1jip
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P450eryF(A245S)/ketoconazole
OverviewOverview
The 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.
About this StructureAbout this Structure
1JIP is a Single protein structure of sequence from Saccharopolyspora erythraea with HEM and KTN as ligands. Full crystallographic information is available from OCA.
ReferenceReference
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
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