1jip
From Proteopedia
(New page: 200px<br /><applet load="1jip" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jip, resolution 2.Å" /> '''P450eryF(A245S)/ketoco...) |
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| - | [[Image:1jip.jpg|left|200px]]<br /><applet load="1jip" size=" | + | [[Image:1jip.jpg|left|200px]]<br /><applet load="1jip" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1jip, resolution 2.Å" /> | caption="1jip, resolution 2.Å" /> | ||
'''P450eryF(A245S)/ketoconazole'''<br /> | '''P450eryF(A245S)/ketoconazole'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The azole-based P450 inhibitor ketoconazole is used to treat fungal | + | 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 Structure== | ==About this Structure== | ||
| - | 1JIP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharopolyspora_erythraea Saccharopolyspora erythraea] with HEM and KTN as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1JIP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharopolyspora_erythraea Saccharopolyspora erythraea] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=KTN:'>KTN</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JIP OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Saccharopolyspora erythraea]] | [[Category: Saccharopolyspora erythraea]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Cupp-Vickery, J | + | [[Category: Cupp-Vickery, J R.]] |
[[Category: Garcia, C.]] | [[Category: Garcia, C.]] | ||
[[Category: Hofacre, A.]] | [[Category: Hofacre, A.]] | ||
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[[Category: p450eryf(a245s)]] | [[Category: p450eryf(a245s)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:23:05 2008'' |
Revision as of 11:23, 21 February 2008
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P450eryF(A245S)/ketoconazole
Overview
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 Structure
1JIP is a Single protein structure of sequence from Saccharopolyspora erythraea with and as ligands. Full crystallographic information is available from OCA.
Reference
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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