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Li Z, Chan KC, Nickels JD, Cheng X. Electrostatic Contributions to the Binding Free Energy of Nicotine to the Acetylcholine Binding Protein. J Phys Chem B 2022; 126:8669-8679. [PMID: 36260486 PMCID: PMC10056799 DOI: 10.1021/acs.jpcb.2c04641] [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: 01/11/2023]
Abstract
Biomolecular binding relies on specific attractive interactions between two partner molecules, including electrostatics, dispersion, hydrophobicity, and solvation. Assessing the contributions of electrostatic interactions to binding is key to the understanding of ligand binding mechanisms and the design of improved biomolecular binders. For example, nicotine is a well-known agonist of nicotinic acetylcholine receptors (nAChRs), but the molecular mechanisms for the differential action of nicotine on brain and muscle nAChRs remain elusive. In this work, we have chosen the acetylcholine binding protein (AChBP) in complex with nicotine as a model system to interrogate the electrostatic contributions to nicotine binding. Our absolute binding free energy simulations confirm that nicotine binds AChBP predominantly in its protonated (charged) form. By comparing energetic contributions from decomposed interactions for either neutral or charged nicotine, our calculations shed light on the nature of the binding of nicotine to the AChBP. The preferred binding of charged nicotine over neutral nicotine originates from its stronger electrostatic interactions with AChBP, a cation-π interaction to a tryptophan residue and a hydrogen bond between nicotine and the backbone carbonyl of the tryptophan, whereas the major force driving the binding process appears to be van der Waals interactions. The various nonelectrostatic terms can also indirectly modulate the electrostatic interactions through fine-tuning the binding pose of the ligand in the binding site, providing an explanation of why the binding specificity of nicotine to the brain versus muscle nAChRs is driven by electrostatic interaction, given that the immediate binding site residues, including the key tryptophan residue, are identical in the two receptors.
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Affiliation(s)
- Zoe Li
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy at The Ohio State University, Columbus, Ohio43210, United States
| | - Kevin C Chan
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy at The Ohio State University, Columbus, Ohio43210, United States
| | - Jonathan D Nickels
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio45221, United States
| | - Xiaolin Cheng
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy at The Ohio State University, Columbus, Ohio43210, United States
- Translational Data Analytics Institute (TDAI) at The Ohio State University, Columbus, Ohio43210, United States
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2
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Dey A, Singh A, Volla CMR. Cobalt-catalyzed highly diastereoselective [3 + 2] carboannulation reactions: facile access to substituted indane derivatives. Chem Commun (Camb) 2022; 58:1386-1389. [PMID: 34989718 DOI: 10.1039/d1cc05245d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Efficient oxidative [3 + 2] annulation reaction involving aryl hydrazones and heterobicyclic alkenes has been realized with inexpensive and earth-abundant cobalt salts under aerobic conditions. The reaction proceeds via directing-group-assisted C-H activation and exo-selective migratory insertion, followed by the intramolecular nucleophilic attack of the alkylcobalt(III) species onto the imine with high anti-diastereoselectivity to provide complex indane derivatives. The generation of three contiguous stereogenic centers within the indanyl unit and the avoidance of the use of stoichiometric amounts of metal oxidants make this transformation more valuable and appealing.
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Affiliation(s)
- Arnab Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Anurag Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Chandra M R Volla
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
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3
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Mechanism of biomolecular recognition of trimethyllysine by the fluorinated aromatic cage of KDM5A PHD3 finger. Commun Chem 2020; 3:69. [PMID: 36703460 PMCID: PMC9814790 DOI: 10.1038/s42004-020-0313-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 05/06/2020] [Indexed: 01/29/2023] Open
Abstract
The understanding of biomolecular recognition of posttranslationally modified histone proteins is centrally important to the histone code hypothesis. Despite extensive binding and structural studies on the readout of histones, the molecular language by which posttranslational modifications on histone proteins are read remains poorly understood. Here we report physical-organic chemistry studies on the recognition of the positively charged trimethyllysine by the electron-rich aromatic cage containing PHD3 finger of KDM5A. The aromatic character of two tryptophan residues that solely constitute the aromatic cage of KDM5A was fine-tuned by the incorporation of fluorine substituents. Our thermodynamic analyses reveal that the wild-type and fluorinated KDM5A PHD3 fingers associate equally well with trimethyllysine. This work demonstrates that the biomolecular recognition of trimethyllysine by fluorinated aromatic cages is associated with weaker cation-π interactions that are compensated by the energetically more favourable trimethyllysine-mediated release of high-energy water molecules that occupy the aromatic cage.
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Xing H, Andrud KW, Soti F, Rouchaud A, Jahn SC, Lu Z, Cho YH, Habibi S, Corsino P, Slavov S, Rocca JR, Lindstrom JM, Lukas RJ, Kem WR. A Methyl Scan of the Pyrrolidinium Ring of Nicotine Reveals Significant Differences in Its Interactions with α7 and α4 β2 Nicotinic Acetylcholine Receptors. Mol Pharmacol 2020; 98:168-180. [PMID: 32474444 DOI: 10.1124/mol.119.118786] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 05/06/2020] [Indexed: 01/15/2023] Open
Abstract
The two major nicotinic acetylcholine receptors (nAChRs) in the brain are the α4β2 and α7 subtypes. A "methyl scan" of the pyrrolidinium ring was used to detect differences in nicotine's interactions with these two receptors. Each methylnicotine was investigated using voltage-clamp and radioligand binding techniques. Methylation at each ring carbon elicited unique changes in nicotine's receptor interactions. Replacing the 1'-N-methyl with an ethyl group or adding a second 1'-N-methyl group significantly reduced interaction with α4β2 but not α7 receptors. The 2'-methylation uniquely enhanced binding and agonist potency at α7 receptors. Although 3'- and 5'-trans-methylations were much better tolerated by α7 receptors than α4β2 receptors, 4'-methylation decreased potency and efficacy at α7 receptors much more than at α4β2 receptors. Whereas cis-5'-methylnicotine lacked agonist activity and displayed a low affinity at both receptors, trans-5'-methylnicotine retained considerable α7 receptor activity. Differences between the two 5'-methylated analogs of the potent pyridyl oxymethylene-bridged nicotine analog A84543 were consistent with what was found for the 5'-methylnicotines. Computer docking of the methylnicotines to the Lymnaea acetylcholine binding protein crystal structure containing two persistent waters predicted most of the changes in receptor affinity that were observed with methylation, particularly the lower affinities of the cis-methylnicotines. The much smaller effects of 1'-, 3'-, and 5'-methylations and the greater effects of 2'- and 4'-methylations on nicotine α7 nAChR interaction might be exploited for the design of new drugs based on the nicotine scaffold. SIGNIFICANCE STATEMENT: Using a comprehensive "methyl scan" approach, we show that the orthosteric binding sites for acetylcholine and nicotine in the two major brain nicotinic acetylcholine receptors interact differently with the pyrrolidinium ring of nicotine, and we suggest reasons for the higher affinity of nicotine for the heteromeric receptor. Potential sites for nicotine structure modification were identified that may be useful in the design of new drugs targeting these receptors.
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Affiliation(s)
- Hong Xing
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Kristin W Andrud
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Ferenc Soti
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Anne Rouchaud
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Stephan C Jahn
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Ziang Lu
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Yeh-Hyon Cho
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Sophia Habibi
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Patrick Corsino
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Svetoslav Slavov
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - James R Rocca
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Jon M Lindstrom
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - Ron J Lukas
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
| | - William R Kem
- Department of Pharmacology and Therapeutics (H.X., K.W.A., F.S., A.R., S.C.J., Z.L., Y.-H.C., S.H., P.C., W.R.K.) and AMRIS, McKnight Brain Institute (J.R.R.), College of Medicine, University of Florida, Gainesville, Florida; National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas (S.S.); Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania (J.M.L.); and Division of Neurobiology, Barrow Neurologic Institute, Phoenix, Arizona (R.J.L.)
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5
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Park YS, Kim Y, Paek K. Specific Encapsulation of Acetylcholine Chloride by a Self-Assembled Molecular Capsule with Sulfonamido Moiety. Org Lett 2019; 21:8300-8303. [PMID: 31560557 DOI: 10.1021/acs.orglett.9b03013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
New molecular capsule 12, which encapsulates only acetylcholine chloride in the ion-pair form, has been developed. Cavitand 1 with four sulfonamido moieties on the upper rim of tetraimino-cavitand self-assembled to form a stable molecular capsule in the presence of an acetylcholine chloride guest through eight intermolecular -NH···O═S hydrogen bonds, two from each of the four paired sulfonamide units.
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Affiliation(s)
- Yeon Sil Park
- Department of Chemistry , Soongsil University , Seoul 06978 , Korea
| | - Yangryeong Kim
- Department of Chemistry , Soongsil University , Seoul 06978 , Korea
| | - Kyungsoo Paek
- Department of Chemistry , Soongsil University , Seoul 06978 , Korea
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6
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Sereikaitė V, Jensen TMT, Bartling CRO, Jemth P, Pless SA, Strømgaard K. Probing Backbone Hydrogen Bonds in Proteins by Amide-to-Ester Mutations. Chembiochem 2018; 19:2136-2145. [PMID: 30073762 DOI: 10.1002/cbic.201800350] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 01/09/2023]
Abstract
All proteins contain characteristic backbones formed of consecutive amide bonds, which can engage in hydrogen bonds. However, the importance of these is not easily addressed by conventional technologies that only allow for side-chain substitutions. By contrast, technologies such as nonsense suppression mutagenesis and protein ligation allow for manipulation of the protein backbone. In particular, replacing the backbone amide groups with ester groups, that is, amide-to-ester mutations, is a powerful tool to examine backbone-mediated hydrogen bonds. In this minireview, we showcase examples of how amide-to-ester mutations can be used to uncover pivotal roles of backbone-mediated hydrogen bonds in protein recognition, folding, function, and structure.
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Affiliation(s)
- Vita Sereikaitė
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2200, Copenhagen, Denmark
| | - Thomas M T Jensen
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2200, Copenhagen, Denmark
| | - Christian R O Bartling
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2200, Copenhagen, Denmark
| | - Per Jemth
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, 75123, Uppsala, Sweden
| | - Stephan A Pless
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2200, Copenhagen, Denmark
| | - Kristian Strømgaard
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2200, Copenhagen, Denmark
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7
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Fitch RW, Snider BB, Zhou Q, Foxman BM, Pandya AA, Yakel JL, Olson TT, Al-Muhtasib N, Xiao Y, Welch KD, Panter KE. Absolute Configuration and Pharmacology of the Poison Frog Alkaloid Phantasmidine. JOURNAL OF NATURAL PRODUCTS 2018; 81:1029-1035. [PMID: 29671588 PMCID: PMC7142328 DOI: 10.1021/acs.jnatprod.8b00062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Phantasmidine, a rigid congener of the well-known nicotinic acetylcholine receptor agonist epibatidine, is found in the same species of poison frog ( Epipedobates anthonyi). Natural phantasmidine was found to be a 4:1 scalemic mixture, enriched in the (2a R,4a S,9a S) enantiomer by chiral-phase LC-MS comparison to the synthetic enantiomers whose absolute configurations were previously established by Mosher's amide analysis. The major enantiomer has the opposite S configuration at the benzylic carbon to natural epibatidine, whose benzylic carbon is R. Pharmacological characterization of the synthetic racemate and separated enantiomers established that phantasmidine is ∼10-fold less potent than epibatidine, but ∼100-fold more potent than nicotine in most receptors tested. Unlike epibatidine, phantasmidine is sharply enantioselective in its activity and the major natural enantiomer whose benzylic carbon has the 4a S configuration is more active. The stereoselective pharmacology of phantasmidine is ascribed to its rigid and asymmetric shape as compared to the nearly symmetric conformations previously suggested for epibatidine enantiomers. While phantasmidine itself is too toxic for direct therapeutic use, we believe it is a useful platform for the development of potent and selective nicotinic agonists, which may have value as pharmacological tools.
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Affiliation(s)
- Richard W Fitch
- Department of Chemistry and Physics , Indiana State University , Terre Haute , Indiana 47809 , United States
| | - Barry B Snider
- Department of Chemistry , Brandeis University MS 015 , Waltham , Massachusetts 02453 , United States
| | - Quan Zhou
- Department of Chemistry , Brandeis University MS 015 , Waltham , Massachusetts 02453 , United States
| | - Bruce M Foxman
- Department of Chemistry , Brandeis University MS 015 , Waltham , Massachusetts 02453 , United States
| | - Anshul A Pandya
- Neurobiology Laboratory , National Institute of Environmental Health Sciences, NIH/DHHS , Research Triangle Park , North Carolina 27709 , United States
| | - Jerrel L Yakel
- Neurobiology Laboratory , National Institute of Environmental Health Sciences, NIH/DHHS , Research Triangle Park , North Carolina 27709 , United States
| | - Thao T Olson
- Department of Pharmacology and Physiology , Georgetown University , Washington , D.C. 20057 , United States
| | - Nour Al-Muhtasib
- Department of Pharmacology and Physiology , Georgetown University , Washington , D.C. 20057 , United States
| | - Yingxian Xiao
- Department of Pharmacology and Physiology , Georgetown University , Washington , D.C. 20057 , United States
| | - Kevin D Welch
- Poisonous Plant Research Laboratory, United States Department of Agriculture , Agricultural Research Service , Logan , Utah 84341 , United States
| | - Kip E Panter
- Poisonous Plant Research Laboratory, United States Department of Agriculture , Agricultural Research Service , Logan , Utah 84341 , United States
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8
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Li DY, Huang ZL, Liu PN. Heterobicyclic Core Retained Hydroarylations through C-H Activation: Synthesis of Epibatidine Analogues. Org Lett 2018; 20:2028-2032. [PMID: 29558151 DOI: 10.1021/acs.orglett.8b00571] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The heterobicyclic core retained hydroarylation of oxa/azabenzonorbornadienes with quinoline N-oxides has been achieved under rhodium catalysis, giving quinoline N-oxide substituted heterobicyclic structures with excellent regioselectivity and in good yields. As the first example of the direct introduction of quinoline N-oxides onto heterobicyclic structures, the strained heterobicyclic core was well retained in the reaction. The products could be successfully transformed into a series of useful compounds, including epibatidine analogues.
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Affiliation(s)
- Deng-Yuan Li
- Shanghai Key Laboratory of Functional Materials Chemistry, Key Lab for Advanced Materials and School of Chemistry & Molecular Engineering , East China University of Science & Technology , Meilong Road 130 , Shanghai 200237 , China
| | - Zheng-Lu Huang
- Shanghai Key Laboratory of Functional Materials Chemistry, Key Lab for Advanced Materials and School of Chemistry & Molecular Engineering , East China University of Science & Technology , Meilong Road 130 , Shanghai 200237 , China
| | - Pei-Nian Liu
- Shanghai Key Laboratory of Functional Materials Chemistry, Key Lab for Advanced Materials and School of Chemistry & Molecular Engineering , East China University of Science & Technology , Meilong Road 130 , Shanghai 200237 , China
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9
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10
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Dymińska L, Janczak J, Sheweshen KSM, Lorenc J, Hanuza J. Crystal and molecular structures, temperature dependence of the IR and Raman spectra and vibrational dynamics of aquo 4,6-dimethyl-5H-[1,2,3]triazolo[4,5-c]pyridine in a new zwitterionic form. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.05.072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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Post MR, Lester HA, Dougherty DA. Probing for and Quantifying Agonist Hydrogen Bonds in α6β2 Nicotinic Acetylcholine Receptors. Biochemistry 2017; 56:1836-1840. [PMID: 28287260 DOI: 10.1021/acs.biochem.7b00213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Designing subtype-selective agonists for neuronal nicotinic acetylcholine receptors is a challenging and significant goal aided by intricate knowledge of each subtype's binding patterns. We previously reported that in α6β2 receptors, acetylcholine makes a functional cation-π interaction with Trp149, but nicotine and TC299423 do not, suggesting a distinctive binding site. This work explores hydrogen binding at the backbone carbonyl associated with α6β2 Trp149. Substituting residue i + 1, Thr150, with its α-hydroxy analogue (Tah) attenuates the carbonyl's hydrogen bond accepting ability. At α6(T150Tah)β2, nicotine shows a 24-fold loss of function, TC299423 shows a modest loss, and acetylcholine shows no effect. Nicotine was further analyzed via a double-mutant cycle analysis utilizing N'-methylnicotinium, which indicated a hydrogen bond in α6β2 with a ΔΔG of 2.6 kcal/mol. Thus, even though nicotine does not make the conserved cation-π interaction with Trp149, it still makes a functional hydrogen bond to its associated backbone carbonyl.
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Affiliation(s)
- Michael R Post
- Division of Chemistry and Chemical Engineering and ‡Division of Biology and Biological Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - Henry A Lester
- Division of Chemistry and Chemical Engineering and ‡Division of Biology and Biological Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - Dennis A Dougherty
- Division of Chemistry and Chemical Engineering and ‡Division of Biology and Biological Engineering, California Institute of Technology , Pasadena, California 91125, United States
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12
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Reactivity of the magnesium phthalocyanine in dry 3,5-lutidine, in 3,5-lutidine/DMSO and in 3,5-lutidine/acetylacetone systems. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Activation and Desensitization of Peripheral Muscle and Neuronal Nicotinic Acetylcholine Receptors by Selected, Naturally-Occurring Pyridine Alkaloids. Toxins (Basel) 2016; 8:toxins8070204. [PMID: 27384586 PMCID: PMC4963837 DOI: 10.3390/toxins8070204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 06/24/2016] [Accepted: 06/24/2016] [Indexed: 11/18/2022] Open
Abstract
Teratogenic alkaloids can cause developmental defects due to the inhibition of fetal movement that results from desensitization of fetal muscle-type nicotinic acetylcholine receptors (nAChRs). We investigated the ability of two known teratogens, the piperidinyl-pyridine anabasine and its 1,2-dehydropiperidinyl analog anabaseine, to activate and desensitize peripheral nAChRs expressed in TE-671 and SH-SY5Y cells. Activation-concentration response curves for each alkaloid were obtained in the same multi-well plate. To measure rapid desensitization, cells were first exposed to five potentially-desensitizing concentrations of each alkaloid in log10 molar increments from 10 nM to 100 µM and then to a fixed concentration of acetylcholine (ACh), which alone produces near-maximal activation. The fifty percent desensitization concentration (DC50) was calculated from the alkaloid concentration-ACh response curve. Agonist fast desensitization potency was predicted by the agonist potency measured in the initial response. Anabaseine was a more potent desensitizer than anabasine. Relative to anabaseine, nicotine was more potent to autonomic nAChRs, but less potent to the fetal neuromuscular nAChRs. Our experiments have demonstrated that anabaseine is more effective at desensitizing fetal muscle-type nAChRs than anabasine or nicotine and, thus, it is predicted to be more teratogenic.
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Niessen K, Muschik S, Langguth F, Rappenglück S, Seeger T, Thiermann H, Worek F. Functional analysis of Torpedo californica nicotinic acetylcholine receptors in multiple activation states by SSM-based electrophysiology. Toxicol Lett 2016; 247:1-10. [DOI: 10.1016/j.toxlet.2016.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/27/2016] [Accepted: 02/02/2016] [Indexed: 01/21/2023]
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15
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Huczyński A, Majcher U, Maj E, Wietrzyk J, Janczak J, Moshari M, Tuszynski JA, Bartl F. Synthesis, antiproliferative activity and molecular docking of Colchicine derivatives. Bioorg Chem 2016; 64:103-12. [DOI: 10.1016/j.bioorg.2016.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 12/17/2022]
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16
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17
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18
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Green BT, Lee ST, Welch KD, Panter KE. Plant alkaloids that cause developmental defects through the disruption of cholinergic neurotransmission. ACTA ACUST UNITED AC 2014; 99:235-46. [PMID: 24339035 DOI: 10.1002/bdrc.21049] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 10/24/2013] [Accepted: 10/24/2013] [Indexed: 12/26/2022]
Abstract
The exposure of a developing embryo or fetus to alkaloids from plants, plant products, or plant extracts has the potential to cause developmental defects in humans and animals. These defects may have multiple causes, but those induced by piperidine and quinolizidine alkaloids arise from the inhibition of fetal movement and are generally referred to as multiple congenital contracture-type deformities. These skeletal deformities include arthrogyrposis, kyposis, lordosis, scoliosis, and torticollis, associated secondary defects, and cleft palate. Structure-function studies have shown that plant alkaloids with a piperidine ring and a minimum of a three-carbon side-chain α to the piperidine nitrogen are teratogenic. Further studies determined that an unsaturation in the piperidine ring, as occurs in gamma coniceine, or anabaseine, enhances the toxic and teratogenic activity, whereas the N-methyl derivatives are less potent. Enantiomers of the piperidine teratogens, coniine, ammodendrine, and anabasine, also exhibit differences in biological activity, as shown in cell culture studies, suggesting variability in the activity due to the optical rotation at the chiral center of these stereoisomers. In this article, we review the molecular mechanism at the nicotinic pharmacophore and biological activities, as it is currently understood, of a group of piperidine and quinolizidine alkaloid teratogens that impart a series of flexure-type skeletal defects and cleft palate in animals.
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Affiliation(s)
- Benedict T Green
- United States Department of Agriculture, Poisonous Plant Research Laboratory, Agricultural Research Service, 1150 E 1400 N, Logan, Utah, 84321
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Huczyński A, Janczak J, Rutkowski J, Brzezinski B. Spectroscopic, crystallographic and theoretical studies of lasalocid complex with ammonia and benzylamine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 125:297-307. [PMID: 24562161 DOI: 10.1016/j.saa.2014.01.083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/08/2014] [Accepted: 01/16/2014] [Indexed: 06/03/2023]
Abstract
A natural antibiotic--Lasalocid is able to form stable complexes with ammonia and organic amines. New complexes of lasalocid with benzylamine and ammonia were obtained in the crystal forms and studied using X-ray, FT-IR, (1)H NMR, (13)C NMR and DFT methods. These studies have shown that in both complexes the proton is transferred from the carboxylic group to the amine group with the formation of a pseudo-cyclic structure of lasalocid anion complexing the protonated amine or NH4(+) cation. The spectroscopic and DFT studies demonstrated that the structure of the complex formed between Lasalocid and benzylamine in the solid is also conserved in the solution and gas phase. In contrast, the structure of the complex formed between lasalocid and ammonium cation found in the solid state undergoes dissociation in chloroform solution accompanied with a change in the coordination form of the NH4(+) cation.
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Affiliation(s)
- Adam Huczyński
- Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland.
| | - Jan Janczak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50950 Wrocław, Poland
| | - Jacek Rutkowski
- Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland
| | - Bogumil Brzezinski
- Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland
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20
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Van Arnam EB, Dougherty DA. Functional probes of drug-receptor interactions implicated by structural studies: Cys-loop receptors provide a fertile testing ground. J Med Chem 2014; 57:6289-300. [PMID: 24568098 PMCID: PMC4136689 DOI: 10.1021/jm500023m] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Structures
of integral membrane receptors provide valuable models
for drug–receptor interactions across many important classes
of drug targets and have become much more widely available in recent
years. However, it remains to be determined to what extent these images
are relevant to human receptors in their biological context and how
subtle issues such as subtype selectivity can be informed by them.
The high precision structural modifications enabled by unnatural amino
acid mutagenesis on mammalian receptors expressed in vertebrate cells
allow detailed tests of predictions from structural studies. Using
the Cys-loop superfamily of ligand-gated ion channels, we show that
functional studies lead to detailed binding models that, at times,
are significantly at odds with the structural studies on related invertebrate
proteins. Importantly, broad variations in binding interactions are
seen for very closely related receptor subtypes and for varying drugs
at a given binding site. These studies highlight the essential interplay
between structural studies and functional studies that can guide efforts
to develop new pharmaceuticals.
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Affiliation(s)
- Ethan B Van Arnam
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
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21
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Janczak J. Synthesis, characterisation and DFT calculations of the magnesium phthalocyanine complexes with n-butanol and n-pentanol. Polyhedron 2014. [DOI: 10.1016/j.poly.2013.12.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Marotta CB, Dilworth CN, Lester HA, Dougherty DA. Probing the non-canonical interface for agonist interaction with an α5 containing nicotinic acetylcholine receptor. Neuropharmacology 2014; 77:342-9. [PMID: 24144909 PMCID: PMC3934363 DOI: 10.1016/j.neuropharm.2013.09.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 11/18/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) containing the α5 subunit are of interest because genome-wide association studies and candidate gene studies have identified polymorphisms in the α5 gene that are linked to an increased risk for nicotine dependence, lung cancer, and/or alcohol addiction. To probe the functional impact of an α5 subunit on nAChRs, a method to prepare a homogeneous population of α5-containing receptors must be developed. Here we use a gain of function (9') mutation to isolate populations of α5-containing nAChRs for characterization by electrophysiology. We find that the α5 subunit modulates nAChR rectification when co-assembled with α4 and β2 subunits. We also probe the α5-α4 interface for possible ligand-binding interactions. We find that mutations expected to ablate an agonist-binding site involving the α5 subunit have no impact on receptor function. The most straightforward interpretation of this observation is that agonists do not bind at the α5-α4 interface, in contrast to what has recently been demonstrated for the α4-α4 interface in related receptors. In addition, our mutational results suggest that the α5 subunit does not replace the α4 or β2 subunits and is relegated to occupying only the auxiliary position of the pentameric receptor.
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Affiliation(s)
- Christopher B Marotta
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Crystal N Dilworth
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Henry A Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Dennis A Dougherty
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA.
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23
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Niessen K, Seeger T, Tattersall J, Timperley C, Bird M, Green C, Thiermann H, Worek F. Affinities of bispyridinium non-oxime compounds to [3H]epibatidine binding sites of Torpedo californica nicotinic acetylcholine receptors depend on linker length. Chem Biol Interact 2013; 206:545-54. [DOI: 10.1016/j.cbi.2013.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/07/2013] [Accepted: 10/07/2013] [Indexed: 01/20/2023]
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24
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Huczyński A, Janczak J, Brzezinski B, Bartl F. Spectroscopic and structural studies of allyl urethane derivative of Monensin A sodium salt. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.03.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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25
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26
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Van Arnam EB, Blythe EE, Lester HA, Dougherty DA. An unusual pattern of ligand-receptor interactions for the α7 nicotinic acetylcholine receptor, with implications for the binding of varenicline. Mol Pharmacol 2013; 84:201-7. [PMID: 23680636 DOI: 10.1124/mol.113.085795] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The α7 nicotinic acetylcholine receptor shows broad pharmacology, complicating the development of subtype-specific nicotinic receptor agonists. Here we use unnatural amino acid mutagenesis to characterize binding to α7 by the smoking cessation drug varenicline (Chantix; Pfizer, Groton, CT), an α4β2-targeted agonist that shows full efficacy and modest potency at the α7 receptor. We find that unlike binding to its target receptor, varenicline does not form a cation-π interaction with TrpB, further supporting a unique binding mode for the cationic amine of nicotinic agonists at the α7 receptor. We also evaluate binding to the complementary face of the receptor's binding site by varenicline, the endogenous agonist acetylcholine, and the potent nicotine analog epibatidine. Interestingly, we find no evidence for functionally important interactions involving backbone NH and CO groups thought to bind the canonical agonist hydrogen bond acceptor of the nicotinic pharmacophore, perhaps reflecting a lesser importance of this pharmacophore element for α7 binding. We also show that the Trp55 and Leu119 side chains of the binding site's complementary face are important for the binding of the larger agonists epibatidine and varenicline, but dispensable for binding of the smaller, endogenous agonist acetylcholine.
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Affiliation(s)
- Ethan B Van Arnam
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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27
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Blum AP, Van Arnam EB, German LA, Lester HA, Dougherty DA. Binding interactions with the complementary subunit of nicotinic receptors. J Biol Chem 2013; 288:6991-7. [PMID: 23349463 DOI: 10.1074/jbc.m112.439968] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The agonist-binding site of nicotinic acetylcholine receptors (nAChRs) spans an interface between two subunits of the pentameric receptor. The principal component of this binding site is contributed by an α subunit, and it binds the cationic moiety of the nicotinic pharmacophore. The other part of the pharmacophore, a hydrogen bond acceptor, has recently been shown to bind to the complementary non-α subunit via the backbone NH of a conserved Leu. This interaction was predicted by studies of ACh-binding proteins and confirmed by functional studies of the neuronal (CNS) nAChR, α4β2. The ACh-binding protein structures further suggested that the hydrogen bond to the backbone NH is mediated by a water molecule and that a second hydrogen bonding interaction occurs between the water molecule and the backbone CO of a conserved Asn, also on the non-α subunit. Here, we provide new insights into the nature of the interactions between the hydrogen bond acceptor of nicotinic agonists and the complementary subunit backbone. We studied both the nAChR of the neuromuscular junction (muscle-type) and a neuronal subtype, (α4)2(β4)3. In the muscle-type receptor, both ACh and nicotine showed a strong interaction with the Leu NH, but the potent nicotine analog epibatidine did not. This interaction was much attenuated in the α4β4 receptor. Surprisingly, we found no evidence for a functionally significant interaction with the backbone carbonyl of the relevant Asn in either receptor with an array of agonists.
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Affiliation(s)
- Angela P Blum
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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28
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Pless SA, Ahern CA. Unnatural Amino Acids as Probes of Ligand-Receptor Interactions and Their Conformational Consequences. Annu Rev Pharmacol Toxicol 2013; 53:211-29. [DOI: 10.1146/annurev-pharmtox-011112-140343] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Stephan A. Pless
- Department of Anesthesiology, Pharmacology and Therapeutics and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - Christopher A. Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242;
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29
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Structure of 1:1 complex of 1-naphthylmethyl ester of monensin A with sodium perchlorate studied by X-ray, FT-IR and ab initio methods. J Mol Struct 2012. [DOI: 10.1016/j.molstruc.2012.03.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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30
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Mahadevi AS, Sastry GN. Cation-π interaction: its role and relevance in chemistry, biology, and material science. Chem Rev 2012; 113:2100-38. [PMID: 23145968 DOI: 10.1021/cr300222d] [Citation(s) in RCA: 719] [Impact Index Per Article: 59.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- A Subha Mahadevi
- Molecular Modeling Group, CSIR-Indian Institute of Chemical Technology Tarnaka, Hyderabad 500 607, Andhra Pradesh, India
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31
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Huczyński A, Janczak J, Łowicki D, Brzezinski B. Monensin A acid complexes as a model of electrogenic transport of sodium cation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2108-19. [DOI: 10.1016/j.bbamem.2012.04.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/17/2012] [Accepted: 04/23/2012] [Indexed: 11/25/2022]
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32
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Tavares XDS, Blum AP, Nakamura DT, Puskar NL, Shanata JAP, Lester HA, Dougherty DA. Variations in binding among several agonists at two stoichiometries of the neuronal, α4β2 nicotinic receptor. J Am Chem Soc 2012; 134:11474-80. [PMID: 22716019 DOI: 10.1021/ja3011379] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Drug-receptor binding interactions of four agonists, ACh, nicotine, and the smoking cessation compounds varenicline (Chantix) and cytisine (Tabex), have been evaluated at both the 2:3 and 3:2 stoichiometries of the α4β2 nicotinic acetylcholine receptor (nAChR). Previous studies have established that unnatural amino acid mutagenesis can probe three key binding interactions at the nAChR: a cation-π interaction, and two hydrogen-bonding interactions to the protein backbone of the receptor. We find that all drugs make a cation-π interaction to TrpB of the receptor. All drugs except ACh, which lacks an N(+)H group, make a hydrogen bond to a backbone carbonyl, and ACh and nicotine behave similarly in acting as a hydrogen-bond acceptor. However, varenicline is not a hydrogen-bond acceptor to the backbone NH that interacts strongly with the other three compounds considered. In addition, we see interesting variations in hydrogen bonding interactions with cytisine that provide a rationalization for the stoichiometry selectivity seen with this compound.
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Affiliation(s)
- Ximena Da Silva Tavares
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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33
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Puskar NL, Lester HA, Dougherty DA. Probing the effects of residues located outside the agonist binding site on drug-receptor selectivity in the nicotinic receptor. ACS Chem Biol 2012; 7:841-6. [PMID: 22296725 DOI: 10.1021/cb200448j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nicotinic acetylcholine receptors (nAChRs) are a family of closely related but pharmacologically distinct neurotransmitter-gated ion channels. They are therapeutic targets for a wide range of neurological disorders, and a key issue in drug development is selective targeting among the more than 20 subtypes of nAChRs that are known. The present work evaluates a proposed hydrogen bonding interaction involving a residue known as the "loop B glycine" that distinguishes receptors that are highly responsive to ACh and nicotine from those that are much less so. We have performed structure-function studies on the loop B site, including unnatural amino acid mutagenesis, in three different nAChR subtypes and found that the correlation between agonist potency and this residue is strong. Low potency receptor subtypes have a glycine at this key site, and mutation to a residue with a side chain converts a low potency receptor to a high potency receptor. Innately high potency receptors have a lysine at the loop B site and show a decrease in potency for the reverse mutation (i.e., introducing a glycine). This residue lies outside of the agonist binding site, and studies of other residues at the agonist binding site show that the details of how changes at the loop B glycine site impact agonist potency vary for differing receptor subtypes. This suggests a model in which the loop B residue influences the global shape of the agonist binding site rather than modulating any specific interaction.
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Affiliation(s)
- Nyssa L. Puskar
- Division of Chemistry and Chemical
Engineering, California Institute of Technology, 164-30, Pasadena, California 91125, United States
| | - Henry A. Lester
- Division of Biology, California Institute of Technology, 156-29, Pasadena
, California 91125, United States
| | - Dennis A. Dougherty
- Division of Chemistry and Chemical
Engineering, California Institute of Technology, 164-30, Pasadena, California 91125, United States
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34
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Janczak J. Mechanism of the catalytic transformation of cyanopyridine isomers into pyridinecarboxamide isomers by magnesium phthalocyanine. Polyhedron 2012. [DOI: 10.1016/j.poly.2012.02.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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35
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Nagy PI, Erhardt PW. On the interaction of aliphatic amines and ammonium ions with carboxylic acids in solution and in receptor pockets. J Phys Chem B 2012; 116:5425-36. [PMID: 22510106 DOI: 10.1021/jp300588q] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Association energies of the acetate ion with cationic amines bearing one to three methyl groups were calculated in the range of -14 to -17 kcal/mol in aqueous solution by means of the IEF-PCM method at the CCSD(T)/CBS//MP2/aug-cc-pvdz and DFT/B97D/CBS//B97D/aug-cc-pvtz levels. The main stabilization factor for the association is the possibility for the formation of an ionic intermolecular hydrogen bond between the elements of the complex. For a quaternary ammonium ion, the favorable electrostatic interaction energy is the only driving force, and the stabilization energy for the complex is reduced to -4 kcal/mol. The internal free energies of the ion-pair tautomers of the studied species are higher by 10-15 kcal/mol in water than those for the neutral, hydrogen-bonded forms. Monte Carlo free energy perturbation calculations at T = 298 K and p = 1 atm predict -11 to -16 kcal/mol relative solvation free energy in favor of the corresponding ionic form. As a result, the ion-pair tautomer is the prevailing form in aqueous solution and on the extracellular surface of a receptor. Modeling the complex of a protonated ligand interacting with an Asp/Glu carboxylate side-chain in the binding cavity of a receptor, two strongly bound water molecules were considered so as to form hydrogen-bonded water bridges between the elements of the ion-pair. Nonetheless, the low polarity environment mimicked by a chloroform solvent cannot stabilize the ionic tautomer. A proton jump was predicted, which suggests that acetylcholine, an inherent cation by structure, might have evolved as the natural agonist for muscarinic receptors because a quaternary ammonium system assures the maintenance of the ion-pair form with a carboxylate side-chain in a protein cavity, the latter perhaps then being needed for receptor activation.
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Affiliation(s)
- Peter I Nagy
- Center for Drug Design and Development, The University of Toledo, Toledo, Ohio 43606, USA.
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36
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van Dijk CW, Sun M, van Wijngaarden J. Microwave Rotational Spectra and Structures of 2-Fluoropyridine and 3-Fluoropyridine. J Phys Chem A 2012; 116:4082-8. [DOI: 10.1021/jp301818x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cody W. van Dijk
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada
| | - Ming Sun
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada
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A novel halogen bond and a better-known hydrogen bond cooperation of neonicotinoid and insect nicotinic acetylcholine receptor recognition. J Mol Model 2012; 18:3867-75. [DOI: 10.1007/s00894-012-1393-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Accepted: 02/22/2012] [Indexed: 02/06/2023]
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38
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Daze KD, Pinter T, Beshara CS, Ibraheem A, Minaker SA, Ma MCF, Courtemanche RJM, Campbell RE, Hof F. Supramolecular hosts that recognize methyllysines and disrupt the interaction between a modified histone tail and its epigenetic reader protein. Chem Sci 2012. [DOI: 10.1039/c2sc20583a] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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39
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40
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Evangelisti L, Grabowiecki A, van Wijngaarden J. Chirped Pulse Fourier Transform Microwave Study of 2,2,2-Trifluoroethyl Formate. J Phys Chem A 2011; 115:8488-92. [DOI: 10.1021/jp2047129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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41
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Puskar NL, Xiu X, Lester HA, Dougherty DA. Two neuronal nicotinic acetylcholine receptors, alpha4beta4 and alpha7, show differential agonist binding modes. J Biol Chem 2011; 286:14618-27. [PMID: 21343288 DOI: 10.1074/jbc.m110.206565] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric, neurotransmitter-gated ion channels responsible for rapid excitatory neurotransmission in the central and peripheral nervous systems, resulting in skeletal muscle tone and various cognitive effects in the brain. These complex proteins are activated by the endogenous neurotransmitter ACh as well as by nicotine and structurally related agonists. Activation and modulation of nAChRs has been implicated in the pathology of multiple neurological disorders, and as such, these proteins are established therapeutic targets. Here we use unnatural amino acid mutagenesis to examine the ligand binding mechanisms of two homologous neuronal nAChRs: the α4β4 and α7 receptors. Despite sequence identity among the residues that form the core of the agonist-binding site, we find that the α4β4 and α7 nAChRs employ different agonist-receptor binding interactions in this region. The α4β4 receptor utilizes a strong cation-π interaction to a conserved tryptophan (TrpB) of the receptor for both ACh and nicotine, and nicotine participates in a strong hydrogen bond with a backbone carbonyl contributed by TrpB. Interestingly, we find that the α7 receptor also employs a cation-π interaction for ligand recognition, but the site has moved to a different aromatic amino acid of the agonist-binding site depending on the agonist. ACh participates in a cation-π interaction with TyrA, whereas epibatidine participates in a cation-π interaction with TyrC2.
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Affiliation(s)
- Nyssa L Puskar
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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42
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Abstract
Cys-loop receptors are membrane-spanning neurotransmitter-gated ion channels that are responsible for fast excitatory and inhibitory transmission in the peripheral and central nervous systems. The best studied members of the Cys-loop family are nACh, 5-HT3, GABAA and glycine receptors. All these receptors share a common structure of five subunits, pseudo-symmetrically arranged to form a rosette with a central ion-conducting pore. Some are cation selective (e.g. nACh and 5-HT3) and some are anion selective (e.g. GABAA and glycine). Each receptor has an extracellular domain (ECD) that contains the ligand-binding sites, a transmembrane domain (TMD) that allows ions to pass across the membrane, and an intracellular domain (ICD) that plays a role in channel conductance and receptor modulation. Cys-loop receptors are the targets for many currently used clinically relevant drugs (e.g. benzodiazepines and anaesthetics). Understanding the molecular mechanisms of these receptors could therefore provide the catalyst for further development in this field, as well as promoting the development of experimental techniques for other areas of neuroscience.In this review, we present our current understanding of Cys-loop receptor structure and function. The ECD has been extensively studied. Research in this area has been stimulated in recent years by the publication of high-resolution structures of nACh receptors and related proteins, which have permitted the creation of many Cys loop receptor homology models of this region. Here, using the 5-HT3 receptor as a typical member of the family, we describe how homology modelling and ligand docking can provide useful but not definitive information about ligand interactions. We briefly consider some of the many Cys-loop receptors modulators. We discuss the current understanding of the structure of the TMD, and how this links to the ECD to allow channel gating, and consider the roles of the ICD, whose structure is poorly understood. We also describe some of the current methods that are beginning to reveal the differences between different receptor states, and may ultimately show structural details of transitions between them.
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Tabatchnik A, Blot V, Pipelier M, Dubreuil D, Renault E, Le Questel JY. Theoretical study of the structures and hydrogen-bond properties of new alternated heterocyclic compounds. J Phys Chem A 2010; 114:6413-22. [PMID: 20465297 DOI: 10.1021/jp101394t] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The conformational preferences of a new bis-pyrrole derivative and its bis-pyridazine precursor have been investigated through quantum chemistry calculations (HF, DFT(MPWB1K), LMP2) and observations in the solid state. The global energetic minima are planar for both structures, with the conformational preferences being explained by pi-electronic conjugation between the aromatic systems and the occurrence of intramolecular hydrogen bonds (HB). For the bis-pyridazine derivative, the all-anti preferred conformation results from CH...Nsp(2) HB whereas the all-syn conformation of the bis-pyrrole is partly due to NH...Nsp(2) HB. For both systems, the validity of the theoretical conformational features is confirmed through the excellent agreement with the experimental data available. Calculations of electrostatic potential computed on the molecular surface of the various structures and their building blocks allow the variations to be rationalized in terms of molecular structure and are used to analyze the HB donor and acceptor sites of the compounds. The HB interaction sites predicted from the quantum chemical calculations are confirmed through the HB interactions observed in relevant crystal structures.
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Affiliation(s)
- Alexandra Tabatchnik
- Université de Nantes, CEISAM UMR 6230, UFR des Sciences et des Techniques, 2 rue de la Houssinière, BP 92208, Nantes F-44000, France
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Nicotinic pharmacophore: the pyridine N of nicotine and carbonyl of acetylcholine hydrogen bond across a subunit interface to a backbone NH. Proc Natl Acad Sci U S A 2010; 107:13206-11. [PMID: 20616056 DOI: 10.1073/pnas.1007140107] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pharmacophore models for nicotinic agonists have been proposed for four decades. Central to these models is the presence of a cationic nitrogen and a hydrogen bond acceptor. It is now well-established that the cationic center makes an important cation-pi interaction to a conserved tryptophan, but the donor to the proposed hydrogen bond acceptor has been more challenging to identify. A structure of nicotine bound to the acetylcholine binding protein predicted that the binding partner of the pharmacophore's second component was a water molecule, which also hydrogen bonds to the backbone of the complementary subunit of the receptors. Here we use unnatural amino acid mutagenesis coupled with agonist analogs to examine whether such a hydrogen bond is functionally significant in the alpha4beta2 neuronal nAChR, the receptor most associated with nicotine addiction. We find evidence for the hydrogen bond with the agonists nicotine, acetylcholine, carbamylcholine, and epibatidine. These data represent a completed nicotinic pharmacophore and offer insight into the design of new therapeutic agents that selectively target these receptors.
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Limapichat W, Lester HA, Dougherty DA. Chemical scale studies of the Phe-Pro conserved motif in the cys loop of Cys loop receptors. J Biol Chem 2010; 285:8976-84. [PMID: 20068044 DOI: 10.1074/jbc.m109.060939] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The functions of two conserved residues, Phe(135) and Pro(136), located at the apex of the Cys loop of the nicotinic acetylcholine receptor are investigated. Both residues were substituted with natural and unnatural amino acids, focusing on the role of aromaticity at Phe(135), backbone conformation at Pro(136), side chain polarity and volume, and the specific interaction between the aromatic side chain and the proline. NMR spectroscopy studies of model peptides containing proline and unnatural proline analogues following a Phe show a consistent increase in the population of the cis conformer relative to peptides lacking the Phe. In the receptor, a strong interaction between the Phe and Pro residues is evident, as is a strong preference for aromaticity and hydrophobicity at the Phe site. A similar influence of hydrophobicity is observed at the proline site. In addition, across a simple homologous series of proline analogues, the results reveal a correlation between receptor function and cis bias at the proline backbone. This could suggest a significant role for the cis proline conformer at this site in receptor function.
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Affiliation(s)
- Walrati Limapichat
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Abstract
The Cys-loop family of ligand-gated ion channels contains both vertebrate and invertebrate members that are activated by GABA (gamma-aminobutyric acid). Many of the residues that are critical for ligand binding have been identified in vertebrate GABA(A) and GABA(C) receptors, and specific interactions between GABA and some of these residues have been determined. In the present paper, I show how a cation-pi interaction for one of the binding site residues has allowed the production of models of GABA docked into the binding site, and these orientations are supported by mutagenesis and functional data. Surprisingly, however, the residue that forms the cation-pi interaction is not conserved, suggesting that GABA occupies subtly different locations even in such closely related receptors.
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Structure–activity relationships of N-substituted ligands for the α7 nicotinic acetylcholine receptor. Bioorg Med Chem Lett 2010; 20:104-7. [DOI: 10.1016/j.bmcl.2009.11.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Accepted: 11/09/2009] [Indexed: 11/18/2022]
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Lewis M, Beg S, Clements A, Tran D, Waggoner K. The effect of substituent rotation on aromatic quadrupole moments. CAN J CHEM 2010. [DOI: 10.1139/v09-152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We recently reported substituent constants for the accurate prediction of molecular quadrupole moments of mono-, di-, tri- and tetra-substituted aromatics. Four of the substituents in the study, –OH, –NO2, –NH2, and –CH3, were polyatomic and for these groups the substituent constants only hold for the lowest energy, or near-lowest energy, geometries. Herein, we report a computational investigation of the effect of rotation of –OH, –NO2, –NH2, and –CH3 groups on the aromatic quadrupole moment, Θzz. As expected, rotation of these substituents significantly affects the aromatic Θzz value; however, the affects are clearly periodic. Additionally, we have modified the methods to best employ our substituent constants.
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Affiliation(s)
- Michael Lewis
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO 63103, USA
| | - Shana Beg
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO 63103, USA
| | - Aimee Clements
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO 63103, USA
| | - Dianne Tran
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO 63103, USA
| | - Kristine Waggoner
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO 63103, USA
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Sgrignani J, Bonaccini C, Grazioso G, Chioccioli M, Cavalli A, Gratteri P. Insights into docking and scoring neuronal alpha4beta2 nicotinic receptor agonists using molecular dynamics simulations and QM/MM calculations. J Comput Chem 2009; 30:2443-54. [PMID: 19360794 DOI: 10.1002/jcc.21251] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A combined quantum mechanical (QM)-polarized docking and molecular dynamics approach to study the binding mode and to predict the binding affinity of ligands acting at the alpha4beta2-nAChR is presented. The results obtained in this study indicate that the quantum mechanical/molecular mechanics docking protocol well describes the charge-driven interactions occurring in the binding of nicotinic agonists, and it is able to represent the polarization effects on the ligand exerted by the surrounding atoms of the receptor at the binding site. This makes it possible to properly score agonists of alpha4beta2-nAChR and to reproduce the experimental binding affinity data with good accuracy, within a mean error of 2.2 kcal/mol. Moreover, applying the QM-polarized docking to an ensemble of nAChR conformations obtained from MD simulations enabled us to accurately capture nAChR-ligand induced-fit effects.
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Affiliation(s)
- Jacopo Sgrignani
- Laboratorio di Molecular Modeling, Cheminformatics and QSAR, Dipartimento di Scienze Farmaceutiche, Laboratorio di Progettazione, Sintesi e Studio di Eterocicli Biologicamente Attivi, Polo Scientifico, Università degli Studi di Firenze, Via Ugo Schiff, 6, 50019 Sesto Fiorentino (FI), Italy
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