Structural characterization of human cholesterol 7α-hydroxylase
Hepatic conversion to bile acids is a major elimination route for cholesterol in mammals. CYP7A1 catalyzes the first and rate-limiting step in classic bile acid biosynthesis, converting cholesterol to 7α-hydroxycholesterol. To identify the structural determinants that govern the stereospecific hydro...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2014-09-01
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| Series: | Journal of Lipid Research |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520356686 |
| _version_ | 1819077130579869696 |
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| author | Wolfram Tempel Irina Grabovec Farrell MacKenzie Yaroslav V. Dichenko Sergey A. Usanov Andrei A. Gilep Hee-Won Park Natallia Strushkevich |
| author_facet | Wolfram Tempel Irina Grabovec Farrell MacKenzie Yaroslav V. Dichenko Sergey A. Usanov Andrei A. Gilep Hee-Won Park Natallia Strushkevich |
| author_sort | Wolfram Tempel |
| collection | DOAJ |
| description | Hepatic conversion to bile acids is a major elimination route for cholesterol in mammals. CYP7A1 catalyzes the first and rate-limiting step in classic bile acid biosynthesis, converting cholesterol to 7α-hydroxycholesterol. To identify the structural determinants that govern the stereospecific hydroxylation of cholesterol, we solved the crystal structure of CYP7A1 in the ligand-free state. The structure-based mutation T104L in the B′ helix, corresponding to the nonpolar residue of CYP7B1, was used to obtain crystals of complexes with cholest-4-en-3-one and with cholesterol oxidation product 7-ketocholesterol (7KCh). The structures reveal a motif of residues that promote cholest-4-en-3-one binding parallel to the heme, thus positioning the C7 atom for hydroxylation. Additional regions of the binding cavity (most distant from the access channel) are involved to accommodate the elongated conformation of the aliphatic side chain. Structural complex with 7KCh shows an active site rigidity and provides an explanation for its inhibitory effect. Based on our previously published data, we proposed a model of cholesterol abstraction from the membrane by CYP7A1 for metabolism. CYP7A1 structural data provide a molecular basis for understanding of the diversity of 7α-hydroxylases, on the one hand, and cholesterol-metabolizing enzymes adapted for their specific activity, on the other hand. |
| first_indexed | 2024-12-21T18:52:18Z |
| format | Article |
| id | doaj.art-d9f4e2677f5a4e7b996e9e894a97ed20 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-21T18:52:18Z |
| publishDate | 2014-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-d9f4e2677f5a4e7b996e9e894a97ed202022-12-21T18:53:42ZengElsevierJournal of Lipid Research0022-22752014-09-0155919251932Structural characterization of human cholesterol 7α-hydroxylaseWolfram Tempel0Irina Grabovec1Farrell MacKenzie2Yaroslav V. Dichenko3Sergey A. Usanov4Andrei A. Gilep5Hee-Won Park6Natallia Strushkevich7Structural Genomics Consortium, University of Toronto, Toronto, Ontario, M5G 1L7, CanadaInstitute of Bioorganic Chemistry NAS of Belarus, Minsk, 220141 BelarusStructural Genomics Consortium, University of Toronto, Toronto, Ontario, M5G 1L7, CanadaInstitute of Bioorganic Chemistry NAS of Belarus, Minsk, 220141 BelarusInstitute of Bioorganic Chemistry NAS of Belarus, Minsk, 220141 BelarusInstitute of Bioorganic Chemistry NAS of Belarus, Minsk, 220141 BelarusDepartment of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112To whom correspondence should be addressed; Institute of Bioorganic Chemistry NAS of Belarus, Minsk, 220141 BelarusHepatic conversion to bile acids is a major elimination route for cholesterol in mammals. CYP7A1 catalyzes the first and rate-limiting step in classic bile acid biosynthesis, converting cholesterol to 7α-hydroxycholesterol. To identify the structural determinants that govern the stereospecific hydroxylation of cholesterol, we solved the crystal structure of CYP7A1 in the ligand-free state. The structure-based mutation T104L in the B′ helix, corresponding to the nonpolar residue of CYP7B1, was used to obtain crystals of complexes with cholest-4-en-3-one and with cholesterol oxidation product 7-ketocholesterol (7KCh). The structures reveal a motif of residues that promote cholest-4-en-3-one binding parallel to the heme, thus positioning the C7 atom for hydroxylation. Additional regions of the binding cavity (most distant from the access channel) are involved to accommodate the elongated conformation of the aliphatic side chain. Structural complex with 7KCh shows an active site rigidity and provides an explanation for its inhibitory effect. Based on our previously published data, we proposed a model of cholesterol abstraction from the membrane by CYP7A1 for metabolism. CYP7A1 structural data provide a molecular basis for understanding of the diversity of 7α-hydroxylases, on the one hand, and cholesterol-metabolizing enzymes adapted for their specific activity, on the other hand.http://www.sciencedirect.com/science/article/pii/S0022227520356686cytochrome P450X-ray crystallography CYP7A1oxysterols |
| spellingShingle | Wolfram Tempel Irina Grabovec Farrell MacKenzie Yaroslav V. Dichenko Sergey A. Usanov Andrei A. Gilep Hee-Won Park Natallia Strushkevich Structural characterization of human cholesterol 7α-hydroxylase Journal of Lipid Research cytochrome P450 X-ray crystallography CYP7A1 oxysterols |
| title | Structural characterization of human cholesterol 7α-hydroxylase |
| title_full | Structural characterization of human cholesterol 7α-hydroxylase |
| title_fullStr | Structural characterization of human cholesterol 7α-hydroxylase |
| title_full_unstemmed | Structural characterization of human cholesterol 7α-hydroxylase |
| title_short | Structural characterization of human cholesterol 7α-hydroxylase |
| title_sort | structural characterization of human cholesterol 7α hydroxylase |
| topic | cytochrome P450 X-ray crystallography CYP7A1 oxysterols |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520356686 |
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