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Hu J, Han Y, Luo A, Zhang H, Tian L, Cai H, Xue B, Lai R, Luo L. Gating elements for carvacrol activation of the OTOP1 proton channel. Commun Biol 2024; 7:1106. [PMID: 39251752 PMCID: PMC11384762 DOI: 10.1038/s42003-024-06818-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 08/30/2024] [Indexed: 09/11/2024] Open
Abstract
Otopetrin 1 (OTOP1) is a proton-activated channel crucial for animals' perception of sour taste. Despite its significance, the gating mechanism of OTOP1 remains poorly understood. Here, we demonstrate that carvacrol activates the mouse OTOP1 (mOTOP1) channel under neutral and acidic conditions. Functional analysis showed that carvacrol enhances pH fluorescence signals in OTOP1-expressing cells, with reduced efficacy at lower pH levels. Carvacrol selectively activates mOTOP1, while mOTOP2, mOTOP3, and Chelonia mydas OTOP1 (CmOTOP1) are insensitive to carvacrol activation under neutral pH. Through chimera and point mutation experiments, swapping S134 in transmembrane segment 3 (TM3) and T247 in the TM5-6 linker abolished carvacrol activation of mOTOP1 and conferred activation on CmOTOP1, suggesting these two residues are critical for carvacrol sensitivity. These findings highlight TM3 and TM5-6 linker as pivotal gating apparatus of OTOP1 channels and potential docking sites for drug design.
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Affiliation(s)
- Jingmei Hu
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Yalan Han
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Anna Luo
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Hao Zhang
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Lifeng Tian
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Huajun Cai
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Beijing, China
- Department of Molecular and Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Beiru Xue
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Beijing, China
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Ren Lai
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China.
- Kunming College of Life Science, University of Chinese Academy of Sciences, Beijing, China.
- Department of Molecular and Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, China.
- Department of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.
| | - Lei Luo
- Engineering Laboratory of Peptides of Chinese Academy of Sciences, Key Laboratory of Bioactive Peptides of Yunnan Province, KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, National Resource Center for Non-Human Primates, National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Key Laboratory of Genetic Evolution & Animal Models, Sino-African Joint Research Center, and New Cornerstone Science Laboratory, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China.
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2
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Devantier K, Kjær VMS, Griffin S, Kragelund BB, Rosenkilde MM. Advancing the field of viroporins-Structure, function and pharmacology: IUPHAR Review X. Br J Pharmacol 2024. [PMID: 39224966 DOI: 10.1111/bph.17317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 06/28/2024] [Accepted: 07/07/2024] [Indexed: 09/04/2024] Open
Abstract
Viroporins possess important potential as antiviral targets due to their critical roles during virus life cycles, spanning from virus entry to egress. Although the antiviral amantadine targets the M2 viroporin of influenza A virus, successful progression of other viroporin inhibitors into clinical use remains challenging. These challenges relate in varying proportions to a lack of reliable full-length 3D-structures, difficulties in functionally characterising individual viroporins, and absence of verifiable direct binding between inhibitor and viroporin. This review offers perspectives to help overcome these challenges. We provide a comprehensive overview of the viroporin family, including their structural and functional features, highlighting the moldability of their energy landscapes and actions. To advance the field, we suggest a list of best practices to aspire towards unambiguous viroporin identification and characterisation, along with considerations of potential pitfalls. Finally, we present current and future scenarios of, and prospects for, viroporin targeting drugs.
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Affiliation(s)
- Kira Devantier
- Molecular and Translational Pharmacology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Viktoria M S Kjær
- Molecular and Translational Pharmacology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stephen Griffin
- Leeds Institute of Medical Research, St James' University Hospital, School of Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Molecular and Translational Pharmacology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Yue Z, Wu J, Teng D, Wang Z, Voth GA. Activation of the influenza B M2 proton channel (BM2). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.26.605324. [PMID: 39091734 PMCID: PMC11291123 DOI: 10.1101/2024.07.26.605324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Influenza B viruses have co-circulated during most seasonal flu epidemics and can cause significant human morbidity and mortality due to their rapid mutation, emerging drug resistance, and severe impact on vulnerable populations. The influenza B M2 proton channel (BM2) plays an essential role in viral replication, but the mechanisms behind its symmetric proton conductance and the involvement of a second histidine (His27) cluster remain unclear. Here we perform the membrane-enabled continuous constant-pH molecular dynamics simulations on wildtype BM2 and a key H27A mutant to explore its pH-dependent conformational switch. Simulations capture the activation as the first histidine (His19) protonates and reveal the transition at lower pH values compared to AM2 is a result of electrostatic repulsions between His19 and pre-protonated His27. Crucially, we provide an atomic-level understanding of the symmetric proton conduction by identifying pre-activating channel hydration in the C-terminal portion. This research advances our understanding of the function of BM2 function and lays the groundwork for further chemically reactive modeling of the explicit proton transport process as well as possible anti-flu drug design efforts.
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Affiliation(s)
- Zhi Yue
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Frank Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Jiangbo Wu
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Frank Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Da Teng
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Frank Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | | | - Gregory A. Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Frank Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
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4
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Georgiou K, Konstantinidi A, Hutterer J, Freudenberger K, Kolarov F, Lambrinidis G, Stylianakis I, Stampelou M, Gauglitz G, Kolocouris A. Accurate calculation of affinity changes to the close state of influenza A M2 transmembrane domain in response to subtle structural changes of adamantyl amines using free energy perturbation methods in different lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184258. [PMID: 37995846 DOI: 10.1016/j.bbamem.2023.184258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/18/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023]
Abstract
Experimental binding free energies of 27 adamantyl amines against the influenza M2(22-46) WT tetramer, in its closed form at pH 8, were measured by ITC in DPC micelles. The measured Kd's range is ~44 while the antiviral potencies (IC50) range is ~750 with a good correlation between binding free energies computed with Kd and IC50 values (r = 0.76). We explored with MD simulations (ff19sb, CHARMM36m) the binding profile of complexes with strong, moderate and weak binders embedded in DMPC, DPPC, POPC or a viral mimetic membrane and using different experimental starting structures of M2. To predict accurately differences in binding free energy in response to subtle changes in the structure of the ligands, we performed 18 alchemical perturbative single topology FEP/MD NPT simulations (OPLS2005) using the BAR estimator (Desmond software) and 20 dual topology calculations TI/MD NVT simulations (ff19sb) using the MBAR estimator (Amber software) for adamantyl amines in complex with M2(22-46) WT in DMPC, DPPC, POPC. We observed that both methods with all lipids show a very good correlation between the experimental and calculated relative binding free energies (r = 0.77-0.87, mue = 0.36-0.92 kcal mol-1) with the highest performance achieved with TI/MBAR and lowest performance with FEP/BAR in DMPC bilayers. When antiviral potencies are used instead of the Kd values for computing the experimental binding free energies we obtained also good performance with both FEP/BAR (r = 0.83, mue = 0.75 kcal mol-1) and TI/MBAR (r = 0.69, mue = 0.77 kcal mol-1).
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Affiliation(s)
- Kyriakos Georgiou
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Athina Konstantinidi
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Johanna Hutterer
- Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität, D-72076 Tübingen, Germany
| | - Kathrin Freudenberger
- Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität, D-72076 Tübingen, Germany
| | - Felix Kolarov
- Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität, D-72076 Tübingen, Germany; Roche, Penzberg, Bavaria, Germany
| | - George Lambrinidis
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Ioannis Stylianakis
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Margarita Stampelou
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece
| | - Günter Gauglitz
- Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität, D-72076 Tübingen, Germany
| | - Antonios Kolocouris
- Laboratory of Medicinal Chemistry, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens (NKUA), Panepistimiopolis-Zografou, 15771 Athens, Greece.
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5
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Schmitt FJ, Mehmood AS, Tüting C, Phan HT, Reisdorf J, Rieder F, Ghane Golmohamadi F, Verma R, Kastritis PL, Laufer J. Effect of Molecular Dynamics and Internal Water Contact on the Photophysical Properties of Red pH-Sensitive Proteins. Biochemistry 2024; 63:82-93. [PMID: 38085825 DOI: 10.1021/acs.biochem.3c00444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The pH dependence of the absorption and (time-resolved) fluorescence of two red-shifted fluorescent proteins, mCardinal and mNeptune, was investigated. Decay-associated spectra were measured following fluorescence excitation at 470 nm in PBS buffer with a pH that ranged from 5.5 to 8.0. The fluorescence of both proteins shows two different decay components. mCardinal exhibits an increase in the long-lived fluorescence component with acidification from 1.34 ns at pH 8.0 to 1.62 ns at pH 5.5. An additional fast decay component with 0.64 ns at pH 8.0 up to 1.1 ns at pH 5.5 was found to be blue-shifted compared to the long-lived component. The fluorescence lifetime of mNeptune is insensitive to pH. DAS of mCardinal were simulated assuming a coupled two-level system to describe the 1S state of the chromophore within two different conformations of the protein. MD simulations were conducted to correlate the experimentally observed pH-induced change in the lifetime in mCardinal with its molecular properties. While the chromophores of both protein variants are stabilized by the same number of hydrogen bonds, it was found that the chromophore in mCardinal exhibits more water contacts compared to mNeptune. In mCardinal, interaction between the chromophore and Glu-145 is reduced as compared to mNeptune, but interaction with Thr-147 which is Ser-147 in mNeptune is stronger in mCardinal. Therefore, the dynamics of the excited-state proton transfer (ESPT) might be different in mCardinal and mNeptune. The pH dependency of ESPT is suggested as a key mechanism for pH sensitivity.
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Affiliation(s)
- Franz-Josef Schmitt
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | - Amna Shah Mehmood
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | - Christian Tüting
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06120 Halle, Saale, Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle, Saale, Germany
| | - Hoang Trong Phan
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
- INM-Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken, Germany
| | - Judith Reisdorf
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | - Fabian Rieder
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | - Farzin Ghane Golmohamadi
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | | | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06120 Halle, Saale, Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle, Saale, Germany
| | - Jan Laufer
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
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Stampolaki Μ, Hoffmann A, Tekwani K, Georgiou K, Tzitzoglaki C, Ma C, Becker S, Schmerer P, Döring K, Stylianakis I, Turcu AL, Wang J, Vázquez S, Andreas LB, Schmidtke M, Kolocouris A. A Study of the Activity of Adamantyl Amines against Mutant Influenza A M2 Channels Identified a Polycyclic Cage Amine Triple Blocker, Explored by Molecular Dynamics Simulations and Solid-State NMR. ChemMedChem 2023; 18:e202300182. [PMID: 37377066 DOI: 10.1002/cmdc.202300182] [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] [Received: 04/03/2023] [Revised: 06/25/2023] [Accepted: 06/26/2023] [Indexed: 06/29/2023]
Abstract
We compared the anti-influenza potencies of 57 adamantyl amines and analogs against influenza A virus with serine-31 M2 proton channel, usually termed as WT M2 channel, which is amantadine sensitive. We also tested a subset of these compounds against viruses with the amantadine-resistant L26F, V27A, A30T, G34E M2 mutant channels. Four compounds inhibited WT M2 virus in vitro with mid-nanomolar potency, with 27 compounds showing sub-micromolar to low micromolar potency. Several compounds inhibited L26F M2 virus in vitro with sub-micromolar to low micromolar potency, but only three compounds blocked L26F M2-mediated proton current as determined by electrophysiology (EP). One compound was found to be a triple blocker of WT, L26F, V27A M2 channels by EP assays, but did not inhibit V27A M2 virus in vitro, and one compound inhibited WT, L26F, V27A M2 in vitro without blocking V27A M2 channel. One compound blocked only L26F M2 channel by EP, but did not inhibit virus replication. The triple blocker compound is as long as rimantadine, but could bind and block V27A M2 channel due to its larger girth as revealed by molecular dynamics simulations, while MAS NMR informed on the interaction of the compound with M2(18-60) WT or L26F or V27A.
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Affiliation(s)
- Μarianna Stampolaki
- Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771, Athens, Greece
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen, Germany
| | - Anja Hoffmann
- Department of Medical Microbiology, Jena University Hospital, CMB Building, R. 443, Hans Knoell Str. 2, 07745, Jena (Germany), Germany
| | - Kumar Tekwani
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Kyriakos Georgiou
- Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771, Athens, Greece
| | - Christina Tzitzoglaki
- Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771, Athens, Greece
| | - Chunlong Ma
- Department of Medicinal Chemistry, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854-8020, USA
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen, Germany
| | - Patrick Schmerer
- Department of Medical Microbiology, Jena University Hospital, CMB Building, R. 443, Hans Knoell Str. 2, 07745, Jena (Germany), Germany
| | - Kristin Döring
- Department of Medical Microbiology, Jena University Hospital, CMB Building, R. 443, Hans Knoell Str. 2, 07745, Jena (Germany), Germany
| | - Ioannis Stylianakis
- Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771, Athens, Greece
| | - Andreea L Turcu
- Facultat de Farmàcia i Ciències de l'Alimentació, and Institute of Biomedicine (IBUB), Universitat de Barcelona, Av. Joan XXIII, 27-31, Barcelona, 08028, Spain
| | - Jun Wang
- Department of Medicinal Chemistry, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854-8020, USA
| | - Santiago Vázquez
- Facultat de Farmàcia i Ciències de l'Alimentació, and Institute of Biomedicine (IBUB), Universitat de Barcelona, Av. Joan XXIII, 27-31, Barcelona, 08028, Spain
| | - Loren B Andreas
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen, Germany
| | - Michaela Schmidtke
- Department of Medical Microbiology, Jena University Hospital, CMB Building, R. 443, Hans Knoell Str. 2, 07745, Jena (Germany), Germany
| | - Antonios Kolocouris
- Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771, Athens, Greece
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7
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Aganovic A. pH-dependent endocytosis mechanisms for influenza A and SARS-coronavirus. Front Microbiol 2023; 14:1190463. [PMID: 37234537 PMCID: PMC10206014 DOI: 10.3389/fmicb.2023.1190463] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
The ongoing SARS-CoV-2 pandemic and the influenza epidemics have revived the interest in understanding how these highly contagious enveloped viruses respond to alterations in the physicochemical properties of their microenvironment. By understanding the mechanisms and conditions by which viruses exploit the pH environment of the host cell during endocytosis, we can gain a better understanding of how they respond to pH-regulated anti-viral therapies but also pH-induced changes in extracellular environments. This review provides a detailed explanation of the pH-dependent viral structural changes preceding and initiating viral disassembly during endocytosis for influenza A (IAV) and SARS coronaviruses. Drawing upon extensive literature from the last few decades and latest research, I analyze and compare the circumstances in which IAV and SARS-coronavirus can undertake endocytotic pathways that are pH-dependent. While there are similarities in the pH-regulated patterns leading to fusion, the mechanisms and pH activation differ. In terms of fusion activity, the measured activation pH values for IAV, across all subtypes and species, vary between approximately 5.0 to 6.0, while SARS-coronavirus necessitates a lower pH of 6.0 or less. The main difference between the pH-dependent endocytic pathways is that the SARS-coronavirus, unlike IAV, require the presence of specific pH-sensitive enzymes (cathepsin L) during endosomal transport. Conversely, the conformational changes in the IAV virus under acidic conditions in endosomes occur due to the specific envelope glycoprotein residues and envelope protein ion channels (viroporins) getting protonated by H+ ions. Despite extensive research over several decades, comprehending the pH-triggered conformational alterations of viruses still poses a significant challenge. The precise mechanisms of protonation mechanisms of certain during endosomal transport for both viruses remain incompletely understood. In absence of evidence, further research is needed.
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George MAR, Dopfer O. Microhydrated clusters of a pharmaceutical drug: infrared spectra and structures of amantadineH +(H 2O) n. Phys Chem Chem Phys 2023; 25:5529-5549. [PMID: 36723361 DOI: 10.1039/d2cp04556g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Solvation of pharmaceutical drugs has an important effect on their structure and function. Analysis of infrared photodissociation spectra of amantadineH+(H2O)n=1-4 clusters in the sensitive OH, NH, and CH stretch range by quantum chemical calculations (B3LYP-D3/cc-pVTZ) provides a first impression of the interaction of this pharmaceutically active cation with water at the molecular level. The size-dependent frequency shifts reveal detailed information about the acidity of the protons of the NH3+ group of N-protonated amantadineH+ (AmaH+) and the strength of the NH⋯O and OH⋯O hydrogen bonds (H-bonds) of the hydration network. The preferred cluster growth begins with sequential hydration of the NH3+ group by NH⋯O ionic H-bonds (n = 1-3), followed by the extension of the solvent network through OH⋯O H-bonds. However, smaller populations of cluster isomers with an H-bonded solvent network and free N-H bonds are already observed for n ≥ 2, indicating the subtle competition between noncooperative ion hydration and cooperative H-bonding. Interestingly, cyclic water ring structures are identified for n ≥ 3, each with two NH⋯O and two OH⋯O H-bonds. Despite the increasing destabilization of the N-H proton donor bonds upon gradual hydration, no proton transfer to the (H2O)n solvent cluster is observed up to n = 4. In addition to ammonium cluster ions, a small population of microhydrated iminium isomers is also detected, which is substantially lower for the hydrophilic H2O than for the hydrophobic Ar environment.
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Affiliation(s)
| | - Otto Dopfer
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany.
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9
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Tian L, Zhang H, Yang S, Luo A, Kamau PM, Hu J, Luo L, Lai R. Vertebrate OTOP1 is also an alkali-activated channel. Nat Commun 2023; 14:26. [PMID: 36596786 PMCID: PMC9810603 DOI: 10.1038/s41467-022-35754-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/23/2022] [Indexed: 01/04/2023] Open
Abstract
Although alkaline sensation is critical for survival, alkali-activated receptors are yet to be identified in vertebrates. Here, we showed that the OTOP1 channel can be directly activated by extracellular alkali. Notably, OTOP1 biphasically mediated proton influx and efflux with extracellular acid and base stimulation, respectively. Mutations of K221 and R554 at the S5-S6 and S11-S12 linkers significantly reduced alkali affinity without affecting acid activation, suggesting that different domains are responsible for acid- and alkali-activation of OTOP1. The selectivity for H+ was significantly higher in OTOP1 activated by alkali than that by acid, further suggesting that the two activations might be independent gating processes. Given that the alkali-activation of OTOP1 and the required key residues were conserved in the six representative vertebrates, we cautiously propose that OTOP1 participates in alkaline sensation in vertebrates. Thus, our study identified OTOP1 as an alkali-activated channel.
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Affiliation(s)
- Lifeng Tian
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China.,School of Molecular Medicine, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 310024, Hangzhou, China.,The cancer Hospital of the University of Chinese Academy of Sciences, Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, 310022, Hangzhou, China
| | - Hao Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Shilong Yang
- College of Wildlife and Protected Area, Northeast Forestry University, 150040, Harbin, China
| | - Anna Luo
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Peter Muiruri Kamau
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China.,Sino-African Joint Research Center, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China
| | - Jingmei Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Lei Luo
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China. .,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China.
| | - Ren Lai
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province/National & Local Joint Engineering Center of Natural Bioactive Peptides, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China. .,National Resource Center for Non-Human Primates, Kunming Primate Research Center/National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, 650107, Kunming, Yunnan, China. .,School of Molecular Medicine, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 310024, Hangzhou, China. .,Sino-African Joint Research Center, Kunming Institute of Zoology, Chinese Academy of Sciences, 650223, Kunming, Yunnan, China.
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10
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Yu HG, Sizemore G, Martinez I, Perrotta P. Inhibition of SARS-CoV-2 Viral Channel Activity Using FDA-Approved Channel Modulators Independent of Variants. Biomolecules 2022; 12:1673. [PMID: 36421688 PMCID: PMC9687591 DOI: 10.3390/biom12111673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/29/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND SARS-CoV-2 has undergone mutations, yielding clinically relevant variants. HYPOTHESIS We hypothesized that in SARS-CoV-2, two highly conserved Orf3a and E channels directly related to the virus replication were a target for the detection and inhibition of the viral replication, independent of the variant, using FDA-approved ion channel modulators. METHODS A combination of a fluorescence potassium ion assay with channel modulators was developed to detect SARS-CoV-2 Orf3a/E channel activity. Two FDA-approved drugs, amantadine (an antiviral) and amitriptyline (an antidepressant), which are ion channel blockers, were tested as to whether they inhibited Orf3a/E channel activity in isolated virus variants and in nasal swab samples from COVID-19 patients. The variants were confirmed by PCR sequencing. RESULTS In isolated SARS-CoV-2 Alpha, Beta, and Delta variants, the channel activity of Orf3a/E was detected and inhibited by emodin and gliclazide (IC50 = 0.42 mM). In the Delta swab samples, amitriptyline and amantadine inhibited the channel activity of viral proteins, with IC50 values of 0.73 mM and 1.11 mM, respectively. In the Omicron swab samples, amitriptyline inhibited the channel activity, with an IC50 of 0.76 mM. CONCLUSIONS We developed an efficient method to screen FDA-approved ion channel modulators that could be repurposed to detect and inhibit SARS-CoV-2 viral replication, independent of variants.
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Affiliation(s)
- Han-Gang Yu
- Department of Physiology and Pharmacology, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Gina Sizemore
- Clinical Medicine Resources, EZCARE Walk-in Medical Center, Moorefield, WV 26836, USA
| | - Ivan Martinez
- Department of Microbiology, Immunology, & Cell Biology, Cancer Institute, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Peter Perrotta
- Anatomy & Laboratory Medicine, Department of Pathology, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
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11
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George MAR, Dopfer O. Opening of the Diamondoid Cage upon Ionization Probed by Infrared Spectra of the Amantadine Cation Solvated by Ar, N 2 , and H 2 O. Chemistry 2022; 28:e202200577. [PMID: 35611807 PMCID: PMC9400954 DOI: 10.1002/chem.202200577] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Indexed: 01/18/2023]
Abstract
Radical cations of diamondoids, a fundamental class of very stable cyclic hydrocarbon molecules, play an important role in their functionalization reactions and the chemistry of the interstellar medium. Herein, we characterize the structure, energy, and intermolecular interaction of clusters of the amantadine radical cation (Ama+ , 1-aminoadamantane) with solvent molecules of different interaction strength by infrared photodissociation (IRPD) spectroscopy of mass-selected Ama+ Ln clusters, with L=Ar (n≤3) and L=N2 and H2 O (n=1), and dispersion-corrected density functional theory calculations (B3LYP-D3/cc-pVTZ). Three isomers of Ama+ generated by electron ionization are identified by the vibrational properties of their rather different NH2 groups. The ligands bind preferentially to the acidic NH2 protons, and the strength of the NH…L ionic H-bonds are probed by the solvation-induced red-shifts in the NH stretch modes. The three Ama+ isomers include the most abundant canonical cage isomer (I) produced by vertical ionization, which is separated by appreciable barriers from two bicyclic distonic iminium ions obtained from cage-opening (primary radical II) and subsequent 1,2 H-shift (tertiary radical III), the latter of which is the global minimum on the Ama+ potential energy surface. The effect of solvation on the energetics of the potential energy profile revealed by the calculations is consistent with the observed relative abundance of the three isomers. Comparison to the adamantane cation indicates that substitution of H by the electron-donating NH2 group substantially lowers the barriers for the isomerization reaction.
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Affiliation(s)
| | - Otto Dopfer
- Institut für Optik und Atomare PhysikTechnische Universität BerlinHardenbergstr. 3610623BerlinGermany
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12
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Shen J, Ye R, Liu Z, Zeng H. Hybrid Pyridine–Pyridone Foldamer Channels as M2‐Like Artificial Proton Channels. Angew Chem Int Ed Engl 2022; 61:e202200259. [DOI: 10.1002/anie.202200259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Jie Shen
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
| | - Ruijuan Ye
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
| | - Zhiwei Liu
- Department of Chemistry & Biochemistry Rowan University 201 Mullica Hill Road Glassboro NJ 08028 USA
| | - Huaqiang Zeng
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
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13
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George MAR, Dopfer O. Infrared spectra and structures of protonated amantadine isomers: detection of ammonium and open-cage iminium ions. Phys Chem Chem Phys 2022; 24:16101-16111. [PMID: 35748364 DOI: 10.1039/d2cp01947g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The protonated form of amantadine (1-C10H15NH2, Ama), the amino derivative of adamantane (C10H16, Ada), is a wide-spread antiviral and anti-Parkinsonian drug and plays a key role in many pharmaceutical processes. Recent studies reveal that the adamantyl cage (C10H15) of Ama can open upon ionization leading to distonic bicyclic iminium isomers, in addition to the canonical nascent Ama+ isomer. Herein, we study protonation of Ama using infrared photodissociation spectroscopy (IRPD) of Ar-tagged ions and density functional theory calculations to characterize cage and open-cage isomers of AmaH+ and the influence of the electron-donating NH2 group on the cage-opening reaction potential. In addition to the canonical ammonium isomer (AmaH+(I)) with an intact adamantyl cage, we identify at least one slightly less stable protonated bicyclic iminium ion (AmaH+(II)). While the ammonium ion is generated by protonation of the basic NH2 group, AmaH+(II) is formally formed by H addition to a distonic bicyclic iminium ion produced upon ionization of Ama and subsequent cage opening.
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Affiliation(s)
| | - Otto Dopfer
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany.
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14
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Shen J, Ye R, Liu Z, Zeng H. Hybrid Pyridine–Pyridone Foldamer Channels as M2‐Like Artificial Proton Channels. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jie Shen
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
| | - Ruijuan Ye
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
| | - Zhiwei Liu
- Department of Chemistry & Biochemistry Rowan University 201 Mullica Hill Road Glassboro NJ 08028 USA
| | - Huaqiang Zeng
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
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15
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Ma Y, Wang Y, Dong C, Gonzalez GX, Song Y, Zhu W, Kim J, Wei L, Wang BZ. Influenza NP core and HA or M2e shell double-layered protein nanoparticles induce broad protection against divergent influenza A viruses. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2022; 40:102479. [PMID: 34743020 PMCID: PMC8897236 DOI: 10.1016/j.nano.2021.102479] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/23/2021] [Accepted: 10/25/2021] [Indexed: 02/03/2023]
Abstract
Influenza viral infection causes acute upper respiratory diseases in humans, posing severe risks to global public health. However, current vaccines provide limited protection against mismatched circulating influenza A viruses. Here, the immune responses induced in mice by novel double-layered protein nanoparticles were investigated. The nanoparticles were composed of influenza nucleoprotein (NP) cores and hemagglutinin (HA) or matrix 2 protein ectodomain (M2e) shells. Vaccination with the nanoparticles significantly enhanced M2e-specific serum antibody titers and concomitant ADCC responses. Robust NP-specific T cell responses and robust HA neutralization were also detected. Moreover, vaccination with a trivalent nanoparticle combination containing two routinely circulated HA, conserved M2e, and NP reduced lung virus titers, pulmonary pathologies, and weight loss after homologous virus challenge. This combination also improved survival rates against heterologous and heterosubtypic influenza virus challenges. Our results demonstrate that the trivalent combination elicited potent and long-lasting immune responses conferring influenza viral cross-protection.
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Affiliation(s)
- Yao Ma
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
| | - Ye Wang
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
| | - Chunhong Dong
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
| | - Gilbert X Gonzalez
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
| | - Yufeng Song
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
| | - Wandi Zhu
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
| | - Joo Kim
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
| | - Lai Wei
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
| | - Bao-Zhong Wang
- Center for Inflammation, Immunity & Infection, Georgia State University Institute for Biomedical Sciences, Atlanta, GA, USA.
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16
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Watkins LC, DeGrado WF, Voth GA. Multiscale Simulation of an Influenza A M2 Channel Mutant Reveals Key Features of Its Markedly Different Proton Transport Behavior. J Am Chem Soc 2022; 144:769-776. [PMID: 34985907 PMCID: PMC8834648 DOI: 10.1021/jacs.1c09281] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The influenza A M2 channel, a prototype for viroporins, is an acid-activated viroporin that conducts protons across the viral membrane, a critical step in the viral life cycle. Four central His37 residues control channel activation by binding subsequent protons from the viral exterior, which opens the Trp41 gate and allows proton flux to the interior. Asp44 is essential for maintaining the Trp41 gate in a closed state at high pH, resulting in asymmetric conduction. The prevalent D44N mutant disrupts this gate and opens the C-terminal end of the channel, resulting in increased conduction and a loss of this asymmetric conduction. Here, we use extensive Multiscale Reactive Molecular Dynamics (MS-RMD) and quantum mechanics/molecular mechanics (QM/MM) molecular dynamics simulations with an explicit, reactive excess proton to calculate the free energy of proton transport in this M2 mutant and to study the dynamic molecular-level behavior of D44N M2. We find that this mutation significantly lowers the barrier of His37 deprotonation in the activated state and shifts the barrier for entry to the Val27 tetrad. These free energy changes are reflected in structural shifts. Additionally, we show that the increased hydration around the His37 tetrad diminishes the effect of the His37 charge on the channel's water structure, facilitating proton transport and enabling activation from the viral interior. Altogether, this work provides key insight into the fundamental characteristics of PT in WT M2 and how the D44N mutation alters this PT mechanism, and it expands understanding of the role of emergent mutations in viroporins.
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Affiliation(s)
- Laura C. Watkins
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, 94158, United States
| | - Gregory A. Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States,Corresponding Author
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17
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Aledavood E, Selmi B, Estarellas C, Masetti M, Luque FJ. From Acid Activation Mechanisms of Proton Conduction to Design of Inhibitors of the M2 Proton Channel of Influenza A Virus. Front Mol Biosci 2022; 8:796229. [PMID: 35096969 PMCID: PMC8795881 DOI: 10.3389/fmolb.2021.796229] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 12/24/2021] [Indexed: 11/26/2022] Open
Abstract
With an estimated 1 billion people affected across the globe, influenza is one of the most serious health concerns worldwide. Therapeutic treatments have encompassed a number of key functional viral proteins, mainly focused on the M2 proton channel and neuraminidase. This review highlights the efforts spent in targeting the M2 proton channel, which mediates the proton transport toward the interior of the viral particle as a preliminary step leading to the release of the fusion peptide in hemagglutinin and the fusion of the viral and endosomal membranes. Besides the structural and mechanistic aspects of the M2 proton channel, attention is paid to the challenges posed by the development of efficient small molecule inhibitors and the evolution toward novel ligands and scaffolds motivated by the emergence of resistant strains.
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Affiliation(s)
- Elnaz Aledavood
- Departament de Nutrició, Ciències de l'Alimentació i Gastronomia, Institut de Biomedicina and Institut de Química Teòrica i Computacional, University of Barcelona, Barcelona, Spain
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum – Università di Bologna, Bologna, Italy
| | - Beatrice Selmi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum – Università di Bologna, Bologna, Italy
| | - Carolina Estarellas
- Departament de Nutrició, Ciències de l'Alimentació i Gastronomia, Institut de Biomedicina and Institut de Química Teòrica i Computacional, University of Barcelona, Barcelona, Spain
- *Correspondence: Carolina Estarellas, ; Matteo Masetti, ; F. Javier Luque,
| | - Matteo Masetti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum – Università di Bologna, Bologna, Italy
- *Correspondence: Carolina Estarellas, ; Matteo Masetti, ; F. Javier Luque,
| | - F. Javier Luque
- Departament de Nutrició, Ciències de l'Alimentació i Gastronomia, Institut de Biomedicina and Institut de Química Teòrica i Computacional, University of Barcelona, Barcelona, Spain
- *Correspondence: Carolina Estarellas, ; Matteo Masetti, ; F. Javier Luque,
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18
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Townsend JA, Sanders HM, Rolland AD, Park CK, Horton NC, Prell JS, Wang J, Marty MT. Influenza AM2 Channel Oligomerization Is Sensitive to Its Chemical Environment. Anal Chem 2021; 93:16273-16281. [PMID: 34813702 DOI: 10.1021/acs.analchem.1c04660] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Viroporins are small viral ion channels that play important roles in the viral infection cycle and are proven antiviral drug targets. Matrix protein 2 from influenza A (AM2) is the best-characterized viroporin, and the current paradigm is that AM2 forms monodisperse tetramers. Here, we used native mass spectrometry and other techniques to characterize the oligomeric state of both the full-length and transmembrane (TM) domain of AM2 in a variety of different pH and detergent conditions. Unexpectedly, we discovered that AM2 formed a range of different oligomeric complexes that were strongly influenced by the local chemical environment. Native mass spectrometry of AM2 in nanodiscs with different lipids showed that lipids also affected the oligomeric states of AM2. Finally, nanodiscs uniquely enabled the measurement of amantadine binding stoichiometries to AM2 in the intact lipid bilayer. These unexpected results reveal that AM2 can form a wider range of oligomeric states than previously thought possible, which may provide new potential mechanisms of influenza pathology and pharmacology.
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Affiliation(s)
- Julia A Townsend
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Henry M Sanders
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Amber D Rolland
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403, United States.,Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, United States
| | - Chad K Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, United States
| | - Nancy C Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, United States
| | - James S Prell
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403, United States.,Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
| | - Jun Wang
- Department of Pharmacology and Toxicology, The University of Arizona, Tucson, Arizona 85721, United States.,Bio5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
| | - Michael T Marty
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States.,Bio5 Institute, The University of Arizona, Tucson, Arizona 85721, United States
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19
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Eurasian Avian-like M1 Plays More Important Role than M2 in Pathogenicity of 2009 Pandemic H1N1 Influenza Virus in Mice. Viruses 2021; 13:v13122335. [PMID: 34960604 PMCID: PMC8707482 DOI: 10.3390/v13122335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/13/2021] [Accepted: 11/19/2021] [Indexed: 12/04/2022] Open
Abstract
Reassortant variant viruses generated between 2009 H1N1 pandemic influenza virus [A(H1N1)pdm09] and endemic swine influenza viruses posed a potential risk to humans. Surprisingly, genetic analysis showed that almost all of these variant viruses contained the M segment from A(H1N1)pdm09, which originated from Eurasian avian-like swine influenza viruses. Studies have shown that the A(H1N1)pdm09 M gene is critical for the transmissibility and pathogenicity of the variant viruses. However, the M gene encodes two proteins, M1 and M2, and which of those plays a more important role in virus pathogenicity remains unknown. In this study, the M1 and M2 genes of A(H1N1)pdm09 were replaced with those of endemic H3N2 swine influenza virus, respectively. The chimeric viruses were rescued and evaluated in vitro and in mice. Both M1 and M2 of H3N2 affected the virus replication in vitro. In mice, the introduction of H3N2 M1 attenuated the chimeric virus, where all the mice survived from the infection, compared with the wild type virus that caused 100 % mortality. However, the chimeric virus containing H3N2 M2 was still virulent to mice, and caused 16.6% mortality, as well as similar body weight loss to the wild type virus infected group. Compared with the wild type virus, the chimeric virus containing H3N2 M1 induced lower levels of inflammatory cytokines and higher levels of anti-inflammatory cytokines, whereas the chimeric virus containing H3N2 M2 induced substantial pro-inflammatory responses, but higher levels of anti-inflammatory cytokines. The study demonstrated that Eurasian avian-like M1 played a more important role than M2 in the pathogenicity of A(H1N1)pdm09 in mice.
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20
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Thomaston JL, Samways ML, Konstantinidi A, Ma C, Hu Y, Bruce Macdonald HE, Wang J, Essex JW, DeGrado WF, Kolocouris A. Rimantadine Binds to and Inhibits the Influenza A M2 Proton Channel without Enantiomeric Specificity. Biochemistry 2021; 60:10.1021/acs.biochem.1c00437. [PMID: 34342217 PMCID: PMC8810914 DOI: 10.1021/acs.biochem.1c00437] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The influenza A M2 wild-type (WT) proton channel is the target of the anti-influenza drug rimantadine. Rimantadine has two enantiomers, though most investigations into drug binding and inhibition have used a racemic mixture. Solid-state NMR experiments using the full length-M2 WT have shown significant spectral differences that were interpreted to indicate tighter binding for (R)- vs (S)-rimantadine. However, it was unclear if this correlates with a functional difference in drug binding and inhibition. Using X-ray crystallography, we have determined that both (R)- and (S)-rimantadine bind to the M2 WT pore with slight differences in the hydration of each enantiomer. However, this does not result in a difference in potency or binding kinetics, as shown by similar values for kon, koff, and Kd in electrophysiological assays and for EC50 values in cellular assays. We concluded that the slight differences in hydration for the (R)- and (S)-rimantadine enantiomers are not relevant to drug binding or channel inhibition. To further explore the effect of the hydration of the M2 pore on binding affinity, the water structure was evaluated by grand canonical ensemble molecular dynamics simulations as a function of the chemical potential of the water. Initially, the two layers of ordered water molecules between the bound drug and the channel's gating His37 residues mask the drug's chirality. As the chemical potential becomes more unfavorable, the drug translocates down to the lower water layer, and the interaction becomes more sensitive to chirality. These studies suggest the feasibility of displacing the upper water layer and specifically recognizing the lower water layers in novel drugs.
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Affiliation(s)
- Jessica L Thomaston
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, University of California, San Francisco, California 94158, United States
| | - Marley L Samways
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Athina Konstantinidi
- Department of Pharmaceutical Chemistry, School of Pharmacy, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Chunlong Ma
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Yanmei Hu
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Hannah E Bruce Macdonald
- Computational and Systems Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Jun Wang
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Jonathan W Essex
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - William F DeGrado
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, University of California, San Francisco, California 94158, United States
| | - Antonios Kolocouris
- Department of Pharmaceutical Chemistry, School of Pharmacy, National and Kapodistrian University of Athens, 15771 Athens, Greece
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21
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Cabrera‐Garcia D, Bekdash R, Abbott GW, Yazawa M, Harrison NL. The envelope protein of SARS-CoV-2 increases intra-Golgi pH and forms a cation channel that is regulated by pH. J Physiol 2021; 599:2851-2868. [PMID: 33709461 PMCID: PMC8251088 DOI: 10.1113/jp281037] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/02/2021] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS We report a novel method for the transient expression of SARS-CoV-2 envelope (E) protein in intracellular organelles and the plasma membrane of mammalian cells and Xenopus oocytes. Intracellular expression of SARS-CoV-2 E protein increases intra-Golgi pH. By targeting the SARS-CoV-2 E protein to the plasma membrane, we show that it forms a cation channel, viroporin, that is modulated by changes of pH. This method for studying the activity of viroporins may facilitate screening for new antiviral drugs to identify novel treatments for COVID-19. ABSTRACT The envelope (E) protein of coronaviruses such as SARS-CoV-1 is proposed to form an ion channel or viroporin that participates in viral propagation and pathogenesis. Here we developed a technique to study the E protein of SARS-CoV-2 in mammalian cells by directed targeting using a carboxyl-terminal fluorescent protein tag, mKate2. The wild-type SARS-CoV-2 E protein can be trafficked to intracellular organelles, notably the endoplasmic reticulum-Golgi intermediate complex, where its expression increases pH inside the organelle. We also succeeded in targeting SARS-CoV-2 E to the plasma membrane, which enabled biophysical analysis using whole-cell patch clamp recording in a mammalian cell line, HEK 293 cells, and two-electrode voltage clamp electrophysiology in Xenopus oocytes. The results suggest that the E protein forms an ion channel that is permeable to monovalent cations such as Na+ , Cs+ and K+ . The E current is nearly time- and voltage-independent when E protein is expressed in mammalian cells, and is modulated by changes of pH. At pH 6.0 and 7.4, the E protein current is activated, whereas at pH 8.0 and 9.0, the amplitude of E protein current is reduced, and in oocytes the inward E current fades at pH 9 in a time- and voltage-dependent manner. Using this directed targeting method and electrophysiological recordings, potential inhibitors of the E protein can be screened and subsequently investigated for antiviral activity against SARS-CoV-2 in vitro and possible efficacy in treating COVID-19.
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Affiliation(s)
| | - Ramsey Bekdash
- Department of Molecular Pharmacology and TherapeuticsColumbia UniversityNew YorkNYUSA
- Columbia Stem Cell Initiative, Department of Rehabilitation and Regenerative MedicineColumbia UniversityNew YorkNYUSA
| | - Geoffrey W. Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of MedicineUniversity of CaliforniaIrvineCAUSA
| | - Masayuki Yazawa
- Department of Molecular Pharmacology and TherapeuticsColumbia UniversityNew YorkNYUSA
- Columbia Stem Cell Initiative, Department of Rehabilitation and Regenerative MedicineColumbia UniversityNew YorkNYUSA
| | - Neil L. Harrison
- Department of AnesthesiologyColumbia UniversityNew YorkNYUSA
- Department of Molecular Pharmacology and TherapeuticsColumbia UniversityNew YorkNYUSA
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22
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Breitinger U, Farag NS, Ali NKM, Ahmed M, El-Azizi MA, Breitinger HG. Cell viability assay as a tool to study activity and inhibition of hepatitis C p7 channels. J Gen Virol 2021; 102. [PMID: 33709903 DOI: 10.1099/jgv.0.001571] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The p7 viroporin of the hepatitis C virus (HCV) forms an intracellular proton-conducting transmembrane channel in virus-infected cells, shunting the pH of intracellular compartments and thus helping virus assembly and release. This activity is essential for virus infectivity, making viroporins an attractive target for drug development. The protein sequence and drug sensitivity of p7 vary between the seven major genotypes of the hepatitis C virus, but the essential channel activity is preserved. Here, we investigated the effect of several inhibitors on recombinant HCV p7 channels corresponding to genotypes 1a-b, 2a-b, 3a and 4a using patch-clamp electrophysiology and cell-based assays. We established a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based cell viability assay for recombinant p7 expressed in HEK293 cells to assess channel activity and its sensitivity to inhibitors. The results from the cell viability assay were consistent with control measurements using established assays of haemadsorption and intracellular pH, and agreed with data from patch-clamp electrophysiology. Hexamethylene amiloride (HMA) was the most potent inhibitor of p7 activity, but possessed cytotoxic activity at higher concentrations. Rimantadine was active against p7 of all genotypes, while amantadine activity was genotype-dependent. The alkyl-chain iminosugars NB-DNJ, NN-DNJ and NN-DGJ were tested and their activity was found to be genotype-specific. In the current study, we introduce cell viability assays as a rapid and cost-efficient technique to assess viroporin activity and identify channel inhibitors as potential novel antiviral drugs.
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Affiliation(s)
- Ulrike Breitinger
- Department of Biochemistry, German University in Cairo, New Cairo, Egypt
| | - Noha S Farag
- Department of Microbiology and Immunology, German University in Cairo, New Cairo, Egypt
| | - Nourhan K M Ali
- Department of Biochemistry, German University in Cairo, New Cairo, Egypt
| | - Marwa Ahmed
- Present address: Institute of Biochemistry and Biophysics Friedrich-Schiller-University Jena, Hans-Knöll-Str. 2, D-07745, Jena, Germany.,Department of Biochemistry, German University in Cairo, New Cairo, Egypt
| | - Mohamed A El-Azizi
- Department of Microbiology and Immunology, German University in Cairo, New Cairo, Egypt
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23
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Mtambo SE, Amoako DG, Somboro AM, Agoni C, Lawal MM, Gumede NS, Khan RB, Kumalo HM. Influenza Viruses: Harnessing the Crucial Role of the M2 Ion-Channel and Neuraminidase toward Inhibitor Design. Molecules 2021; 26:880. [PMID: 33562349 PMCID: PMC7916051 DOI: 10.3390/molecules26040880] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 12/18/2022] Open
Abstract
As a member of the Orthomyxoviridae family of viruses, influenza viruses (IVs) are known causative agents of respiratory infection in vertebrates. They remain a major global threat responsible for the most virulent diseases and global pandemics in humans. The virulence of IVs and the consequential high morbidity and mortality of IV infections are primarily attributed to the high mutation rates in the IVs' genome coupled with the numerous genomic segments, which give rise to antiviral resistant and vaccine evading strains. Current therapeutic options include vaccines and small molecule inhibitors, which therapeutically target various catalytic processes in IVs. However, the periodic emergence of new IV strains necessitates the continuous development of novel anti-influenza therapeutic options. The crux of this review highlights the recent studies on the biology of influenza viruses, focusing on the structure, function, and mechanism of action of the M2 channel and neuraminidase as therapeutic targets. We further provide an update on the development of new M2 channel and neuraminidase inhibitors as an alternative to existing anti-influenza therapy. We conclude by highlighting therapeutic strategies that could be explored further towards the design of novel anti-influenza inhibitors with the ability to inhibit resistant strains.
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Affiliation(s)
- Sphamadla E. Mtambo
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4000, South Africa; (S.E.M.); (A.M.S.); (C.A.); (M.M.L.); (N.S.G.); (R.B.K.)
| | - Daniel G. Amoako
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4000, South Africa; (S.E.M.); (A.M.S.); (C.A.); (M.M.L.); (N.S.G.); (R.B.K.)
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, Johannesburg 2131, South Africa
| | - Anou M. Somboro
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4000, South Africa; (S.E.M.); (A.M.S.); (C.A.); (M.M.L.); (N.S.G.); (R.B.K.)
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, Johannesburg 2131, South Africa
| | - Clement Agoni
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4000, South Africa; (S.E.M.); (A.M.S.); (C.A.); (M.M.L.); (N.S.G.); (R.B.K.)
| | - Monsurat M. Lawal
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4000, South Africa; (S.E.M.); (A.M.S.); (C.A.); (M.M.L.); (N.S.G.); (R.B.K.)
| | - Nelisiwe S. Gumede
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4000, South Africa; (S.E.M.); (A.M.S.); (C.A.); (M.M.L.); (N.S.G.); (R.B.K.)
| | - Rene B. Khan
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4000, South Africa; (S.E.M.); (A.M.S.); (C.A.); (M.M.L.); (N.S.G.); (R.B.K.)
| | - Hezekiel M. Kumalo
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4000, South Africa; (S.E.M.); (A.M.S.); (C.A.); (M.M.L.); (N.S.G.); (R.B.K.)
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24
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Mechanism and Kinetics of Copper Complexes Binding to the Influenza A M2 S31N and S31N/G34E Channels. Biophys J 2020; 120:168-177. [PMID: 33248127 DOI: 10.1016/j.bpj.2020.11.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/21/2020] [Accepted: 11/13/2020] [Indexed: 01/13/2023] Open
Abstract
Copper(II) is known to bind in the influenza virus His37 cluster in the homotetrameric M2 proton channel and block the proton current needed for uncoating. Copper complexes based on iminodiacetate also block the M2 proton channel and show reduced cytotoxicity and zebrafish-embryo toxicity. In voltage-clamp oocyte studies using the ubiquitous amantadine-insensitive M2 S31N variant, the current block showed fast and slow phases, in contrast to the single phase found for amantadine block of wild-type M2. Here, we evaluate the mechanism of block by copper adamantyl iminodiacitate and copper cyclooctyl iminodiacitate complexes and address whether the complexes can coordinate with one or more of the His37 imidazoles. The current traces were fitted to parametrized master equations. The energetics of binding and the rate constants suggest that the first step is copper complex binding within the channel, and the slow step in the current block is the formation of a Cu-histidine coordination complex. Solution-phase isothermal titration calorimetry and density functional theory (DFT) calculations indicate that imidazole binds to the copper complexes. Structural optimization using DFT reveals that the complexes fit inside the channel and project the Cu(II) toward the His37 cluster, allowing one imidazole to form a coordination complex with Cu(II). Electrophysiology and DFT studies also show that the complexes block the G34E amantadine-resistant mutant despite some crowding in the binding site by the glutamates.
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25
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Lamb RA. The Structure, Function, and Pathobiology of the Influenza A and B Virus Ion Channels. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a038505. [PMID: 31988204 DOI: 10.1101/cshperspect.a038505] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Influenza A virus AM2 protein is an integral membrane protein that is an ion channel (also known as a viroporin). The channel has 24 extracellular residues, 19 residues that span the membrane once and acts as both the channel pore and also the membrane anchoring domain, and a 54-residue cytoplasmic tail. The M2 protein has four identical chains linked via two disulfide bonds that form a four-helix bundle that is 107-108 more permeable to protons than Na+ ions. The M2 channel is activated by low pH, His residue 37 is the pH sensor, and Trp residue 41 is the channel gate. The channel is blocked by the antiviral drug amantadine hydrochloride. The influenza B virus BM2 protein does not have homology with the AM2 channel, but BM2 does have the His proton sensor, Trp gate, and is activated by low pH. It is thought that the AM2 and BM2 proteins have common functions in the influenza A and B virus life cycles. Both BM2 and AM2 also facilitate virus budding. The amphipathic helix in the AM2 cytoplasmic tail has an important role in the assembly of the virus, and functional AM2 protein makes the virus independent of the "endosomal sorting complex required for transport" (ESCRT) complex scission.
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Affiliation(s)
- Robert A Lamb
- Department of Molecular Biosciences, Howard Hughes Medical Institute, Northwestern University, Evanston, Illinois 60208-3500, USA
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26
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Watkins LC, DeGrado WF, Voth GA. Influenza A M2 Inhibitor Binding Understood through Mechanisms of Excess Proton Stabilization and Channel Dynamics. J Am Chem Soc 2020; 142:17425-17433. [PMID: 32933245 PMCID: PMC7564090 DOI: 10.1021/jacs.0c06419] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
![]()
Prevalent resistance to inhibitors
that target the influenza A
M2 proton channel has necessitated a continued drug design effort,
supported by a sustained study of the mechanism of channel function
and inhibition. Recent high-resolution X-ray crystal structures present
the first opportunity to see how the adamantyl amine class of inhibitors
bind to M2 and disrupt and interact with the channel’s water
network, providing insight into the critical properties that enable
their effective inhibition in wild-type M2. In this work, we examine
the hypothesis that these drugs act primarily as mechanism-based inhibitors
by comparing hydrated excess proton stabilization during proton transport
in M2 with the interactions revealed in the crystal structures, using
the Multiscale Reactive Molecular Dynamics (MS-RMD) methodology. MS-RMD,
unlike classical molecular dynamics, models the hydrated proton (hydronium-like
cation) as a dynamic excess charge defect and allows bonds to break
and form, capturing the intricate interactions between the hydrated
excess proton, protein atoms, and water. Through this, we show that
the ammonium group of the inhibitors is effectively positioned to
take advantage of the channel’s natural ability to stabilize
an excess protonic charge and act as a hydronium mimic. Additionally,
we show that the channel is especially stable in the drug binding
region, highlighting the importance of this property for binding the
adamantane group. Finally, we characterize an additional hinge point
near Val27, which dynamically responds to charge and inhibitor binding.
Altogether, this work further illuminates a dynamic understanding
of the mechanism of drug inhibition in M2, grounded in the fundamental
properties that enable the channel to transport and stabilize excess
protons, with critical implications for future drug design efforts.
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Affiliation(s)
- Laura C Watkins
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158, United States
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
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27
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Stylianakis I, Shalev A, Scheiner S, Sigalas MP, Arkin IT, Glykos N, Kolocouris A. The balance between side-chain and backbone-driven association in folding of the α-helical influenza A transmembrane peptide. J Comput Chem 2020; 41:2177-2188. [PMID: 32735736 DOI: 10.1002/jcc.26381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 11/07/2022]
Abstract
The correct balance between attractive, repulsive and peptide hydrogen bonding interactions must be attained for proteins to fold correctly. To investigate these important contributors, we sought a comparison of the folding between two 25-residues peptides, the influenza A M2 protein transmembrane domain (M2TM) and the 25-Ala (Ala25 ). M2TM forms a stable α-helix as is shown by circular dichroism (CD) experiments. Molecular dynamics (MD) simulations with adaptive tempering show that M2TM monomer is more dynamic in nature and quickly interconverts between an ensemble of various α-helical structures, and less frequently turns and coils, compared to one α-helix for Ala25 . DFT calculations suggest that folding from the extended structure to the α-helical structure is favored for M2TM compared with Ala25 . This is due to CH⋯O attractive interactions which favor folding to the M2TM α-helix, and cannot be described accurately with a force field. Using natural bond orbital (NBO) analysis and quantum theory atoms in molecules (QTAIM) calculations, 26 CH⋯O interactions and 22 NH⋯O hydrogen bonds are calculated for M2TM. The calculations show that CH⋯O hydrogen bonds, although individually weaker, have a cumulative effect that cannot be ignored and may contribute as much as half of the total hydrogen bonding energy, when compared to NH⋯O, to the stabilization of the α-helix in M2TM. Further, a strengthening of NH⋯O hydrogen bonding interactions is calculated for M2TM compared to Ala25 . Additionally, these weak CH⋯O interactions can dissociate and associate easily leading to the ensemble of folded structures for M2TM observed in folding MD simulations.
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Affiliation(s)
- Ioannis Stylianakis
- Section of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece
| | - Ariella Shalev
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus Givat-Ram, Jerusalem, Israel
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah, USA
| | - Michael P Sigalas
- Department of Chemistry, Laboratory of Applied Quantum Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Isaiah T Arkin
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus Givat-Ram, Jerusalem, Israel
| | - Nikolas Glykos
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Antonios Kolocouris
- Section of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece
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28
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Site-directed M2 proton channel inhibitors enable synergistic combination therapy for rimantadine-resistant pandemic influenza. PLoS Pathog 2020; 16:e1008716. [PMID: 32780760 PMCID: PMC7418971 DOI: 10.1371/journal.ppat.1008716] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 06/19/2020] [Indexed: 12/05/2022] Open
Abstract
Pandemic influenza A virus (IAV) remains a significant threat to global health. Preparedness relies primarily upon a single class of neuraminidase (NA) targeted antivirals, against which resistance is steadily growing. The M2 proton channel is an alternative clinically proven antiviral target, yet a near-ubiquitous S31N polymorphism in M2 evokes resistance to licensed adamantane drugs. Hence, inhibitors capable of targeting N31 containing M2 (M2-N31) are highly desirable. Rational in silico design and in vitro screens delineated compounds favouring either lumenal or peripheral M2 binding, yielding effective M2-N31 inhibitors in both cases. Hits included adamantanes as well as novel compounds, with some showing low micromolar potency versus pandemic “swine” H1N1 influenza (Eng195) in culture. Interestingly, a published adamantane-based M2-N31 inhibitor rapidly selected a resistant V27A polymorphism (M2-A27/N31), whereas this was not the case for non-adamantane compounds. Nevertheless, combinations of adamantanes and novel compounds achieved synergistic antiviral effects, and the latter synergised with the neuraminidase inhibitor (NAi), Zanamivir. Thus, site-directed drug combinations show potential to rejuvenate M2 as an antiviral target whilst reducing the risk of drug resistance. "Swine flu" illustrated that the spread of influenza pandemics in the modern era is rapid, making antiviral drugs the best way of limiting disease. One proven influenza drug target is the M2 proton channel, which plays an essential role during virus entry. However, resistance against licensed drugs targeting this protein is now ubiquitous, largely due to an S31N change in the M2 sequence. Understandably, considerable effort has focused on developing M2-N31 inhibitors, yet this has been hampered by controversy surrounding two potential drug binding sites. Here, we show that both sites can in fact be targeted by new M2-N31 inhibitors, generating synergistic antiviral effects. Developing such drug combinations should improve patient outcomes and minimise the emergence of future drug resistance.
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29
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Zhang Y, Zhang HX, Zheng QC. In Silico Study of Membrane Lipid Composition Regulating Conformation and Hydration of Influenza Virus B M2 Channel. J Chem Inf Model 2020; 60:3603-3615. [PMID: 32589410 DOI: 10.1021/acs.jcim.0c00329] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The proton conduction of transmembrane influenza virus B M2 (BM2) proton channel is possibly mediated by the membrane environment, but the detailed molecular mechanism is challenging to determine. In this work, how membrane lipid composition regulates the conformation and hydration of BM2 channel is elucidated in silico. The appearance of several important hydrogen-bond networks has been discovered, as the addition of negatively charged lipid palmitoyloleoyl phosphatidylglycerol (POPG) and cholesterol reduces membrane fluidity and augments membrane rigidity. A more rigid membrane environment is beneficial to expand the channel, allow more water to enter the channel, promote channel hydration, and then even affect the proton conduction facilitated by the hydrated channel. Thus, membrane environment could be identified as an important influence factor of conformation and hydration of BM2. These findings can provide a unique perspective for understanding the mechanism of membrane lipid composition regulating conformation and hydration of BM2 and have important significance to the further study of anti-influenza virus B drugs.
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Affiliation(s)
- Yue Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, College of Chemistry, Jilin University, Changchun 130023, People's Republic of China
| | - Hong-Xing Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, College of Chemistry, Jilin University, Changchun 130023, People's Republic of China
| | - Qing-Chuan Zheng
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, College of Chemistry, Jilin University, Changchun 130023, People's Republic of China.,Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun 130023, People's Republic of China
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30
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Comparative Analyses of the Antiviral Activities of IgG and IgA Antibodies to Influenza A Virus M2 Protein. Viruses 2020; 12:v12070780. [PMID: 32698456 PMCID: PMC7411592 DOI: 10.3390/v12070780] [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: 06/29/2020] [Revised: 07/16/2020] [Accepted: 07/19/2020] [Indexed: 01/22/2023] Open
Abstract
The influenza A virus (IAV) matrix-2 (M2) protein is an antigenically conserved viral envelope protein that plays an important role in virus budding together with another envelope protein, hemagglutinin (HA). An M2-specific mouse monoclonal IgG antibody, rM2ss23, which binds to the ectodomain of the M2 protein, has been shown to be a non-neutralizing antibody, but inhibits plaque formation of IAV strains. In this study, we generated chimeric rM2ss23 (ch-rM2ss23) IgG and IgA antibodies with the same variable region and compared their antiviral activities. Using gel chromatography, ch-rM2ss23 IgA were divided into three antibody subsets: monomeric IgA (m-IgA), dimeric IgA (d-IgA), and trimeric and tetrameric IgA (t/q-IgA). We found that t/q-IgA had a significantly higher capacity to reduce the plaque size of IAVs than IgG and m-IgA, most likely due to the decreased number of progeny virus particles produced from infected cells. Interestingly, HA-M2 colocalization was remarkably reduced on the infected cell surface in the presence of ch-rM2ss23 antibodies. These results indicate that anti-M2 polymeric IgA restricts IAV budding more efficiently than IgG and suggest a role of anti-M2 IgA in cross-protective immunity to IAVs.
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31
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Wobig L, Wolfenstetter T, Fechner S, Bönigk W, Körschen HG, Jikeli JF, Trötschel C, Feederle R, Kaupp UB, Seifert R, Berger TK. A family of hyperpolarization-activated channels selective for protons. Proc Natl Acad Sci U S A 2020; 117:13783-13791. [PMID: 32467169 PMCID: PMC7306766 DOI: 10.1073/pnas.2001214117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Proton (H+) channels are special: They select protons against other ions that are up to a millionfold more abundant. Only a few proton channels have been identified so far. Here, we identify a family of voltage-gated "pacemaker" channels, HCNL1, that are exquisitely selective for protons. HCNL1 activates during hyperpolarization and conducts protons into the cytosol. Surprisingly, protons permeate through the channel's voltage-sensing domain, whereas the pore domain is nonfunctional. Key to proton permeation is a methionine residue that interrupts the series of regularly spaced arginine residues in the S4 voltage sensor. HCNL1 forms a tetramer and thus contains four proton pores. Unlike classic HCN channels, HCNL1 is not gated by cyclic nucleotides. The channel is present in zebrafish sperm and carries a proton inward current that acidifies the cytosol. Our results suggest that protons rather than cyclic nucleotides serve as cellular messengers in zebrafish sperm. Through small modifications in two key functional domains, HCNL1 evolutionarily adapted to a low-Na+ freshwater environment to conserve sperm's ability to depolarize.
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Affiliation(s)
- Lea Wobig
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany
| | - Thérèse Wolfenstetter
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany
| | - Sylvia Fechner
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany
| | - Wolfgang Bönigk
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany
| | - Heinz G Körschen
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany
| | - Jan F Jikeli
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany
| | - Christian Trötschel
- Department of Plant Biochemistry, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Regina Feederle
- Monoclonal Antibody Core Facility and Research Group, Institute for Diabetes and Obesity, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - U Benjamin Kaupp
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany;
- Life & Medical Sciences Institute (LIMES), University of Bonn, 53115 Bonn, Germany
| | - Reinhard Seifert
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany;
| | - Thomas K Berger
- Department of Molecular Sensory Systems, Research Center Caesar, 53175 Bonn, Germany;
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps-University Marburg, 35037 Marburg, Germany
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Jalily PH, Duncan MC, Fedida D, Wang J, Tietjen I. Put a cork in it: Plugging the M2 viral ion channel to sink influenza. Antiviral Res 2020; 178:104780. [PMID: 32229237 PMCID: PMC7102647 DOI: 10.1016/j.antiviral.2020.104780] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 02/12/2020] [Accepted: 03/20/2020] [Indexed: 12/17/2022]
Abstract
The ongoing threat of seasonal and pandemic influenza to human health requires antivirals that can effectively supplement existing vaccination strategies. The M2 protein of influenza A virus (IAV) is a proton-gated, proton-selective ion channel that is required for virus replication and is an established antiviral target. While licensed adamantane-based M2 antivirals have been historically used, M2 mutations that confer major adamantane resistance are now so prevalent in circulating virus strains that these drugs are no longer recommended. Here we review the current understanding of IAV M2 structure and function, mechanisms of inhibition, the rise of drug resistance mutations, and ongoing efforts to develop new antivirals that target resistant forms of M2.
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Affiliation(s)
- Pouria H Jalily
- Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Maggie C Duncan
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - David Fedida
- Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Jun Wang
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tuscon, AZ, USA
| | - Ian Tietjen
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada; The Wistar Institute, Philadelphia, PA, USA.
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Li X, Zhang H, Hou J, Ou R, Zhu Y, Zhao C, Qian T, Easton CD, Selomulya C, Hill MR, Wang H. Sulfonated Sub-1-nm Metal–Organic Framework Channels with Ultrahigh Proton Selectivity. J Am Chem Soc 2020; 142:9827-9833. [DOI: 10.1021/jacs.0c03554] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Xingya Li
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Huacheng Zhang
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Jue Hou
- Manufacturing, CSIRO, Clayton, 3168, Australia
| | - Ranwen Ou
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Yinlong Zhu
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Chen Zhao
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Tianyue Qian
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | | | | | - Matthew R. Hill
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
- Manufacturing, CSIRO, Clayton, 3168, Australia
| | - Huanting Wang
- Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
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Recent advances in "universal" influenza virus antibodies: the rise of a hidden trimeric interface in hemagglutinin globular head. Front Med 2020; 14:149-159. [PMID: 32239416 PMCID: PMC7110985 DOI: 10.1007/s11684-020-0764-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 03/04/2020] [Indexed: 01/05/2023]
Abstract
Influenza causes seasonal outbreaks yearly and unpredictable pandemics with high morbidity and mortality rates. Despite significant efforts to address influenza, it remains a major threat to human public health. This issue is partially due to the lack of antiviral drugs with potent antiviral activity and broad reactivity against all influenza virus strains and the rapid emergence of drug-resistant variants. Moreover, designing a universal influenza vaccine that is sufficiently immunogenic to induce universal antibodies is difficult. Some novel epitopes hidden in the hemagglutinin (HA) trimeric interface have been discovered recently, and a number of antibodies targeting these epitopes have been found to be capable of neutralizing a broad range of influenza isolates. These findings may have important implications for the development of universal influenza vaccines and antiviral drugs. In this review, we focused on the antibodies targeting these newly discovered epitopes in the HA domain of the influenza virus to promote the development of universal anti-influenza antibodies or vaccines and extend the discovery to other viruses with similar conformational changes in envelope proteins.
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Farag NS, Breitinger U, Breitinger HG, El Azizi MA. Viroporins and inflammasomes: A key to understand virus-induced inflammation. Int J Biochem Cell Biol 2020; 122:105738. [PMID: 32156572 PMCID: PMC7102644 DOI: 10.1016/j.biocel.2020.105738] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 02/07/2023]
Abstract
The article provides a summary on cellular receptors involved in virus immunity. It summarizes key findings on viroporins, a novel class of viral proteins and their role in the virus life cycle and host cell interactions. It presents an overview of the current understanding of inflammasomes complex activation, with special focus on NLRP3. It discusses the correlation between viroporins and inflammasomes activation and aggravated inflammatory cytokines production.
Viroporins are virus encoded proteins that alter membrane permeability and can trigger subsequent cellular signals. Oligomerization of viroporin subunits results in formation of a hydrophilic pore which facilitates ion transport across host cell membranes. These viral channel proteins may be involved in different stages of the virus infection cycle. Inflammasomes are large multimolecular complexes best recognized for their ability to control activation of caspase-1, which in turn regulates the maturation of interleukin-1 β (IL-1β) and interleukin 18 (IL-18). IL-1β was originally identified as a pro-inflammatory cytokine able to induce both local and systemic inflammation and a febrile reaction in response to infection or injury. Excessive production of IL-1β is associated with autoimmune and inflammatory diseases. Microbial derivatives, bacterial pore-forming toxins, extracellular ATP and other pathogen-associated molecular patterns trigger activation of NLRP3 inflammasomes. Recent studies have reported that viroporin activity is capable of inducing inflammasome activity and production of IL-1β, where NLRP3 is shown to be regulated by fluxes of K+, H+ and Ca2+ in addition to reactive oxygen species, autophagy and endoplasmic reticulum stress. The aim of this review is to present an overview of the key findings on viroporin activity with special emphasis on their role in virus immunity and as possible activators of inflammasomes.
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Affiliation(s)
- N S Farag
- Department of Microbiology and Immunology, German University inCairo, New Cairo, Egypt.
| | - U Breitinger
- Department of Biochemistry, German University in Cairo, New Cairo, Egypt
| | - H G Breitinger
- Department of Biochemistry, German University in Cairo, New Cairo, Egypt
| | - M A El Azizi
- Department of Microbiology and Immunology, German University inCairo, New Cairo, Egypt
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Thomaston JL, Konstantinidi A, Liu L, Lambrinidis G, Tan J, Caffrey M, Wang J, DeGrado WF, Kolocouris A. X-ray Crystal Structures of the Influenza M2 Proton Channel Drug-Resistant V27A Mutant Bound to a Spiro-Adamantyl Amine Inhibitor Reveal the Mechanism of Adamantane Resistance. Biochemistry 2020; 59:627-634. [PMID: 31894969 PMCID: PMC7224692 DOI: 10.1021/acs.biochem.9b00971] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The V27A mutation confers adamantane resistance on the influenza A matrix 2 (M2) proton channel and is becoming more prevalent in circulating populations of influenza A virus. We have used X-ray crystallography to determine structures of a spiro-adamantyl amine inhibitor bound to M2(22-46) V27A and also to M2(21-61) V27A in the Inwardclosed conformation. The spiro-adamantyl amine binding site is nearly identical for the two crystal structures. Compared to the M2 "wild type" (WT) with valine at position 27, we observe that the channel pore is wider at its N-terminus as a result of the V27A mutation and that this removes V27 side chain hydrophobic interactions that are important for binding of amantadine and rimantadine. The spiro-adamantyl amine inhibitor blocks proton conductance in the WT and V27A mutant channels by shifting its binding site in the pore depending on which residue is present at position 27. Additionally, in the structure of the M2(21-61) V27A construct, the C-terminus of the channel is tightly packed relative to that of the M2(22-46) construct. We observe that residues Asp44, Arg45, and Phe48 face the center of the channel pore and would be well-positioned to interact with protons exiting the M2 channel after passing through the His37 gate. A 300 ns molecular dynamics simulation of the M2(22-46) V27A-spiro-adamantyl amine complex predicts with accuracy the position of the ligands and waters inside the pore in the X-ray crystal structure of the M2(22-46) V27A complex.
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Affiliation(s)
- Jessica L. Thomaston
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
- Membrane Structural and Functional Biology (MS&FB) Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin D02 R590, Ireland
| | - Athina Konstantinidi
- Department of Pharmaceutical Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Lijun Liu
- State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
- DLX Scientific, Lawrence, KS 66049, USA
| | - George Lambrinidis
- Department of Pharmaceutical Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Jingquan Tan
- Membrane Structural and Functional Biology (MS&FB) Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin D02 R590, Ireland
| | - Martin Caffrey
- Membrane Structural and Functional Biology (MS&FB) Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin D02 R590, Ireland
| | - Jun Wang
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, USA
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Antonios Kolocouris
- Department of Pharmaceutical Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece
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Konstantinidi A, Chountoulesi M, Naziris N, Sartori B, Amenitsch H, Mali G, Čendak T, Plakantonaki M, Triantafyllakou I, Tselios T, Demetzos C, Busath DD, Mavromoustakos T, Kolocouris A. The boundary lipid around DMPC-spanning influenza A M2 transmembrane domain channels: Its structure and potential for drug accommodation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183156. [PMID: 31846647 DOI: 10.1016/j.bbamem.2019.183156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 10/25/2022]
Abstract
We have investigated the perturbation of influenza A M2TM in DMPC bilayers. We have shown that (a) DSC and SAXS detect changes in membrane organization caused by small changes (micromolar) in M2TM or aminoadamantane concentration and aminoadamantane structure, by comparison of amantadine and spiro[pyrrolidine-2,2'-adamantane] (AK13), (b) that WAXS and MD can suggest details of ligand topology. DSC and SAXS show that at a low M2TM micromolar concentration in DPMC bilayers, two lipid domains are observed, which likely correspond to M2TM boundary lipids and bulk-like lipids. At higher M2TM concentrations, one domain only is identified, which constitutes essentially all of the lipid molecules behaving as boundary lipids. According to SAXS, WAXS, and DSC in the absence of M2TM, both aminoadamantane drugs exert a similar perturbing effect on the bilayer at low concentrations. At the same concentrations of the drug when M2TM is present, amantadine and, to a lesser extent, AK13 cause, according to WAXS, a significant disordering of chain-stacking, which also leads to the formation of two lipid domains. This effect is likely due, according to MD simulations, to the preference of the more lipophilic AK13 to locate closer to the lateral surfaces of M2TM when compared to amantadine, which forms stronger ionic interactions with phosphate groups. The preference of AK13 to concentrate inside the lipid bilayer close to the exterior of the hydrophobic M2TM helices may contribute to its higher binding affinity compared to amantadine.
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Affiliation(s)
- Athina Konstantinidi
- Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Athens 15771, Greece
| | - Maria Chountoulesi
- Section of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Athens 15771, Greece
| | - Nikolaos Naziris
- Section of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Athens 15771, Greece
| | - Barbara Sartori
- Institute of Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9/IV, A-8010 Graz, Austria
| | - Heinz Amenitsch
- Institute of Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9/IV, A-8010 Graz, Austria
| | - Gregor Mali
- Department of Inorganic Chemistry and Technology, National Institute of Chemistry, Ljubljana SI-1001, Slovenia
| | - Tomaž Čendak
- Department of Inorganic Chemistry and Technology, National Institute of Chemistry, Ljubljana SI-1001, Slovenia
| | - Maria Plakantonaki
- Department of Chemistry, School of Natural Sciences, University of Patras, Rion, Patras 26500, Greece
| | - Iro Triantafyllakou
- Department of Chemistry, School of Natural Sciences, University of Patras, Rion, Patras 26500, Greece
| | - Theodore Tselios
- Department of Chemistry, School of Natural Sciences, University of Patras, Rion, Patras 26500, Greece
| | - Costas Demetzos
- Section of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Athens 15771, Greece
| | - David D Busath
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
| | - Thomas Mavromoustakos
- Section of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens 15771, Greece.
| | - Antonios Kolocouris
- Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Athens 15771, Greece.
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Moreno N, Recio R, Valdivia V, Khiar N, Fernández I. N-Isopropylsulfinylimines vs. N-tert-butylsulfinylimines in the stereoselective synthesis of sterically hindered amines: an improved synthesis of enantiopure (R)- and (S)-rimantadine and the trifluoromethylated analogues. Org Biomol Chem 2019; 17:9854-9858. [PMID: 31720674 DOI: 10.1039/c9ob02241d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An improved fully stereoselective synthesis of both enantiomers of rimantadine and its trifluoromethylated analogues has been developed, using N-isopropylsulfinylimines as a starting chiral material, proving the superiority of the isopropyl group as a chiral inducer over the tert-butyl group in the case of hindered N-sulfinylimines.
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Affiliation(s)
- Nazaret Moreno
- Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, C/Profesor García González, 2, 41012, Sevilla, Spain.
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Mezhenskaya D, Isakova-Sivak I, Rudenko L. M2e-based universal influenza vaccines: a historical overview and new approaches to development. J Biomed Sci 2019; 26:76. [PMID: 31629405 PMCID: PMC6800501 DOI: 10.1186/s12929-019-0572-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/01/2019] [Indexed: 01/04/2023] Open
Abstract
The influenza A virus was isolated for the first time in 1931, and the first attempts to develop a vaccine against the virus began soon afterwards. In addition to causing seasonal epidemics, influenza viruses can cause pandemics at random intervals, which are very hard to predict. Vaccination is the most effective way of preventing the spread of influenza infection. However, seasonal vaccination is ineffective against pandemic influenza viruses because of antigenic differences, and it takes approximately six months from isolation of a new virus to develop an effective vaccine. One of the possible ways to fight the emergence of pandemics may be by using a new type of vaccine, with a long and broad spectrum of action. The extracellular domain of the M2 protein (M2e) of influenza A virus is a conservative region, and an attractive target for a universal influenza vaccine. This review gives a historical overview of the study of M2 protein, and summarizes the latest developments in the preparation of M2e-based universal influenza vaccines.
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Affiliation(s)
- Daria Mezhenskaya
- Department of Virology, Institute of Experimental Medicine, 12 Acad. Pavlov Street, St. Petersburg, 197376, Russia
| | - Irina Isakova-Sivak
- Department of Virology, Institute of Experimental Medicine, 12 Acad. Pavlov Street, St. Petersburg, 197376, Russia.
| | - Larisa Rudenko
- Department of Virology, Institute of Experimental Medicine, 12 Acad. Pavlov Street, St. Petersburg, 197376, Russia
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40
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Watkins LC, Liang R, Swanson JMJ, DeGrado WF, Voth GA. Proton-Induced Conformational and Hydration Dynamics in the Influenza A M2 Channel. J Am Chem Soc 2019; 141:11667-11676. [PMID: 31264413 DOI: 10.1021/jacs.9b05136] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The influenza A M2 protein is an acid-activated proton channel responsible for acidification of the inside of the virus, a critical step in the viral life cycle. This channel has four central histidine residues that form an acid-activated gate, binding protons from the outside until an activated state allows proton transport to the inside. While previous work has focused on proton transport through the channel, the structural and dynamic changes that accompany proton flux and enable activation have yet to be resolved. In this study, extensive Multiscale Reactive Molecular Dynamics simulations with explicit Grotthuss-shuttling hydrated excess protons are used to explore detailed molecular-level interactions that accompany proton transport in the +0, + 1, and +2 histidine charge states. The results demonstrate how the hydrated excess proton strongly influences both the protein and water hydrogen-bonding network throughout the channel, providing further insight into the channel's acid-activation mechanism and rectification behavior. We find that the excess proton dynamically, as a function of location, shifts the protein structure away from its equilibrium distributions uniquely for different pH conditions consistent with acid-activation. The proton distribution in the xy-plane is also shown to be asymmetric about the channel's main axis, which has potentially important implications for the mechanism of proton conduction and future drug design efforts.
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Affiliation(s)
- Laura C Watkins
- Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Ruibin Liang
- Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Jessica M J Swanson
- Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute , The University of Chicago , Chicago , Illinois 60637 , United States
| | - William F DeGrado
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Gregory A Voth
- Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute , The University of Chicago , Chicago , Illinois 60637 , United States
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41
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Thomaston JL, Wu Y, Polizzi N, Liu L, Wang J, DeGrado WF. X-ray Crystal Structure of the Influenza A M2 Proton Channel S31N Mutant in Two Conformational States: An Open and Shut Case. J Am Chem Soc 2019; 141:11481-11488. [PMID: 31184871 DOI: 10.1021/jacs.9b02196] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The amantadine-resistant S31N mutant of the influenza A M2 proton channel has become prevalent in currently circulating viruses. Here, we have solved an X-ray crystal structure of M2(22-46) S31N that contains two distinct conformational states within its asymmetric unit. This structure reveals the mechanism of adamantane resistance in both conformational states of the M2 channel. In the Inwardopen conformation, the mutant Asn31 side chain faces the channel pore and sterically blocks the adamantane binding site. In the Inwardclosed conformation, Asn31 forms hydrogen bonds with carbonyls at the monomer-monomer interface, which twists the monomer helices and constricts the channel pore at the drug binding site. We also examine M2(19-49) WT and S31N using solution NMR spectroscopy and show that distribution of the two conformational states is dependent on both detergent choice and experimental pH.
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Affiliation(s)
- Jessica L Thomaston
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Yibing Wu
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Nicholas Polizzi
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Lijun Liu
- State Key Laboratory of Chemical Oncogenomics , Peking University Shenzhen Graduate School , Shenzhen 518055 , China.,DLX Scientific , Lawrence , Kansas 66049 , United States
| | - Jun Wang
- Department of Pharmacology and Toxicology, College of Pharmacy , University of Arizona , Tucson , Arizona 85721 , United States
| | - William F DeGrado
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
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42
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To J, Torres J. Viroporins in the Influenza Virus. Cells 2019; 8:cells8070654. [PMID: 31261944 PMCID: PMC6679168 DOI: 10.3390/cells8070654] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 06/21/2019] [Accepted: 06/27/2019] [Indexed: 12/28/2022] Open
Abstract
Influenza is a highly contagious virus that causes seasonal epidemics and unpredictable pandemics. Four influenza virus types have been identified to date: A, B, C and D, with only A–C known to infect humans. Influenza A and B viruses are responsible for seasonal influenza epidemics in humans and are responsible for up to a billion flu infections annually. The M2 protein is present in all influenza types and belongs to the class of viroporins, i.e., small proteins that form ion channels that increase membrane permeability in virus-infected cells. In influenza A and B, AM2 and BM2 are predominantly proton channels, although they also show some permeability to monovalent cations. By contrast, M2 proteins in influenza C and D, CM2 and DM2, appear to be especially selective for chloride ions, with possibly some permeability to protons. These differences point to different biological roles for M2 in types A and B versus C and D, which is also reflected in their sequences. AM2 is by far the best characterized viroporin, where mechanistic details and rationale of its acid activation, proton selectivity, unidirectionality, and relative low conductance are beginning to be understood. The present review summarizes the biochemical and structural aspects of influenza viroporins and discusses the most relevant aspects of function, inhibition, and interaction with the host.
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Affiliation(s)
- Janet To
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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43
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Konstantinidi A, Naziris N, Chountoulesi M, Kiriakidi S, Sartori B, Kolokouris D, Amentisch H, Mali G, Ntountaniotis D, Demetzos C, Mavromoustakos T, Kolocouris A. Comparative Perturbation Effects Exerted by the Influenza A M2 WT Protein Inhibitors Amantadine and the Spiro[pyrrolidine-2,2'-adamantane] Variant AK13 to Membrane Bilayers Studied Using Biophysical Experiments and Molecular Dynamics Simulations. J Phys Chem B 2018; 122:9877-9895. [PMID: 30285441 DOI: 10.1021/acs.jpcb.8b07071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Aminoadamantane drugs are lipophilic amines that block the membrane-embedded influenza A M2 WT (wild type) ion channel protein. The comparative effects of amantadine ( Amt) and its synthetic spiro[pyrrolidine-2,2'-adamantane] (AK13) analogue in dimyristoylphosphatidylcholine (DMPC) bilayers were studied using a combination of experimental biophysical methods, differential scanning calorimetry (DSC), X-ray diffraction, solid-state NMR (ssNMR) spectroscopy, and molecular dynamics (MD) simulations. All three experimental methods pointed out that the two analogues perturbed drastically the DMPC bilayers with AK13 to be more effective at high concentrations. AK13 was tolerated in lipid bilayers at very high concentrations, while Amt was crystallized. This is an important consideration in the formulations of drugs as it designates a limitation of Amt incorporation. MD simulations verify provided details about the strong interactions of the drugs in the interface region between phosphoglycerol backbone and lipophilic segments. The two drugs form hydrogen bonding with both water and sn-2 carbonyls in their amine form or water and phosphate oxygens in their ammonium form. Such localization of the drugs explains the DMPC bilayers reorientation and their strong perturbing effect evidenced by all biophysical methodologies applied.
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Affiliation(s)
| | | | | | | | - Barbara Sartori
- Institute of Inorganic Chemistry , Graz University of Technology , Stremayrgasse 9/5 , A-8010 Graz , Austria
| | | | - Heinz Amentisch
- Institute of Inorganic Chemistry , Graz University of Technology , Stremayrgasse 9/5 , A-8010 Graz , Austria
| | - Gregor Mali
- Department of Inorganic Chemistry and Technology , National Institute of Chemistry , Ljubljana SI-1001 , Slovenia
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Santner P, Martins JMDS, Kampmeyer C, Hartmann-Petersen R, Laursen JS, Stein A, Olsen CA, Arkin IT, Winther JR, Willemoës M, Lindorff-Larsen K. Random Mutagenesis Analysis of the Influenza A M2 Proton Channel Reveals Novel Resistance Mutants. Biochemistry 2018; 57:5957-5968. [PMID: 30230310 DOI: 10.1021/acs.biochem.8b00722] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The influenza M2 proton channel is a major drug target, but unfortunately, the acquisition of resistance mutations greatly reduces the functional life span of a drug in influenza treatment. New M2 inhibitors that inhibit mutant M2 channels otherwise resistant to the early adamantine-based drugs have been reported, but it remains unclear whether and how easy resistance could arise to such inhibitors. We have combined a newly developed proton conduction assay with an established method for selection and screening, both Escherichia coli-based, to enable the study of M2 function and inhibition. Combining this platform with two groups of structurally different M2 inhibitors allowed us to isolate drug resistant M2 channels from a mutant library. Two groups of M2 variants emerged from this analysis. A first group appeared almost unaffected by the inhibitor, M_089 (N13I, I35L, and F47L) and M_272 (G16C and D44H), and the single-substitution variants derived from these (I35L, L43P, D44H, and L46P). Functionally, these resemble the known drug resistant M2 channels V27A, S31N, and swine flu. In addition, a second group of tested M2 variants were all still inhibited by drugs but to a lesser extent than wild type M2. Molecular dynamics simulations aided in distinguishing the two groups where drug binding to the wild type and the less resistant M2 group showed a stable positioning of the ligand in the canonical binding pose, as opposed to the drug resistant group in which the ligand rapidly dissociated from the complex during the simulations.
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Affiliation(s)
- Paul Santner
- Department of Biology, Section for Biomolecular Sciences, Linderstrøm-Lang Centre for Protein Science , University of Copenhagen , Ole Maaloes Vej 5 , 2200 Copenhagen N, Denmark
| | - João Miguel da Silva Martins
- Department of Biology, Section for Biomolecular Sciences, Linderstrøm-Lang Centre for Protein Science , University of Copenhagen , Ole Maaloes Vej 5 , 2200 Copenhagen N, Denmark
| | - Caroline Kampmeyer
- Department of Biology, Section for Biomolecular Sciences, Linderstrøm-Lang Centre for Protein Science , University of Copenhagen , Ole Maaloes Vej 5 , 2200 Copenhagen N, Denmark
| | - Rasmus Hartmann-Petersen
- Department of Biology, Section for Biomolecular Sciences, Linderstrøm-Lang Centre for Protein Science , University of Copenhagen , Ole Maaloes Vej 5 , 2200 Copenhagen N, Denmark
| | - Jonas S Laursen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , 2100 Copenhagen , Denmark
| | - Amelie Stein
- Department of Biology, Section for Biomolecular Sciences, Linderstrøm-Lang Centre for Protein Science , University of Copenhagen , Ole Maaloes Vej 5 , 2200 Copenhagen N, Denmark
| | - Christian A Olsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , 2100 Copenhagen , Denmark.,Center for Biopharmaceuticals, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , 2100 Copenhagen , Denmark
| | - Isaiah T Arkin
- Department of Biological Chemistry , The Hebrew University of Jerusalem , Edmond J. Safra Campus , Givat-Ram, Jerusalem 91904 , Israel
| | - Jakob R Winther
- Department of Biology, Section for Biomolecular Sciences, Linderstrøm-Lang Centre for Protein Science , University of Copenhagen , Ole Maaloes Vej 5 , 2200 Copenhagen N, Denmark
| | - Martin Willemoës
- Department of Biology, Section for Biomolecular Sciences, Linderstrøm-Lang Centre for Protein Science , University of Copenhagen , Ole Maaloes Vej 5 , 2200 Copenhagen N, Denmark
| | - Kresten Lindorff-Larsen
- Department of Biology, Section for Biomolecular Sciences, Linderstrøm-Lang Centre for Protein Science , University of Copenhagen , Ole Maaloes Vej 5 , 2200 Copenhagen N, Denmark
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45
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Complement C3 Plays a Key Role in Inducing Humoral and Cellular Immune Responses to Influenza Virus Strain-Specific Hemagglutinin-Based or Cross-Protective M2 Extracellular Domain-Based Vaccination. J Virol 2018; 92:JVI.00969-18. [PMID: 30068650 DOI: 10.1128/jvi.00969-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/20/2018] [Indexed: 12/12/2022] Open
Abstract
The complement pathway is involved in eliminating antigen immune complexes. However, the role of the C3 complement system remains largely unknown in influenza virus M2 extracellular (M2e) domain or hemagglutinin (HA) vaccine-mediated protection after vaccination. Using a C3 knockout (C3 KO) mouse model, we found that complement protein C3 was required for effective induction of immune responses to vaccination with M2e-based or HA-based vaccines, which include isotype class-switched antibodies and effector CD4 and CD8 T cell responses. C3 KO mice after active immunization with cross-protective nonneutralizing M2e-based vaccine were not protected against influenza virus, although low levels of M2e-specific antibodies were protective after passive coadministration with virus in wild-type mice. In contrast, C3 KO mice that were immunized with strain-specific neutralizing HA-based vaccine were protected against homologous virus challenge despite lower levels of HA antibody responses. C3 KO mice showed impaired maintenance of innate immune cells and a defect in innate immune responses upon exposure to antigens. The findings in this study suggest that C3 is required for effective induction of humoral and cellular adaptive immune responses as well as protective immunity after nonneutralizing influenza M2e vaccination.IMPORTANCE Complement is the well-known innate immune defense system involved in the opsonization and lysis of pathogens but is less studied in establishing adaptive immunity after vaccination. Influenza virus HA-based vaccination confers protection via strain-specific neutralizing antibodies, whereas M2e-based vaccination induces a broad spectrum of protection by immunity against the conserved M2e epitopes. This study revealed the critical roles of C3 complement in inducing humoral and cellular immune responses after immunization with M2e or HA vaccines. C3 was found to be required for protection by M2e-based but not by HA-based active vaccination as well as for maintaining innate antigen-presenting cells. Findings in this study have insight into better understanding the roles of C3 complement in inducing effective innate and adaptive immunity as well as in conferring protection by cross-protective conserved M2e vaccination.
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Thomaston JL, Polizzi NF, Konstantinidi A, Wang J, Kolocouris A, DeGrado WF. Inhibitors of the M2 Proton Channel Engage and Disrupt Transmembrane Networks of Hydrogen-Bonded Waters. J Am Chem Soc 2018; 140:15219-15226. [PMID: 30165017 DOI: 10.1021/jacs.8b06741] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Water-mediated interactions play key roles in drug binding. In protein sites with sparse polar functionality, a small-molecule approach is often viewed as insufficient to achieve high affinity and specificity. Here we show that small molecules can enable potent inhibition by targeting key waters. The M2 proton channel of influenza A is the target of the antiviral drugs amantadine and rimantadine. Structural studies of drug binding to the channel using X-ray crystallography have been limited because of the challenging nature of the target, with the one previously solved crystal structure limited to 3.5 Å resolution. Here we describe crystal structures of amantadine bound to M2 in the Inwardclosed conformation (2.00 Å), rimantadine bound to M2 in both the Inwardclosed (2.00 Å) and Inwardopen (2.25 Å) conformations, and a spiro-adamantyl amine inhibitor bound to M2 in the Inwardclosed conformation (2.63 Å). These X-ray crystal structures of the M2 proton channel with bound inhibitors reveal that ammonium groups bind to water-lined sites that are hypothesized to stabilize transient hydronium ions formed in the proton-conduction mechanism. Furthermore, the ammonium and adamantyl groups of the adamantyl-amine class of drugs are free to rotate in the channel, minimizing the entropic cost of binding. These drug-bound complexes provide the first high-resolution structures of drugs that interact with and disrupt networks of hydrogen-bonded waters that are widely utilized throughout nature to facilitate proton diffusion within proteins.
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Affiliation(s)
- Jessica L Thomaston
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Nicholas F Polizzi
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
| | - Athina Konstantinidi
- Department of Pharmaceutical Chemistry , National and Kapodistrian University of Athens , 15771 Athens , Greece
| | - Jun Wang
- Department of Pharmacology and Toxicology, College of Pharmacy , University of Arizona , Tucson , Arizona 85721 , United States
| | - Antonios Kolocouris
- Department of Pharmaceutical Chemistry , National and Kapodistrian University of Athens , 15771 Athens , Greece
| | - William F DeGrado
- Department of Pharmaceutical Chemistry , University of California , San Francisco , California 94158 , United States
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47
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Hay AJ, McCauley JW. The WHO global influenza surveillance and response system (GISRS)-A future perspective. Influenza Other Respir Viruses 2018; 12:551-557. [PMID: 29722140 PMCID: PMC6086842 DOI: 10.1111/irv.12565] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2018] [Indexed: 12/26/2022] Open
Abstract
In the centenary year of the devastating 1918-19 pandemic, it seems opportune to reflect on the success of the WHO Global Influenza Surveillance and Response System (GISRS) initiated 70 years ago to provide early warning of changes in influenza viruses circulating in the global population to help mitigate the consequences of such a pandemic and maintain the efficacy of seasonal influenza vaccines. Three pandemics later and in the face of pandemic threats from highly pathogenic zoonotic infections by different influenza A subtypes, it continues to represent a model platform for global collaboration and timely sharing of viruses, reagents and information to forestall and respond to public health emergencies.
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48
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DeCoursey TE. Voltage and pH sensing by the voltage-gated proton channel, H V1. J R Soc Interface 2018; 15:20180108. [PMID: 29643227 PMCID: PMC5938591 DOI: 10.1098/rsif.2018.0108] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 03/19/2018] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated proton channels are unique ion channels, membrane proteins that allow protons but no other ions to cross cell membranes. They are found in diverse species, from unicellular marine life to humans. In all cells, their function requires that they open and conduct current only under certain conditions, typically when the electrochemical gradient for protons is outwards. Consequently, these proteins behave like rectifiers, conducting protons out of cells. Their activity has electrical consequences and also changes the pH on both sides of the membrane. Here we summarize what is known about the way these proteins sense the membrane potential and the pH inside and outside the cell. Currently, it is hypothesized that membrane potential is sensed by permanently charged arginines (with very high pKa) within the protein, which results in parts of the protein moving to produce a conduction pathway. The mechanism of pH sensing appears to involve titratable side chains of particular amino acids. For this purpose their pKa needs to be within the operational pH range. We propose a 'counter-charge' model for pH sensing in which electrostatic interactions within the protein are selectively disrupted by protonation of internally or externally accessible groups.
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Affiliation(s)
- Thomas E DeCoursey
- Department of Physiology & Biophysics, Rush University, 1750 West Harrison, Chicago, IL 60612, USA
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49
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Tu YH, Cooper AJ, Teng B, Chang RB, Artiga DJ, Turner HN, Mulhall EM, Ye W, Smith AD, Liman ER. An evolutionarily conserved gene family encodes proton-selective ion channels. Science 2018; 359:1047-1050. [PMID: 29371428 DOI: 10.1126/science.aao3264] [Citation(s) in RCA: 155] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/08/2018] [Indexed: 12/20/2022]
Abstract
Ion channels form the basis for cellular electrical signaling. Despite the scores of genetically identified ion channels selective for other monatomic ions, only one type of proton-selective ion channel has been found in eukaryotic cells. By comparative transcriptome analysis of mouse taste receptor cells, we identified Otopetrin1 (OTOP1), a protein required for development of gravity-sensing otoconia in the vestibular system, as forming a proton-selective ion channel. We found that murine OTOP1 is enriched in acid-detecting taste receptor cells and is required for their zinc-sensitive proton conductance. Two related murine genes, Otop2 and Otop3, and a Drosophila ortholog also encode proton channels. Evolutionary conservation of the gene family and its widespread tissue distribution suggest a broad role for proton channels in physiology and pathophysiology.
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Affiliation(s)
- Yu-Hsiang Tu
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Alexander J Cooper
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Bochuan Teng
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Rui B Chang
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Daniel J Artiga
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Heather N Turner
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Eric M Mulhall
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Wenlei Ye
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA.
| | - Andrew D Smith
- Department of Biological Sciences, Section of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Emily R Liman
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA. .,Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
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50
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Abstract
An implicit aim in cellular infection biology is to understand the mechanisms how viruses, microbes, eukaryotic parasites, and fungi usurp the functions of host cells and cause disease. Mechanistic insight is a deep understanding of the biophysical and biochemical processes that give rise to an observable phenomenon. It is typically subject to falsification, that is, it is accessible to experimentation and empirical data acquisition. This is different from logic and mathematics, which are not empirical, but built on systems of inherently consistent axioms. Here, we argue that modeling and computer simulation, combined with mechanistic insights, yields unprecedented deep understanding of phenomena in biology and especially in virus infections by providing a way of showing sufficiency of a hypothetical mechanism. This ideally complements the necessity statements accessible to empirical falsification by additional positive evidence. We discuss how computational implementations of mathematical models can assist and enhance the quantitative measurements of infection dynamics of enveloped and non-enveloped viruses and thereby help generating causal insights into virus infection biology.
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