title: Slow-binding inhibition of acetylcholinesterase by an alkylammonium derivative of 6-methyluracil: mechanism and possible advantages for myasthenia gravis treatment.
abstract: Inhibition of human AChE (acetylcholinesterase) and BChE (butyrylcholinesterase) by an alkylammonium derivative of 6-methyluracil, C-547, a potential drug for the treatment of MG (myasthenia gravis) was studied. Kinetic analysis of AChE inhibition showed that C-547 is a slow-binding inhibitor of type B, i.e. after formation of the initial enzyme·inhibitor complex (Ki=140 pM), an induced-fit step allows establishment of the final complex (Ki*=22 pM). The estimated koff is low, 0.05 min(-1) On the other hand, reversible inhibition of human BChE is a fast-binding process of mixed-type (Ki=1.77 μM; Ki'=3.17 μM). The crystal structure of mouse AChE complexed with C-547 was solved at 3.13 Å resolution. The complex is stabilized by cation-π, stacking and hydrogen-bonding interactions. Molecular dynamics simulations of the binding/dissociation processes of C-547 and C-35 (a non-charged analogue) to mouse and human AChEs were performed. Molecular modelling on mouse and human AChE showed that the slow step results from an enzyme conformational change that allows C-547 to cross the bottleneck in the active-site gorge, followed by formation of tight complex, as observed in the crystal structure. In contrast, the related non-charged compound C-35 is not a slow-binding inhibitor. It does not cross the bottleneck because it is not sensitive to the electrostatic driving force to reach the bottom of the gorge. Thus C-547 is one of the most potent and selective reversible inhibitors of AChE with a long residence time, τ=20 min, longer than for other reversible inhibitors used in the treatment of MG. This makes C-547 a promising drug for the treatment of this disease.
authors.affiliation: A.E. Arbuzov Institute of Organic and Physical Chemistry of Russian Academy of Sciences, Arbuzov Str. 8, Kazan 420088 Russia.
authors.forename: Alexandra D
authors.initials: AD
authors.lastname: Kharlamova
authors.affiliation: N.M. Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, Moscow 119334, Russia.
authors.forename: Sofya V
authors.initials: SV
authors.lastname: Lushchekina
authors.affiliation: A.E. Arbuzov Institute of Organic and Physical Chemistry of Russian Academy of Sciences, Arbuzov Str. 8, Kazan 420088 Russia.
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Petrov
authors.affiliation: N.M. Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, Moscow 119334, Russia.
authors.forename: Ekaterina D
authors.initials: ED
authors.lastname: Kots
authors.affiliation: Institut de Recherche Biomédicale des Armées, 91223 Brétigny-sur-Orge, France.
authors.forename: Florian
authors.initials: F
authors.lastname: Nachon
authors.affiliation: Institut de Recherche Biomédicale des Armées, 91223 Brétigny-sur-Orge, France.
authors.forename: Marielle
authors.initials: M
authors.lastname: Villard-Wandhammer
authors.affiliation: A.E. Arbuzov Institute of Organic and Physical Chemistry of Russian Academy of Sciences, Arbuzov Str. 8, Kazan 420088 Russia.
authors.forename: Irina V
authors.initials: IV
authors.lastname: Zueva
authors.affiliation: COGNition ACtion Group, CNRS, Université Paris Descartes 75006 Paris, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Krejci
authors.affiliation: A.E. Arbuzov Institute of Organic and Physical Chemistry of Russian Academy of Sciences, Arbuzov Str. 8, Kazan 420088 Russia.
authors.forename: Vladimir S
authors.initials: VS
authors.lastname: Reznik
authors.affiliation: A.E. Arbuzov Institute of Organic and Physical Chemistry of Russian Academy of Sciences, Arbuzov Str. 8, Kazan 420088 Russia.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Zobov
authors.affiliation: Kazan Institute of Biochemistry and Biophysics of Russian Academy of Sciences, P.O. Box 30, Kazan 420111, Russia Kazan Federal University, Neuropharmacology Lab., Kremlevskaia St. 18, Kazan 420000, Russia.
authors.forename: Evgeny E
authors.initials: EE
authors.lastname: Nikolsky
authors.affiliation: Kazan Federal University, Neuropharmacology Lab., Kremlevskaia St. 18, Kazan 420000, Russia pym.masson@free.fr.
authors.forename: Patrick
authors.initials: P
authors.lastname: Masson
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry*; D000818:Animals; D016466:CHO Cells; D002800:Cholinesterase Inhibitors / Q000737:chemistry* / Q000627:therapeutic use; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D051379:Mice; D062105:Molecular Docking Simulation; D009157:Myasthenia Gravis / Q000188:drug therapy / Q000201:enzymology; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000627:therapeutic use; D014498:Uracil / Q000031:analogs & derivatives* / Q000737:chemistry / Q000627:therapeutic use
chemical_list: C449662:C-547 compound; D002800:Cholinesterase Inhibitors; D000644:Quaternary Ammonium Compounds; D014498:Uracil; C008378:6-methyluracil; D000110:Acetylcholinesterase
keywords: 6-methyluracil; X-ray structure; acetylcholinesterase; butyrylcholinesterase; molecular modelling; slow-binding inhibition