2nnh | pdb_00002nnh
CYP2C8dH complexed with 2 molecules of 9-cis retinoic acid
Structural highlights
FunctionCP2C8_HUMAN Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. In the epoxidation of arachidonic acid it generates only 14,15- and 11,12-cis-epoxyeicosatrienoic acids. It is the principal enzyme responsible for the metabolism the anti-cancer drug paclitaxel (taxol).[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAlthough a crystal structure and a pharmacophore model are available for cytochrome P450 2C8, the role of protein flexibility and specific ligand-protein interactions that govern substrate binding are poorly understood. X-ray crystal structures of P450 2C8 complexed with montelukast (2.8 A), troglitazone (2.7 A), felodipine (2.3 A), and 9-cis-retinoic acid (2.6 A) were determined to examine ligand-protein interactions for these chemically diverse compounds. Montelukast is a relatively large anionic inhibitor that exhibits a tripartite structure and complements the size and shape of the active-site cavity. The inhibitor troglitazone occupies the upper portion of the active-site cavity, leaving a substantial part of the cavity unoccupied. The smaller neutral felodipine molecule is sequestered with its dichlorophenyl group positioned close to the heme iron, and water molecules fill the distal portion of the cavity. The structure of the 9-cis-retinoic acid complex reveals that two substrate molecules bind simultaneously in the active site of P450 2C8. A second molecule of 9-cis-retinoic acid is located above the proximal molecule and can restrain the position of the latter for more efficient oxygenation. Solution binding studies do not discriminate between cooperative and noncooperative models for multiple substrate binding. The complexes with structurally distinct ligands further demonstrate the conformational adaptability of active site-constituting residues, especially Arg-241, that can reorient in the active-site cavity to stabilize a negatively charged functional group and define two spatially distinct binding sites for anionic moieties of substrates. Determinants of cytochrome P450 2C8 substrate binding: structures of complexes with montelukast, troglitazone, felodipine, and 9-cis-retinoic acid.,Schoch GA, Yano JK, Sansen S, Dansette PM, Stout CD, Johnson EF J Biol Chem. 2008 Jun 20;283(25):17227-37. Epub 2008 Apr 15. PMID:18413310[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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