1
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Trofimov YA, Krylov NA, Minakov AS, Nadezhdin KD, Neuberger A, Sobolevsky AI, Efremov RG. Dynamic molecular portraits of ion-conducting pores characterize functional states of TRPV channels. Commun Chem 2024; 7:119. [PMID: 38824263 PMCID: PMC11144267 DOI: 10.1038/s42004-024-01198-z] [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: 04/16/2024] [Accepted: 05/06/2024] [Indexed: 06/03/2024] Open
Abstract
Structural biology is solving an ever-increasing number of snapshots of ion channel conformational ensembles. Deciphering ion channel mechanisms, however, requires understanding the ensemble dynamics beyond the static structures. Here, we present a molecular modeling-based approach characterizing the ion channel structural intermediates, or their "dynamic molecular portraits", by assessing water and ion conductivity along with the detailed evaluation of pore hydrophobicity and residue packing. We illustrate the power of this approach by analyzing structures of few vanilloid-subfamily transient receptor potential (TRPV) channels. Based on the pore architecture, there are three major states that are common for TRPVs, which we call α-closed, π-closed, and π-open. We show that the pore hydrophobicity and residue packing for the open state is most favorable for the pore conductance. On the contrary, the α-closed state is the most hydrophobic and always non-conducting. Our approach can also be used for structural and functional classification of ion channels.
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Affiliation(s)
- Yury A Trofimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Nikolay A Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | | | - Kirill D Nadezhdin
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Arthur Neuberger
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Alexander I Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Roman G Efremov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
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2
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Mondal R, Vaissier Welborn V. Dynamics accelerate the kinetics of ion diffusion through channels: Continuous-time random walk models beyond the mean field approximation. J Chem Phys 2024; 160:144109. [PMID: 38597306 DOI: 10.1063/5.0188469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/14/2024] [Indexed: 04/11/2024] Open
Abstract
Ion channels are proteins that play a significant role in physiological processes, including neuronal excitability and signal transduction. However, the precise mechanisms by which these proteins facilitate ion diffusion through cell membranes are not well understood. This is because experimental techniques to characterize ion channel activity operate on a time scale too large to understand the role of the various protein conformations on diffusion. Meanwhile, computational approaches operate on a time scale too short to rationalize the observed behavior at the microscopic scale. In this paper, we present a continuous-time random walk model that aims to bridge the scales between the atomistic models of ion channels and the experimental measurement of their conductance. We show how diffusion slows down in complex systems by using 3D lattices that map out the pore geometry of two channels: Nav1.7 and gramicidin. We also introduce spatial and dynamic site disorder to account for system heterogeneity beyond the mean field approximation. Computed diffusion coefficients show that an increase in spatial disorder slows down diffusion kinetics, while dynamic disorder has the opposite effect. Our results imply that microscopic or phenomenological models based on the potential of mean force data overlook the functional importance of protein dynamics on ion diffusion through channels.
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Affiliation(s)
- Ronnie Mondal
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, USA
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Valerie Vaissier Welborn
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, USA
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, USA
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3
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Melancon K, Pliushcheuskaya P, Meiler J, Künze G. Targeting ion channels with ultra-large library screening for hit discovery. Front Mol Neurosci 2024; 16:1336004. [PMID: 38249296 PMCID: PMC10796734 DOI: 10.3389/fnmol.2023.1336004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/05/2023] [Indexed: 01/23/2024] Open
Abstract
Ion channels play a crucial role in a variety of physiological and pathological processes, making them attractive targets for drug development in diseases such as diabetes, epilepsy, hypertension, cancer, and chronic pain. Despite the importance of ion channels in drug discovery, the vastness of chemical space and the complexity of ion channels pose significant challenges for identifying drug candidates. The use of in silico methods in drug discovery has dramatically reduced the time and cost of drug development and has the potential to revolutionize the field of medicine. Recent advances in computer hardware and software have enabled the screening of ultra-large compound libraries. Integration of different methods at various scales and dimensions is becoming an inevitable trend in drug development. In this review, we provide an overview of current state-of-the-art computational chemistry methodologies for ultra-large compound library screening and their application to ion channel drug discovery research. We discuss the advantages and limitations of various in silico techniques, including virtual screening, molecular mechanics/dynamics simulations, and machine learning-based approaches. We also highlight several successful applications of computational chemistry methodologies in ion channel drug discovery and provide insights into future directions and challenges in this field.
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Affiliation(s)
- Kortney Melancon
- Department of Chemistry, Vanderbilt University, Nashville, TN, United States
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | | | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, TN, United States
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
- Medical Faculty, Institute for Drug Discovery, Leipzig University, Leipzig, Germany
- Center for Scalable Data Analytics and Artificial Intelligence, Leipzig University, Leipzig, Germany
| | - Georg Künze
- Medical Faculty, Institute for Drug Discovery, Leipzig University, Leipzig, Germany
- Center for Scalable Data Analytics and Artificial Intelligence, Leipzig University, Leipzig, Germany
- Interdisciplinary Center for Bioinformatics, Leipzig University, Leipzig, Germany
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4
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Yue Y, Liu L, Wu LJ, Wu Y, Wang L, Li F, Liu J, Han GW, Chen B, Lin X, Brouillette RL, Breault É, Longpré JM, Shi S, Lei H, Sarret P, Stevens RC, Hanson MA, Xu F. Structural insight into apelin receptor-G protein stoichiometry. Nat Struct Mol Biol 2022; 29:688-697. [PMID: 35817871 DOI: 10.1038/s41594-022-00797-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/26/2022] [Indexed: 11/09/2022]
Abstract
The technique of cryogenic-electron microscopy (cryo-EM) has revolutionized the field of membrane protein structure and function with a focus on the dominantly observed molecular species. This report describes the structural characterization of a fully active human apelin receptor (APJR) complexed with heterotrimeric G protein observed in both 2:1 and 1:1 stoichiometric ratios. We use cryo-EM single-particle analysis to determine the structural details of both species from the same sample preparation. Protein preparations, in the presence of the endogenous peptide ligand ELA or a synthetic small molecule, both demonstrate these mixed stoichiometric states. Structural differences in G protein engagement between dimeric and monomeric APJR suggest a role for the stoichiometry of G protein-coupled receptor- (GPCR-)G protein coupling on downstream signaling and receptor pharmacology. Furthermore, a small, hydrophobic dimer interface provides a starting framework for additional class A GPCR dimerization studies. Together, these findings uncover a mechanism of versatile regulation through oligomerization by which GPCRs can modulate their signaling.
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Affiliation(s)
- Yang Yue
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Lier Liu
- iHuman Institute, ShanghaiTech University, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Li-Jie Wu
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Yiran Wu
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Ling Wang
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Fei Li
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Junlin Liu
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Gye-Won Han
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA, USA
| | - Bo Chen
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Xi Lin
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Rebecca L Brouillette
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Institute of Pharmacology at Sherbrooke, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Émile Breault
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Institute of Pharmacology at Sherbrooke, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Jean-Michel Longpré
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Institute of Pharmacology at Sherbrooke, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Songting Shi
- Structure Therapeutics, South San Francisco, CA, USA
| | - Hui Lei
- Structure Therapeutics, South San Francisco, CA, USA
| | - Philippe Sarret
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Institute of Pharmacology at Sherbrooke, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Raymond C Stevens
- iHuman Institute, ShanghaiTech University, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,Structure Therapeutics, South San Francisco, CA, USA
| | | | - Fei Xu
- iHuman Institute, ShanghaiTech University, Shanghai, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, China. .,University of Chinese Academy of Sciences, Beijing, China.
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5
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Mernea M, Ulăreanu RȘ, Cucu D, Al-Saedi JH, Pop CE, Fendrihan S, Anghelescu GDC, Mihăilescu DF. Epithelial Sodium Channel Inhibition by Amiloride Addressed with THz Spectroscopy and Molecular Modeling. Molecules 2022; 27:3271. [PMID: 35630748 PMCID: PMC9144217 DOI: 10.3390/molecules27103271] [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: 04/01/2022] [Revised: 05/08/2022] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
THz spectroscopy is important for the study of ion channels because it directly addresses the low frequency collective motions relevant for their function. Here we used THz spectroscopy to investigate the inhibition of the epithelial sodium channel (ENaC) by its specific blocker, amiloride. Experiments were performed on A6 cells' suspensions, which are cells overexpressing ENaC derived from Xenopus laevis kidney. THz spectra were investigated with or without amiloride. When ENaC was inhibited by amiloride, a substantial increase in THz absorption was noticed. Molecular modeling methods were used to explain the observed spectroscopic differences. THz spectra were simulated using the structural models of ENaC and ENaC-amiloride complexes built here. The agreement between the experiment and the simulations allowed us to validate the structural models and to describe the amiloride dynamics inside the channel pore. The amiloride binding site validated using THz spectroscopy agrees with previous mutagenesis studies. Altogether, our results show that THz spectroscopy can be successfully used to discriminate between native and inhibited ENaC channels and to characterize the dynamics of channels in the presence of their specific antagonist.
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Affiliation(s)
- Maria Mernea
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Roxana Ștefania Ulăreanu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Dana Cucu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Jasim Hafedh Al-Saedi
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Cristian-Emilian Pop
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania;
- Non-Governmental Research Organization Biologic, 14 Schitului Str., 032044 Bucharest, Romania;
| | - Sergiu Fendrihan
- Non-Governmental Research Organization Biologic, 14 Schitului Str., 032044 Bucharest, Romania;
- Faculty of Medicine, University “Vasile Goldis”, Bulevardul Revoluției 94, 310025 Arad, Romania
| | - Giorgiana Diana Carmen Anghelescu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
| | - Dan Florin Mihăilescu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95 Splaiul Independenței Str., 050095 Bucharest, Romania; (M.M.); (R.Ș.U.); (J.H.A.-S.); (G.D.C.A.); (D.F.M.)
- Biometric Psychiatric Genetics Research Unit, Alexandru Obregia Psychiatric Hospital, 10 Șoseaua Berceni Str., 041914 Bucharest, Romania
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6
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Puthenveetil R, Christenson ET, Vinogradova O. New Horizons in Structural Biology of Membrane Proteins: Experimental Evaluation of the Role of Conformational Dynamics and Intrinsic Flexibility. MEMBRANES 2022; 12:227. [PMID: 35207148 PMCID: PMC8877495 DOI: 10.3390/membranes12020227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 02/08/2023]
Abstract
A plethora of membrane proteins are found along the cell surface and on the convoluted labyrinth of membranes surrounding organelles. Since the advent of various structural biology techniques, a sub-population of these proteins has become accessible to investigation at near-atomic resolutions. The predominant bona fide methods for structure solution, X-ray crystallography and cryo-EM, provide high resolution in three-dimensional space at the cost of neglecting protein motions through time. Though structures provide various rigid snapshots, only an amorphous mechanistic understanding can be inferred from interpolations between these different static states. In this review, we discuss various techniques that have been utilized in observing dynamic conformational intermediaries that remain elusive from rigid structures. More specifically we discuss the application of structural techniques such as NMR, cryo-EM and X-ray crystallography in studying protein dynamics along with complementation by conformational trapping by specific binders such as antibodies. We finally showcase the strength of various biophysical techniques including FRET, EPR and computational approaches using a multitude of succinct examples from GPCRs, transporters and ion channels.
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Affiliation(s)
- Robbins Puthenveetil
- Section on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 35A Convent Dr., Bethesda, MD 20892, USA
| | | | - Olga Vinogradova
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA
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7
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The Kv1.3 K + channel in the immune system and its "precision pharmacology" using peptide toxins. Biol Futur 2021; 72:75-83. [PMID: 34554500 DOI: 10.1007/s42977-021-00071-7] [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] [Received: 11/20/2020] [Accepted: 01/12/2021] [Indexed: 01/28/2023]
Abstract
Since the discovery of the Kv1.3 voltage-gated K+ channel in human T cells in 1984, ion channels are considered crucial elements of the signal transduction machinery in the immune system. Our knowledge about Kv1.3 and its inhibitors is outstanding, motivated by their potential application in autoimmune diseases mediated by Kv1.3 overexpressing effector memory T cells (e.g., Multiple Sclerosis). High affinity Kv1.3 inhibitors are either small organic molecules (e.g., Pap-1) or peptides isolated from venomous animals. To date, the highest affinity Kv1.3 inhibitors with the best Kv1.3 selectivity are the engineered analogues of the sea anemone peptide ShK (e.g., ShK-186), the engineered scorpion toxin HsTx1[R14A] and the natural scorpion toxin Vm24. These peptides inhibit Kv1.3 in picomolar concentrations and are several thousand-fold selective for Kv1.3 over other biologically critical ion channels. Despite the significant progress in the field of Kv1.3 molecular pharmacology several progressive questions remain to be elucidated and discussed here. These include the conjugation of the peptides to carriers to increase the residency time of the peptides in the circulation (e.g., PEGylation and engineering the peptides into antibodies), use of rational drug design to create novel peptide inhibitors and understanding the potential off-target effects of Kv1.3 inhibition.
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8
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Şterbuleac D. Molecular dynamics: a powerful tool for studying the medicinal chemistry of ion channel modulators. RSC Med Chem 2021; 12:1503-1518. [PMID: 34671734 PMCID: PMC8459385 DOI: 10.1039/d1md00140j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 07/21/2021] [Indexed: 01/10/2023] Open
Abstract
Molecular dynamics (MD) simulations allow researchers to investigate the behavior of desired biological targets at ever-decreasing costs with ever-increasing precision. Among the biological macromolecules, ion channels are remarkable transmembrane proteins, capable of performing special biological processes and revealing a complex regulatory matrix, including modulation by small molecules, either endogenous or exogenous. Recently, given the developments in ion channel structure determination and accessibility of bio-computational techniques, MD and related tools are becoming increasingly popular in the intense research area regarding ligand-channel interactions. This review synthesizes and presents the most important fields of MD involvement in investigating channel-molecule interactions, including, but not limited to, deciphering the binding modes of ligands to their ion channel targets and the mechanisms through which chemical compounds exert their effect on channel function. Special attention is devoted to the importance of more elaborate methods, such as free energy calculations, while principles regarding drug design and discovery are highlighted. Several technical aspects involving the creation and simulation of channel-molecule MD systems (ligand parameterization, proper membrane setup, system building, etc.) are also presented.
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Affiliation(s)
- Daniel Şterbuleac
- Department of Health and Human Development, "Ştefan cel Mare" University of Suceava Str. Universităţii 13, 720229, E Building Suceava Romania
- Department of Forestry and Environmental Protection, "Ştefan cel Mare" University of Suceava Str. Universităţii 13, 720229, E Building Suceava Romania
- Integrated Center for Research, Development and Innovation in Advanced Materials, Nanotechnologies and Distributed Systems for Fabrication and Control (MANSiD), "Ştefan cel Mare" University of Suceava Str. Universităţii 13 720229 Suceava Romania
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9
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Pohorille A, Wilson MA. Computational Electrophysiology from a Single Molecular Dynamics Simulation and the Electrodiffusion Model. J Phys Chem B 2021; 125:3132-3144. [DOI: 10.1021/acs.jpcb.0c10737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrew Pohorille
- Exobiology Branch, MS239-4, NASA Ames Research Center, Moffett Field, California 94035, United States
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94132, United States
| | - Michael A. Wilson
- Exobiology Branch, MS239-4, NASA Ames Research Center, Moffett Field, California 94035, United States
- SETI Institute, 189 Bernardo Avenue, Suite 200, Mountain View, California 94043, United States
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10
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Shah B, Sindhikara D, Borrelli K, Leffler AE. Water Thermodynamics of Peptide Toxin Binding Sites on Ion Channels. Toxins (Basel) 2020; 12:toxins12100652. [PMID: 33053750 PMCID: PMC7599640 DOI: 10.3390/toxins12100652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/21/2020] [Accepted: 10/09/2020] [Indexed: 12/20/2022] Open
Abstract
Peptide toxins isolated from venomous creatures, long prized as research tools due to their innate potency for ion channels, are emerging as drugs as well. However, it remains challenging to understand why peptide toxins bind with high potency to ion channels, to identify residues that are key for activity, and to improve their affinities via mutagenesis. We use WaterMap, a molecular dynamics simulation-based method, to gain computational insight into these three questions by calculating the locations and thermodynamic properties of water molecules in the peptide toxin binding sites of five ion channels. These include an acid-sensing ion channel, voltage-gated potassium channel, sodium channel in activated and deactivated states, transient-receptor potential channel, and a nicotinic receptor whose structures were recently determined by crystallography and cryo-electron microscopy (cryo-EM). All channels had water sites in the peptide toxin binding site, and an average of 75% of these sites were stable (low-energy), and 25% were unstable (medium or high energy). For the sodium channel, more unstable water sites were present in the deactivated state structure than the activated. Additionally, for each channel, unstable water sites coincided with the positions of peptide toxin residues that previous mutagenesis experiments had shown were important for activity. Finally, for the sodium channel in the deactivated state, unstable water sites were present in the peptide toxin binding pocket but did not overlap with the peptide toxin, suggesting that future experimental efforts could focus on targeting these sites to optimize potency.
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Affiliation(s)
- Binita Shah
- Schrödinger, Inc. 120 W. 45th St, New York, NY 10036, USA; (B.S.); (D.S.); (K.B.)
- PhD Program in Biological and Biomedical Sciences, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA
| | - Dan Sindhikara
- Schrödinger, Inc. 120 W. 45th St, New York, NY 10036, USA; (B.S.); (D.S.); (K.B.)
| | - Ken Borrelli
- Schrödinger, Inc. 120 W. 45th St, New York, NY 10036, USA; (B.S.); (D.S.); (K.B.)
| | - Abba E. Leffler
- Schrödinger, Inc. 120 W. 45th St, New York, NY 10036, USA; (B.S.); (D.S.); (K.B.)
- Correspondence:
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11
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Barros F, de la Peña P, Domínguez P, Sierra LM, Pardo LA. The EAG Voltage-Dependent K + Channel Subfamily: Similarities and Differences in Structural Organization and Gating. Front Pharmacol 2020; 11:411. [PMID: 32351384 PMCID: PMC7174612 DOI: 10.3389/fphar.2020.00411] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/18/2020] [Indexed: 12/17/2022] Open
Abstract
EAG (ether-à-go-go or KCNH) are a subfamily of the voltage-gated potassium (Kv) channels. Like for all potassium channels, opening of EAG channels drives the membrane potential toward its equilibrium value for potassium, thus setting the resting potential and repolarizing action potentials. As voltage-dependent channels, they switch between open and closed conformations (gating) when changes in membrane potential are sensed by a voltage sensing domain (VSD) which is functionally coupled to a pore domain (PD) containing the permeation pathway, the potassium selectivity filter, and the channel gate. All Kv channels are tetrameric, with four VSDs formed by the S1-S4 transmembrane segments of each subunit, surrounding a central PD with the four S5-S6 sections arranged in a square-shaped structure. Structural information, mutagenesis, and functional experiments, indicated that in "classical/Shaker-type" Kv channels voltage-triggered VSD reorganizations are transmitted to PD gating via the α-helical S4-S5 sequence that links both modules. Importantly, these Shaker-type channels share a domain-swapped VSD/PD organization, with each VSD contacting the PD of the adjacent subunit. In this case, the S4-S5 linker, acting as a rigid mechanical lever (electromechanical lever coupling), would lead to channel gate opening at the cytoplasmic S6 helices bundle. However, new functional data with EAG channels split between the VSD and PD modules indicate that, in some Kv channels, alternative VSD/PD coupling mechanisms do exist. Noticeably, recent elucidation of the architecture of some EAG channels, and other relatives, showed that their VSDs are non-domain swapped. Despite similarities in primary sequence and predicted structural organization for all EAG channels, they show marked kinetic differences whose molecular basis is not completely understood. Thus, while a common general architecture may establish the gating system used by the EAG channels and the physicochemical coupling of voltage sensing to gating, subtle changes in that common structure, and/or allosteric influences of protein domains relatively distant from the central gating machinery, can crucially influence the gating process. We consider here the latest advances on these issues provided by the elucidation of eag1 and erg1 three-dimensional structures, and by both classical and more recent functional studies with different members of the EAG subfamily.
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Affiliation(s)
- Francisco Barros
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Oviedo, Spain
| | - Pilar de la Peña
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Oviedo, Spain
| | - Pedro Domínguez
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Oviedo, Spain
| | - Luisa Maria Sierra
- Departamento de Biología Funcional (Area de Genética), Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Universidad de Oviedo, Oviedo, Spain
| | - Luis A. Pardo
- Oncophysiology Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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12
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Liang YL, Belousoff MJ, Fletcher MM, Zhang X, Khoshouei M, Deganutti G, Koole C, Furness SGB, Miller LJ, Hay DL, Christopoulos A, Reynolds CA, Danev R, Wootten D, Sexton PM. Structure and Dynamics of Adrenomedullin Receptors AM 1 and AM 2 Reveal Key Mechanisms in the Control of Receptor Phenotype by Receptor Activity-Modifying Proteins. ACS Pharmacol Transl Sci 2020; 3:263-284. [PMID: 32296767 PMCID: PMC7155201 DOI: 10.1021/acsptsci.9b00080] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Indexed: 12/14/2022]
Abstract
Adrenomedullin (AM) and calcitonin gene-related peptide (CGRP) receptors are critically important for metabolism, vascular tone, and inflammatory response. AM receptors are also required for normal lymphatic and blood vascular development and angiogenesis. They play a pivotal role in embryo implantation and fertility and can provide protection against hypoxic and oxidative stress. CGRP and AM receptors are heterodimers of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1) (CGRPR), as well as RAMP2 or RAMP3 (AM1R and AM2R, respectively). However, the mechanistic basis for RAMP modulation of CLR phenotype is unclear. In this study, we report the cryo-EM structure of the AM1R in complex with AM and Gs at a global resolution of 3.0 Å, and structures of the AM2R in complex with either AM or intermedin/adrenomedullin 2 (AM2) and Gs at 2.4 and 2.3 Å, respectively. The structures reveal distinctions in the primary orientation of the extracellular domains (ECDs) relative to the receptor core and distinct positioning of extracellular loop 3 (ECL3) that are receptor-dependent. Analysis of dynamic data present in the cryo-EM micrographs revealed additional distinctions in the extent of mobility of the ECDs. Chimeric exchange of the linker region of the RAMPs connecting the TM helix and the ECD supports a role for this segment in controlling receptor phenotype. Moreover, a subset of the motions of the ECD appeared coordinated with motions of the G protein relative to the receptor core, suggesting that receptor ECD dynamics could influence G protein interactions. This work provides fundamental advances in our understanding of GPCR function and how this can be allosterically modulated by accessory proteins.
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Affiliation(s)
- Yi-Lynn Liang
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Matthew J. Belousoff
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Madeleine M. Fletcher
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Xin Zhang
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Maryam Khoshouei
- Department
of Molecular Structural Biology, Max Planck
Institute of Biochemistry, 82152 Martinsried, Germany
| | - Giuseppe Deganutti
- School
of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Cassandra Koole
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Sebastian G. B. Furness
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Laurence J. Miller
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- Department
of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259, United States
| | - Debbie L. Hay
- School
of Biological Sciences, and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland 1142, New Zealand
| | - Arthur Christopoulos
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | | | - Radostin Danev
- Graduate
School of Medicine, University of Tokyo, S402, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Tokyo, Japan
| | - Denise Wootten
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- School
of Pharmacy, Fudan University, Shanghai 201203, China
| | - Patrick M. Sexton
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
- School
of Pharmacy, Fudan University, Shanghai 201203, China
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13
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Souza Bomfim GH, Costiniti V, Li Y, Idaghdour Y, Lacruz RS. TRPM7 activation potentiates SOCE in enamel cells but requires ORAI. Cell Calcium 2020; 87:102187. [PMID: 32146159 DOI: 10.1016/j.ceca.2020.102187] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/26/2020] [Accepted: 02/26/2020] [Indexed: 12/21/2022]
Abstract
Calcium (Ca2+) release-activated Ca2+ (CRAC) channels mediated by STIM1/2 and ORAI (ORAI1-3) proteins form the dominant store-operated Ca2+ entry (SOCE) pathway in a wide variety of cells. Among these, the enamel-forming cells known as ameloblasts rely on CRAC channel function to enable Ca2+ influx, which is important for enamel mineralization. This key role of the CRAC channel is supported by human mutations and animal models lacking STIM1 and ORAI1, which results in enamel defects and hypomineralization. A number of recent reports have highlighted the role of the chanzyme TRPM7 (transient receptor potential melastanin 7), a transmembrane protein containing an ion channel permeable to divalent cations (Mg2+, Ca2+), as a modulator of SOCE. This raises the question as to whether TRPM7 should be considered an alternative route for Ca2+ influx, or if TRPM7 modifies CRAC channel activity in enamel cells. To address these questions, we monitored Ca2+ influx mediated by SOCE using the pharmacological TRPM7 activator naltriben and the inhibitor NS8593 in rat primary enamel cells and in the murine ameloblast cell line LS8 cells stimulated with thapsigargin. We also measured Ca2+ dynamics in ORAI1/2-deficient (shOrai1/2) LS8 cells and in cells with siRNA knock-down of Trpm7. We found that primary enamel cells stimulated with the TRPM7 activator potentiated Ca2+ influx via SOCE compared to control cells. However, blockade of TRPM7 with NS8593 did not decrease the SOCE peak. Furthermore, activation of TRPM7 in shOrai1/2 LS8 cells lacking SOCE failed to elicit Ca2+ influx, and Trpm7 knock-down had no effect on SOCE. Taken together, our data suggest that TRPM7 is a positive modulator of SOCE potentiating Ca2+ influx in enamel cells, but its function is fully dependent on the prior activation of the ORAI channels.
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Affiliation(s)
- Guilherme H Souza Bomfim
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Veronica Costiniti
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Yi Li
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Youssef Idaghdour
- Biology Program, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY, 10010, USA.
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14
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Subramanian G, Zhu Y, Bowen SJ, Roush N, White JA, Huczek D, Zachary T, Javens C, Williams T, Janssen A, Gonzales A. Lead identification and characterization of hTrkA type 2 inhibitors. Bioorg Med Chem Lett 2019; 29:126680. [PMID: 31610943 DOI: 10.1016/j.bmcl.2019.126680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/08/2019] [Accepted: 09/09/2019] [Indexed: 12/26/2022]
Abstract
Virtual in silico structure-guided modeling, followed by in vitro biochemical screening of a subset of commercially purchasable compound collection resulted in the identification of several human tropomyosin receptor kinase A (hTrkA) inhibitors that bind the orthosteric ATP site and exhibit binding preference for the inactive kinase conformation. The type 2 binding mode with the DFG-out and αC-helix out hTrkA kinase domain conformation was confirmed from X-ray crystallographic solution of a representative inhibitor analog, 1b. Additional hTrkA and hTrkB (selectivity) assays in recombinant cells, neurite outgrowth inhibition using rat PC12 cells, early ADME profiling, and preliminary pharmacokinetic evaluation in rodents guided the lead inhibitor progression in the discovery screening funnel.
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Affiliation(s)
- Govindan Subramanian
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA.
| | - Yaqi Zhu
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Scott J Bowen
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Nicole Roush
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Julie A White
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Dennis Huczek
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Theresa Zachary
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Christopher Javens
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Tracey Williams
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Ann Janssen
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
| | - Andrea Gonzales
- Veterinary Medicine Research & Development, Zoetis, 333 Portage Street, Bldg. 300, Kalamazoo, MI 49007, USA
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15
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García-Nafría J, Tate CG. Cryo-Electron Microscopy: Moving Beyond X-Ray Crystal Structures for Drug Receptors and Drug Development. Annu Rev Pharmacol Toxicol 2019; 60:51-71. [PMID: 31348870 DOI: 10.1146/annurev-pharmtox-010919-023545] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Electron cryo-microscopy (cryo-EM) has revolutionized structure determination of membrane proteins and holds great potential for structure-based drug discovery. Here we discuss the potential of cryo-EM in the rational design of therapeutics for membrane proteins compared to X-ray crystallography. We also detail recent progress in the field of drug receptors, focusing on cryo-EM of two protein families with established therapeutic value, the γ-aminobutyric acid A receptors (GABAARs) and G protein-coupled receptors (GPCRs). GABAARs are pentameric ion channels, and cryo-EM structures of physiological heteromeric receptors in a lipid environment have uncovered the molecular basis of receptor modulation by drugs such as diazepam. The structures of ten GPCR-G protein complexes from three different classes of GPCRs have now been determined by cryo-EM. These structures give detailed insights into molecular interactions with drugs, GPCR-G protein selectivity, how accessory membrane proteins alter receptor-ligand pharmacology, and the mechanism by which HIV uses GPCRs to enter host cells.
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Affiliation(s)
- Javier García-Nafría
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; .,Current affiliation: Institute for Biocomputation and Physics of Complex Systems (BIFI) and Laboratorio de Microscopias Avanzadas, University of Zaragoza, 50018 Zaragoza, Spain;
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16
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Flood E, Boiteux C, Lev B, Vorobyov I, Allen TW. Atomistic Simulations of Membrane Ion Channel Conduction, Gating, and Modulation. Chem Rev 2019; 119:7737-7832. [DOI: 10.1021/acs.chemrev.8b00630] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Emelie Flood
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Céline Boiteux
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Bogdan Lev
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Igor Vorobyov
- Department of Physiology & Membrane Biology/Department of Pharmacology, University of California, Davis, 95616, United States
| | - Toby W. Allen
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
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17
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Baker MAB. ABA/ASB biophysics and medicine session 2018. Biophys Rev 2019; 11:273-274. [PMID: 31055759 DOI: 10.1007/s12551-019-00529-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 04/24/2019] [Indexed: 01/21/2023] Open
Affiliation(s)
- Matthew A B Baker
- School of Biotechnology and Biomolecular Science, UNSW Sydney, Kensington, Australia.
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18
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Barros F, Pardo LA, Domínguez P, Sierra LM, de la Peña P. New Structures and Gating of Voltage-Dependent Potassium (Kv) Channels and Their Relatives: A Multi-Domain and Dynamic Question. Int J Mol Sci 2019; 20:ijms20020248. [PMID: 30634573 PMCID: PMC6359393 DOI: 10.3390/ijms20020248] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/30/2018] [Accepted: 01/07/2019] [Indexed: 12/15/2022] Open
Abstract
Voltage-dependent potassium channels (Kv channels) are crucial regulators of cell excitability that participate in a range of physiological and pathophysiological processes. These channels are molecular machines that display a mechanism (known as gating) for opening and closing a gate located in a pore domain (PD). In Kv channels, this mechanism is triggered and controlled by changes in the magnitude of the transmembrane voltage sensed by a voltage-sensing domain (VSD). In this review, we consider several aspects of the VSD–PD coupling in Kv channels, and in some relatives, that share a common general structure characterized by a single square-shaped ion conduction pore in the center, surrounded by four VSDs located at the periphery. We compile some recent advances in the knowledge of their architecture, based in cryo-electron microscopy (cryo-EM) data for high-resolution determination of their structure, plus some new functional data obtained with channel variants in which the covalent continuity between the VSD and PD modules has been interrupted. These advances and new data bring about some reconsiderations about the use of exclusively a classical electromechanical lever model of VSD–PD coupling by some Kv channels, and open a view of the Kv-type channels as allosteric machines in which gating may be dynamically influenced by some long-range interactional/allosteric mechanisms.
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Affiliation(s)
- Francisco Barros
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006 Oviedo, Asturias, Spain.
| | - Luis A Pardo
- Oncophysiology Group, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen, Germany.
| | - Pedro Domínguez
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006 Oviedo, Asturias, Spain.
| | - Luisa Maria Sierra
- Departamento de Biología Funcional (Area de Genética), Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo, 33006 Oviedo, Asturias, Spain.
| | - Pilar de la Peña
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006 Oviedo, Asturias, Spain.
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