1jin | pdb_00001jin
P450eryF/ketoconazole
Structural highlights
Function[CPXJ_SACEN] Catalyzes the NADPH-dependent conversion of 6-deoxyerythronolide B (6-DEB) to erythronolide B (EB) by the insertion of an oxygen at the 6S position of 6-DEB. Requires the participation of a ferredoxin and a ferredoxin reductase for the transfer of electrons from NADPH to the monooxygenase.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe azole-based P450 inhibitor ketoconazole is used to treat fungal infections and functions by blocking ergosterol biosynthesis in yeast. Ketoconazole binds to mammalian P450 enzymes and this can result in drug-drug interactions and lead to liver damage. To identify protein-drug interactions that contribute to binding specificity and affinity, we determined the crystal structure of ketoconazole complexed with P450eryF. In the P450eryF/ketoconazole structure, the azole moiety and nearby rings of ketoconzole are positioned in the active site similar to the substrate, 6-deoxyerythronolide B, with the azole nitrogen atom coordinated to the heme iron atom. The remainder of the ketoconazole molecule extends into the active-site pocket, which is occupied by water in the substrate complex. Binding of ketoconazole led to unexpected conformational changes in the I-helix. The I-helix cleft near the active site has collapsed with a helical pitch of 5.4 A compared to 6.6 A in the substrate complex. P450eryF/ketoconazole crystals soaked in 6-deoxyerythronolide B to exchange ligands exhibit a structure identical with that of the original P450eryF/substrate complex, with the I-helix cleft restored to a pitch of 6.6 A. These findings indicate that the I-helix region of P450eryF is flexible and can adopt multiple conformations. An improved understanding of the flexibility of the active-site region of cytochrome P450 enzymes is important to gain insight into determinants of ligand binding/specificity as well as to evaluate models for catalytic mechanism based on static crystal structures. Ketoconazole-induced conformational changes in the active site of cytochrome P450eryF.,Cupp-Vickery JR, Garcia C, Hofacre A, McGee-Estrada K J Mol Biol. 2001 Aug 3;311(1):101-10. PMID:11469860[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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