title: Behavior of human cytochromes P450 on lipid membranes.
abstract: Human cytochromes P450 (CYPs) are membrane-anchored enzymes involved in biotransformation of many marketed drugs. We constructed atomic models of six human CYPs (CYP1A2, 2A6, 2C9, 2D6, 2E1, and 3A4) anchored to a lipid bilayer to investigate the positions and orientations of CYPs on a membrane. We equilibrated the models by molecular dynamics simulations on a 100+ ns time scale. Catalytic domains of all studied CYPs were found to be partially immersed in the lipid bilayer, whereas the N-terminal part and F'/G' loop are deeply immersed. The proximal side of the enzyme faces the cytosol, whereas the distal side, where openings of substrate access and product release channels to the active site are primarily located, points toward the lipid bilayer. Access channels with openings in the vicinity of the B/C and F/G loops are typically positioned below the lipid head groups, whereas the solvent channel points toward the membrane-water interface. We found that the access channel opening positions match the preferred substrate positions, whereas the product release channel exit positions correspond closely with the positions of the products. This may indicate that membrane-anchored CYPs have evolutionarily adapted to facilitate uptake of nonpolar substrates from the membrane and uptake/release of polar substrates or products from/to the membrane-water interface.
authors.affiliation: Department of Physical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University Olomouc , tř. 17. listopadu 12, 771 46, Olomouc, Czech Republic.
authors.forename: Karel
authors.initials: K
authors.lastname: Berka
authors.forename: Markéta
authors.initials: M
authors.lastname: Paloncýová
authors.forename: Pavel
authors.initials: P
authors.lastname: Anzenbacher
authors.forename: Michal
authors.initials: M
authors.lastname: Otyepka
mesh_terms: D001189:Aryl Hydrocarbon Hydroxylases / Q000737:chemistry; D020134:Catalytic Domain; D019388:Cytochrome P-450 CYP1A2 / Q000737:chemistry; D065637:Cytochrome P-450 CYP2A6; D065729:Cytochrome P-450 CYP2C9; D051544:Cytochrome P-450 CYP3A / Q000737:chemistry; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry*; D006418:Heme / Q000737:chemistry; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010713:Phosphatidylcholines / Q000737:chemistry; D011487:Protein Conformation; D012997:Solvents / Q000737:chemistry; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D012997:Solvents; D014867:Water; D006418:Heme; D003577:Cytochrome P-450 Enzyme System; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases; C504573:CYP1A2 protein, human; D019388:Cytochrome P-450 CYP1A2; D065637:Cytochrome P-450 CYP2A6; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; C017251:1,2-oleoylphosphatidylcholine