title: Design of high-activity mutants of human butyrylcholinesterase against (-)-cocaine: structural and energetic factors affecting the catalytic efficiency.
abstract: The present study was aimed to explore the correlation between the protein structure and catalytic efficiency of butyrylcholinesterase (BChE) mutants against (-)-cocaine by modeling the rate-determining transition state (TS1), i.e., the transition state for the first step of chemical reaction process, of (-)-cocaine hydrolysis catalyzed by various mutants of human BChE in comparison with the wild type. Molecular modeling of the TS1 structures revealed that mutations on certain nonactive site residues can indirectly affect the catalytic efficiency of the enzyme against (-)-cocaine through enhancing or weakening the overall hydrogen bonding between the carbonyl oxygen of (-)-cocaine benzoyl ester and the oxyanion hole of the enzyme. Computational insights and predictions were supported by the catalytic activity data obtained from wet experimental tests on the mutants of human BChE, including five new mutants reported for the first time. The BChE mutants with at least ∼1000-fold improved catalytic efficiency against (-)-cocaine compared to the wild-type BChE are all associated with the TS1 structures having stronger overall hydrogen bonding between the carbonyl oxygen of (-)-cocaine benzoyl ester and the oxyanion hole of the enzyme. The combined computational and experimental data demonstrate a reasonable correlation relationship between the hydrogen-bonding distances in the TS1 structure and the catalytic efficiency of the enzyme against (-)-cocaine.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, Kentucky 40536, United States.
authors.forename: Fang
authors.initials: F
authors.lastname: Zheng
authors.forename: Wenchao
authors.initials: W
authors.lastname: Yang
authors.forename: Liu
authors.initials: L
authors.lastname: Xue
authors.forename: Shurong
authors.initials: S
authors.lastname: Hou
authors.forename: Junjun
authors.initials: J
authors.lastname: Liu
authors.forename: Chang-Guo
authors.initials: CG
authors.lastname: Zhan
mesh_terms: D019943:Amino Acid Substitution; D002091:Butyrylcholinesterase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain / Q000235:genetics; D003042:Cocaine / Q000378:metabolism*; D006801:Humans; D006860:Hydrogen Bonding; D066298:In Vitro Techniques; D007700:Kinetics; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015202:Protein Engineering; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D050505:Mutant Proteins; D011994:Recombinant Proteins; D002091:Butyrylcholinesterase; D003042:Cocaine