1SUO

Structure of mammalian cytochrome P450 2B4 with bound 4-(4-chlorophenyl)imidazole

Summary for 1SUO

• Entry DOI: 10.2210/pdb1suo/pdb
• Related: 1PO5
• Descriptor: Cytochrome P450 2B4, PROTOPORPHYRIN IX CONTAINING FE, 4-(4-CHLOROPHENYL)IMIDAZOLE, ... (4 entities in total)
• Functional Keywords: oxidoreductase, membrane protein, cyp 2b4, cyp lm2, cytochrome p450, monooxygenase
• Biological source: Oryctolagus cuniculus (rabbit)
• Cellular location: Endoplasmic reticulum membrane; Peripheral membrane protein: P00178
• Total number of polymer chains: 1
• Total formula weight: 54964.19

Authors

Scott, E.E.,White, M.A.,He, Y.A.,Johnson, E.F.,Stout, C.D.,Halpert, J.R. (deposition date: 2004-03-26, release date: 2004-07-20, Last modification date: 2023-08-23)

Primary citation

Scott, E.E.,White, M.A.,He, Y.A.,Johnson, E.F.,Stout, C.D.,Halpert, J.R.
Structure of mammalian cytochrome P450 2B4 complexed with 4-(4-chlorophenyl)imidazole at 1.9 {angstrom} resolution: Insight into the range of P450 conformations and coordination of redox partner binding.
J.Biol.Chem., 279:27294-27301, 2004

PubMed Abstract: 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.

PubMed: 15100217
DOI: 10.1074/jbc.M403349200

Experimental method

X-RAY DIFFRACTION (1.9 Å)