1jip: Difference between revisions
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{{STRUCTURE_1jip| PDB=1jip | SCENE= }} | |||
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'''P450eryF(A245S)/ketoconazole''' | '''P450eryF(A245S)/ketoconazole''' | ||
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[[Category: Hofacre, A.]] | [[Category: Hofacre, A.]] | ||
[[Category: McGee-Estrada, K.]] | [[Category: McGee-Estrada, K.]] | ||
[[Category: | [[Category: Azole drug]] | ||
[[Category: | [[Category: Cytochrome p450]] | ||
[[Category: | [[Category: Ketoconazole]] | ||
[[Category: | [[Category: P450eryf]] | ||
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Revision as of 21:16, 2 May 2008
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. 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 Page seeded by OCA on Fri May 2 21:16:17 2008