by a few species of intestinal bacteria in the genus Clostridium through a multistep biochemical pathway that removes a 7α-hydroxyl group. The rate-determining enzyme in this pathway is bile acid 7α-dehydratase (baiE). In this study, crystal structures of apo-BaiE and its putative product-bound [3-oxo-Δ(4,6) -lithocholyl-Coenzyme A (CoA)] complex are reported. BaiE is a trimer with a twisted α + β barrel fold with similarity to the Nuclear Transport Factor 2 (NTF2) superfamily. Tyr30, Asp35, and His83 form a catalytic triad that is conserved across this family. Site-directed mutagenesis of BaiE from Clostridium scindens VPI 12708 confirm that these residues are essential for catalysis and also the importance of other conserved residues, Tyr54 and Arg146, which are involved in substrate binding and affect catalytic turnover. Steady-state kinetic studies reveal that the BaiE homologs are able to turn over 3-oxo-Δ(4) -bile acid and CoA-conjugated 3-oxo-Δ(4) -bile acid substrates with comparable efficiency questioning the role of CoA-conjugation in the bile acid metabolism pathway. << Less
Proteins 84:316-331(2016) [PubMed] [EuropePMC]
This publication is cited by 2 other entries.