Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium
The human bile acid pool composition is composed of both primary bile acids (cholic acid and chenodeoxycholic acid) and secondary bile acids (deoxycholic acid and lithocholic acid). Secondary bile acids are formed by the 7α-dehydroxylation of primary bile acids carried out by intestinal anaerobic ba...
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| Language: | English |
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Elsevier
2012-01-01
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| Series: | Journal of Lipid Research |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520408004 |
| _version_ | 1818598988565184512 |
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| author | Jason M. Ridlon Phillip B. Hylemon |
| author_facet | Jason M. Ridlon Phillip B. Hylemon |
| author_sort | Jason M. Ridlon |
| collection | DOAJ |
| description | The human bile acid pool composition is composed of both primary bile acids (cholic acid and chenodeoxycholic acid) and secondary bile acids (deoxycholic acid and lithocholic acid). Secondary bile acids are formed by the 7α-dehydroxylation of primary bile acids carried out by intestinal anaerobic bacteria. We have previously described a multistep biochemical pathway in Clostridium scindens that is responsible for bile acid 7α-dehydroxylation. We have identified a large (12 kb) bile acid inducible (bai) operon in this bacterium that encodes eight genes involved in bile acid 7α-dehydroxylation. However, the function of the baiF gene product in this operon has not been elucidated. In the current study, we cloned and expressed the baiF gene in E. coli and discovered it has bile acid CoA transferase activity. In addition, we discovered a second bai operon encoding three genes. The baiK gene in this operon was expressed in E. coli and found to encode a second bile acid CoA transferase. Both bile acid CoA transferases were determined to be members of the type III family by amino acid sequence comparisons. Both bile acid CoA transferases had broad substrate specificity, except the baiK gene product, which failed to use lithocholyl-CoA as a CoA donor. Primary bile acids are ligated to CoA via an ATP-dependent mechanism during the initial steps of 7α-dehydroxylation. The bile acid CoA transferases conserve the thioester bond energy, saving the cell ATP molecules during bile acid 7α-dehydroxylation. ATP-dependent CoA ligation is likely quickly supplanted by ATP-independent CoA transfer. |
| first_indexed | 2024-12-16T12:12:27Z |
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| id | doaj.art-ef62bd619ab144718e7fcb3de08c1574 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-16T12:12:27Z |
| publishDate | 2012-01-01 |
| publisher | Elsevier |
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| series | Journal of Lipid Research |
| spelling | doaj.art-ef62bd619ab144718e7fcb3de08c15742022-12-21T22:32:09ZengElsevierJournal of Lipid Research0022-22752012-01-015316676Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacteriumJason M. Ridlon0Phillip B. Hylemon1Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VATo whom correspondence should be addressed; To whom correspondence should be addressed; Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VAThe human bile acid pool composition is composed of both primary bile acids (cholic acid and chenodeoxycholic acid) and secondary bile acids (deoxycholic acid and lithocholic acid). Secondary bile acids are formed by the 7α-dehydroxylation of primary bile acids carried out by intestinal anaerobic bacteria. We have previously described a multistep biochemical pathway in Clostridium scindens that is responsible for bile acid 7α-dehydroxylation. We have identified a large (12 kb) bile acid inducible (bai) operon in this bacterium that encodes eight genes involved in bile acid 7α-dehydroxylation. However, the function of the baiF gene product in this operon has not been elucidated. In the current study, we cloned and expressed the baiF gene in E. coli and discovered it has bile acid CoA transferase activity. In addition, we discovered a second bai operon encoding three genes. The baiK gene in this operon was expressed in E. coli and found to encode a second bile acid CoA transferase. Both bile acid CoA transferases were determined to be members of the type III family by amino acid sequence comparisons. Both bile acid CoA transferases had broad substrate specificity, except the baiK gene product, which failed to use lithocholyl-CoA as a CoA donor. Primary bile acids are ligated to CoA via an ATP-dependent mechanism during the initial steps of 7α-dehydroxylation. The bile acid CoA transferases conserve the thioester bond energy, saving the cell ATP molecules during bile acid 7α-dehydroxylation. ATP-dependent CoA ligation is likely quickly supplanted by ATP-independent CoA transfer.http://www.sciencedirect.com/science/article/pii/S0022227520408004secondary bile acidsdeoxycholic acidHPLCprotein expression |
| spellingShingle | Jason M. Ridlon Phillip B. Hylemon Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium Journal of Lipid Research secondary bile acids deoxycholic acid HPLC protein expression |
| title | Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium |
| title_full | Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium |
| title_fullStr | Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium |
| title_full_unstemmed | Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium |
| title_short | Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium |
| title_sort | identification and characterization of two bile acid coenzyme a transferases from clostridium scindens a bile acid 7α dehydroxylating intestinal bacterium |
| topic | secondary bile acids deoxycholic acid HPLC protein expression |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520408004 |
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