title: Flexibility of human cytochromes P450: molecular dynamics reveals differences between CYPs 3A4, 2C9, and 2A6, which correlate with their substrate preferences.
abstract: Molecular dynamics (MD) simulations at normal and high temperature were used to study the flexibility and malleability of three microsomal cytochromes P450 (CYPs): CYP3A4, CYP2C9, and CYP2A6. Comparison of B-factors (describing the atomic fluctuations) between X-ray and MD data shows that the X-ray B-factors are significantly lower in the regions where the crystal contacts occur than for other regions. Consequently, the conclusions about CYP flexibility based solely on the X-ray data might be misleading. Comparison of flexibility patterns of the three CYPs enabled common features and variations in flexibility and malleability of the studied CYPs to be identified. The previously described pattern of flexibility in topological elements of microsomal CYPs (a rigid heme binding core, a malleable distal side and intermediately flexible proximal side) was confirmed. These topological features provide an important combination of high stereo- and regio-specificity (mediated by the relative rigidity in the neighborhood of the heme), together with high substrate promiscuity due to the more flexible active site and the malleability of the distal side. The data acquired here show that the malleability of the three studied CYPs correlates with their substrate specificity: CYP2A6 has a narrow substrate range and is the most rigid, CYP3A4 is the most promiscuous CYP known and is the most malleable, and CYP2C9 is intermediate in terms of both its substrate specificity and malleability. Thus, the malleability of CYPs is probably a major determinant of their substrate specificity.
authors.affiliation: Department of Physical Chemistry and Center for Biomolecules and Complex Molecular Systems, Palacky University, Trida Svobody 26, 771 46, Olomouc, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Skopalík
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 / Q000378:metabolism; D001665:Binding Sites; D003374:Coumarins / Q000378:metabolism; D065637:Cytochrome P-450 CYP2A6; D065729:Cytochrome P-450 CYP2C9; D051544:Cytochrome P-450 CYP3A / Q000737:chemistry / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism; D008958:Models, Molecular; D009538:Nicotine / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000378:metabolism; D011487:Protein Conformation; D013256:Steroids / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D014026:Nicotiana / Q000378:metabolism
chemical_list: D003374:Coumarins; D004364:Pharmaceutical Preparations; D013256:Steroids; D009538:Nicotine; D003577:Cytochrome P-450 Enzyme System; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human