1eup
From Proteopedia
(New page: 200px<br /><applet load="1eup" size="450" color="white" frame="true" align="right" spinBox="true" caption="1eup, resolution 2.1Å" /> '''X-RAY CRYSTAL STRUCTU...) |
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| - | [[Image:1eup.gif|left|200px]]<br /><applet load="1eup" size=" | + | [[Image:1eup.gif|left|200px]]<br /><applet load="1eup" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1eup, resolution 2.1Å" /> | caption="1eup, resolution 2.1Å" /> | ||
'''X-RAY CRYSTAL STRUCTURE OF CYTOCHROME P450ERYF WITH ANDROSTENDIONE BOUND'''<br /> | '''X-RAY CRYSTAL STRUCTURE OF CYTOCHROME P450ERYF WITH ANDROSTENDIONE BOUND'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Several mammalian cytochrome P450 (P450) isoforms demonstrate homotropic | + | Several mammalian cytochrome P450 (P450) isoforms demonstrate homotropic cooperativity with a number of substrates, including steroids and polycyclic aromatic hydrocarbons. To identify structural factors contributing to steroid and polycyclic aromatic hydrocarbon binding to P450 enzymes and to determine the location of the allosteric site, we investigated interactions of the macrolide hydroxylase P450eryF from Saccharopolyspora erythraea with androstenedione and 9-aminophenanthrene. Spectroscopic binding assays indicate that P450eryF binds androstenedione with an affinity of 365 microM and a Hill coefficient of 1.31 +/- 0.6 and coordinates with 9-aminophenanthrene with an affinity of 91 microM and a Hill coefficient of 1.38 +/- 0.2. Crystals of complexes of androstenedione and 9-aminophenanthrene with P450eryF were grown and diffracted to 2.1 A and 2.35 A, respectively. Electron density maps indicate that for both complexes two ligand molecules are simultaneously present in the active site. The P450eryF/androstenedione model was refined to an r = 18.9%, and the two androstenedione molecules have similar conformations. The proximal androstenedione is positioned such that the alpha-face of carbon-6 is closest to the heme iron, and the second steroid molecule is positioned 5.5 A distal in the active site. The P450eryF/9-aminophenanthrene model was refined to an r = 19.7% with the proximal 9-aminophenanthrene coordinated with the heme iron through the 9-amino group and the second ligand positioned approximately 6 A distal in the active site. These results establish that homotropic cooperativity in ligand binding can result from binding of two substrate molecules within the active site pocket without major conformational changes in the protein. |
==About this Structure== | ==About this Structure== | ||
| - | 1EUP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ] with HEM and ASD as [http://en.wikipedia.org/wiki/ligands ligands]. This structure | + | 1EUP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=ASD:'>ASD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1EH0. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EUP OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Anderson, R.]] | [[Category: Anderson, R.]] | ||
| - | [[Category: Cupp-Vickery, J | + | [[Category: Cupp-Vickery, J R.]] |
[[Category: Hatziris, Z.]] | [[Category: Hatziris, Z.]] | ||
[[Category: ASD]] | [[Category: ASD]] | ||
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[[Category: steroid]] | [[Category: steroid]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:31:42 2008'' |
Revision as of 10:31, 21 February 2008
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X-RAY CRYSTAL STRUCTURE OF CYTOCHROME P450ERYF WITH ANDROSTENDIONE BOUND
Overview
Several mammalian cytochrome P450 (P450) isoforms demonstrate homotropic cooperativity with a number of substrates, including steroids and polycyclic aromatic hydrocarbons. To identify structural factors contributing to steroid and polycyclic aromatic hydrocarbon binding to P450 enzymes and to determine the location of the allosteric site, we investigated interactions of the macrolide hydroxylase P450eryF from Saccharopolyspora erythraea with androstenedione and 9-aminophenanthrene. Spectroscopic binding assays indicate that P450eryF binds androstenedione with an affinity of 365 microM and a Hill coefficient of 1.31 +/- 0.6 and coordinates with 9-aminophenanthrene with an affinity of 91 microM and a Hill coefficient of 1.38 +/- 0.2. Crystals of complexes of androstenedione and 9-aminophenanthrene with P450eryF were grown and diffracted to 2.1 A and 2.35 A, respectively. Electron density maps indicate that for both complexes two ligand molecules are simultaneously present in the active site. The P450eryF/androstenedione model was refined to an r = 18.9%, and the two androstenedione molecules have similar conformations. The proximal androstenedione is positioned such that the alpha-face of carbon-6 is closest to the heme iron, and the second steroid molecule is positioned 5.5 A distal in the active site. The P450eryF/9-aminophenanthrene model was refined to an r = 19.7% with the proximal 9-aminophenanthrene coordinated with the heme iron through the 9-amino group and the second ligand positioned approximately 6 A distal in the active site. These results establish that homotropic cooperativity in ligand binding can result from binding of two substrate molecules within the active site pocket without major conformational changes in the protein.
About this Structure
1EUP is a Single protein structure of sequence from [1] with and as ligands. This structure supersedes the now removed PDB entry 1EH0. Full crystallographic information is available from OCA.
Reference
Crystal structures of ligand complexes of P450eryF exhibiting homotropic cooperativity., Cupp-Vickery J, Anderson R, Hatziris Z, Proc Natl Acad Sci U S A. 2000 Mar 28;97(7):3050-5. PMID:10716705
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