title: Binding of quinidine radically increases the stability and decreases the flexibility of the cytochrome P450 2D6 active site.
abstract: Human cytochrome P450 2D6 (CYP2D6) is an enzyme of the CYP superfamily responsible for biotransformation of about 20% of drugs of known metabolism containing a basic nitrogen and a planar aromatic ring. Here, we present a combined experimental and computational study on the compressibility and flexibility of unliganded and quinidine-bound CYP2D6. Experimentally, high-pressure induced Soret band shifts of the enzyme were measured by UV/VIS spectroscopy, while 100 ns all atomic molecular dynamics (MD) simulations in explicit water were used in the computational analysis. We identified sharp differences between ligand-free and quinidine-bound CYP2D6 forms in compressibility, flexibility parameters and active site solvation. While the unliganded CYP2D6 is compressible, quinidine binding significantly rigidifies the CYP2D6 active site. In addition, MD simulations show that quinidine binding results in pronounced reductions in active site flexibility and solvation.
authors.affiliation: Department of Physical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, tr. 17. listopadu 12, 771 46 Olomouc, Czech Republic.
authors.forename: Karel
authors.initials: K
authors.lastname: Berka
authors.forename: Eva
authors.initials: E
authors.lastname: Anzenbacherová
authors.forename: Tereza
authors.initials: T
authors.lastname: Hendrychová
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lange
authors.forename: Vlastimil
authors.initials: V
authors.lastname: Mašek
authors.forename: Pavel
authors.initials: P
authors.lastname: Anzenbacher
authors.forename: Michal
authors.initials: M
authors.lastname: Otyepka
mesh_terms: D020134:Catalytic Domain; D019389:Cytochrome P-450 CYP2D6 / Q000737:chemistry*; D004795:Enzyme Stability; D006801:Humans; D011485:Protein Binding; D011802:Quinidine / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D019389:Cytochrome P-450 CYP2D6; D011802:Quinidine