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Infield DT, Schene ME, Galpin JD, Ahern CA. Genetic Code Expansion for Mechanistic Studies in Ion Channels: An (Un)natural Union of Chemistry and Biology. Chem Rev 2024. [PMID: 39207057 DOI: 10.1021/acs.chemrev.4c00306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Ion channels play central roles in biology and human health by catalyzing the transmembrane flow of electrical charge. These proteins are ideal targets for genetic code expansion (GCE) methods because it is feasible to measure ion channel activity from miniscule amounts of protein and to analyze the resulting data via rigorous, established biophysical methods. In an ideal scenario, the encoding of synthetic, noncanonical amino acids via GCE allows the experimenter to ask questions inaccessible to traditional methods. For this reason, GCE has been successfully applied to a variety of ligand- and voltage-gated channels wherein extensive structural, functional, and pharmacological data exist. Here, we provide a comprehensive summary of GCE as applied to ion channels. We begin with an overview of the methods used to encode noncanonical amino acids in channels and then describe mechanistic studies wherein GCE was used for photochemistry (cross-linking; caged amino acids) and atomic mutagenesis (isosteric manipulation of charge and aromaticity; backbone mutation). Lastly, we cover recent advances in the encoding of fluorescent amino acids for the real-time study of protein conformational dynamics.
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Affiliation(s)
- Daniel T Infield
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242, United States
| | - Miranda E Schene
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242, United States
| | - Jason D Galpin
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242, United States
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242, United States
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2
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Munafó JP, Biscussi B, Obiol D, Costabel M, Bouzat C, Murray AP, Antollini S. New Multitarget Molecules Derived from Caffeine as Potentiators of the Cholinergic System. ACS Chem Neurosci 2024; 15:994-1009. [PMID: 38407056 DOI: 10.1021/acschemneuro.3c00710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024] Open
Abstract
Cholinergic deficit is a characteristic factor of several pathologies, such as myasthenia gravis, some types of congenital myasthenic syndromes, and Alzheimer's Disease. Two molecular targets for its treatment are acetylcholinesterase (AChE) and nicotinic acetylcholine receptor (nAChR). In previous studies, we found that caffeine behaves as a partial nAChR agonist and confirmed that it inhibits AChE. Here, we present new bifunctional caffeine derivatives consisting of a theophylline ring connected to amino groups by different linkers. All of them were more potent AChE inhibitors than caffeine. Furthermore, although some of them also activated muscle nAChR as partial agonists, not all of them stabilized nAChR in its desensitized conformation. To understand the molecular mechanism underlying these results, we performed docking studies on AChE and nAChR. The nAChR agonist behavior of the compounds depends on their accessory group, whereas their ability to stabilize the receptor in a desensitized state depends on the interactions of the linker at the binding site. Our results show that the new compounds can inhibit AChE and activate nAChR with greater potency than caffeine and provide further information on the modulation mechanisms of pharmacological targets for the design of novel therapeutic interventions in cholinergic deficit.
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Affiliation(s)
- Juan Pablo Munafó
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, Camino La Carrindanga km 7, Bahía Blanca 8000, Argentina
| | - Brunella Biscussi
- Instituto de Química del Sur, Departamento de Química, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, Avda. Alem 1253, Bahía Blanca 8000, Argentina
| | - Diego Obiol
- Grupo de Biofísica, Instituto de Física del Sur, Departamento de Física, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, Avda. Alem 1253, Bahía Blanca 8000, Argentina
| | - Marcelo Costabel
- Grupo de Biofísica, Instituto de Física del Sur, Departamento de Física, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, Avda. Alem 1253, Bahía Blanca 8000, Argentina
| | - Cecilia Bouzat
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, Camino La Carrindanga km 7, Bahía Blanca 8000, Argentina
| | - Ana Paula Murray
- Instituto de Química del Sur, Departamento de Química, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, Avda. Alem 1253, Bahía Blanca 8000, Argentina
| | - Silvia Antollini
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, Camino La Carrindanga km 7, Bahía Blanca 8000, Argentina
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3
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Selvam B, Landagaray E, Cartereau A, Laurent AD, Graton J, Lebreton J, Thany SH, Mathé-Allainmat M, Le Questel JY. Identification of sulfonamide compounds active on the insect nervous system: Molecular modeling, synthesis and biological evaluation. Bioorg Med Chem Lett 2023; 80:129124. [PMID: 36610552 DOI: 10.1016/j.bmcl.2023.129124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 12/01/2022] [Accepted: 01/02/2023] [Indexed: 01/05/2023]
Abstract
Insect nicotinic acetylcholine receptors (nAChRs) are a recognized target for insecticide design. In this work, we have identified, from a structure-based approach using molecular modeling tools, ligands with potential selective activity for pests versus pollinators. A high-throughput virtual screening with the Openeye software was performed using a library from the ZINC database, thiacloprid being used as the target structure. The top sixteen molecules were then docked in α6 cockroach and honeybee homomeric nAChRs to check from a theoretical point of view relevant descriptors in favor of pest selectivity. Among the selected molecules, one original sulfonamide compound has afterward been synthesized, together with various analogs. Two compounds of this family have been shown to behave as activators of the cockroach cholinergic synaptic transmission.
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Affiliation(s)
- Balaji Selvam
- Nantes Université, CNRS, CEISAM, UMR 6230, F-44000 Nantes, France; Gossamer Bio, 3013 Science Park Road, Suite 200, San Diego, CA 92121, France
| | | | - Alison Cartereau
- Université d'Orléans, Laboratoire Biologie des Ligneux et des Grandes Cultures, USC INRAE 1328, Rue de Chartres, BP 6759, 45067 Orléans Cedex 2, France
| | - Adèle D Laurent
- Nantes Université, CNRS, CEISAM, UMR 6230, F-44000 Nantes, France
| | - Jérôme Graton
- Nantes Université, CNRS, CEISAM, UMR 6230, F-44000 Nantes, France
| | - Jacques Lebreton
- Nantes Université, CNRS, CEISAM, UMR 6230, F-44000 Nantes, France
| | - Steeve H Thany
- Université d'Orléans, Laboratoire Biologie des Ligneux et des Grandes Cultures, USC INRAE 1328, Rue de Chartres, BP 6759, 45067 Orléans Cedex 2, France
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4
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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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5
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Knox HJ, Rego Campello H, Lester HA, Gallagher T, Dougherty DA. Characterization of Binding Site Interactions and Selectivity Principles in the α3β4 Nicotinic Acetylcholine Receptor. J Am Chem Soc 2022; 144:16101-16117. [PMID: 36006801 DOI: 10.1021/jacs.2c06495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) play an important role in neurotransmission and are also involved in addiction and several disease states. There is significant interest in therapeutic targeting of nAChRs; however, achieving selectivity for one subtype over others has been a longstanding challenge, given the close structural similarities across the family. Here, we characterize binding interactions in the α3β4 nAChR subtype via structure-function studies involving noncanonical amino acid mutagenesis and two-electrode voltage clamp electrophysiology. We establish comprehensive binding models for both the endogenous neurotransmitter ACh and the smoking cessation drug cytisine. We also use a panel of C(10)-substituted cytisine derivatives to probe the effects of subtle changes in the ligand structure on binding. By comparing our results to those obtained for the well-studied α4β2 subtype, we identify several features of both the receptor and agonist structure that can be utilized to enhance selectivity for either α3β4 or α4β2. Finally, we characterize binding interactions of the α3β4-selective partial agonist AT-1001 to determine factors that contribute to its selectivity. These results shed new light on the design of selective nAChR-targeted ligands and can be used to inform the design of improved therapies with minimized off-target effects.
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Affiliation(s)
- Hailey J Knox
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | | | - Henry A Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | | | - Dennis A Dougherty
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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6
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Maity AN, Chen JR, Li QY, Ke SC. The Nitrogen Atom of Vitamin B 6 Is Essential for the Catalysis of Radical Aminomutases. Int J Mol Sci 2022; 23:ijms23095210. [PMID: 35563602 PMCID: PMC9105233 DOI: 10.3390/ijms23095210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/03/2022] [Accepted: 05/04/2022] [Indexed: 11/16/2022] Open
Abstract
Radical aminomutases are pyridoxal 5'-phosphate (PLP, a B6 vitamer)-dependent enzymes that require the generation of a 5'-deoxyadenosyl radical to initiate the catalytic cycle, to perform a 1,2 amino group shift reaction. The role of the nitrogen atom of PLP in radical aminomutases has not been investigated extensively yet. We report an alternative synthetic procedure to provide easy access to 1-deazaPLP (dAPLP), an isosteric analog of PLP which acts as a probe for studying the role of the nitrogen atom. Our results revealed that lysine 5,6-aminomutase (5,6-LAM), a radical aminomutase, reconstituted with dAPLP cannot turn over a substrate, demonstrating that the nitrogen atom is essential for radical aminomutases. In contrast, biochemical and spectroscopic studies on the S238A variant reconstituted with PLP revealed a minuscule loss of activity. This apparent anomaly can be explained by a water-mediated rescue of activity in S238A, as if mimicking the active site of lysine 2,3-aminomutase. This study leads to a better comprehension of how enzymes harness the optimum capability of PLP to realize catalysis.
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7
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Conformational transitions and ligand-binding to a muscle-type nicotinic acetylcholine receptor. Neuron 2022; 110:1358-1370.e5. [PMID: 35139364 DOI: 10.1016/j.neuron.2022.01.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/02/2021] [Accepted: 01/10/2022] [Indexed: 12/15/2022]
Abstract
Fast synaptic communication requires receptors that respond to the presence of neurotransmitter by opening an ion channel across the post-synaptic membrane. The muscle-type nicotinic acetylcholine receptor from the electric fish, Torpedo, is the prototypic ligand-gated ion channel, yet the structural changes underlying channel activation remain undefined. Here we use cryo-EM to solve apo and agonist-bound structures of the Torpedo nicotinic receptor embedded in a lipid nanodisc. Using both a direct biochemical assay to define the conformational landscape and molecular dynamics simulations to assay flux through the pore, we correlate structures with functional states and elucidate the motions that lead to pore activation of a heteromeric nicotinic receptor. We highlight an underappreciated role for the complementary subunit in channel gating, establish the structural basis for the differential agonist affinities of α/δ versus α /γ sites, and explain why nicotine is less potent at muscle nicotinic receptors compared to neuronal ones.
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8
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Fabiani C, Biscussi B, Munafo JP, Murray AP, Corradi J, Antollini SS. NEW SYNTHETIC CAFFEINE ANALOGS AS MODULATORS OF THE CHOLINERGIC SYSTEM. Mol Pharmacol 2021; 101:154-167. [PMID: 34969831 DOI: 10.1124/molpharm.121.000415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/26/2021] [Indexed: 11/22/2022] Open
Abstract
Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder. Since cholinergic deficit is a major factor in this disease, two molecular targets for its treatment are the acetylcholinesterase (AChE) and the nicotinic acetylcholine receptors (nAChRs). Given that caffeine is a natural compound that behaves as an AChE inhibitor and as a partial agonist of nAChRs, the aim of this work was to synthetize more potent bifunctional caffeine analogs that modulate these two molecular targets. To this end, a theophylline structure was connected to a pyrrolidine structure through a methylene chain of different lengths (3 to 7 carbon atoms) to give compounds 7-11 All caffeine derivatives inhibited the AChE, of which compound 11 showed the strongest effect. Electrophysiological studies showed that all compounds behave as agonists of the muscle and the neuronal α7 nAChR with greater potency than caffeine. To explore if the different analogs could affect the nAChR conformational state, the nAChR conformational-sensitive probe crystal violet (CrV) was used. Compounds 9 and 10 conduced the nAChR to a different conformational state comparable with a control nAChR desensitized state. Finally, molecular docking experiments showed that all derivatives interacted with both the catalytic and anionic sites of AChE and with the orthosteric binding site of the nAChR. Thus, the new synthetized compounds can inhibit the AChE and activate muscle and α7 nAChRs with greater potency than caffeine, which suggests that they could be useful leaders for the development of new therapies for the treatment of different neurological diseases. Significance Statement In this work we synthetized caffeine derivatives which can inhibit the AChE and activate both muscle and α7 nAChRs with higher potency than caffeine. These analogs can be divided into two groups: a non-desensitizing and a desensitizing nAChR group. From the nAChR-non desensitizing group, we propose compound 11 as the most interesting analog for further studies since it inhibits AChE with the highest potency and activates the nAChRs in the picomolar range without inducing receptor desensitization.
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Affiliation(s)
- Camila Fabiani
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas, Camino La Carrindanga km 7, Argentina
| | - Brunella Biscussi
- Instituto de Química del Sur, Departamento de Química, Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Alem 1253, Argentina
| | - Juan Pablo Munafo
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas, Camino La Carrindanga km 7, Argentina
| | - Ana Paula Murray
- Instituto de Química del Sur, Departamento de Química, Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Alem 1253, Argentina
| | - Jeremias Corradi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas, Camino La Carrindanga km 7, Argentina
| | - Silvia Susana Antollini
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur y Consejo Nacional de Investigaciones Científicas y Técnicas, Camino La Carrindanga km 7, Argentina
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de Oliveira VM, da Rocha MN, Magalhães EP, da Silva Mendes FR, Marinho MM, de Menezes RRPPB, Sampaio TL, Dos Santos HS, Martins AMC, Marinho ES. Computational approach towards the design of artemisinin-thymoquinone hybrids against main protease of SARS-COV-2. FUTURE JOURNAL OF PHARMACEUTICAL SCIENCES 2021; 7:185. [PMID: 34514004 PMCID: PMC8419828 DOI: 10.1186/s43094-021-00334-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/26/2021] [Indexed: 01/22/2023] Open
Abstract
Background The sanitary emergency installed in the world, generated by the pandemic of COVID-19, instigates the search for scientific strategies to mitigate the damage caused by the disease to different sectors of society. The disease caused by the coronavirus, SARS-CoV-2, reached 216 countries/territories, where about 199 million people were reported with the infection. Of these, more than 4 million died. In this sense, strategies involving the development of new antiviral molecules are extremely important. The main protease (Mpro) from SARS-CoV-2 is an important target, which has been widely studied for antiviral treatment. This work aims to perform a screening of pharmacodynamics and pharmacokinetics of synthetic hybrids from thymoquinone and artemisin (THY-ART) against COVID-19. Results Molecular docking studies indicated that hybrids of artemisinin and thymoquinone showed a relevant interaction with the active fraction of the enzyme Mpro, when compared to the reference drugs. Furthermore, hybrids show an improvement in the interaction of substances with the enzyme, mainly due to the higher frequency of interactions with the Thr199 residue. ADMET studies indicated that hybrids tend to permeate biological membranes, allowing good human intestinal absorption, with low partition to the central nervous system, potentiation for CYP-450 enzyme inhibitors, low risk of toxicity compared to commercially available drugs, considering mainly mutagenicity and cardiotoxicity, low capacity of hybrids to permeate the blood–brain barrier, high absorption and moderate permeability in Caco-2 cells. In addition, T1–T7 tend to have a better distribution of their available fractions to carry out diffusion and transport across cell membranes, as well as increase the energy of interaction with the SARS-CoV-2 target. Conclusions Hybrid products of artemisinin and thymoquinone have the potential to inhibit Mpro, with desirable pharmacokinetic and toxicity characteristics compared to commercially available drugs, being indicated for preclinical and subsequent clinical studies against SARS-CoV-2. Emphasizing the possibility of synergistic use with currently used drugs in order to increase half-life and generate a possible synergistic effect. This work represents an important step for the development of specific drugs against COVID-19.
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Affiliation(s)
- Victor Moreira de Oliveira
- Theoretical and Electrochemical Chemistry Research Group/FAFIDAM, State University of Ceará, Limoeiro do Norte, CE CEP 62930-000 Brazil
| | - Matheus Nunes da Rocha
- Theoretical and Electrochemical Chemistry Research Group/FAFIDAM, State University of Ceará, Limoeiro do Norte, CE CEP 62930-000 Brazil
| | - Emanuel Paula Magalhães
- Department of Clinical and Toxicological Analysis, Federal University of Ceara, Fortaleza, CE CEP 60430-172 Brazil
| | - Francisco Rogênio da Silva Mendes
- Theoretical and Electrochemical Chemistry Research Group/FAFIDAM, State University of Ceará, Limoeiro do Norte, CE CEP 62930-000 Brazil
| | - Márcia Machado Marinho
- Iguatu Faculty of Education, Science and Letters/FECLI, State University of Ceará, Iguatu, CE CEP 63502-253 Brazil
| | | | - Tiago Lima Sampaio
- Department of Clinical and Toxicological Analysis, Federal University of Ceara, Fortaleza, CE CEP 60430-172 Brazil
| | - Hélcio Silva Dos Santos
- Laboratory of Natural Products Chemistry, Synthesis and Biocatalysis of Organic Compounds - LBPNSB, State University of Vale do Acaraú, Sobral, CE CEP 62040370 Brazil
| | - Alice Maria Costa Martins
- Department of Clinical and Toxicological Analysis, Federal University of Ceara, Fortaleza, CE CEP 60430-172 Brazil
| | - Emmanuel Silva Marinho
- Theoretical and Electrochemical Chemistry Research Group/FAFIDAM, State University of Ceará, Limoeiro do Norte, CE CEP 62930-000 Brazil
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Bavo F, Pallavicini M, Appiani R, Bolchi C. Determinants for α4β2 vs. α3β4 Subtype Selectivity of Pyrrolidine-Based nAChRs Ligands: A Computational Perspective with Focus on Recent cryo-EM Receptor Structures. Molecules 2021; 26:molecules26123603. [PMID: 34204637 PMCID: PMC8231201 DOI: 10.3390/molecules26123603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 12/26/2022] Open
Abstract
The selectivity of α4β2 nAChR agonists over the α3β4 nicotinic receptor subtype, predominant in ganglia, primarily conditions their therapeutic range and it is still a complex and challenging issue for medicinal chemists and pharmacologists. Here, we investigate the determinants for such subtype selectivity in a series of more than forty α4β2 ligands we have previously reported, docking them into the structures of the two human subtypes, recently determined by cryo-electron microscopy. They are all pyrrolidine based analogues of the well-known α4β2 agonist N-methylprolinol pyridyl ether A-84543 and differ in the flexibility and pattern substitution of their aromatic portion. Indeed, the direct or water mediated interaction with hydrophilic residues of the relatively narrower β2 minus side through the elements decorating the aromatic ring and the stabilization of the latter by facing to the not conserved β2-Phe119 result as key distinctive features for the α4β2 affinity. Consistently, these compounds show, despite the structural similarity, very different α4β2 vs. α3β4 selectivities, from modest to very high, which relate to rigidity/extensibility degree of the portion containing the aromatic ring and to substitutions at the latter. Furthermore, the structural rationalization of the rat vs. human differences of α4β2 vs. α3β4 selectivity ratios is here proposed.
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Affiliation(s)
- Francesco Bavo
- Dipartimento di Scienze Farmaceutiche, Universita’degli Studi di Milano, I-20133 Milano, Italy; (F.B.); (M.P.); (R.A.)
- Department of Drug Design and Pharmacology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Marco Pallavicini
- Dipartimento di Scienze Farmaceutiche, Universita’degli Studi di Milano, I-20133 Milano, Italy; (F.B.); (M.P.); (R.A.)
| | - Rebecca Appiani
- Dipartimento di Scienze Farmaceutiche, Universita’degli Studi di Milano, I-20133 Milano, Italy; (F.B.); (M.P.); (R.A.)
| | - Cristiano Bolchi
- Dipartimento di Scienze Farmaceutiche, Universita’degli Studi di Milano, I-20133 Milano, Italy; (F.B.); (M.P.); (R.A.)
- Correspondence:
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11
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Roy A, Kaneriya D, Pandya SR, Sangani CB, Pavagadhi TH, Undre SB, Muddassir M. Intermolecular interactions of nicotine with biomolecules to optimize and develop extraction formulations moderated through physicochemical properties at 303.15 K. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Kaji MD, Geary TG, Beech RN. A Functional Comparison of Homopentameric Nicotinic Acetylcholine Receptors (ACR-16) Receptors From Necator americanus and Ancylostoma ceylanicum. Front Mol Neurosci 2020; 13:601102. [PMID: 33324163 PMCID: PMC7725692 DOI: 10.3389/fnmol.2020.601102] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/04/2020] [Indexed: 12/24/2022] Open
Abstract
Effective control of hookworm infections in humans and animals relies on using a small group of anthelmintics. Many of these drugs target cholinergic ligand-gated ion channels, yet the direct activity of anthelmintics has only been studied in a subset of these receptors, primarily in the non-parasitic nematode, Caenorhabditis elegans. Here we report the characterization of a homopentameric ionotropic acetylcholine receptor (AChR), ACR-16, from Necator americanus and Ancylostoma ceylanicum, the first known characterization of human hookworm ion channels. We used two-electrode voltage clamp electrophysiology in Xenopus laevis oocytes to determine the pharmacodynamics of cholinergics and anthelmintics on ACR-16 from both species of hookworm. The A. ceylanicum receptor (Ace-ACR-16) was more sensitive to acetylcholine (EC50 = 20.64 ± 0.32 μM) and nicotine (EC50 = 24.37 ± 2.89 μM) than the N. americanus receptor (Nam-ACR-16) (acetylcholine EC50 = 170.1 ± 19.23 μM; nicotine EC50 = 597.9 ± 59.12 μM), at which nicotine was a weak partial agonist (% maximal acetylcholine response = 30.4 ± 7.4%). Both receptors were inhibited by 500 μM levamisole (Ace-ACR-16 = 65.1 ± 14.3% inhibition, Nam-ACR-16 = 79.5 ± 7.7% inhibition), and responded to pyrantel, but only Ace-ACR-16 responded to oxantel. We used in silico homology modeling to investigate potential structural differences that account for the differences in agonist binding and identified a loop E isoleucine 130 of Nam-ACR-16 as possibly playing a role in oxantel insensitivity. These data indicate that key functional differences exist among ACR-16 receptors from closely related species and suggest mechanisms for differential drug sensitivity.
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Affiliation(s)
- Mark D. Kaji
- Institute of Parasitology, McGill University, Montreal, QC, Canada
| | - Timothy G. Geary
- Institute of Parasitology, McGill University, Montreal, QC, Canada
- School of Biological Sciences, Queen’s University-Belfast, Belfast, United Kingdom
| | - Robin N. Beech
- Institute of Parasitology, McGill University, Montreal, QC, Canada
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13
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Tinzl M, Hilvert D. Trapping Transient Protein Species by Genetic Code Expansion. Chembiochem 2020; 22:92-99. [PMID: 32810341 DOI: 10.1002/cbic.202000523] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/18/2020] [Indexed: 12/24/2022]
Abstract
Nature employs a limited number of genetically encoded amino acids for the construction of functional proteins. By engineering components of the cellular translation machinery, however, it is now possible to genetically encode noncanonical building blocks with tailored electronic and structural properties. The ability to incorporate unique chemical functionality into proteins provides a powerful tool to probe mechanism and create novel function. In this minireview, we highlight several recent studies that illustrate how noncanonical amino acids have been used to capture and characterize reactive intermediates, fine-tune the catalytic properties of enzymes, and stabilize short-lived protein-protein complexes.
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Affiliation(s)
- Matthias Tinzl
- Laboratory of Organic Chemistry, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
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14
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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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15
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Progress in nicotinic receptor structural biology. Neuropharmacology 2020; 171:108086. [PMID: 32272141 DOI: 10.1016/j.neuropharm.2020.108086] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 03/31/2020] [Indexed: 02/07/2023]
Abstract
Here we begin by briefly reviewing landmark structural studies on the nicotinic acetylcholine receptor. We highlight challenges that had to be overcome to push through resolution barriers, then focus on what has been gleaned in the past few years from crystallographic and single particle cryo-EM studies of different nicotinic receptor subunit assemblies and ligand complexes. We discuss insights into ligand recognition, ion permeation, and allosteric gating. We then highlight some foundational aspects of nicotinic receptor structural biology that remain unresolved and are areas ripe for future exploration. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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16
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Alijevic O, McHugh D, Rufener L, Mazurov A, Hoeng J, Peitsch M. An electrophysiological characterization of naturally occurring tobacco alkaloids and their action on human α4β2 and α7 nicotinic acetylcholine receptors. PHYTOCHEMISTRY 2020; 170:112187. [PMID: 31865001 DOI: 10.1016/j.phytochem.2019.112187] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 06/10/2023]
Abstract
Nicotinic acetylcholine receptor (nAChR) subtype-selective pharmacological profiles of tobacco alkaloids are essential for understanding the physiological effects of tobacco products. In this study, automated electrophysiology was used to functionally characterize the effects of distinct groups of tobacco alkaloids on human α4β2 and α7 nAChRs. We found that, in tobacco alkaloids, pyridine as a hydrogen bond acceptor and a basic nitrogen atom at a distance of 4-7 Å are pharmacophoric elements necessary for molecular recognition by α4β2 and α7 nAChRs with various degrees of selectivity, potency, and efficacy. While four alkaloids-nicotine, nornicotine, anabasine and R-anatabine-potently activated α4β2, they were also weak agonists of α7 nAChRs. Nicotine was the most potent agonist of α4β2, while anabasine elicited the highest activation of α7. None of the tobacco alkaloids enhanced nAChR activity elicited by the endogenous ligand acetylcholine; therefore, none was considered to be a positive allosteric modulator (PAM) of either α4β2 or α7 nAChRs. In contrast, we identified tobacco alkaloids, such as the tryptophan metabolite 6-hydroxykynurenic acid, that decreased the activity of both α4β2 and α7 nAChRs. Our study identified a class of alkaloids with positive and negative effects against human α4β2 and α7 nAChRs. It also revealed human α4β2 to be the principal receptor for sensing the most abundant alkaloids in tobacco leaves.
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Affiliation(s)
- Omar Alijevic
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Damian McHugh
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland.
| | | | - Anatoly Mazurov
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Julia Hoeng
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Manuel Peitsch
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
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17
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Blom AE, Campello HR, Lester HA, Gallagher T, Dougherty DA. Probing Binding Interactions of Cytisine Derivatives to the α4β2 Nicotinic Acetylcholine Receptor. J Am Chem Soc 2019; 141:15840-15849. [DOI: 10.1021/jacs.9b06580] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
| | - Hugo Rego Campello
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | | | - Timothy Gallagher
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
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18
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Sruthi PK, Sarkar S, Ramanathan N, Sundararajan K. Elusive hypervalent phosphorus⋯π interactions: evidence for paradigm transformation from hydrogen to phosphorus bonding at low temperatures. Phys Chem Chem Phys 2019; 21:12250-12264. [DOI: 10.1039/c9cp01925a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A paradigm transformation from hydrogen to phosphorus bonding is found to depend on the proton affinity of the interacting π-systems.
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Affiliation(s)
- P. K. Sruthi
- Materials Chemistry and Metal Fuel Cycle Group
- Homi Bhabha National Institute
- Indira Gandhi Centre for Atomic Research
- Kalpakkam-603 102
- India
| | - Shubhra Sarkar
- Materials Chemistry and Metal Fuel Cycle Group
- Homi Bhabha National Institute
- Indira Gandhi Centre for Atomic Research
- Kalpakkam-603 102
- India
| | - N. Ramanathan
- Materials Chemistry and Metal Fuel Cycle Group
- Homi Bhabha National Institute
- Indira Gandhi Centre for Atomic Research
- Kalpakkam-603 102
- India
| | - K. Sundararajan
- Materials Chemistry and Metal Fuel Cycle Group
- Homi Bhabha National Institute
- Indira Gandhi Centre for Atomic Research
- Kalpakkam-603 102
- India
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19
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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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20
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López JJ, García-Colunga J, Pérez EG, Fierro A. Methylpiperidinium Iodides as Novel Antagonists for α7 Nicotinic Acetylcholine Receptors. Front Pharmacol 2018; 9:744. [PMID: 30042682 PMCID: PMC6048275 DOI: 10.3389/fphar.2018.00744] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/19/2018] [Indexed: 11/17/2022] Open
Abstract
The α7 nicotinic acetylcholine receptor (nAChR) is expressed in neuronal and non-neuronal cells and is involved in several physiopathological processes, and is thus an important drug target. We have designed and synthesized novel piperidine derivatives as α7 nAChR antagonists. Thus, we describe here a new series of 1-[2-(4-alkoxy-phenoxy-ethyl)]piperidines and 1-[2-(4-alkyloxy-phenoxy-ethyl)]-1-methylpiperidinium iodides (compounds 11a-11c and 12a-12c), and their actions on α7 nAChRs. The pharmacological activity of these compounds was studied in rat CA1 hippocampal interneurons by using the whole-cell voltage-clamp technique. Inhibition of the choline-induced current was less for 11a-11c than for the methylpiperidinium iodides 12a-12c and depended on the length of the aliphatic chain. Those compounds showing strong effects were studied further using molecular docking and molecular dynamics simulations. The strongest and non-voltage dependent antagonism was shown by 12a, which could establish cation–π interactions with the principal (+)-side and van der Waals interactions with the complementary (-)-side in the α7 nAChRs. Furthermore, compound 11a forms hydrogen bonds with residue Q115 of the complementary (-)-side through water molecules without forming cation–π interactions. Our findings have led to the establishment of a new family of antagonists that interact with the agonist binding cavity of the α7 nAChR, which represent a promising new class of compounds for the treatment of pathologies where these receptors need to be negatively modulated, including neuropsychiatric disorders as well as different types of cancer.
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Affiliation(s)
- Jhon J López
- Department of Chemistry, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Jesús García-Colunga
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Edwin G Pérez
- Department of Organic Chemistry, Faculty of Chemistry, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Angélica Fierro
- Department of Organic Chemistry, Faculty of Chemistry, Pontificia Universidad Católica de Chile, Santiago, Chile
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21
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Fu DY, Meiler J. Predictive Power of Different Types of Experimental Restraints in Small Molecule Docking: A Review. J Chem Inf Model 2018; 58:225-233. [PMID: 29286651 DOI: 10.1021/acs.jcim.7b00418] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Incorporating experimental restraints is a powerful method of increasing accuracy in computational protein small molecule docking simulations. Different algorithms integrate distinct forms of biochemical data during the docking and/or scoring stages. These so-called hybrid methods make use of receptor-based information such as nuclear magnetic resonance (NMR) restraints or small molecule-based information such as structure-activity relationships (SARs). A third class of methods directly interrogates contacts between the protein receptor and the small molecule. This work reviews the current state of using such restraints in docking simulations, evaluates their feasibility across broad systems, and identifies potential areas of algorithm development.
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Affiliation(s)
- Darwin Y Fu
- Department of Chemistry Vanderbilt University Nashville, Tennessee 37235, United States
| | - Jens Meiler
- Department of Chemistry Vanderbilt University Nashville, Tennessee 37235, United States
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22
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Secondary Ammonium Agonists Make Dual Cation-π Interactions in α4β2 Nicotinic Receptors. eNeuro 2017; 4:eN-NWR-0032-17. [PMID: 28589175 PMCID: PMC5458768 DOI: 10.1523/eneuro.0032-17.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 11/21/2022] Open
Abstract
A cation-π interaction between the ammonium group of an agonist and a conserved tryptophan termed TrpB is a near universal feature of agonist binding to nicotinic acetylcholine receptors (nAChRs). TrpB is one of five residues that form the aromatic box of the agonist binding site, and for the prototype agonists ACh and nicotine, only TrpB makes a functional cation-π interaction. We report that, in addition to TrpB, a significant cation-π interaction is made to a second aromatic, TyrC2, by the agonists metanicotine, TC299423, varenicline, and nornicotine. A common structural feature of these agonists, and a distinction from ACh and nicotine, is a protonated secondary amine that provides the cation for the cation-π interaction. These results indicate a distinction in binding modes between agonists with subtly different structures that may provide guidance for the development of subtype-selective agonists of nAChRs.
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23
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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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24
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Matsui JK, Molander GA. Organocatalyzed, Photoredox Heteroarylation of 2-Trifluoroboratochromanones via C-H Functionalization. Org Lett 2017; 19:950-953. [PMID: 28157320 PMCID: PMC5321137 DOI: 10.1021/acs.orglett.7b00196] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Heteroarylation
via C–H functionalization has been synthetically
challenging, but such transformations represent an atom-economical
and highly convergent route toward complex molecules. Reported herein
is a photoredox-catalyzed coupling between 2-trifluoroborato-4-chromanones
and various heteroarenes through a Minisci pathway. Mesitylacridinium
perchlorate, an organic photocatalyst, proved to be a better photocatalyst
than transition-metal counterparts for such transformations. To highlight
the utility of this approach, a library of unprecedented heteroaryl-substituted
chromanones was generated that was composed of numerous, specifically
substituted molecules containing a broad range of functional groups.
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Affiliation(s)
- Jennifer K Matsui
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Gary A Molander
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
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25
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Bruhova I, Auerbach A. Molecular recognition at cholinergic synapses: acetylcholine versus choline. J Physiol 2016; 595:1253-1261. [PMID: 27779761 DOI: 10.1113/jp273291] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 10/12/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Neuromuscular acetylcholine (ACh) receptors have a high affinity for the neurotransmitter ACh and a low affinity for its metabolic product choline. At each transmitter binding site three aromatic groups determine affinity, and together provide ∼50% more binding energy for ACh than for choline. Deprotonation of αY190 by a nearby lysine strengthens the interaction between this aromatic ring and both ACh and choline. H-bonds position ACh and choline differently in the aromatic cage to generate the different affinities. ABSTRACT Acetylcholine (ACh) released at the vertebrate nerve-muscle synapse is hydrolysed rapidly to choline (Cho), so endplate receptors (AChRs) are exposed to high concentrations of both of these structurally related ligands. To understand how these receptors distinguish ACh and Cho, we used single-channel electrophysiology to measure resting affinities (binding free energies) of these and other agonists in adult-type mouse AChRs having a mutation(s) at the transmitter-binding sites. The aromatic rings of αY190, αW149 and αY198 each provide ∼50% less binding energy for Cho compared to ACh. At αY198 a phenylalanine substitution had no effect, but at αY190 this substitution caused a large, agonist-independent loss in binding energy that depended on the presence of αK145. The results suggest that (1) αY190 is deprotonated by αK145 to strengthen the interaction between this benzene ring and the agonist's quaternary ammonium (QA) and (2) AChRs respond strongly to ACh because an H-bond positions the QA to interact optimally with the rings, and weakly to Cho because a different H-bond tethers the ligand to misalign the QA and form weaker interactions with the aromatic groups. The results suggest that the difference in ACh versus Cho binding energies is determined by different ligand positions within a fixed protein structure.
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Affiliation(s)
- Iva Bruhova
- Department of Physiology and Biophysics, SUNY at Buffalo, Buffalo, NY, 14214, USA
| | - Anthony Auerbach
- Department of Physiology and Biophysics, SUNY at Buffalo, Buffalo, NY, 14214, USA
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26
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Zheng F, Du X, Chou TH, Robertson AP, Yu EW, VanVeller B, Martin RJ. (S)-5-ethynyl-anabasine, a novel compound, is a more potent agonist than other nicotine alkaloids on the nematode Asu-ACR-16 receptor. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2016; 7:12-22. [PMID: 28033523 PMCID: PMC5196235 DOI: 10.1016/j.ijpddr.2016.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/23/2016] [Accepted: 12/02/2016] [Indexed: 12/13/2022]
Abstract
Nematode parasites infect ∼2 billion people world-wide. Infections are treated and prevented by anthelmintic drugs, some of which act on nicotinic acetylcholine receptors (nAChRs). There is an unmet need for novel therapeutic agents because of concerns about the development of resistance. We have selected Asu-ACR-16 from a significant nematode parasite genus, Ascaris suum, as a pharmaceutical target and nicotine as our basic moiety (EC50 6.21 ± 0.56 μM, Imax 82.39 ± 2.52%) to facilitate the development of more effective anthelmintics. We expressed Asu-ACR-16 in Xenopus oocytes and used two-electrode voltage clamp electrophysiology to determine agonist concentration-current-response relationships and determine the potencies (EC50s) of the agonists. Here, we describe the synthesis of a novel agonist, (S)-5-ethynyl-anabasine, and show that it is more potent (EC50 0.14 ± 0.01 μM) than other nicotine alkaloids on Asu-ACR-16. Agonists acting on ACR-16 receptors have the potential to circumvent drug resistance to anthelmintics, like levamisole, that do not act on the ACR-16 receptors. ACR-16 receptor agonists may overcome resistance to anthelmintics like levamisole. We modeled the Asu-ACR-16 of Ascaris as a target for novel anthelmintic development. We synthesized novel nicotinic agonists including (S)-5-ethynyl-anabasine. We expressed Asu-ACR-16 in Xenopus oocytes to determine agonists potencies. (S)-5-ethynyl-anabasine is more potent (EC50 0.1 μM) than other nicotinic alkaloids.
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Affiliation(s)
- Fudan Zheng
- Department of Chemistry, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, USA
| | - Xiangwei Du
- Department of Chemistry, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, USA
| | - Tsung-Han Chou
- Department of Physics and Astronomy, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Edward W Yu
- Department of Physics and Astronomy, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, USA
| | - Brett VanVeller
- Department of Chemistry, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, USA
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
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27
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AutoDock-GIST: Incorporating Thermodynamics of Active-Site Water into Scoring Function for Accurate Protein-Ligand Docking. Molecules 2016; 21:molecules21111604. [PMID: 27886114 PMCID: PMC6274120 DOI: 10.3390/molecules21111604] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/15/2016] [Accepted: 11/16/2016] [Indexed: 11/27/2022] Open
Abstract
Water plays a significant role in the binding process between protein and ligand. However, the thermodynamics of water molecules are often underestimated, or even ignored, in protein-ligand docking. Usually, the free energies of active-site water molecules are substantially different from those of waters in the bulk region. The binding of a ligand to a protein causes a displacement of these waters from an active site to bulk, and this displacement process substantially contributes to the free energy change of protein-ligand binding. The free energy of active-site water molecules can be calculated by grid inhomogeneous solvation theory (GIST), using molecular dynamics (MD) and the trajectory of a target protein and water molecules. Here, we show a case study of the combination of GIST and a docking program and discuss the effectiveness of the displacing gain of unfavorable water in protein-ligand docking. We combined the GIST-based desolvation function with the scoring function of AutoDock4, which is called AutoDock-GIST. The proposed scoring function was assessed employing 51 ligands of coagulation factor Xa (FXa), and results showed that both scoring accuracy and docking success rate were improved. We also evaluated virtual screening performance of AutoDock-GIST using FXa ligands in the directory of useful decoys-enhanced (DUD-E), thus finding that the displacing gain of unfavorable water is effective for a successful docking campaign.
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28
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Comitani F, Limongelli V, Molteni C. The Free Energy Landscape of GABA Binding to a Pentameric Ligand-Gated Ion Channel and Its Disruption by Mutations. J Chem Theory Comput 2016; 12:3398-406. [PMID: 27228114 DOI: 10.1021/acs.jctc.6b00303] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pentameric ligand-gated ion channels (pLGICs) of the Cys-loop superfamily are important neuroreceptors that mediate fast synaptic transmission. They are activated by the binding of a neurotransmitter, but the details of this process are still not fully understood. As a prototypical pLGIC, here we choose the insect resistance to dieldrin (RDL) receptor involved in resistance to insecticides and investigate the binding of the neurotransmitter GABA to its extracellular domain at the atomistic level. We achieve this by means of μ-sec funnel-metadynamics simulations, which efficiently enhance the sampling of bound and unbound states by using a funnel-shaped restraining potential to limit the exploration in the solvent. We reveal the sequence of events in the binding process from the capture of GABA from the solvent to its pinning between the charged residues Arg111 and Glu204 in the binding pocket. We characterize the associated free energy landscapes in the wild-type RDL receptor and in two mutant forms, where the key residues Arg111 and Glu204 are mutated to Ala. Experimentally these mutations produce nonfunctional channels, which is reflected in the reduced ligand binding affinities due to the loss of essential interactions. We also analyze the dynamical behavior of the crucial loop C, whose opening allows the access of GABA to the binding site and closure locks the ligand into the protein. The RDL receptor shares structural and functional features with other pLGICs; hence, our work outlines a valuable protocol to study the binding of ligands to pLGICs beyond conventional docking and molecular dynamics techniques.
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Affiliation(s)
- Federico Comitani
- Department of Physics, King's College London , Strand, London WC2R 2LS, United Kingdom
| | - Vittorio Limongelli
- Universitá della Svizzera Italiana (USI) , Faculty of Informatics, Institute of Computational Science - Center for Computational Medicine in Cardiology, via G. Buffi 13, CH-6900 Lugano, Switzerland.,Department of Pharmacy, University of Naples "Federico II" , via D. Montesano 49, I-80131 Naples, Italy
| | - Carla Molteni
- Department of Physics, King's College London , Strand, London WC2R 2LS, United Kingdom
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29
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Abstract
On the basis of many literature measurements, a critical overview is given on essential noncovalent interactions in synthetic supramolecular complexes, accompanied by analyses with selected proteins. The methods, which can be applied to derive binding increments for single noncovalent interactions, start with the evaluation of consistency and additivity with a sufficiently large number of different host-guest complexes by applying linear free energy relations. Other strategies involve the use of double mutant cycles, of molecular balances, of dynamic combinatorial libraries, and of crystal structures. Promises and limitations of these strategies are discussed. Most of the analyses stem from solution studies, but a few also from gas phase. The empirically derived interactions are then presented on the basis of selected complexes with respect to ion pairing, hydrogen bonding, electrostatic contributions, halogen bonding, π-π-stacking, dispersive forces, cation-π and anion-π interactions, and contributions from the hydrophobic effect. Cooperativity in host-guest complexes as well as in self-assembly, and entropy factors are briefly highlighted. Tables with typical values for single noncovalent free energies and polarity parameters are in the Supporting Information.
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Affiliation(s)
- Frank Biedermann
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Hans-Jörg Schneider
- FR Organische Chemie der Universität des Saarlandes , D-66041 Saarbrücken, Germany
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30
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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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31
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Shahsavar A, Gajhede M, Kastrup JS, Balle T. Structural Studies of Nicotinic Acetylcholine Receptors: Using Acetylcholine-Binding Protein as a Structural Surrogate. Basic Clin Pharmacol Toxicol 2016; 118:399-407. [DOI: 10.1111/bcpt.12528] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/02/2015] [Indexed: 01/09/2023]
Affiliation(s)
- Azadeh Shahsavar
- Department of Molecular Biology and Genetics; Danish Research Institute of Translational Neuroscience - DANDRITE; Aarhus University; Aarhus Denmark
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Michael Gajhede
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Jette S. Kastrup
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Thomas Balle
- Faculty of Pharmacy; The University of Sydney; Sydney NSW Australia
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32
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Modification of the anabaseine pyridine nucleus allows achieving binding and functional selectivity for the α3β4 nicotinic acetylcholine receptor subtype. Eur J Med Chem 2016; 108:392-405. [DOI: 10.1016/j.ejmech.2015.11.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 11/19/2022]
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33
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Reddi R, Singarapu KK, Pal D, Addlagatta A. The unique functional role of the C–H⋯S hydrogen bond in the substrate specificity and enzyme catalysis of type 1 methionine aminopeptidase. MOLECULAR BIOSYSTEMS 2016; 12:2408-16. [DOI: 10.1039/c6mb00259e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Unique C–H⋯S hydrogen bonding interactions allow nature to attain recognition specificity between molecular interfaces where there is no apparent scope for classical hydrogen bonding or polar interactions.
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Affiliation(s)
- Ravikumar Reddi
- Centre for Chemical Biology
- CSIR-Indian Institute of Chemical Technology
- Hyderabad 500 007
- India
| | - Kiran Kumar Singarapu
- Centre for NMR and Structural Chemistry
- CSIR-Indian Institute of Chemical Technology
- Hyderabad 500 007
- India
| | - Debnath Pal
- Department of Computational and Data Sciences
- Indian Institute of Science
- Bangalore 560 012
- India
| | - Anthony Addlagatta
- Centre for Chemical Biology
- CSIR-Indian Institute of Chemical Technology
- Hyderabad 500 007
- India
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34
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Alamiddine Z, Selvam B, Cerón-Carrasco JP, Mathé-Allainmat M, Lebreton J, Thany SH, Laurent AD, Graton J, Le Questel JY. Molecular recognition of thiaclopride by Aplysia californica AChBP: new insights from a computational investigation. J Comput Aided Mol Des 2015; 29:1151-67. [PMID: 26589615 DOI: 10.1007/s10822-015-9884-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/16/2015] [Indexed: 11/29/2022]
Abstract
The binding of thiaclopride (THI), a neonicotinoid insecticide, with Aplysia californica acetylcholine binding protein (Ac-AChBP), the surrogate of the extracellular domain of insects nicotinic acetylcholine receptors, has been studied with a QM/QM' hybrid methodology using the ONIOM approach (M06-2X/6-311G(d):PM6). The contributions of Ac-AChBP key residues for THI binding are accurately quantified from a structural and energetic point of view. The importance of water mediated hydrogen-bond (H-bond) interactions involving two water molecules and Tyr55 and Ser189 residues in the vicinity of the THI nitrile group, is specially highlighted. A larger stabilization energy is obtained with the THI-Ac-AChBP complex compared to imidacloprid (IMI), the forerunner of neonicotinoid insecticides. Pairwise interaction energy calculations rationalize this result with, in particular, a significantly more important contribution of the pivotal aromatic residues Trp147 and Tyr188 with THI through CH···π/CH···O and π-π stacking interactions, respectively. These trends are confirmed through a complementary non-covalent interaction (NCI) analysis of selected THI-Ac-AChBP amino acid pairs.
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Affiliation(s)
- Zakaria Alamiddine
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes, 44322, France
| | - Balaji Selvam
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes, 44322, France.,Roger Adams Laboratory, University of Illinois at Urbana-Champaign, 600 S Mathews Ave, Urbana, IL, 61801, USA
| | - José P Cerón-Carrasco
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes, 44322, France.,Bioinformatics and High Performance Computing Research Group (BIO-HPC), Computer Science Department, Universidad Católica San Antonio de Murcia (UCAM), Campus de los Jerónimos, 30107, Murcia, Spain
| | - Monique Mathé-Allainmat
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes, 44322, France
| | - Jacques Lebreton
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes, 44322, France
| | - Steeve H Thany
- Laboratoire de Biologie des Ligneux et des Grandes Cultures, Université d'Orléans, UPRES EA 1207. Rue de Chartres, BP 6759, 45067, Orléans Cedex 2, France
| | - Adèle D Laurent
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes, 44322, France
| | - Jérôme Graton
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes, 44322, France
| | - Jean-Yves Le Questel
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes, 44322, France.
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35
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Forli S. Charting a Path to Success in Virtual Screening. Molecules 2015; 20:18732-58. [PMID: 26501243 PMCID: PMC4630810 DOI: 10.3390/molecules201018732] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/07/2015] [Accepted: 10/12/2015] [Indexed: 12/27/2022] Open
Abstract
Docking is commonly applied to drug design efforts, especially high-throughput virtual screenings of small molecules, to identify new compounds that bind to a given target. Despite great advances and successful applications in recent years, a number of issues remain unsolved. Most of the challenges and problems faced when running docking experiments are independent of the specific software used, and can be ascribed to either improper input preparation or to the simplified approaches applied to achieve high-throughput speed. Being aware of approximations and limitations of such methods is essential to prevent errors, deal with misleading results, and increase the success rate of virtual screening campaigns. In this review, best practices and most common issues of docking and virtual screening will be discussed, covering the journey from the design of the virtual experiment to the hit identification.
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Affiliation(s)
- Stefano Forli
- Molecular Graphics Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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36
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Price KL, Lillestol RK, Ulens C, Lummis SCR. Varenicline Interactions at the 5-HT3 Receptor Ligand Binding Site are Revealed by 5-HTBP. ACS Chem Neurosci 2015; 6:1151-7. [PMID: 25648658 PMCID: PMC4505686 DOI: 10.1021/cn500369h] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cys-loop receptors are the site of action of many therapeutic drugs. One of these is the smoking cessation agent varenicline, which has its major therapeutic effects at nicotinic acetylcholine (nACh) receptors but also acts at 5-HT3 receptors. Here, we report the X-ray crystal structure of the 5-HT binding protein (5-HTBP) in complex with varenicline, and test the predicted interactions by probing the potency of varenicline in a range of mutant 5-HT3 receptors expressed in HEK293 cells and Xenopus oocytes. The structure reveals a range of interactions between varenicline and 5-HTBP. We identified residues within 5 Å of varenicline and substituted the equivalent residues in the 5-HT3 receptor with Ala or a residue with similar chemical properties. Functional characterization of these mutant 5-HT3 receptors, using a fluorescent membrane potential dye in HEK cells and voltage clamp in oocytes, supports interactions between varenicline and the receptor that are similar to those in 5-HTBP. The structure also revealed C-loop closure that was less than in the 5-HT-bound 5-HTBP, and hydrogen bonding between varenicline and the complementary face of the binding pocket via a water molecule, which are characteristics consistent with partial agonist behavior of varenicline in the 5-HT3 receptor. Together, these data reveal detailed insights into the molecular interaction of varenicline in the 5-HT3 receptor.
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Affiliation(s)
- Kerry L Price
- †Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom
| | - Reidun K Lillestol
- †Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom
| | - Chris Ulens
- ‡The Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, PB 601, B-3000 Leuven, Belgium
| | - Sarah C R Lummis
- †Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom
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37
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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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38
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Dougherty DA, Van Arnam EB. In vivo incorporation of non-canonical amino acids by using the chemical aminoacylation strategy: a broadly applicable mechanistic tool. Chembiochem 2014; 15:1710-20. [PMID: 24990307 DOI: 10.1002/cbic.201402080] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Indexed: 01/05/2023]
Abstract
We describe a strategy for incorporating non-canonical amino acids site-specifically into proteins expressed in living cells, involving organic synthesis to chemically aminoacylate a suppressor tRNA, protein expression in Xenopus oocytes, and monitoring protein function, primarily by electrophysiology. With this protocol, a very wide range of non-canonical amino acids can be employed, allowing both systematic structure-function studies and the incorporation of reactive functionalities. Here, we present an overview of the methodology and examples meant to illustrate the versatility and power of the method as a tool for investigating protein structure and function.
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Affiliation(s)
- 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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39
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Yu LF, Zhang HK, Caldarone BJ, Eaton JB, Lukas RJ, Kozikowski AP. Recent developments in novel antidepressants targeting α4β2-nicotinic acetylcholine receptors. J Med Chem 2014; 57:8204-23. [PMID: 24901260 PMCID: PMC4207546 DOI: 10.1021/jm401937a] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
![]()
Nicotinic acetylcholine receptors
(nAChRs) have been investigated
for developing drugs that can potentially treat various central nervous
system disorders. Considerable evidence supports the hypothesis that
modulation of the cholinergic system through activation and/or desensitization/inactivation
of nAChR holds promise for the development of new antidepressants.
The introductory portion of this Miniperspective discusses the basic
pharmacology that underpins the involvement of α4β2-nAChRs
in depression, along with the structural features that are essential
to ligand recognition by the α4β2-nAChRs. The remainder
of this Miniperspective analyzes reported nicotinic ligands in terms
of drug design considerations and their potency and selectivity, with
a particular focus on compounds exhibiting antidepressant-like effects
in preclinical or clinical studies. This Miniperspective aims to provide
an in-depth analysis of the potential for using nicotinic ligands
in the treatment of depression, which may hold some promise in addressing
an unmet clinical need by providing relief from depressive symptoms
in refractory patients.
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Affiliation(s)
- Li-Fang Yu
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago , 833 South Wood Street, Chicago, Illinois 60612, United States
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40
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Yoshida T, Farone WA, Xantheas SS. Isomers and conformational barriers of gas-phase nicotine, nornicotine, and their protonated forms. J Phys Chem B 2014; 118:8273-85. [PMID: 24654683 DOI: 10.1021/jp501646p] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report extensive conformational searches of the gas-phase neutral nicotine, nornicotine, and their protonated analogs and the pathways and barriers for the interconversion between their various isomers that are based on ab initio second-order Møller-Plesset perturbation (MP2) electronic structure calculations. Initial searches were performed with the 6-31G(d,p), and the energetics of the most important structures were further refined from geometry optimizations with the larger aug-cc-pVTZ basis set. On the basis of the calculated free energies at T = 298 K for the gas-phase molecules, neutral nicotine has two dominant trans conformers, whereas neutral nornicotine is a mixture of several conformers. For nicotine, the protonation on both the pyridine and the pyrrolidine sites is energetically competitive, whereas nornicotine prefers protonation on the pyridine nitrogen. The protonated form of nicotine is mainly a mixture of two pyridine-protonated trans conformers and two pyrrolidine-protonated trans conformers, whereas the protonated form of nornicotine is a mixture of four pyridine-protonated trans conformers. Nornicotine is conformationally more flexible than nicotine; however, it is less protonated at the biologically important pyrrolidine nitrogen site. The lowest energy isomers for each case were found to interconvert via low (<6 kcal/mol) rotational barriers around the pyridine-pyrrolidine bond. These barriers are much lower than previous estimates based on lower levels of theory obtained without relaxation of the structure along the path. Nicotine was found to bind more strongly to tryptophan (Trp) than nornicotine, a finding that is consistent with nicotine's enhanced affinity in the nicotinic acetylcholide receptor.
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Affiliation(s)
- Tomoki Yoshida
- Center for Quantum Life Sciences and Department of Chemistry, Graduate School of Science, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
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41
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Pascual-Escudero A, González-Esguevillas M, Padilla S, Adrio J, Carretero JC. Enantioselective Synthesis of α-Heteroarylpyrrolidines by Copper-Catalyzed 1,3-Dipolar Cycloaddition of α-Silylimines. Org Lett 2014; 16:2228-31. [DOI: 10.1021/ol5007373] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ana Pascual-Escudero
- Departamento de Química
Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - María González-Esguevillas
- Departamento de Química
Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Silvia Padilla
- Departamento de Química
Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Javier Adrio
- Departamento de Química
Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Juan C. Carretero
- Departamento de Química
Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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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
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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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Comitani F, Cohen N, Ashby J, Botten D, Lummis SCR, Molteni C. Insights into the binding of GABA to the insect RDL receptor from atomistic simulations: a comparison of models. J Comput Aided Mol Des 2014; 28:35-48. [PMID: 24442887 PMCID: PMC3927061 DOI: 10.1007/s10822-013-9704-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 12/26/2013] [Indexed: 01/19/2023]
Abstract
The resistance to dieldrin (RDL) receptor is an insect pentameric ligand-gated ion channel (pLGIC). It is activated by the neurotransmitter γ-aminobutyric acid (GABA) binding to its extracellular domain; hence elucidating the atomistic details of this interaction is important for understanding how the RDL receptor functions. As no high resolution structures are currently available, we built homology models of the extracellular domain of the RDL receptor using different templates, including the widely used acetylcholine binding protein and two pLGICs, the Erwinia Chrysanthemi ligand-gated ion channel (ELIC) and the more recently resolved GluCl. We then docked GABA into the selected three dimensional structures, which we used as starting points for classical molecular dynamics simulations. This allowed us to analyze in detail the behavior of GABA in the binding sites, including the hydrogen bond and cation-π interaction networks it formed, the conformers it visited and the possible role of water molecules in mediating the interactions; we also estimated the binding free energies. The models were all stable and showed common features, including interactions consistent with experimental data and similar to other pLGICs; differences could be attributed to the quality of the models, which increases with increasing sequence identity, and the use of a pLGIC template. We supplemented the molecular dynamics information with metadynamics, a rare event method, by exploring the free energy landscape of GABA binding to the RDL receptor. Overall, we show that the GluCl template provided the best models. GABA forming direct salt-bridges with Arg211 and Glu204, and cation-π interactions with an aromatic cage including Tyr109, Phe206 and Tyr254, represents a favorable binding arrangement, and the interaction with Glu204 can also be mediated by a water molecule.
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Affiliation(s)
- Federico Comitani
- Physics Department, King's College London, Strand, London, WC2R 2LS, UK
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44
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Sambasivarao SV, Roberts J, Bharadwaj VS, Slingsby JG, Rohleder C, Mallory C, Groome JR, McDougal OM, Maupin CM. Acetylcholine promotes binding of α-conotoxin MII at α3 β2 nicotinic acetylcholine receptors. Chembiochem 2014; 15:413-24. [PMID: 24420650 DOI: 10.1002/cbic.201300577] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Indexed: 11/09/2022]
Abstract
α-Conotoxin MII (α-CTxMII) is a 16-residue peptide with the sequence GCCSNPVCHLEHSNLC, containing Cys2-Cys8 and Cys3-Cys16 disulfide bonds. This peptide, isolated from the venom of the marine cone snail Conus magus, is a potent and selective antagonist of neuronal nicotinic acetylcholine receptors (nAChRs). To evaluate the impact of channel-ligand interactions on ligand-binding affinity, homology models of the heteropentameric α3β2-nAChR were constructed. The models were created in MODELLER with the aid of experimentally characterized structures of the Torpedo marmorata-nAChR (Tm-nAChR, PDB ID: 2BG9) and the Aplysia californica-acetylcholine binding protein (Ac-AChBP, PDB ID: 2BR8) as templates for the α3- and β2-subunit isoforms derived from rat neuronal nAChR primary amino acid sequences. Molecular docking calculations were performed with AutoDock to evaluate interactions of the heteropentameric nAChR homology models with the ligands acetylcholine (ACh) and α-CTxMII. The nAChR homology models described here bind ACh with binding energies commensurate with those of previously reported systems, and identify critical interactions that facilitate both ACh and α-CTxMII ligand binding. The docking calculations revealed an increased binding affinity of the α3β2-nAChR for α-CTxMII with ACh bound to the receptor, and this was confirmed through two-electrode voltage clamp experiments on oocytes from Xenopus laevis. These findings provide insights into the inhibition and mechanism of electrostatically driven antagonist properties of the α-CTxMIIs on nAChRs.
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Affiliation(s)
- Somisetti V Sambasivarao
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401 (USA)
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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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Eibl C, Tomassoli I, Munoz L, Stokes C, Papke RL, Gündisch D. The 3,7-diazabicyclo[3.3.1]nonane scaffold for subtype selective nicotinic acetylcholine receptor (nAChR) ligands. Part 1: the influence of different hydrogen bond acceptor systems on alkyl and (hetero)aryl substituents. Bioorg Med Chem 2013; 21:7283-308. [PMID: 24156938 PMCID: PMC4519239 DOI: 10.1016/j.bmc.2013.09.059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 09/15/2013] [Accepted: 09/24/2013] [Indexed: 12/21/2022]
Abstract
3,7-Diazabicyclo[3.3.1]nonane is a naturally occurring scaffold interacting with nicotinic acetylcholine receptors (nAChRs). When one nitrogen of the 3,7-diazabicyclo[3.3.1]nonane scaffold was implemented in a carboxamide motif displaying a hydrogen bond acceptor (HBA) functionality, compounds with higher affinities and subtype selectivity for α4β2(∗) were obtained. The nature of the HBA system (carboxamide, sulfonamide, urea) had a strong impact on nAChR interaction. High affinity ligands for α4β2(∗) possessed small alkyl chains, small un-substituted hetero-aryl groups or para-substituted phenyl ring systems along with a carboxamide group. Electrophysiological responses of selected 3,7-diazabicyclo[3.3.1]nonane derivatives to Xenopus oocytes expressing various nAChR subtypes showed diverse activation profiles. Compounds with strongest agonistic profiles were obtained with small alkyl groups whereas a shift to partial agonism/antagonism was observed for aryl substituents.
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Affiliation(s)
- Christoph Eibl
- Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-533121 Bonn, Germany
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai’i at Hilo, 34 Rainbow Drive, Hilo, HI 96720, USA
| | - Isabelle Tomassoli
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai’i at Hilo, 34 Rainbow Drive, Hilo, HI 96720, USA
| | - Lenka Munoz
- Department of Pharmacology, School of Medical Sciences, The University of Sydney, NSW 2006, Australia
| | - Clare Stokes
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL32610, USA
| | - Roger L. Papke
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL32610, USA
| | - Daniela Gündisch
- Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-533121 Bonn, Germany
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai’i at Hilo, 34 Rainbow Drive, Hilo, HI 96720, USA
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47
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Investigating the hydrogen-bond acceptor site of the nicotinic pharmacophore model: a computational and experimental study using epibatidine-related molecular probes. J Comput Aided Mol Des 2013; 27:975-87. [DOI: 10.1007/s10822-013-9694-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 11/19/2013] [Indexed: 12/16/2022]
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Arias HR, López JJ, Feuerbach D, Fierro A, Ortells MO, Pérez EG. Novel 2-(substituted benzyl)quinuclidines inhibit human α7 and α4β2 nicotinic receptors by different mechanisms. Int J Biochem Cell Biol 2013; 45:2420-30. [DOI: 10.1016/j.biocel.2013.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/11/2013] [Accepted: 08/06/2013] [Indexed: 01/12/2023]
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49
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Bruhova I, Gregg T, Auerbach A. Energy for wild-type acetylcholine receptor channel gating from different choline derivatives. Biophys J 2013; 104:565-74. [PMID: 23442907 DOI: 10.1016/j.bpj.2012.11.3833] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 11/25/2012] [Accepted: 11/27/2012] [Indexed: 02/01/2023] Open
Abstract
Agonists, including the neurotransmitter acetylcholine (ACh), bind at two sites in the neuromuscular ACh receptor channel (AChR) to promote a reversible, global change in protein conformation that regulates the flow of ions across the muscle cell membrane. In the synaptic cleft, ACh is hydrolyzed to acetate and choline. Replacement of the transmitter's ester acetyl group with a hydroxyl (ACh→choline) results in a + 1.8 kcal/mol reduction in the energy for gating generated by each agonist molecule from a low- to high-affinity change of the transmitter binding site (ΔG(B)). To understand the distinct actions of structurally related agonist molecules, we measured ΔG(B) for 10 related choline derivatives. Replacing the hydroxyl group of choline with different substituents, such as hydrogen, chloride, methyl, or amine, increased the energy for gating (i.e., it made ΔG(B) more negative relative to choline). Extending the ethyl hydroxide tail of choline to propyl and butyl hydroxide also increased this energy. Our findings reveal the amount of energy that is available for the AChR conformational change provided by different, structurally related agonists. We speculate that a hydrogen bond between the choline hydroxyl and the backbone carbonyl of αW149 positions this agonist's quaternary ammonium group so as to reduce the cation-π interaction between this moiety and the aromatic groups at the binding site.
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Affiliation(s)
- Iva Bruhova
- Department of Physiology and Biophysics, SUNY at Buffalo, Buffalo, New York, USA
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50
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Jadey S, Purohit P, Auerbach A. Action of nicotine and analogs on acetylcholine receptors having mutations of transmitter-binding site residue αG153. ACTA ACUST UNITED AC 2013; 141:95-104. [PMID: 23277476 PMCID: PMC3536520 DOI: 10.1085/jgp.201210896] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A primary target for nicotine is the acetylcholine receptor channel (AChR). Some of the ability of nicotine to activate differentially AChR subtypes has been traced to a transmitter-binding site amino acid that is glycine in lower affinity and lysine in higher affinity AChRs. We studied the effects of mutations of this residue (αG153) in neuromuscular AChRs activated by nicotine and eight other agonists including nornicotine and anabasine. All of the mutations increased the unliganded gating equilibrium constant. The affinity of the resting receptor (Kd) and the net binding energy from the agonist for gating (ΔGB) were estimated by cross-concentration fitting of single-channel currents. In all but one of the agonist/mutant combinations there was a moderate decrease in Kd and essentially no change in ΔGB. The exceptional case was nicotine plus lysine, which showed a large, >8,000-fold decrease in Kd but no change in ΔGB. The extraordinary specificity of this combination leads us to speculate that AChRs with a lysine at position αG153 may be exposed to a nicotine-like compound in vivo.
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Affiliation(s)
- Snehal Jadey
- Department of Physiology and Biophysics, State University of New York, Buffalo, NY 14214, USA
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