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Zheng F, Hou S, Xue L, Yang W, Zhan CG. Human Butyrylcholinesterase Mutants for (-)-Cocaine Hydrolysis: A Correlation Relationship between Catalytic Efficiency and Total Hydrogen Bonding Energy with an Oxyanion Hole. J Phys Chem B 2023; 127:10723-10729. [PMID: 38063500 DOI: 10.1021/acs.jpcb.3c06392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
A combined computational and experimental study has been carried out to explore and test a quantitative correlation relationship between the relative catalytic efficiency (RCE) of human butyrylcholinesrase (BChE) mutant-catalyzed hydrolysis of substrate (-)-cocaine and the total hydrogen bonding energy (tHBE) of the carbonyl oxygen of the substrate with the oxyanion hole of the enzyme in the modeled transition-state structure (TS1), demonstrating a satisfactory linear correlation relationship between ln(RCE) and tHBE. The satisfactory correlation relationship has led us to computationally predict and experimentally confirm new human BChE mutants that have a further improved catalytic activity against (-)-cocaine, including the most active one (the A199S/F227S/S287G/A328W/Y332G mutant) with a 2790-fold improved catalytic efficiency (kcat/KM = 2.5 × 109 min-1 M-1) compared to the wild-type human BChE. Compared to the reference mutant (the A199S/S287G/A328W/Y332G mutant) tested in the reported clinical development of an enzyme therapy for cocaine dependence treatment, this new mutant (with a newly predicted additional F227S mutation) has an improved catalytic efficiency against (-)-cocaine by ∼2.6-fold. The good agreement between the computational and experimental ln(RCE) values suggests that the obtained correlation relationship is robust for computational prediction. A similar correlation relationship could also be explored in studying BChE or other serine hydrolases/esterases with an oxyanion hole stabilizing the carbonyl oxygen in the rate-determining reaction step of the enzymatic hydrolysis of other substrates.
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Affiliation(s)
- Fang Zheng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Shurong Hou
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Liu Xue
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Wenchao Yang
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
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2
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From tryptophan-based amides to tertiary amines: Optimization of a butyrylcholinesterase inhibitor series. Eur J Med Chem 2022; 234:114248. [DOI: 10.1016/j.ejmech.2022.114248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 02/20/2022] [Accepted: 02/28/2022] [Indexed: 12/29/2022]
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3
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De Boer D, Nguyen N, Mao J, Moore J, Sorin EJ. A Comprehensive Review of Cholinesterase Modeling and Simulation. Biomolecules 2021; 11:580. [PMID: 33920972 PMCID: PMC8071298 DOI: 10.3390/biom11040580] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/08/2021] [Accepted: 04/11/2021] [Indexed: 01/18/2023] Open
Abstract
The present article reviews published efforts to study acetylcholinesterase and butyrylcholinesterase structure and function using computer-based modeling and simulation techniques. Structures and models of both enzymes from various organisms, including rays, mice, and humans, are discussed to highlight key structural similarities in the active site gorges of the two enzymes, such as flexibility, binding site location, and function, as well as differences, such as gorge volume and binding site residue composition. Catalytic studies are also described, with an emphasis on the mechanism of acetylcholine hydrolysis by each enzyme and novel mutants that increase catalytic efficiency. The inhibitory activities of myriad compounds have been computationally assessed, primarily through Monte Carlo-based docking calculations and molecular dynamics simulations. Pharmaceutical compounds examined herein include FDA-approved therapeutics and their derivatives, as well as several other prescription drug derivatives. Cholinesterase interactions with both narcotics and organophosphate compounds are discussed, with the latter focusing primarily on molecular recognition studies of potential therapeutic value and on improving our understanding of the reactivation of cholinesterases that are bound to toxins. This review also explores the inhibitory properties of several other organic and biological moieties, as well as advancements in virtual screening methodologies with respect to these enzymes.
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Affiliation(s)
- Danna De Boer
- Department of Chemistry & Biochemistry, California State University, Long Beach, CA 90840, USA;
| | - Nguyet Nguyen
- Department of Chemical Engineering, California State University, Long Beach, CA 90840, USA; (N.N.); (J.M.)
| | - Jia Mao
- Department of Chemical Engineering, California State University, Long Beach, CA 90840, USA; (N.N.); (J.M.)
| | - Jessica Moore
- Department of Biomedical Engineering, California State University, Long Beach, CA 90840, USA;
| | - Eric J. Sorin
- Department of Chemistry & Biochemistry, California State University, Long Beach, CA 90840, USA;
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4
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Sobolova K, Hrabinova M, Hepnarova V, Kucera T, Kobrlova T, Benkova M, Janockova J, Dolezal R, Prchal L, Benek O, Mezeiova E, Jun D, Soukup O, Korabecny J. Discovery of novel berberine derivatives with balanced cholinesterase and prolyl oligopeptidase inhibition profile. Eur J Med Chem 2020; 203:112593. [PMID: 32688201 DOI: 10.1016/j.ejmech.2020.112593] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/15/2020] [Accepted: 06/15/2020] [Indexed: 12/16/2022]
Abstract
Berberine, a naturally occurring compound, possesses an interesting multipotent pharmacological profile potentially applicable for Alzheimer's disease (AD) treatment. In this study, a series of novel 22 berberine derivatives was developed and tested in vitro. Berberine core was substituted at position 9-O of its aromatic ring region. All the hybrids under the study revealed multi-targeted profile inhibiting prolyl oligopeptidase, acetylcholinesterase and butyrylcholinesterase highlighting 4a, 4g, 4j, 4l and 4s possessing balanced activities in the micromolar range. The top-ranked candidates in terms of the most pronounced potency against POP, AChE and BChE can be classified as 4d, 4u and 4v, bearing 4-methylbenzyl, (naphthalen-2-yl)methylene and 1-phenoxyethyl moieties, respectively. In vitro data were corroborated by detailed kinetic analysis of the selected lead molecules. 4d, 4u and 4v were also inspected for their potential to inhibit aggregation of two abberant proteins in AD, namely amyloid beta and tau, indicating their potential disease-modifying properties. To explain the results of our study, we carried out docking simulation to the active sites of the respective enzyme with the best berberine derivatives, along with QSAR study. We also investigated compounds' potential permeability through blood-brain barrier by applying parallel artificial membrane permeation assay and addressed their cytotoxicity profile.
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Affiliation(s)
- Katerina Sobolova
- Department of Toxicology and Military Pharmacy, Department of Military Medical Service Organisation and Management, Faculty of Military Health Sciences, University of Defense, Trebesska 1575, 500 05, Hradec Kralove, Czech Republic
| | - Martina Hrabinova
- Department of Toxicology and Military Pharmacy, Department of Military Medical Service Organisation and Management, Faculty of Military Health Sciences, University of Defense, Trebesska 1575, 500 05, Hradec Kralove, Czech Republic; Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic
| | - Vendula Hepnarova
- Department of Toxicology and Military Pharmacy, Department of Military Medical Service Organisation and Management, Faculty of Military Health Sciences, University of Defense, Trebesska 1575, 500 05, Hradec Kralove, Czech Republic
| | - Tomas Kucera
- Department of Toxicology and Military Pharmacy, Department of Military Medical Service Organisation and Management, Faculty of Military Health Sciences, University of Defense, Trebesska 1575, 500 05, Hradec Kralove, Czech Republic
| | - Tereza Kobrlova
- Department of Toxicology and Military Pharmacy, Department of Military Medical Service Organisation and Management, Faculty of Military Health Sciences, University of Defense, Trebesska 1575, 500 05, Hradec Kralove, Czech Republic; Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic
| | - Marketa Benkova
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic
| | - Jana Janockova
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic
| | - Rafael Dolezal
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic; Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic
| | - Lukas Prchal
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic
| | - Ondrej Benek
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic
| | - Eva Mezeiova
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic
| | - Daniel Jun
- Department of Toxicology and Military Pharmacy, Department of Military Medical Service Organisation and Management, Faculty of Military Health Sciences, University of Defense, Trebesska 1575, 500 05, Hradec Kralove, Czech Republic; Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic
| | - Ondrej Soukup
- Department of Toxicology and Military Pharmacy, Department of Military Medical Service Organisation and Management, Faculty of Military Health Sciences, University of Defense, Trebesska 1575, 500 05, Hradec Kralove, Czech Republic; Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.
| | - Jan Korabecny
- Department of Toxicology and Military Pharmacy, Department of Military Medical Service Organisation and Management, Faculty of Military Health Sciences, University of Defense, Trebesska 1575, 500 05, Hradec Kralove, Czech Republic; Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.
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5
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Maříková J, Ritomská A, Korábečný J, Peřinová R, Al Mamun A, Kučera T, Kohelová E, Hulcová D, Kobrlová T, Kuneš J, Nováková L, Cahlíková L. Aromatic Esters of the Crinane Amaryllidaceae Alkaloid Ambelline as Selective Inhibitors of Butyrylcholinesterase. JOURNAL OF NATURAL PRODUCTS 2020; 83:1359-1367. [PMID: 32309949 DOI: 10.1021/acs.jnatprod.9b00561] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A total of 20 derivatives (1-20) of the crinane-type alkaloid ambelline were synthesized. These semisynthetic derivatives were assessed for their potency to inhibit both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). To predict central nervous system (CNS) availability, logBB was calculated, and the data correlated well with those obtained from the parallel artificial membrane permeability assay (PAMPA). All compounds should be able to permeate the blood-brain barrier (BBB) according to the obtained results. A total of 7 aromatic derivatives (5, 6, 7, 9, 10, 12, and 16) with different substitution patterns showed inhibitory potency against human serum BuChE (IC50 < 5 μM), highlighting the three top-ranked compounds as follows: 11-O-(1-naphthoyl)ambelline (16), 11-O-(2-methylbenzoyl)ambelline (6), and 11-O-(2-methoxybenzoyl)ambelline (9) with IC50 values of 0.10 ± 0.01, 0.28 ± 0.02, and 0.43 ± 0.04 μM, respectively. Notably, derivatives 6, 7, 9, and 16 displayed selective human BuChE (hBuChE) inhibition profiles with a selectivity index > 100. The in vitro results were supported by computational studies predicting plausible binding modes of the compounds in the active sites of hBuChE.
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Affiliation(s)
| | | | - Jan Korábečný
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01 Hradec Kralove, Czech Republic
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05 Hradec Kralove, Czech Republic
| | | | | | - Tomáš Kučera
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01 Hradec Kralove, Czech Republic
| | | | | | - Tereza Kobrlová
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01 Hradec Kralove, Czech Republic
- Biomedical Research Centre, University Hospital Hradec Kralove, Sokolska 581, 500 05 Hradec Kralove, Czech Republic
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6
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Alvarado W, Bremer PL, Choy A, Dinh HN, Eung A, Gonzalez J, Ly P, Tran T, Nakayama K, Schwans JP, Sorin EJ. Understanding the enzyme-ligand complex: insights from all-atom simulations of butyrylcholinesterase inhibition. J Biomol Struct Dyn 2019; 38:1028-1041. [PMID: 30909811 DOI: 10.1080/07391102.2019.1596836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
All-atom molecular dynamics simulations of butyrylcholinesterase (BChE) sans inhibitor and in complex with each of 15 dialkyl phenyl phosphate derivatives were conducted to characterize inhibitor binding modes and strengths. Each system was sampled on the 250 ns timescale in explicit ionic solvent, for a total of over 4 μs of simulation time. A K-means algorithm was used to cluster the resulting structures into distinct binding modes, which were further characterized based on atomic-level contacts between inhibitor chemical groups and active site residues. Comparison of experimentally observed inhibition constants (KI) with the resulting contact tables provides structural explanations for relative binding coefficients and highlights several notable interaction motifs. These include ubiquitous contact between glycines in the oxyanion hole and the inhibitor phosphate group; a sterically driven binding preference for positional isomers that extend aromaticity; a stereochemical binding preference for choline-containing inhibitors, which mimic natural BChE substrates; and the mechanically induced opening of the omega loop region to fully expose the active site gorge in the presence of choline-containing inhibitors. Taken together, these observations can greatly inform future design of BChE inhibitors, and the approach reported herein is generalizable to other enzyme-inhibitor systems and similar complexes that depend on non-covalent molecular recognition.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Walter Alvarado
- Department of Physics & Astronomy, California State University Long Beach, Long Beach, CA, USA
| | - Parker Ladd Bremer
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA, USA
| | - Angela Choy
- Department of Chemical Engineering, California State University Long Beach, Long Beach, CA, USA
| | - Helen N Dinh
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA, USA
| | - Aingty Eung
- Department of Computer Engineering & Computer Science, California State University Long Beach, Long Beach, CA, USA
| | - Jeannette Gonzalez
- Department of Biological Sciences, California State University Long Beach, Long Beach, CA, USA
| | - Phillippe Ly
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA, USA
| | - Trina Tran
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA, USA
| | - Kensaku Nakayama
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA, USA
| | - Jason P Schwans
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA, USA
| | - Eric J Sorin
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA, USA
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7
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Xu YL, Li FY, Ndikuryayo F, Yang WC, Wang HM. Cholinesterases and Engineered Mutants for the Detection of Organophosphorus Pesticide Residues. SENSORS (BASEL, SWITZERLAND) 2018; 18:E4281. [PMID: 30563111 PMCID: PMC6312092 DOI: 10.3390/s18124281] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/27/2018] [Accepted: 12/01/2018] [Indexed: 02/04/2023]
Abstract
Nowadays, pesticide residues constitute an increasing public health concern. Cholinesterases, acetylcholinesterase, and butyrylcholinesterase, are reported to be involved in detoxification processes owing to their capability of scavenging organophosphates and carbamates. Thus, these enzymes are targeted for the discovery of sensors aiming at detecting pesticide residues. In recent years, cholinesterase-based biosensors have attracted more and more attention in the detection of pesticides. Herein, this review describes the recent progress on the engineering of cholinesterases and the development of the corresponding sensors that could be used for the detection of organophosphorus pesticide residues.
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Affiliation(s)
- Yu-Ling Xu
- School of Chemical & Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023, China.
| | - Feng-Ye Li
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, and International Joint Research Center for Intelligent Biosensor Technology and Health, and Chemical Biology Center, College of Chemistry, Central China Normal University, Wuhan 430079, China.
| | - Ferdinand Ndikuryayo
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, and International Joint Research Center for Intelligent Biosensor Technology and Health, and Chemical Biology Center, College of Chemistry, Central China Normal University, Wuhan 430079, China.
| | - Wen-Chao Yang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, and International Joint Research Center for Intelligent Biosensor Technology and Health, and Chemical Biology Center, College of Chemistry, Central China Normal University, Wuhan 430079, China.
| | - Hong-Mei Wang
- Hubei Key Laboratory of Wudang Local Chinese Medicine Research, School of Pharmacy, Hubei University of Medicine, Shiyan 442000, China.
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8
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Szöcs L, Völgyi G, Urai Á, Hosztafi S, Tóth G, Gergó L, Noszál B. Site- and species-specific hydrolysis rates of cocaine. J Pharm Biomed Anal 2017; 145:372-378. [PMID: 28715790 DOI: 10.1016/j.jpba.2017.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/30/2017] [Accepted: 07/01/2017] [Indexed: 11/30/2022]
Abstract
The hydroxide-catalyzed non-enzymatic hydrolysis of cocaine is quantified in terms of ten site- and species-specific rate constants in connection with also ten site- and species-specific acid-base equilibrium constants, comprising all the twelve coexisting species in solution. This characterization involves the major and minor decomposition pathways via benzoylecgonine and ecgonine methyl ester, respectively, leading to ecgonine, the final product. Hydrolysis has been found to be 10-330 times faster at site 2 than at site 3, depending on the ionization status of the amino moiety and the rest of the molecule. Nitrogen protonation accelerates the hydrolyses approximately ten times both at site 2 and site 3.
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Affiliation(s)
- Levente Szöcs
- Semmelweis University, Department of Pharmaceutical Chemistry, Research Group for Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences Hőgyes E. u. 9, H-1092 Budapest, Hungary
| | - Gergely Völgyi
- Semmelweis University, Department of Pharmaceutical Chemistry, Research Group for Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences Hőgyes E. u. 9, H-1092 Budapest, Hungary
| | - Ákos Urai
- Semmelweis University, Department of Pharmaceutical Chemistry, Research Group for Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences Hőgyes E. u. 9, H-1092 Budapest, Hungary
| | - Sándor Hosztafi
- Semmelweis University, Department of Pharmaceutical Chemistry, Research Group for Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences Hőgyes E. u. 9, H-1092 Budapest, Hungary
| | - Gergő Tóth
- Semmelweis University, Department of Pharmaceutical Chemistry, Research Group for Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences Hőgyes E. u. 9, H-1092 Budapest, Hungary
| | - Lajos Gergó
- Eötvös Loránd University, Faculty of Informatics, Department of Numerical Analysis, Hungary
| | - Béla Noszál
- Semmelweis University, Department of Pharmaceutical Chemistry, Research Group for Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences Hőgyes E. u. 9, H-1092 Budapest, Hungary.
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9
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Siano A, Garibotto FF, Andujar SA, Baldoni HA, Tonarelli GG, Enriz RD. Molecular design and synthesis of novel peptides from amphibians skin acting as inhibitors of cholinesterase enzymes. J Pept Sci 2017; 23:236-244. [DOI: 10.1002/psc.2974] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 01/06/2023]
Affiliation(s)
- Alvaro Siano
- Departamento de Química Orgánica, Facultad de Bioquímica y Cs. Biológicas (FBCB); Universidad Nacional del Litoral (UNL), Ciudad Universitaria; 3000 Santa Fe Argentina
| | - Francisco F. Garibotto
- Facultad de Química, Bioquímica y Farmacia; Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO-SL. CONICET), Universidad Nacional de San Luis; Chacabuco 915 5700 San Luis Argentina
| | - Sebastian A. Andujar
- Facultad de Química, Bioquímica y Farmacia; Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO-SL. CONICET), Universidad Nacional de San Luis; Chacabuco 915 5700 San Luis Argentina
| | - Hector A. Baldoni
- Facultad de Química, Bioquímica y Farmacia; Instituto de Matemática Aplicada San Luis, Universidad Nacional de San Luis (UNSL, CONICET); Ejército de Los Andes 950 5700 San Luis Argentina
| | - Georgina G. Tonarelli
- Departamento de Química Orgánica, Facultad de Bioquímica y Cs. Biológicas (FBCB); Universidad Nacional del Litoral (UNL), Ciudad Universitaria; 3000 Santa Fe Argentina
| | - Ricardo D. Enriz
- Facultad de Química, Bioquímica y Farmacia; Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO-SL. CONICET), Universidad Nacional de San Luis; Chacabuco 915 5700 San Luis Argentina
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10
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Zhang Y, Huang X, Han K, Zheng F, Zhan CG. Free energy profiles of cocaine esterase-cocaine binding process by molecular dynamics and potential of mean force simulations. Chem Biol Interact 2016; 259:142-147. [PMID: 27163853 DOI: 10.1016/j.cbi.2016.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 04/29/2016] [Accepted: 05/05/2016] [Indexed: 11/29/2022]
Abstract
The combined molecular dynamics (MD) and potential of mean force (PMF) simulations have been performed to determine the free energy profile of the CocE)-(+)-cocaine binding process in comparison with that of the corresponding CocE-(-)-cocaine binding process. According to the MD simulations, the equilibrium CocE-(+)-cocaine binding mode is similar to the CocE-(-)-cocaine binding mode. However, based on the simulated free energy profiles, a significant free energy barrier (∼5 kcal/mol) exists in the CocE-(+)-cocaine binding process whereas no obvious free energy barrier exists in the CocE-(-)-cocaine binding process, although the free energy barrier of ∼5 kcal/mol is not high enough to really slow down the CocE-(+)-cocaine binding process. In addition, the obtained free energy profiles also demonstrate that (+)-cocaine and (-)-cocaine have very close binding free energies with CocE, with a negligible difference (∼0.2 kcal/mol), which is qualitatively consistent with the nearly same experimental KM values of the CocE enzyme for (+)-cocaine and (-)-cocaine. The consistency between the computational results and available experimental data suggests that the mechanistic insights obtained from this study are reasonable.
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Affiliation(s)
- Yuxin Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Zhongshan Road 457, Dalian 116023, PR China; Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Xiaoqin Huang
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Keli Han
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Zhongshan Road 457, Dalian 116023, PR China
| | - Fang Zheng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA.
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11
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Yao Y, Liu J, Zheng F, Zhan CG. Reaction Pathway for Cocaine Hydrolase-Catalyzed Hydrolysis of (+)-Cocaine. Theor Chem Acc 2016; 135. [PMID: 28250715 DOI: 10.1007/s00214-015-1788-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A recently designed and discovered cocaine hydrolase (CocH), engineered from human butyrylcholinesterase (BChE), has been proven promising as a novel enzyme therapy for treatment of cocaine overdose and addiction because it is highly efficient in catalyzing hydrolysis of naturally occurring (-)-cocaine. It has been known that the CocH also has a high catalytic efficiency against (+)-cocaine, a synthetic enantiomer of cocaine. Reaction pathway and the corresponding free energy profile for the CocH-catalyzed hydrolysis of (+)-cocaine have been determined, in the present study, by performing first-principles pseudobond quantum mechanical/molecular mechanical (QM/MM)-free energy (FE) calculations. Acordingt to the QM/MM-FE results, the catalytic hydrolysis process is initiated by the nucleophilic attack on carbonyl carbon of (-)-cocaine benzoyl ester via hydroxyl oxygen of S198 side chain, and the second reaction step (i.e. dissociation of benzoyl ester) is rate-determining. This finding for CocH-catalyzed hydrolysis of (+)-cocaine is remarkably different from that for the (+)-cocaine hydrolysis catalyzed by bacterial cocaine esterase in which the first reaction step of the deacylation is associated with the highest free energy barrier (~17.9 kcal/mol). The overall free energy barrier (~16.0 kcal/mol) calculated for the acylation stage of CocH-catalyzed hydrolysis of (+)-cocaine is in good agreement with the experimental free energy barrier of ~14.5 kcal/mol derivated from the experimental kinetic data.
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Affiliation(s)
- Yuan Yao
- Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536; The Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080, P.R. China
| | - Junjun Liu
- Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536; Tongji School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei 430030, P.R. China
| | - Fang Zheng
- Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536
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12
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Reilly PJ, Rovira C. Computational Studies of Glycoside, Carboxylic Ester, and Thioester Hydrolase Mechanisms: A Review. Ind Eng Chem Res 2015. [DOI: 10.1021/acs.iecr.5b01312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter J. Reilly
- Department
of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011-2230, United States
| | - Carme Rovira
- Departament de Química Orgànica
and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, 08028 Barcelona, Spain
- Institució
Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
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13
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Chung LW, Sameera WMC, Ramozzi R, Page AJ, Hatanaka M, Petrova GP, Harris TV, Li X, Ke Z, Liu F, Li HB, Ding L, Morokuma K. The ONIOM Method and Its Applications. Chem Rev 2015; 115:5678-796. [PMID: 25853797 DOI: 10.1021/cr5004419] [Citation(s) in RCA: 758] [Impact Index Per Article: 84.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lung Wa Chung
- †Department of Chemistry, South University of Science and Technology of China, Shenzhen 518055, China
| | - W M C Sameera
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Romain Ramozzi
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Alister J Page
- §Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan 2308, Australia
| | - Miho Hatanaka
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Galina P Petrova
- ∥Faculty of Chemistry and Pharmacy, University of Sofia, Bulgaria Boulevard James Bourchier 1, 1164 Sofia, Bulgaria
| | - Travis V Harris
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan.,⊥Department of Chemistry, State University of New York at Oswego, Oswego, New York 13126, United States
| | - Xin Li
- #State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Zhuofeng Ke
- ∇School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Fengyi Liu
- ○Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Hai-Bei Li
- ■School of Ocean, Shandong University, Weihai 264209, China
| | - Lina Ding
- ▲School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Keiji Morokuma
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
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14
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Nagy T, Yosa Reyes J, Meuwly M. Multisurface Adiabatic Reactive Molecular Dynamics. J Chem Theory Comput 2014; 10:1366-75. [PMID: 26580356 DOI: 10.1021/ct400953f] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Adiabatic reactive molecular dynamics (ARMD) simulation method is a surface-crossing algorithm for modeling chemical reactions in classical molecular dynamics simulations using empirical force fields. As the ARMD Hamiltonian is time dependent during crossing, it allows only approximate energy conservation. In the current work, the range of applicability of conventional ARMD is explored, and a new multisurface ARMD (MS-ARMD) method is presented, implemented in CHARMM and applied to the vibrationally induced photodissociation of sulfuric acid (H2SO4) in the gas phase. For this, an accurate global potential energy surface (PES) involving 12 H2SO4 and 4 H2O + SO3 force fields fitted to MP2/6-311G++(2d,2p) reference energies is employed. The MS-ARMD simulations conserve total energy and feature both intramolecular H-transfer reactions and water elimination. An analytical treatment of the dynamics in the crossing region finds that conventional ARMD can approximately conserve total energy for limiting cases. In one of them, the reduced mass of the system is large, which often occurs for simulations of solvated biomolecular systems. On the other hand, MS-ARMD is a general approach for modeling chemical reactions including gas-phase, homogeneous, heterogeneous, and enzymatic catalytic reactions while conserving total energy in atomistic simulations.
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Affiliation(s)
- Tibor Nagy
- Department of Chemistry, University of Basel , 4056 Basel, Switzerland
| | | | - Markus Meuwly
- Department of Chemistry, University of Basel , 4056 Basel, Switzerland
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15
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Zheng F, Xue L, Hou S, Liu J, Zhan M, Yang W, Zhan CG. A highly efficient cocaine-detoxifying enzyme obtained by computational design. Nat Commun 2014; 5:3457. [PMID: 24643289 PMCID: PMC3996704 DOI: 10.1038/ncomms4457] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/17/2014] [Indexed: 11/09/2022] Open
Abstract
Compared to naturally occurring enzymes, computationally designed enzymes are usually much less efficient, with their catalytic activities being more than six orders of magnitude below the diffusion limit. Here we use a two-step computational design approach, combined with experimental work, to design a highly efficient cocaine hydrolising enzyme. We engineer E30-6 from human butyrylcholinesterase (BChE), which is specific for cocaine hydrolysis, and obtain a much higher catalytic efficiency for cocaine conversion than for conversion of the natural BChE substrate, acetylcholine (ACh). The catalytic efficiency of E30-6 for cocaine hydrolysis is comparable to that of the most efficient known naturally-occurring hydrolytic enzyme, acetylcholinesterase, the catalytic activity of which approaches the diffusion limit. We further show that E30-6 can protect mice from a subsequently administered lethal dose of cocaine, suggesting the enzyme may have therapeutic potential in the setting of cocaine detoxification or cocaine abuse.
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Affiliation(s)
- Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Liu Xue
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Shurong Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Junjun Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Max Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Wenchao Yang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
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16
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Zhan CG. Novel pharmacological approaches to treatment of drug overdose and addiction. Expert Rev Clin Pharmacol 2014; 2:1-4. [PMID: 21072135 DOI: 10.1586/17512433.2.1.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chang-Guo Zhan
- University of Kentucky, Department of Pharmaceutical Sciences, College of Pharmacy, 789 South Limestone Street, Lexington, KY 40536, USA TEL: 859-323-3943 FAX: 859-323-3575
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17
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Hou S, Xue L, Yang W, Fang L, Zheng F, Zhan CG. Substrate selectivity of high-activity mutants of human butyrylcholinesterase. Org Biomol Chem 2013; 11:7477-85. [PMID: 24077614 PMCID: PMC3836059 DOI: 10.1039/c3ob41713a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cocaine is one of the most addictive drugs, and there is still no FDA (Food and Drug Administration)-approved medication specific for cocaine abuse. A promising therapeutic strategy is to accelerate cocaine metabolism, producing biologically inactive metabolites via a route similar to the primary cocaine-metabolizing pathway, i.e. cocaine hydrolysis catalyzed by butyrylcholinesterase (BChE) in plasma. However, the native BChE has a low catalytic efficiency against the abused cocaine, i.e. (-)-cocaine. Our recently designed and discovered A199S/F227A/S287G/A328W/Y332G mutant and other mutants of human BChE have a considerably improved catalytic efficiency against (-)-cocaine. In the present study, we carried out both computational modeling and experimental kinetic analysis on the catalytic activities of these promising new BChE mutants against other known substrates, including neurotransmitter acetylcholine (ACh), acetylthiocholine (ATC), butyrylthiocholine (BTC), and (+)-cocaine, in comparison with the corresponding catalytic activity against (-)-cocaine. Both the computational modeling and kinetic analysis have consistently revealed that all the examined amino acid mutations only considerably improve the catalytic efficiency of human BChE against (-)-cocaine, without significantly improving the catalytic efficiency of the enzyme against any of the other substrates examined. In particular, all the examined BChE mutants have a slightly lower catalytic efficiency against neurotransmitter ACh compared to the wild-type BChE. This observation gives us confidence in developing an anti-cocaine enzyme therapy by using one of these BChE mutants, particularly the A199S/F227A/S287G/A328W/Y332G mutant.
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Affiliation(s)
- Shurong Hou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA.
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18
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van der Kamp MW, Mulholland AJ. Combined quantum mechanics/molecular mechanics (QM/MM) methods in computational enzymology. Biochemistry 2013; 52:2708-28. [PMID: 23557014 DOI: 10.1021/bi400215w] [Citation(s) in RCA: 399] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Computational enzymology is a rapidly maturing field that is increasingly integral to understanding mechanisms of enzyme-catalyzed reactions and their practical applications. Combined quantum mechanics/molecular mechanics (QM/MM) methods are important in this field. By treating the reacting species with a quantum mechanical method (i.e., a method that calculates the electronic structure of the active site) and including the enzyme environment with simpler molecular mechanical methods, enzyme reactions can be modeled. Here, we review QM/MM methods and their application to enzyme-catalyzed reactions to investigate fundamental and practical problems in enzymology. A range of QM/MM methods is available, from cheaper and more approximate methods, which can be used for molecular dynamics simulations, to highly accurate electronic structure methods. We discuss how modeling of reactions using such methods can provide detailed insight into enzyme mechanisms and illustrate this by reviewing some recent applications. We outline some practical considerations for such simulations. Further, we highlight applications that show how QM/MM methods can contribute to the practical development and application of enzymology, e.g., in the interpretation and prediction of the effects of mutagenesis and in drug and catalyst design.
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Affiliation(s)
- Marc W van der Kamp
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
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19
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Zheng F, Zhan CG. Modeling of pharmacokinetics of cocaine in human reveals the feasibility for development of enzyme therapies for drugs of abuse. PLoS Comput Biol 2012; 8:e1002610. [PMID: 22844238 PMCID: PMC3406004 DOI: 10.1371/journal.pcbi.1002610] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 05/29/2012] [Indexed: 12/05/2022] Open
Abstract
A promising strategy for drug abuse treatment is to accelerate the drug metabolism by administration of a drug-metabolizing enzyme. The question is how effectively an enzyme can actually prevent the drug from entering brain and producing physiological effects. In the present study, we have developed a pharmacokinetic model through a combined use of in vitro kinetic parameters and positron emission tomography data in human to examine the effects of a cocaine-metabolizing enzyme in plasma on the time course of cocaine in plasma and brain of human. Without an exogenous enzyme, cocaine half-lives in both brain and plasma are almost linearly dependent on the initial cocaine concentration in plasma. The threshold concentration of cocaine in brain required to produce physiological effects has been estimated to be 0.22±0.07 µM, and the threshold area under the cocaine concentration versus time curve (AUC) value in brain (denoted by AUC2∞) required to produce physiological effects has been estimated to be 7.9±2.7 µM·min. It has been demonstrated that administration of a cocaine hydrolase/esterase (CocH/CocE) can considerably decrease the cocaine half-lives in both brain and plasma, the peak cocaine concentration in brain, and the AUC2∞. The estimated maximum cocaine plasma concentration which a given concentration of drug-metabolizing enzyme can effectively prevent from entering brain and producing physiological effects can be used to guide future preclinical/clinical studies on cocaine-metabolizing enzymes. Understanding of drug-metabolizing enzymes is key to the science of pharmacokinetics. The general insights into the effects of a drug-metabolizing enzyme on drug kinetics in human should be valuable also in future development of enzyme therapies for other drugs of abuse. In this computational study, we have examined, for the first time, the potential effects of a drug-metabolizing enzyme on drug pharmacokinetics in human, showing that a high-activity drug-metabolizing enzyme can completely/effectively prevent the drug of abuse from entering brain to produce physiological effects. Based on this encouraging insight, it is feasible to develop enzyme therapies for drugs of abuse. Through pharmacokinetic modeling, we have demonstrated that, without an exogenous enzyme, the drug half-lives in both brain and plasma are almost linearly dependent on the initial drug concentration in plasma. This finding indicates that one may not simply say the half-life of a drug without clearly indicating the actual dose condition. We have also demonstrated for the first time how a high-activity drug-metabolizing enzyme can considerably decrease the peak concentration of drug in brain and drug half-lives in both brain and plasma. In addition, we have calculated the minimum (threshold) concentration of cocaine in brain required to produce physiological effects. The predicted threshold concentration, along with all of the general insights obtained in this study, will provide a rational base for future design of further experimental studies required for the enzyme therapy development.
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Affiliation(s)
- Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, United States of America
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20
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Liu J, Zhan CG. Reaction Pathway and Free Energy Profile for Cocaine Hydrolase-Catalyzed Hydrolysis of (-)-Cocaine. J Chem Theory Comput 2012; 8:1426-1435. [PMID: 23066354 PMCID: PMC3469271 DOI: 10.1021/ct200810d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction pathway of (-)-cocaine hydrolysis catalyzed by our recently discovered most efficient cocaine hydrolase, which is the A199S/F227A/S287G/A328W/Y332G mutant of human butyrylcholinesterase (BChE), and the corresponding free energy profile have been studied by performing first-principles pseudobond quantum mechanical/molecular mechanical (QM/MM)-free energy (FE) calculations. Based on the QM/MM-FE results, the catalytic hydrolysis process consists of four major reaction steps, including the nucleophilic attack on carbonyl carbon of (-)-cocaine benzoyl ester by hydroxyl group of S198, dissociation of (-)-cocaine benzoyl ester, nucleophilic attack on carbonyl carbon of (-)-cocaine benzoyl ester by water, and finally the dissociation between (-)-cocaine benzoyl group and S198 of the enzyme. The second reaction step is rate-determining. The calculated free energy barrier associated with the transition state for the rate-determining step is ~15.0 kcal/mol, which is in excellent agreement with the experimentally-derived activation free energy of ~14.7 kcal/mol. The mechanistic insights obtained from the present study will be valuable for rational design of more active cocaine hydrolase against (-)-cocaine. In particular, future efforts aiming at further increasing the catalytic activity of the enzyme against (-)-cocaine should focus on stabilization of the transition state for the second reaction step in which the benzoyl ester of (-)-cocaine dissociates.
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Affiliation(s)
- Junjun Liu
- Tongji School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei 430030, P.R. China
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
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21
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Chen X, Fang L, Liu J, Zhan CG. Reaction pathway and free energy profiles for butyrylcholinesterase-catalyzed hydrolysis of acetylthiocholine. Biochemistry 2012; 51:1297-305. [PMID: 22304234 DOI: 10.1021/bi201786s] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The catalytic mechanism for butyrylcholineserase (BChE)-catalyzed hydrolysis of acetylthiocholine (ATCh) has been studied by performing pseudobond first-principles quantum mechanical/molecular mechanical-free energy (QM/MM-FE) calculations on both acylation and deacylation of BChE. Additional quantum mechanical (QM) calculations have been carried out, along with the QM/MM-FE calculations, to understand the known substrate activation effect on the enzymatic hydrolysis of ATCh. It has been shown that the acylation of BChE with ATCh consists of two reaction steps including the nucleophilic attack on the carbonyl carbon of ATCh and the dissociation of thiocholine ester. The deacylation stage includes nucleophilic attack of a water molecule on the carboxyl carbon of substrate and dissociation between the carboxyl carbon of substrate and hydroxyl oxygen of Ser198 side chain. QM/MM-FE calculation results reveal that the acylation of BChE is rate-determining. It has also been demonstrated that an additional substrate molecule binding to the peripheral anionic site (PAS) of BChE is responsible for the substrate activation effect. In the presence of this additional substrate molecule at PAS, the calculated free energy barrier for the acylation stage (rate-determining step) is decreased by ~1.7 kcal/mol. All of our computational predictions are consistent with available experimental kinetic data. The overall free energy barriers calculated for BChE-catalyzed hydrolysis of ATCh at regular hydrolysis phase and substrate activation phase are ~13.6 and ~11.9 kcal/mol, respectively, which are in reasonable agreement with the corresponding experimentally derived activation free energies of 14.0 kcal/mol (for regular hydrolysis phase) and 13.5 kcal/mol (for substrate activation phase).
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Affiliation(s)
- Xi Chen
- Key Laboratory of Pesticide & Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
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22
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Sousa SF, Fernandes PA, Ramos MJ. Computational enzymatic catalysis – clarifying enzymatic mechanisms with the help of computers. Phys Chem Chem Phys 2012; 14:12431-41. [DOI: 10.1039/c2cp41180f] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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23
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Huang X, Zheng F, Zhan CG. Human butyrylcholinesterase-cocaine binding pathway and free energy profiles by molecular dynamics and potential of mean force simulations. J Phys Chem B 2011; 115:11254-60. [PMID: 21902185 DOI: 10.1021/jp2047807] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present study, we have performed combined molecular dynamics and potential of mean force (PMF) simulations to determine the enzyme-substrate (ES) binding pathway and the corresponding free energy profiles for wild-type butyrylcholinesterase (BChE) binding with (-)/(+)-cocaine and for the A328W/Y332G mutant binding with (-)-cocaine. According to the PMF simulations, for each ES binding system, the substrate first binds with the enzyme at a peripheral anionic site around the entrance of the active-site gorge to form the first ES complex (ES1-like) during the binding process. Further evolution from the ES1-like complex to the nonprereactive ES complex is nearly barrierless, with a free energy barrier lower than 1.0 kcal/mol. So, the nonprereactive ES binding process should be very fast. The rate-determining step of the entire ES binding process is the subsequent evolution from the nonprereactive ES complex to the prereactive ES complex. Further accounting for the entire ES binding process, the PMF-based simulations qualitatively reproduced the relative order of the experimentally derived binding free energies (ΔG(bind)), although the simulations systematically overestimated the magnitude of the binding affinity and systematically underestimated the differences between the ΔG(bind) values. The obtained structural and energetic insights into the entire ES binding process provide a valuable base for future rational design of high-activity mutants of BChE as candidates for an enzyme therapy for cocaine overdose and abuse.
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Affiliation(s)
- Xiaoqin Huang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, USA
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24
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Recent progress in protein drug design and discovery with a focus on novel approaches to the development of anti-cocaine medications. Future Med Chem 2011; 1:515-28. [PMID: 20161378 DOI: 10.4155/fmc.09.20] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cocaine is highly addictive and no anti-cocaine medication is currently available. Accelerating cocaine metabolism, producing biologically inactive metabolites, is recognized as an ideal anti-cocaine medication strategy, especially for the treatment of acute cocaine toxicity. However, currently known wild-type enzymes have either too low a catalytic efficiency against the abused cocaine, in other words (-)-cocaine, or the in vivo half-life is too short. Novel computational strategies and design approaches have been developed recently to design and discover thermostable or high-activity mutants of enzymes based on detailed structures and catalytic/inactivation mechanisms. The structure- and mechanism-based computational design efforts have led to the discovery of high-activity mutants of butyrylcholinesterase and thermostable mutants of cocaine esterase as promising anti-cocaine therapeutics. The structure- and mechanism-based computational strategies and design approaches may be used to design high-activity and/or thermostable mutants of many other proteins that have clear therapeutic potentials and to design completely new therapeutic enzymes.
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25
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Liu J, Zhao X, Yang W, Zhan CG. Reaction mechanism for cocaine esterase-catalyzed hydrolyses of (+)- and (-)-cocaine: unexpected common rate-determining step. J Phys Chem B 2011; 115:5017-25. [PMID: 21486046 PMCID: PMC3087188 DOI: 10.1021/jp200975v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
First-principles quantum mechanical/molecular mechanical free energy calculations have been performed to examine the catalytic mechanism for cocaine esterase (CocE)-catalyzed hydrolysis of (+)-cocaine in comparison with CocE-catalyzed hydrolysis of (-)-cocaine. It has been shown that the acylation of (+)-cocaine consists of nucleophilic attack of the hydroxyl group of Ser117 on the carbonyl carbon of (+)-cocaine benzoyl ester and the dissociation of (+)-cocaine benzoyl ester. The first reaction step of deacylation of (+)-cocaine, which is identical to that of (-)-cocaine, is rate-determining, indicating that CocE-catalyzed hydrolyses of (+)- and (-)-cocaine have a common rate-determining step. The computational results predict that the catalytic rate constant of CocE against (+)-cocaine should be the same as that of CocE against (-)-cocaine, in contrast with the remarkable difference between human butyrylcholinesterase-catalyzed hydrolyses of (+)- and (-)-cocaine. The prediction has been confirmed by experimental kinetic analysis on CocE-catalyzed hydrolysis of (+)-cocaine in comparison with CocE-catalyzed hydrolysis of (-)-cocaine. The determined common rate-determining step indicates that rational design of a high-activity mutant of CocE should be focused on the first reaction step of the deacylation. Furthermore, the obtained mechanistic insights into the detailed differences in the acylation between the (+)- and (-)-cocaine hydrolyses provide indirect clues for rational design of amino acid mutations that could more favorably stabilize the rate-determining transition state in the deacylation and, thus, improve the catalytic activity of CocE. This study provides a valuable mechanistic base for rational design of an improved esterase for therapeutic treatment of cocaine abuse.
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Affiliation(s)
| | | | - Wenchao Yang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
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26
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Huang X, Pan Y, Zheng F, Zhan CG. Reaction pathway and free energy profile for prechemical reaction step of human butyrylcholinesterase-catalyzed hydrolysis of (-)-cocaine by combined targeted molecular dynamics and potential of mean force simulations. J Phys Chem B 2011; 114:13545-54. [PMID: 20883001 DOI: 10.1021/jp106539w] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Combined targeted molecular dynamics (TMD) and potential of mean force (PMF) simulations have been carried out to uncover the detailed pathway and determine the corresponding free energy profile for the structural transformation from the nonprereactive butyrylcholinesterase (BChE)-(-)-cocaine binding to the prereactive BChE-(-)-cocaine binding associated with the (-)-cocaine rotation in the binding pocket of BChE. It has been shown that the structural transformation involves two transition states (TS1(rot) and TS2(rot)). TS1(rot) is mainly associated with the deformation of the nonprereactive complex, whereas TS2(rot) is mainly associated with the formation of the prereactive complex. It has also been demonstrated that the A328W/Y332G mutation significantly reduces the steric hindrance for (-)-cocaine rotation in the binding pocket of BChE and, thus, decreases the free energy barrier for the structural transformation from the nonprereactive binding to the prereactive binding. The calculated relative free energy barriers are all consistent with available experimental kinetic data. The new mechanistic insights obtained and the novel computational protocol tested in this study should be valuable for future computational design of high-activity mutants of BChE. The general computational strategy and approach based on the combined TMD and PMF simulations may be also valuable in computational studies of detailed pathways and free energy profiles for other similar mechanistic problems involving ligand rotation or another type of structural transformation in the binding pocket of a protein.
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Affiliation(s)
- Xiaoqin Huang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone, Lexington, Kentucky 40536, USA
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27
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Xue L, Ko MC, Tong M, Yang W, Hou S, Fang L, Liu J, Zheng F, Woods JH, Tai HH, Zhan CG. Design, preparation, and characterization of high-activity mutants of human butyrylcholinesterase specific for detoxification of cocaine. Mol Pharmacol 2011; 79:290-7. [PMID: 20971807 PMCID: PMC3033707 DOI: 10.1124/mol.110.068494] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Accepted: 10/22/2010] [Indexed: 11/22/2022] Open
Abstract
Cocaine is a widely abused drug without a U.S. Food and Drug Administration-approved medication. There is a recognized, promising anticocaine medication to accelerate cocaine metabolism, producing biologically inactive metabolites via a route similar to the primary cocaine-metabolizing pathway [i.e., cocaine hydrolysis catalyzed by butyrylcholinesterase (BChE) in plasma]. An ideal, therapeutically valuable mutant of human BChE should have not only a significantly improved catalytic activity against (-)-cocaine but also certain selectivity for (-)-cocaine over neurotransmitter acetylcholine (ACh), such that one would not expect systemic administration of the BChE mutant to interrupt cholinergic transmission. The present study accounting for the mutation-caused changes of the catalytic activities of BChE against both (-)-cocaine and ACh by means of molecular modeling and site-directed mutagenesis has led to identification of three BChE mutants that have not only a considerably improved catalytic efficiency against (-)-cocaine but also the desirable selectivity for (-)-cocaine over ACh. Two representative BChE mutants have been confirmed to be potent in actual protection of mice from acute toxicity (convulsion and lethality) of a lethal dose of cocaine (180 mg/kg). Pretreatment with the BChE mutant (i.e., 1 min before cocaine administration) dose-dependently protected mice against cocaine-induced convulsions and lethality. In particular, all mice pretreated with the mutant (e.g., 0.02 mg or more of A199S/F227A/S287G/A328W/E441D BChE) survived. The in vivo data reveal the primary factor (i.e., the relative catalytic efficiency), determining the efficacy in practical protection of mice from the acute cocaine toxicity and future direction for further improving the efficacy of the enzyme in the cocaine overdose treatment.
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Affiliation(s)
- Liu Xue
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street Lexington, KY 40536, USA
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Abstract
“Recent progress in the study of cocaine-metabolizing enzymes demonstrates that enzyme-therapy approaches using appropriately designed enzymes show promise for the treatment of drug overdose and addiction.”
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Affiliation(s)
- Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
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29
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Chen X, Fang L, Liu J, Zhan CG. Reaction pathway and free energy profile for butyrylcholinesterase-catalyzed hydrolysis of acetylcholine. J Phys Chem B 2010; 115:1315-22. [PMID: 21175195 DOI: 10.1021/jp110709a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A catalytic mechanism for the butyrylcholinesterase (BChE)-catalyzed hydrolysis of acetylcholine (ACh) has been studied by performing pseudobond first-principles quantum mechanical/molecular mechanical-free energy calculations on both acylation and deacylation of BChE. It has been shown that the acylation with ACh includes two reaction steps, including nucleophilic attack on the carbonyl carbon of ACh and dissociation of choline ester. The deacylation stage includes nucleophilic attack of a water molecule on the carboxyl carbon of the substrate and dissociation between the carboxyl carbon of the substrate and the hydroxyl oxygen of the Ser198 side chain. Notably, despite the fact that acetylcholinesterase (AChE) and BChE are very similar enzymes, the acylation of BChE with ACh is rate-determining, which is remarkably different from the AChE-catalyzed hydrolysis of ACh, in which the deacylation is rate-determining. The computational prediction is consistent with available experimental kinetic data. The overall free energy barrier calculated for BChE-catalyzed hydrolysis of ACh is 13.8 kcal/mol, which is in good agreement with the experimentally derived activation free energy of 13.3 kcal/mol.
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Affiliation(s)
- Xi Chen
- Key Laboratory of Pesticide & Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, P R China
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30
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Zheng F, Yang W, Xue L, Hou S, Liu J, Zhan CG. Design of high-activity mutants of human butyrylcholinesterase against (-)-cocaine: structural and energetic factors affecting the catalytic efficiency. Biochemistry 2010; 49:9113-9. [PMID: 20886866 DOI: 10.1021/bi1011628] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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.
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Affiliation(s)
- Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, Kentucky 40536, United States
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31
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Yang W, Xue L, Fang L, Chen X, Zhan CG. Characterization of a high-activity mutant of human butyrylcholinesterase against (-)-cocaine. Chem Biol Interact 2010; 187:148-52. [PMID: 20060817 PMCID: PMC2891156 DOI: 10.1016/j.cbi.2010.01.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 12/30/2009] [Accepted: 01/04/2010] [Indexed: 11/30/2022]
Abstract
Cocaine addiction and overdose are a well-known public health problem. There is no approved medication available for cocaine abuse treatment. Our recently designed and discovered high-activity mutant (A199S/S287G/A328W/Y332G) of human butyrylcholinesterase (BChE) has been recognized to be worth exploring for clinical application in humans as a potential anti-cocaine medication. The catalytic rate constant (k(cat)) and Michaelis-Menten constant (K(M)) for (-)-cocaine hydrolysis catalyzed by A199S/S287G/A328W/Y332G BChE (without fusion with any other peptide) have been determined to be 3,060 min(-1) and 3.1 microM, respectively, in the present study. The determined kinetic parameters reveal that the un-fused A199S/S287G/A328W/Y332G mutant has a approximately 1,080-fold improved catalytic efficiency (k(cat)/K(M)) against (-)-cocaine compared to the wild-type BChE. The approximately 1,080-fold improvement in the catalytic efficiency of the un-fused A199S/S287G/A328W/Y332G mutant is very close to the previously reported the approximately 1,000-fold improvement in the catalytic efficiency of the A199S/S287G/A328W/Y332G mutant fused with human serum albumin. These results suggest that the albumin fusion did not significantly change the catalytic efficiency of the BChE mutant while extending the plasma half-life. In addition, we have also examined the catalytic activities of the A199S/S287G/A328W/Y332G mutant against two other substrates, acetylthiocholine (ATC) and butyrylthiocholine (BTC). It has been shown that the A199S/S287G/A328W/Y332G mutations actually decreased the catalytic efficiencies of BChE against ATC and BTC, while considerably improving the catalytic efficiency of BChE against (-)-cocaine.
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Affiliation(s)
- Wenchao Yang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536, USA
| | - Liu Xue
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536, USA
| | - Lei Fang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536, USA
| | - Xi Chen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536, USA
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536, USA
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32
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Yang W, Pan Y, Fang L, Gao D, Zheng F, Zhan CG. Free energy perturbation simulation on transition states and high-activity mutants of human butyrylcholinesterase for (-)-cocaine hydrolysis. J Phys Chem B 2010; 114:10889-96. [PMID: 20677742 PMCID: PMC2930763 DOI: 10.1021/jp104989b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A unified computational approach based on free energy perturbation (FEP) simulations of transition states has been employed to calculate the mutation-caused shifts of the free energy change from the free enzyme to the rate-determining transition state for (-)-cocaine hydrolysis catalyzed by the currently most promising series of mutants of human butyrylcholinesterase (BChE) that contain the A199S/A328W/Y332G mutations. The FEP simulations were followed by Michaelis-Menten kinetics analysis determining the individual k(cat) and K(M) values missing for the A199S/F227A/A328W/Y332G mutant in this series. The calculated mutation-caused shifts of the free energy change from the free enzyme to the rate-determining transition state are in good agreement with the experimental kinetic data, demonstrating that the unified computational approach based on the FEP simulations of the transition states may be valuable for future computational design of new BChE mutants with a further improved catalytic efficiency against (-)-cocaine.
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Affiliation(s)
- Wenchao Yang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536
| | - Yongmei Pan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536
| | - Lei Fang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536
| | - Daquan Gao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536
| | - Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone, Lexington, KY 40536
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33
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Modeling of the mechanism of hydrolysis of succinylcholine in the active site of native and modified (Asp70Gly) human butyrylcholinesterase. Russ Chem Bull 2010. [DOI: 10.1007/s11172-010-0044-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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34
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Huang X, Gu HH, Zhan CG. Mechanism for cocaine blocking the transport of dopamine: insights from molecular modeling and dynamics simulations. J Phys Chem B 2010; 113:15057-66. [PMID: 19831380 DOI: 10.1021/jp900963n] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Molecular modeling and dynamics simulations have been performed to study how cocaine inhibits dopamine transporter (DAT) for the transport of dopamine. The computationally determined DAT-ligand binding mode is totally different from the previously proposed overlap binding mode in which cocaine- and dopamine-binding sites are the same (Beuming, T.; et al. Nat. Neurosci. 2008, 11, 780-789). The new cocaine-binding site does not overlap with, but is close to, the dopamine-binding site. Analysis of all results reveals that when cocaine binds to DAT, the initial binding site is likely the one modeled in this study because this binding site can naturally accommodate cocaine. Then cocaine may move to the dopamine-binding site after DAT makes some necessary conformational change and expands the binding site cavity. It has been demonstrated that cocaine may inhibit the transport of dopamine through both blocking the initial DAT-dopamine binding and reducing the kinetic turnover of the transporter following the DAT-dopamine binding. The relative contributions to the phenomenological inhibition of the transport of dopamine from blocking the initial binding and reducing the kinetic turnover can be different in different types of assays. The obtained general structural and mechanistic insights are consistent with available experimental data and could be valuable for guiding future studies toward understanding cocaine's inhibiting of other transporters.
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Affiliation(s)
- Xiaoqin Huang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, Kentucky 40536, USA
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35
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Ranaghan KE, Mulholland AJ. Investigations of enzyme-catalysed reactions with combined quantum mechanics/molecular mechanics (QM/MM) methods. INT REV PHYS CHEM 2010. [DOI: 10.1080/01442350903495417] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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36
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Liu J, Zhang Y, Zhan CG. Reaction pathway and free-energy barrier for reactivation of dimethylphosphoryl-inhibited human acetylcholinesterase. J Phys Chem B 2009. [PMID: 19924840 DOI: 10.1021/jp903600r] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
The dephosphorylation/reactivation mechanism and the corresponding free-energy profile of the dimethylphosphoryl-inhibited conjugate of human acetylcholinesterase (AChE) has been studied by performing first-principles quantum mechanical/molecular mechanical free-energy (QM/MM-FE) calculations. On the basis of the QM/MM-FE results, for the favorable reaction pathway, the entire dephosphorylation/reactivation process consists of three reaction steps, including the nucleophilic water attack on the P atom, the spatial reorganization of the dimethylphosphoryl group, and the dissociation between the dimethylphosphoryl group and Ser203 of AChE. The overall free-energy barrier for the entire dephosphorylation/reactivation reaction is found to be the free-energy change from the initial reactant to the transition state associated with the spatial reorganization step, and the calculated overall free-energy barrier (20.1 to 23.5 kcal/mol) is reasonably close to the experimentally derived activation free energy of 22.3 kcal/mol. In addition, key amino acid residues and their specific roles in the reaction process have been identified.
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Affiliation(s)
- Junjun Liu
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
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37
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Liu J, Zhang Y, Zhan CG. Reaction pathway and free-energy barrier for reactivation of dimethylphosphoryl-inhibited human acetylcholinesterase. J Phys Chem B 2009; 113:16226-36. [PMID: 19924840 PMCID: PMC2795121 DOI: 10.1021/jp9055335] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The dephosphorylation/reactivation mechanism and the corresponding free-energy profile of the dimethylphosphoryl-inhibited conjugate of human acetylcholinesterase (AChE) has been studied by performing first-principles quantum mechanical/molecular mechanical free-energy (QM/MM-FE) calculations. On the basis of the QM/MM-FE results, for the favorable reaction pathway, the entire dephosphorylation/reactivation process consists of three reaction steps, including the nucleophilic water attack on the P atom, the spatial reorganization of the dimethylphosphoryl group, and the dissociation between the dimethylphosphoryl group and Ser203 of AChE. The overall free-energy barrier for the entire dephosphorylation/reactivation reaction is found to be the free-energy change from the initial reactant to the transition state associated with the spatial reorganization step, and the calculated overall free-energy barrier (20.1 to 23.5 kcal/mol) is reasonably close to the experimentally derived activation free energy of 22.3 kcal/mol. In addition, key amino acid residues and their specific roles in the reaction process have been identified.
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Affiliation(s)
- Junjun Liu
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
| | - Yingkai Zhang
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
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38
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Liu J, Hamza A, Zhan CG. Fundamental reaction mechanism and free energy profile for (-)-cocaine hydrolysis catalyzed by cocaine esterase. J Am Chem Soc 2009; 131:11964-75. [PMID: 19642701 PMCID: PMC2738781 DOI: 10.1021/ja903990p] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fundamental reaction mechanism of cocaine esterase (CocE)-catalyzed hydrolysis of (-)-cocaine and the corresponding free energy profile have been studied by performing pseudobond first-principles quantum mechanical/molecular mechanical free energy (QM/MM-FE) calculations. On the basis of the QM/MM-FE results, the entire hydrolysis reaction consists of four reaction steps, including the nucleophilic attack on the carbonyl carbon of (-)-cocaine benzoyl ester by the hydroxyl group of Ser117, dissociation of (-)-cocaine benzoyl ester, nucleophilic attack on the carbonyl carbon of (-)-cocaine benzoyl ester by water, and finally dissociation between the (-)-cocaine benzoyl group and Ser117 of CocE. The third reaction step involving the nucleophilic attack of a water molecule was found to be rate-determining, which is remarkably different from (-)-cocaine hydrolysis catalyzed by wild-type butyrylcholinesterase (BChE; where the formation of the prereactive BChE-(-)-cocaine complex is rate-determining) or its mutants containing Tyr332Gly or Tyr332Ala mutation (where the first chemical reaction step is rate-determining). Besides, the role of Asp259 in the catalytic triad of CocE does not follow the general concept of the "charge-relay system" for all serine esterases. The free energy barrier calculated for the rate-determining step of CocE-catalyzed hydrolysis of (-)-cocaine is 17.9 kcal/mol, which is in good agreement with the experimentally derived activation free energy of 16.2 kcal/mol. In the present study, where many sodium ions are present, the effects of counterions are found to be significant in determining the free energy barrier. The finding of the significant effects of counterions on the free energy barrier may also be valuable in guiding future mechanistic studies on other charged enzymes.
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Affiliation(s)
- Junjun Liu
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
| | - Adel Hamza
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
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39
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Pan Y, Muzyka JL, Zhan CG. Model of human butyrylcholinesterase tetramer by homology modeling and dynamics simulation. J Phys Chem B 2009; 113:6543-52. [PMID: 19402731 DOI: 10.1021/jp8114995] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A mutant of human butyrylcholinesterase (BChE) with high activity against cocaine would be highly promising as a drug for therapeutic treatment of cocaine abuse and overdose. It is desirable to design a recombinant BChE mutant with a long half-life in human circulation. Studies showed that BChE subunits can be assembled by a peptide containing the proline-rich attachment domain (PRAD) to form a stable tetramer. The models of BChE tetramer complexed with PRAD with various sequences have been constructed, in the present study, on the basis of homology modeling and molecular dynamics simulation of explicit water-solvated systems. The 3D models enable us to understand how the BChE subunits are arranged in the tetramer and how the tetramerization domain of BChE is associated with PRAD to form a stable tetramer of human BChE. It has been shown that the six conserved hydrophobic residues located on the C-terminal of BChE are responsible for the key electrostatic and hydrophobic interactions between the tetramerization domain of BChE and PRAD. The simulated tetramer structures suggest that mutation of three residues, i.e., Phe547, Met554, and Phe561, to other hydrophobic residues may be beneficial for increasing the binding between the tetramerization domain of BChE and PRAD. Thus, the detailed structural insights obtained from this study may be valuable for rational design of a recombinant BChE tetramer with a longer residence time in circulation.
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Affiliation(s)
- Yongmei Pan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, Kentucky 40536, USA
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40
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Yang W, Pan Y, Zheng F, Cho H, Tai HH, Zhan CG. Free-energy perturbation simulation on transition states and redesign of butyrylcholinesterase. Biophys J 2009; 96:1931-8. [PMID: 19254552 DOI: 10.1016/j.bpj.2008.11.051] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 11/24/2008] [Indexed: 11/28/2022] Open
Abstract
It is recognized that an ideal anti-cocaine treatment is to accelerate cocaine metabolism by producing biologically inactive metabolites via a route similar to the primary cocaine-metabolizing pathway, i.e., butyrylcholinesterase (BChE)-catalyzed hydrolysis of cocaine. BChE mutants with a higher catalytic activity against (-)-cocaine are highly desired for use as an exogenous enzyme in humans. To develop a rational design for high-activity mutants, we carried out free-energy perturbation (FEP) simulations on various mutations of the transition-state structures in addition to the corresponding free-enzyme structures by using an extended FEP procedure. The FEP simulations on the mutations of both the free-enzyme and transition-state structures allowed us to calculate the mutation-caused shift of the free-energy change from the free enzyme (BChE) to the transition state, and thus to theoretically predict the mutation-caused shift of the catalytic efficiency (k(cat)/K(M)). The computational predictions are supported by the kinetic data obtained from the wet experiments, demonstrating that the FEP-based computational design approach is promising for rational design of high-activity mutants of an enzyme. One of the BChE mutants designed and discovered in this study has an approximately 1800-fold improved catalytic efficiency against (-)-cocaine compared to wild-type BChE. The high-activity mutant may be therapeutically valuable.
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Affiliation(s)
- Wenchao Yang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, PR China
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41
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Smith AJT, Müller R, Toscano MD, Kast P, Hellinga HW, Hilvert D, Houk KN. Structural reorganization and preorganization in enzyme active sites: comparisons of experimental and theoretically ideal active site geometries in the multistep serine esterase reaction cycle. J Am Chem Soc 2008; 130:15361-73. [PMID: 18939839 DOI: 10.1021/ja803213p] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many enzymes catalyze reactions with multiple chemical steps, requiring the stabilization of multiple transition states during catalysis. Such enzymes must strike a balance between the conformational reorganization required to stabilize multiple transition states of a reaction and the confines of a preorganized active site in the polypeptide tertiary structure. Here we investigate the compromise between structural reorganization during the catalytic process and preorganization of the active site for a multistep enzyme-catalyzed reaction, the hydrolysis of esters by the Ser-His-Asp/Glu catalytic triad. Quantum mechanical transition states were used to generate ensembles of geometries that can catalyze each individual step in the mechanism. These geometries are compared to each other by superpositions of catalytic atoms to find "consensus" geometries that can catalyze all steps with minimal rearrangement. These consensus geometries are found to be excellent matches for the natural active site. Preorganization is therefore found to be the major defining characteristic of the active site, and reorganizational motions often proposed to promote catalysis have been minimized. The variability of enzyme active sites observed by X-ray crystallography was also investigated empirically. A catalog of geometrical parameters relating active site residues to each other and to bound inhibitors was collected from a set of crystal structures. The crystal-structure-derived values were then compared to the ranges found in quantum mechanically optimized structures along the entire reaction coordinate. The empirical ranges are found to encompass the theoretical ranges when thermal fluctuations are taken into account. Therefore, the active sites are preorganized to a geometry that can be objectively and quantitatively defined as minimizing conformational reorganization while maintaining optimal transition state stabilization for every step during catalysis. The results provide a useful guiding principle for de novo design of enzymes with multistep mechanisms.
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Affiliation(s)
- Adam J T Smith
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
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42
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Zheng F, Yang W, Ko MC, Liu J, Cho H, Gao D, Tong M, Tai HH, Woods JH, Zhan CG. Most efficient cocaine hydrolase designed by virtual screening of transition states. J Am Chem Soc 2008; 130:12148-55. [PMID: 18710224 DOI: 10.1021/ja803646t] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cocaine is recognized as the most reinforcing of all drugs of abuse. There is no anticocaine medication available. The disastrous medical and social consequences of cocaine addiction have made the development of an anticocaine medication a high priority. It has been recognized that an ideal anticocaine medication is one that accelerates cocaine metabolism producing biologically inactive metabolites via a route similar to the primary cocaine-metabolizing pathway, i.e., cocaine hydrolysis catalyzed by plasma enzyme butyrylcholinesterase (BChE). However, wild-type BChE has a low catalytic efficiency against the abused cocaine. Design of a high-activity enzyme mutant is extremely challenging, particularly when the chemical reaction process is rate-determining for the enzymatic reaction. Here we report the design and discovery of a high-activity mutant of human BChE by using a novel, systematic computational design approach based on transition-state simulations and activation energy calculations. The novel computational design approach has led to discovery of the most efficient cocaine hydrolase, i.e., a human BChE mutant with an approximately 2000-fold improved catalytic efficiency, promising for therapeutic treatment of cocaine overdose and addiction as an exogenous enzyme in human. The encouraging discovery resulted from the computational design not only provides a promising anticocaine medication but also demonstrates that the novel, generally applicable computational design approach is promising for rational enzyme redesign and drug discovery.
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Affiliation(s)
- Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, Kentucky 40536, USA
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43
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Pan Y, Gao D, Zhan CG. Modeling the catalysis of anti-cocaine catalytic antibody: competing reaction pathways and free energy barriers. J Am Chem Soc 2008; 130:5140-9. [PMID: 18341277 DOI: 10.1021/ja077972s] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The competing reaction pathways and the corresponding free energy barriers for cocaine hydrolysis catalyzed by an anti-cocaine catalytic antibody, mAb15A10, were studied by using a novel computational strategy based on the binding free energy calculations on the antibody binding with cocaine and transition states. The calculated binding free energies were used to evaluate the free energy barrier shift from the cocaine hydrolysis in water to the antibody-catalyzed cocaine hydrolysis for each reaction pathway. The free energy barriers for the antibody-catalyzed cocaine hydrolysis were predicted to be the corresponding free energy barriers for the cocaine hydrolysis in water plus the calculated free energy barrier shifts. The calculated free energy barrier shift of -6.87 kcal/mol from the dominant reaction pathway of the cocaine benzoyl ester hydrolysis in water to the dominant reaction pathway of the antibody-catalyzed cocaine hydrolysis is in good agreement with the experimentally derived free energy barrier shift of -5.93 kcal/mol. The calculated mutation-caused shifts of the free energy barrier are also reasonably close to the available experimental activity data. The good agreement suggests that the protocol for calculating the free energy barrier shift from the cocaine hydrolysis in water to the antibody-catalyzed cocaine hydrolysis may be used in future rational design of possible high-activity mutants of the antibody as anti-cocaine therapeutics. The general strategy of the free energy barrier shift calculation may also be valuable in studying a variety of chemical reactions catalyzed by other antibodies or proteins through noncovalent bonding interactions with the substrates.
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Affiliation(s)
- Yongmei Pan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, Kentucky 40536, USA
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Zheng F, Zhan CG. Structure-and-mechanism-based design and discovery of therapeutics for cocaine overdose and addiction. Org Biomol Chem 2007; 6:836-43. [PMID: 18292872 DOI: 10.1039/b716268e] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
(-)-Cocaine is a widely abused drug and there is currently no available anti-cocaine therapeutic. Promising agents, such as anti-cocaine catalytic antibodies and high-activity mutants of human butyrylcholinesterase (BChE), for therapeutic treatment of cocaine overdose have been developed through structure-and-mechanism-based design and discovery. In particular, a unique computational design strategy based on the modeling and simulation of the rate-determining transition state has been developed and used to design and discover desirable high-activity mutants of BChE. One of the discovered high-activity mutants of BChE has a approximately 456-fold improved catalytic efficiency against (-)-cocaine. The encouraging outcome of the structure-and-mechanism-based design and discovery effort demonstrates that the unique computational design approach based on transition state modeling and simulation is promising for rational enzyme redesign and drug discovery. The general approach of the structure-and-mechanism-based design and discovery may be used to design high-activity mutants of any enzyme or catalytic antibody.
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Affiliation(s)
- Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536, USA
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45
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Rational design of an enzyme mutant for anti-cocaine therapeutics. J Comput Aided Mol Des 2007; 22:661-71. [PMID: 17989928 DOI: 10.1007/s10822-007-9144-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Accepted: 10/24/2007] [Indexed: 10/22/2022]
Abstract
(-)-Cocaine is a widely abused drug and there is no available anti-cocaine therapeutic. The disastrous medical and social consequences of cocaine addiction have made the development of an effective pharmacological treatment a high priority. An ideal anti-cocaine medication would be to accelerate (-)-cocaine metabolism producing biologically inactive metabolites. The main metabolic pathway of cocaine in body is the hydrolysis at its benzoyl ester group. Reviewed in this article is the state-of-the-art computational design of high-activity mutants of human butyrylcholinesterase (BChE) against (-)-cocaine. The computational design of BChE mutants have been based on not only the structure of the enzyme, but also the detailed catalytic mechanisms for BChE-catalyzed hydrolysis of (-)-cocaine and (+)-cocaine. Computational studies of the detailed catalytic mechanisms and the structure-and-mechanism-based computational design have been carried out through the combined use of a variety of state-of-the-art techniques of molecular modeling. By using the computational insights into the catalytic mechanisms, a recently developed unique computational design strategy based on the simulation of the rate-determining transition state has been employed to design high-activity mutants of human BChE for hydrolysis of (-)-cocaine, leading to the exciting discovery of BChE mutants with a considerably improved catalytic efficiency against (-)-cocaine. One of the discovered BChE mutants (i.e., A199S/S287G/A328W/Y332G) has a approximately 456-fold improved catalytic efficiency against (-)-cocaine. The encouraging outcome of the computational design and discovery effort demonstrates that the unique computational design approach based on the transition-state simulation is promising for rational enzyme redesign and drug discovery.
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Pan Y, Gao D, Yang W, Cho H, Zhan CG. Free energy perturbation (FEP) simulation on the transition states of cocaine hydrolysis catalyzed by human butyrylcholinesterase and its mutants. J Am Chem Soc 2007; 129:13537-43. [PMID: 17927177 DOI: 10.1021/ja073724k] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel computational protocol based on free energy perturbation (FEP) simulations on both the free enzyme and transition state structures has been developed and tested to predict the mutation-caused shift of the free energy change from the free enzyme to the rate-determining transition state for human butyrylcholinesterase (BChE)-catalyzed hydrolysis of (-)-cocaine. The calculated shift, denoted by DeltaDeltaG(1 --> 2), of such kind of free energy change determines the catalytic efficiency (kcat/KM) change caused by the simulated mutation transforming enzyme 1 to enzyme 2. By using the FEP-based computational protocol, the DeltaDeltaG(1 --> 2) values for the mutations A328W/Y332A --> A328W/Y332G and A328W/Y332G --> A328W/Y332G/A199S were calculated to be -0.22 and -1.94 kcal/mol, respectively. The calculated DeltaDeltaG(1 --> 2) values predict that the change from the A328W/Y332A mutant to the A328W/Y332G mutant should slightly improve the catalytic efficiency and that the change from the A328W/Y332G mutant to the A328W/Y332G/A199S mutant should significantly improve the catalytic efficiency of the enzyme for the (-)-cocaine hydrolysis. The predicted catalytic efficiency increases are supported by the experimental data showing that kcat/KM = 8.5 x 10(6), 1.4 x 10(7), and 7.2 x 10(7) min(-1) M(-1) for the A328W/Y332A, A328W/Y332G, and A328W/Y332G/A199S mutants, respectively. The qualitative agreement between the computational and experimental data suggests that the FEP simulations may provide a promising protocol for rational design of high-activity mutants of an enzyme. The general computational strategy of the FEP simulation on a transition state can be used to study the effects of a mutation on the activation free energy for any enzymatic reaction.
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Affiliation(s)
- Yongmei Pan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536, USA
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Lu H, Chen X, Zhan CG. First-principles calculation of pKa for cocaine, nicotine, neurotransmitters, and anilines in aqueous solution. J Phys Chem B 2007; 111:10599-605. [PMID: 17691837 PMCID: PMC2882246 DOI: 10.1021/jp072917r] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The absolute pKa values of 24 representative amine compounds, including cocaine, nicotine, 10 neurotransmitters, and 12 anilines, in aqueous solution were calculated by performing first-principles electronic structure calculations that account for the solvent effects using four different solvation models, i.e., the surface and volume polarization for electrostatic interaction (SVPE) model, the standard polarizable continuum model (PCM), the integral equation formalism for the polarizable continuum model (IEFPCM), and the conductor-like screening solvation model (COSMO). Within the examined computational methods, the calculations using the SVPE model lead to the absolute pKa values with the smallest root-mean-square-deviation (rmsd) value (1.18). When the SVPE model was replaced by the PCM, IEFPCM, and COSMO, the rmsd value of the calculated absolute pKa values became 3.21, 2.72, and 3.08, respectively. All types of calculated pKa values linearly correlate with the experimental pKa values very well. With the empirical corrections using the linear correlation relationships, the theoretical pKa values are much closer to the corresponding experimental data and the rmsd values become 0.51-0.83. The smallest rmsd value (0.51) is also associated with the SVPE model. All of the results suggest that the first-principles electronic structure calculations using the SVPE model are a reliable approach to the pKa prediction for the amine compounds.
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Affiliation(s)
- Haiting Lu
- Key Laboratory of Pesticide & Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
| | - Xi Chen
- Key Laboratory of Pesticide & Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
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Huang X, Zhan CG. How dopamine transporter interacts with dopamine: insights from molecular modeling and simulation. Biophys J 2007; 93:3627-39. [PMID: 17704152 PMCID: PMC2072054 DOI: 10.1529/biophysj.107.110924] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
By performing homology modeling, molecular docking, and molecular dynamics simulations, we have developed three-dimensional (3D) structural models of both dopamine transporter and dopamine transporter-dopamine complex in the environment of lipid bilayer and solvent water. According to the simulated structure of dopamine transporter-dopamine complex, dopamine was orientated in a hydrophobic pocket at the midpoint of the membrane. The modeled 3D structures provide some detailed structural and mechanistic insights concerning how dopamine transporter (DAT) interacts with dopamine at atomic level, extending our mechanistic understanding of the dopamine reuptake with the help of Na(+) ions. The general features of the modeled 3D structures are consistent with available experimental data. Based on the modeled structures, our calculated binding free energy (DeltaG(bind) = -6.4 kcal/mol) for dopamine binding with DAT is also reasonably close to the experimentally derived DeltaG(bind) value of -7.4 kcal/mol. Finally, a possible dopamine-entry pathway, which involves formation and breaking of the salt bridge between side chains of Arg(85) and Asp(476), is proposed based on the results obtained from the modeling and molecular dynamics simulation. The new structural and mechanistic insights obtained from this computational study are expected to stimulate future, further biochemical and pharmacological studies on the detailed structures and mechanisms of DAT and other homologous transporters.
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Affiliation(s)
- Xiaoqin Huang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, USA
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Masson P, Froment MT, Gillon E, Nachon F, Darvesh S, Schopfer LM. Kinetic analysis of butyrylcholinesterase-catalyzed hydrolysis of acetanilides. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:1139-47. [PMID: 17690023 DOI: 10.1016/j.bbapap.2007.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 06/09/2007] [Accepted: 06/13/2007] [Indexed: 10/23/2022]
Abstract
The aryl-acylamidase (AAA) activity of butyrylcholinesterase (BuChE) has been known for a long time. However, the kinetic mechanism of aryl-acylamide hydrolysis by BuChE has not been investigated. Therefore, the catalytic properties of human BuChE and its peripheral site mutant (D70G) toward neutral and charged aryl-acylamides were determined. Three neutral (o-nitroacetanilide, m-nitroacetanilide, o-nitrophenyltrifluoroacetamide) and one positively charged (3-(acetamido) N,N,N-trimethylanilinium, ATMA) acetanilides were studied. Hydrolysis of ATMA by wild-type and D70G enzymes showed a long transient phase preceding the steady state. The induction phase was characterized by a hysteretic "burst". This reflects the existence of two enzyme states in slow equilibrium with different catalytic properties. Steady-state parameters for hydrolysis of the three acetanilides were compared to catalytic parameters for hydrolysis of esters giving the same acetyl intermediate. Wild-type BuChE showed substrate activation while D70G displayed a Michaelian behavior with ATMA as with positively charged esters. Owing to the low affinity of BuChE for amide substrates, the hydrolysis kinetics of neutral amides was first order. Acylation was the rate-determining step for hydrolysis of aryl-acetylamide substrates. Slow acylation of the enzyme, relative to that by esters may, in part, be due suboptimal fit of the aryl-acylamides in the active center of BuChE. The hypothesis that AAA and esterase active sites of BuChE are non-identical was tested with mutant BuChE. It was found that mutations on the catalytic serine, S198C and S198D, led to complete loss of both activities. The silent variant (FS117) had neither esterase nor AAA activity. Mutation in the peripheral site (D70G) had the same effect on esterase and AAA activities. Echothiophate inhibited both activities identically. It was concluded that the active sites for esterase and AAA activities are identical, i.e. S198. This excludes any other residue present in the gorge for being the catalytic nucleophile pole.
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Affiliation(s)
- Patrick Masson
- Centre de Recherches du Service de Santé des Armées, Département de Toxicologie, Unité d'Enzymologie, BP 87, 38702 La Tronche cedex, France.
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Yao L, Yan H, Cukier RI. A Combined ONIOM Quantum Chemical−Molecular Dynamics Study of Zinc−Uracil Bond Breaking in Yeast Cytosine Deaminase. J Phys Chem B 2006; 110:26320-6. [PMID: 17181291 DOI: 10.1021/jp064301s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A QM/MM method that combines ONIOM quantum chemistry and molecular dynamics is developed and applied to a step in the deamination of cytosine to uracil in yeast cytosine deaminase (yCD). A two-layer ONIOM calculation is used for the reaction complex, with an inner part treated at a high level for the chemical reaction (bond breaking) and a middle part treated at a lower level for relevant protein residues that are frozen in the quantum optimization. An outer layer (protein and solvent) is treated using MD. Configurations for the entire system are generated using MD and optimized with ONIOM. The method permits the use of high-level quantum calculations along with sufficient configurational sampling to approximate the potential of mean force for certain bond-breaking reactions. A previously proposed reaction mechanism for deamination (Sklenak, S.; Yao, L. S.; Cukier, R. I.; Yan, H. G. J. Am. Chem. Soc. 2004, 126, 14879) requires breaking the bond between a catalytic zinc and the O4 of uracil in order to permit product release. Using an ONIOM approach, direct bond cleavage was found to be energetically unfavorable. In the work presented here, the combined ONIOM MD method is used to show that the barrier for bond cleavage is small, approximately 3 kcal/mol, and, consequently, should not be the rate-limiting step in the reaction.
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Affiliation(s)
- Lishan Yao
- Department of Chemistry, and MSU Center for Biological Modeling, Michigan State University, East Lansing, Michigan 48824, USA
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