1suo
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Structure of mammalian cytochrome P450 2B4 with bound 4-(4-chlorophenyl)imidazole
OverviewOverview
A 1.9-A molecular structure of the microsomal cytochrome P450 2B4 with the, specific inhibitor 4-(4-chlorophenyl)imidazole (CPI) in the active site, was determined by x-ray crystallography. In contrast to the previous, experimentally determined 2B4 structure, this complex adopted a closed, conformation similar to that observed for the mammalian 2C enzymes. The, differences between the open and closed structures of 2B4 were primarily, limited to the lid domain of helices F through G, helices B' and C, the N, terminus of helix I, and the beta(4) region. These large-scale, conformational changes were generally due to the relocation of conserved, structural elements toward each other with remarkably little remodeling at, the secondary structure level. For example, the F' and G' helices were, maintained with a sharp turn between them but are placed to form the, exterior ceiling of the active site in the CPI complex. CPI was closely, surrounded by residues from substrate recognition sites 1, 4, 5, and 6 to, form a small, isolated hydrophobic cavity. The switch from open to closed, conformation dramatically relocated helix C to a more proximal position., As a result, heme binding interactions were altered, and the putative, NADPH-cytochrome P450 reductase binding site was reformed. This suggests a, structural mechanism whereby ligand-induced conformational changes may, coordinate catalytic activity. Comparison of the 2B4/CPI complex with the, open 2B4 structure yields insights into the dynamics involved in substrate, access, tight inhibitor binding, and coordination of substrate and redox, partner binding.
About this StructureAbout this Structure
1SUO is a Single protein structure of sequence from Oryctolagus cuniculus with HEM and CPZ as ligands. Active as Unspecific monooxygenase, with EC number 1.14.14.1 Full crystallographic information is available from OCA.
ReferenceReference
Structure of mammalian cytochrome P450 2B4 complexed with 4-(4-chlorophenyl)imidazole at 1.9-A resolution: insight into the range of P450 conformations and the coordination of redox partner binding., Scott EE, White MA, He YA, Johnson EF, Stout CD, Halpert JR, J Biol Chem. 2004 Jun 25;279(26):27294-301. Epub 2004 Apr 20. PMID:15100217
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