1
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Bray SM, Hämälä T, Zhou M, Busoms S, Fischer S, Desjardins SD, Mandáková T, Moore C, Mathers TC, Cowan L, Monnahan P, Koch J, Wolf EM, Lysak MA, Kolar F, Higgins JD, Koch MA, Yant L. Kinetochore and ionomic adaptation to whole-genome duplication in Cochlearia shows evolutionary convergence in three autopolyploids. Cell Rep 2024; 43:114576. [PMID: 39116207 DOI: 10.1016/j.celrep.2024.114576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 05/17/2024] [Accepted: 07/18/2024] [Indexed: 08/10/2024] Open
Abstract
Whole-genome duplication (WGD) occurs in all kingdoms and impacts speciation, domestication, and cancer outcome. However, doubled DNA management can be challenging for nascent polyploids. The study of within-species polyploidy (autopolyploidy) permits focus on this DNA management aspect, decoupling it from the confounding effects of hybridization (in allopolyploid hybrids). How is autopolyploidy tolerated, and how do young polyploids stabilize? Here, we introduce a powerful model to address this: the genus Cochlearia, which has experienced many polyploidization events. We assess meiosis and other polyploid-relevant phenotypes, generate a chromosome-scale genome, and sequence 113 individuals from 33 ploidy-contrasting populations. We detect an obvious autopolyploidy-associated selection signal at kinetochore components and ion transporters. Modeling the selected alleles, we detail evidence of the kinetochore complex mediating adaptation to polyploidy. We compare candidates in independent autopolyploids across three genera separated by 40 million years, highlighting a common function at the process and gene levels, indicating evolutionary flexibility in response to polyploidy.
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Affiliation(s)
- Sian M Bray
- The University of Nottingham, Nottingham NG7 2RD, UK; The John Innes Centre, Norwich NR4 7UH, UK
| | - Tuomas Hämälä
- The University of Nottingham, Nottingham NG7 2RD, UK
| | - Min Zhou
- The University of Nottingham, Nottingham NG7 2RD, UK
| | - Silvia Busoms
- The John Innes Centre, Norwich NR4 7UH, UK; Department of Plant Physiology, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Sina Fischer
- The University of Nottingham, Nottingham NG7 2RD, UK
| | - Stuart D Desjardins
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Terezie Mandáková
- Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Chris Moore
- The University of Nottingham, Nottingham NG7 2RD, UK
| | - Thomas C Mathers
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Laura Cowan
- The University of Nottingham, Nottingham NG7 2RD, UK
| | | | | | - Eva M Wolf
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
| | - Martin A Lysak
- Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Filip Kolar
- Department of Botany, Charles University, Benátská 2, 12801 Prague, Czech Republic; The Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
| | - James D Higgins
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Marcus A Koch
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
| | - Levi Yant
- The University of Nottingham, Nottingham NG7 2RD, UK; Department of Botany, Charles University, Benátská 2, 12801 Prague, Czech Republic.
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2
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Milenkovic S, Bodrenko IV, Carpaneto A, Ceccarelli M. The key role of the central cavity in sodium transport through ligand-gated two-pore channels. Phys Chem Chem Phys 2021; 23:18461-18474. [PMID: 34612386 DOI: 10.1039/d1cp02947a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Subcellular and organellar mechanisms have manifested a prominent importance for a broad variety of processes that maintain cellular life at its most basic level. Mammalian two-pore channels (TPCs) appear to be cornerstones of these processes in endo-lysosomes by controlling delicate ion-concentrations in their interiors. With evolutionary remarkable architecture and one-of-a-kind selectivity filter, TPCs are an extremely attractive topic per se. In the light of the current COVID-19 pandemic, hTPC2 emerges to be more than attractive. As a key regulator of the endocytosis pathway, it is potentially essential for diverse viral infections in humans, as demonstrated. Here, by means of multiscale molecular simulations, we propose a model of sodium transport from the lumen to the cytosol where the central cavity works as a reservoir. Since the inhibition of hTPC2 is proven to stop SARS-CoV2 in vitro, shedding light on the hTPC2 function and mechanism is the first step towards the selection of potential inhibiting candidates.
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Affiliation(s)
- Stefan Milenkovic
- Department of Physics, University of Cagliari, 09042 Monserrato, Italy.
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3
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Domene C, Ocello R, Masetti M, Furini S. Ion Conduction Mechanism as a Fingerprint of Potassium Channels. J Am Chem Soc 2021; 143:12181-12193. [PMID: 34323472 DOI: 10.1021/jacs.1c04802] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
K+-channels are membrane proteins that regulate the selective conduction of potassium ions across cell membranes. Although the atomic mechanisms of K+ permeation have been extensively investigated, previous work focused on characterizing the selectivity and occupancy of the binding sites, the role of water molecules in the conduction process, or the identification of the minimum energy pathways enabling permeation. Here, we exploit molecular dynamics simulations and the analytical power of Markov state models to perform a comparative study of ion conduction in three distinct channel models. Significant differences emerged in terms of permeation mechanisms and binding site occupancy by potassium ions and/or water molecules from 100 μs cumulative trajectories. We found that, at odds with the current paradigm, each system displays a characteristic permeation mechanism, and thus, there is not a unique way by which potassium ions move through K+-channels. The high functional diversity of K+-channels can be attributed in part to the differences in conduction features that have emerged from this work. This study provides crucial information and further inspiration for wet-lab chemists designing new synthetic strategies to produce versatile artificial ion channels that emulate membrane transport for their applications in diagnosis, sensors, the next generation of water treatment technologies, etc., as the ability of synthetic channels to transport molecular ions across a bilayer in a controlled way is usually governed through the choice of metal ions, their oxidation states, or their coordination geometries.
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Affiliation(s)
- Carmen Domene
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, U.K.,Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K
| | - Riccardo Ocello
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-Università di Bologna, Via Belmeloro 6, 40126 Bologna, Italy
| | - Matteo Masetti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-Università di Bologna, Via Belmeloro 6, 40126 Bologna, Italy
| | - Simone Furini
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
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4
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Negoro T, Hirata K, Lisy JM, Ishiuchi SI, Fujii M. Potassium and sodium ion complexes with a partial peptide of the selectivity filter in K + channels studied by cold ion trap infrared spectroscopy: the effect of hydration. Phys Chem Chem Phys 2021; 23:12045-12050. [PMID: 34075971 DOI: 10.1039/d1cp00936b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Potassium channels allow K+ to rapidly diffuse, while the selectivity filter (SF) actively blocks Na+. The presence of water in the SF during ion translocation remains under debate due to the experimental and computational challenges in characterizing the interactions between water, ions, and the SF. Our bottom-up approach has been applied to a system composed of a partial peptide of the SF (Ac-tyrosine-NHMe) with a metal ion and a single water molecule to probe these interactions. The IR photodissociation spectra of M+Ac-tyrosine-NHMe(H2O) (M = Na, K) combined with quantum chemical calculations revealed that the water molecule binding sites are ion-dependent. In addition, the ion-peptide distances are elongated significantly for the K+ complex in comparison to the Na+ complex by the addition of a single water molecule. This striking structural difference with the water molecule is discussed in relation to ion selectivity and translocation within the K+ channel.
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Affiliation(s)
- Takumi Negoro
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan. and School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Keisuke Hirata
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan. and Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. and Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - James M Lisy
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. and Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shun-Ichi Ishiuchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan. and Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. and Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Masaaki Fujii
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan. and School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan and Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan.
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5
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Oakes V, Furini S, Domene C. Effect of anionic lipids on ion permeation through the KcsA K+-channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183406. [DOI: 10.1016/j.bbamem.2020.183406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 12/21/2022]
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6
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Furini S, Domene C. Critical Assessment of Common Force Fields for Molecular Dynamics Simulations of Potassium Channels. J Chem Theory Comput 2020; 16:7148-7159. [DOI: 10.1021/acs.jctc.0c00331] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Simone Furini
- Department of Medical Biotechnologies, University of Siena, Siena 53100, Italy
| | - Carmen Domene
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
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7
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Mikušević V, Schrecker M, Kolesova N, Patiño-Ruiz M, Fendler K, Hänelt I. A channel profile report of the unusual K + channel KtrB. J Gen Physiol 2019; 151:1357-1368. [PMID: 31624134 PMCID: PMC6888753 DOI: 10.1085/jgp.201912384] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 09/03/2019] [Accepted: 09/27/2019] [Indexed: 11/20/2022] Open
Abstract
KtrAB is a key player in bacterial K+ uptake required for K+ homeostasis and osmoadaptation. The system is unique in structure and function. It consists of the K+-translocating channel subunit KtrB, which forms a dimer in the membrane, and the soluble regulatory subunit KtrA, which attaches to the cytoplasmic side of the dimer as an octameric ring conferring Na+ and ATP dependency to the system. Unlike most K+ channels, KtrB lacks the highly conserved T(X)GYG selectivity filter sequence. Instead, only a single glycine residue is found in each pore loop, which raises the question of how selective the ion channel is. Here, we characterized the KtrB subunit from the Gram-negative pathogen Vibrio alginolyticus by isothermal titration calorimetry, solid-supported membrane-based electrophysiology, whole-cell K+ uptake, and ACMA-based transport assays. We found that, despite its simple selectivity filter, KtrB selectively binds K+ with micromolar affinity. Rb+ and Cs+ bind with millimolar affinities. However, only K+ and the poorly binding Na+ are efficiently translocated, based on size exclusion by the gating loop. Importantly, the physiologically required K+ over Na+ selectivity is provided by the channel's high affinity for potassium, which interestingly results from the presence of the sodium ions themselves. In the presence of the KtrA subunit, sodium ions further decrease the Michaelis-Menten constant for K+ uptake from milli- to micromolar concentrations and increase the Vmax, suggesting that Na+ also facilitates channel gating. In conclusion, high binding affinity and facilitated K+ gating allow KtrAB to function as a selective K+ channel.
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Affiliation(s)
- Vedrana Mikušević
- Institute of Biochemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Marina Schrecker
- Institute of Biochemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Natalie Kolesova
- Institute of Biochemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Miyer Patiño-Ruiz
- Department of Biophysical Chemistry, Max Planck Institute for Biophysics, Frankfurt, Germany
| | - Klaus Fendler
- Department of Biophysical Chemistry, Max Planck Institute for Biophysics, Frankfurt, Germany
| | - Inga Hänelt
- Institute of Biochemistry, Goethe University Frankfurt, Frankfurt, Germany
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8
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Conformational landscapes of membrane proteins delineated by enhanced sampling molecular dynamics simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:909-926. [PMID: 29113819 DOI: 10.1016/j.bbamem.2017.10.033] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/24/2017] [Accepted: 10/28/2017] [Indexed: 11/22/2022]
Abstract
The expansion of computational power, better parameterization of force fields, and the development of novel algorithms to enhance the sampling of the free energy landscapes of proteins have allowed molecular dynamics (MD) simulations to become an indispensable tool to understand the function of biomolecules. The temporal and spatial resolution of MD simulations allows for the study of a vast number of processes of interest. Here, we review the computational efforts to uncover the conformational free energy landscapes of a subset of membrane proteins: ion channels, transporters and G-protein coupled receptors. We focus on the various enhanced sampling techniques used to study these questions, how the conclusions come together to build a coherent picture, and the relationship between simulation outcomes and experimental observables.
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9
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Zhekova HR, Ngo V, da Silva MC, Salahub D, Noskov S. Selective ion binding and transport by membrane proteins – A computational perspective. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.03.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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10
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Jorgensen C, Furini S, Domene C. Energetics of Ion Permeation in an Open-Activated TRPV1 Channel. Biophys J 2017; 111:1214-1222. [PMID: 27653480 DOI: 10.1016/j.bpj.2016.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 08/11/2016] [Accepted: 08/15/2016] [Indexed: 01/11/2023] Open
Abstract
Ion channels enable diffusion of ions down physiological electrochemical gradients. Modulation of ion permeation is crucial for the physiological functioning of cells, and misregulation of ion channels is linked to a myriad of channelopathies. The ion permeation mechanism in the transient receptor potential (TRP) ion channel family is currently not understood at an atomistic level. In this work, we employed a simulation strategy for ion permeation (molecular-dynamics simulations with bias-exchange metadynamics) to study and compare monovalent (Na(+), K(+)) ion permeation in the open-activated TRP vanniloid-1 (TRPV1) ion channel. Using ∼3.6 μs of simulation trajectories, we obtained atomistic evidence for the nonselective nature of TRPV1. Our analysis shows that solvated monovalent ions permeate through the selectivity filter with comparable energetic barriers via a two-site mechanism. Finally, we confirmed that an intracellular binding site is located between the intracellular gate residues I679 and E684.
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Affiliation(s)
| | - Simone Furini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Carmen Domene
- Department of Chemistry, King's College London, London, United Kingdom; Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
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11
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Bernsteiner H, Bründl M, Stary-Weinzinger A. Dynamics of the EAG1 K + channel selectivity filter assessed by molecular dynamics simulations. Biochem Biophys Res Commun 2017; 484:107-112. [PMID: 28109880 PMCID: PMC6531291 DOI: 10.1016/j.bbrc.2017.01.064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 01/13/2017] [Indexed: 01/14/2023]
Abstract
EAG1 channels belong to the KCNH family of voltage gated potassium channels. They are expressed in several brain regions and increased expression is linked to certain cancer types. Recent cryo-EM structure determination finally revealed the structure of these channels in atomic detail, allowing computational investigations. In this study, we performed molecular dynamics simulations to investigate the ion binding sites and the dynamical behavior of the selectivity filter. Our simulations suggest that sites S2 and S4 form stable ion binding sites, while ions placed at sites S1 and S3 rapidly switched to sites S2 and S4. Further, ions tended to dissociate away from S0 within less than 20 ns, due to increased filter flexibility. This was followed by water influx from the extracellular side, leading to a widening of the filter in this region, and likely non-conductive filter configurations. Simulations with the inactivation-enhancing mutant Y464A or Na+ ions lead to trapped water molecules behind the SF, suggesting that these simulations captured early conformational changes linked to C-type inactivation.
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Affiliation(s)
- Harald Bernsteiner
- Department of Pharmacology and Toxicology, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Michael Bründl
- Department of Pharmacology and Toxicology, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Anna Stary-Weinzinger
- Department of Pharmacology and Toxicology, University of Vienna, Althanstraße 14, 1090 Vienna, Austria.
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12
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Temperature-sensitive gating of TRPV1 channel as probed by atomistic simulations of its trans- and juxtamembrane domains. Sci Rep 2016; 6:33112. [PMID: 27612191 PMCID: PMC5017144 DOI: 10.1038/srep33112] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 08/22/2016] [Indexed: 12/20/2022] Open
Abstract
Heat-activated transient receptor potential channel TRPV1 is one of the most studied eukaryotic proteins involved in temperature sensation. Upon heating, it exhibits rapid reversible pore gating, which depolarizes neurons and generates action potentials. Underlying molecular details of such effects in the pore region of TRPV1 is of a crucial importance to control temperature responses of the organism. Despite the spatial structure of the channel in both open (O) and closed (C) states is known, microscopic nature of channel gating and mechanism of thermal sensitivity are still poorly understood. In this work, we used unrestrained atomistic molecular dynamics simulations of TRPV1 (without N- and C-terminal cytoplasmic domains) embedded into explicit lipid bilayer in its O- and C-states. We found that the pore domain with its neighboring loops undergoes large temperature-dependent conformational transitions in an asymmetric way, when fragments of only one monomer move with large amplitude, freeing the pore upon heating. Such an asymmetrical gating looks rather biologically relevant because it is faster and more reliable than traditionally proposed “iris-like” symmetric scheme of channel opening. Analysis of structural, dynamic, and hydrophobic organization of the pore domain revealed entropy growth upon TRPV1 gating, which is in line with current concepts of thermal sensitivity.
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13
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Domene C, Barbini P, Furini S. Bias-Exchange Metadynamics Simulations: An Efficient Strategy for the Analysis of Conduction and Selectivity in Ion Channels. J Chem Theory Comput 2016; 11:1896-906. [PMID: 26574394 DOI: 10.1021/ct501053x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Conduction through ion channels possesses two interesting features: (i) different ionic species are selected with high-selectivity and (ii) ions travel across the channel with rates approaching free-diffusion. Molecular dynamics simulations have the potential to reveal how these processes take place at the atomic level. However, analysis of conduction and selectivity at atomistic detail is still hampered by the short time scales accessible by computer simulations. Several algorithms have been developed to "accelerate" sampling along the slow degrees of freedom of the process under study and thus to probe longer time scales. In these algorithms, the slow degrees of freedom need to be defined in advance, which is a well-known shortcoming. In the particular case of ion conduction, preliminary assumptions about the number and type of ions participating in the permeation process need to be made. In this study, a novel approach for the analysis of conduction and selectivity based on bias-exchange metadynamics simulations was tested. This approach was compared with umbrella sampling simulations, using a model of a Na(+)-selective channel. Analogous conclusions resulted from both techniques, but the computational cost of bias-exchange simulations was lower. In addition, with bias-exchange metadynamics it was possible to calculate free energy profiles in the presence of a variable number and type of permeating ions. This approach might facilitate the definition of the set of collective variables required to analyze conduction and selectivity in ion channels.
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Affiliation(s)
- Carmen Domene
- Chemistry Research Laboratory, University of Oxford , 12 Mansfield Road, Oxford OX1 3TA, U.K.,Department of Chemistry, King's College London , Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - Paolo Barbini
- Department of Medical Biotechnologies, University of Siena , viale Mario Bracci 16, I-53100, Siena, Siena, Italy
| | - Simone Furini
- Department of Medical Biotechnologies, University of Siena , viale Mario Bracci 16, I-53100, Siena, Siena, Italy
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14
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Vianello R, Domene C, Mavri J. The Use of Multiscale Molecular Simulations in Understanding a Relationship between the Structure and Function of Biological Systems of the Brain: The Application to Monoamine Oxidase Enzymes. Front Neurosci 2016; 10:327. [PMID: 27471444 PMCID: PMC4945635 DOI: 10.3389/fnins.2016.00327] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 06/28/2016] [Indexed: 01/17/2023] Open
Abstract
HIGHLIGHTS Computational techniques provide accurate descriptions of the structure and dynamics of biological systems, contributing to their understanding at an atomic level.Classical MD simulations are a precious computational tool for the processes where no chemical reactions take place.QM calculations provide valuable information about the enzyme activity, being able to distinguish among several mechanistic pathways, provided a carefully selected cluster model of the enzyme is considered.Multiscale QM/MM simulation is the method of choice for the computational treatment of enzyme reactions offering quantitative agreement with experimentally determined reaction parameters.Molecular simulation provide insight into the mechanism of both the catalytic activity and inhibition of monoamine oxidases, thus aiding in the rational design of their inhibitors that are all employed and antidepressants and antiparkinsonian drugs. Aging society and therewith associated neurodegenerative and neuropsychiatric diseases, including depression, Alzheimer's disease, obsessive disorders, and Parkinson's disease, urgently require novel drug candidates. Targets include monoamine oxidases A and B (MAOs), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and various receptors and transporters. For rational drug design it is particularly important to combine experimental synthetic, kinetic, toxicological, and pharmacological information with structural and computational work. This paper describes the application of various modern computational biochemistry methods in order to improve the understanding of a relationship between the structure and function of large biological systems including ion channels, transporters, receptors, and metabolic enzymes. The methods covered stem from classical molecular dynamics simulations to understand the physical basis and the time evolution of the structures, to combined QM, and QM/MM approaches to probe the chemical mechanisms of enzymatic activities and their inhibition. As an illustrative example, the later will focus on the monoamine oxidase family of enzymes, which catalyze the degradation of amine neurotransmitters in various parts of the brain, the imbalance of which is associated with the development and progression of a range of neurodegenerative disorders. Inhibitors that act mainly on MAO A are used in the treatment of depression, due to their ability to raise serotonin concentrations, while MAO B inhibitors decrease dopamine degradation and improve motor control in patients with Parkinson disease. Our results give strong support that both MAO isoforms, A and B, operate through the hydride transfer mechanism. Relevance of MAO catalyzed reactions and MAO inhibition in the context of neurodegeneration will be discussed.
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Affiliation(s)
- Robert Vianello
- Computational Organic Chemistry and Biochemistry Group, Ruđer Bošković InstituteZagreb, Croatia
| | - Carmen Domene
- Department of Chemistry, King's College LondonLondon, UK
- Chemistry Research Laboratory, University of OxfordOxford, UK
| | - Janez Mavri
- Department of Computational Biochemistry and Drug Design, National Institute of ChemistryLjubljana, Slovenia
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15
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Jorgensen C, Darré L, Oakes V, Torella R, Pryde D, Domene C. Lateral Fenestrations in K(+)-Channels Explored Using Molecular Dynamics Simulations. Mol Pharm 2016; 13:2263-73. [PMID: 27173896 DOI: 10.1021/acs.molpharmaceut.5b00942] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Potassium channels are of paramount physiological and pathological importance and therefore constitute significant drug targets. One of the keys to rationalize the way drugs modulate ion channels is to understand the ability of such small molecules to access their respective binding sites, from which they can exert an activating or inhibitory effect. Many computational studies have probed the energetics of ion permeation, and the mechanisms of voltage gating, but little is known about the role of fenestrations as possible mediators of drug entry in potassium channels. To explore the existence, structure, and conformational dynamics of transmembrane fenestrations accessible by drugs in potassium channels, molecular dynamics simulation trajectories were analyzed from three potassium channels: the open state voltage-gated channel Kv1.2, the G protein-gated inward rectifying channel GIRK2 (Kir3.2), and the human two-pore domain TWIK-1 (K2P1.1). The main results of this work were the identification of the sequence identity of four main lateral fenestrations of similar length and with bottleneck radius in the range of 0.9-2.4 Å for this set of potassium channels. It was found that the fenestrations in Kv1.2 and Kir3.2 remain closed to the passage of molecules larger than water. In contrast, in the TWIK-1 channel, both open and closed fenestrations are sampled throughout the simulation, with bottleneck radius shown to correlate with the random entry of lipid membrane molecules into the aperture of the fenestrations. Druggability scoring function analysis of the fenestration regions suggests that Kv and Kir channels studied are not druggable in practice due to steric constraining of the fenestration bottleneck. A high (>50%) fenestration sequence identity was found in each potassium channel subfamily studied, Kv1, Kir3, and K2P1. Finally, the reported fenestration sequence of TWIK-1 compared favorably with another channel, K2P channel TREK-2, reported to possess open fenestrations, suggesting that K2P channels could be druggable via fenestrations, for which we reported atomistic detail of the fenestration region, including the flexible residues M260 and L264 that interact with POPC membrane in a concerted fashion with the aperture and closure of the fenestrations.
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Affiliation(s)
- Christian Jorgensen
- Department of Chemistry, King's College London , Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - Leonardo Darré
- Department of Chemistry, King's College London , Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - Victoria Oakes
- Department of Chemistry, King's College London , Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - Rubben Torella
- Pfizer Neuroscience and Pain Research Unit, Worldwide Medicinal Chemistry , Portway Building, Granta Park, Great Abington, Cambridge CB21 6GS, U.K
| | - David Pryde
- Pfizer Neuroscience and Pain Research Unit, Worldwide Medicinal Chemistry , Portway Building, Granta Park, Great Abington, Cambridge CB21 6GS, U.K
| | - Carmen Domene
- Department of Chemistry, King's College London , Britannia House, 7 Trinity Street, London SE1 1DB, U.K.,Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K
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16
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Oakes V, Furini S, Domene C. Voltage-Gated Sodium Channels: Mechanistic Insights From Atomistic Molecular Dynamics Simulations. CURRENT TOPICS IN MEMBRANES 2016; 78:183-214. [PMID: 27586285 DOI: 10.1016/bs.ctm.2015.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The permeation of ions and other molecules across biological membranes is an inherent requirement of all cellular organisms. Ion channels, in particular, are responsible for the conduction of charged species, hence modulating the propagation of electrical signals. Despite the universal physiological implications of this property, the molecular functioning of ion channels remains ambiguous. The combination of atomistic structural data with computational methodologies, such as molecular dynamics (MD) simulations, is now considered routine to investigate structure-function relationships in biological systems. A fuller understanding of conduction, selectivity, and gating, therefore, is steadily emerging due to the applicability of these techniques to ion channels. However, because their structure is known at atomic resolution, studies have consistently been biased toward K(+) channels, thus the molecular determinants of ionic selectivity, activation, and drug blockage in Na(+) channels are often overlooked. The recent increase of available crystallographic data has eminently encouraged the investigation of voltage-gated sodium (NaV) channels via computational methods. Here, we present an overview of simulation studies that have contributed to our understanding of key principles that underlie ionic conduction and selectivity in Na(+) channels, in comparison to the K(+) channel analogs.
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Affiliation(s)
- V Oakes
- King's College London, London, United Kingdom
| | - S Furini
- University of Siena, Siena, Italy
| | - C Domene
- King's College London, London, United Kingdom; University of Oxford, Oxford, United Kingdom
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17
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Ing C, Pomès R. Simulation Studies of Ion Permeation and Selectivity in Voltage-Gated Sodium Channels. CURRENT TOPICS IN MEMBRANES 2016; 78:215-60. [DOI: 10.1016/bs.ctm.2016.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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18
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Brettmann JB, Urusova D, Tonelli M, Silva JR, Henzler-Wildman KA. Role of protein dynamics in ion selectivity and allosteric coupling in the NaK channel. Proc Natl Acad Sci U S A 2015; 112:15366-71. [PMID: 26621745 PMCID: PMC4687598 DOI: 10.1073/pnas.1515965112] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Flux-dependent inactivation that arises from functional coupling between the inner gate and the selectivity filter is widespread in ion channels. The structural basis of this coupling has only been well characterized in KcsA. Here we present NMR data demonstrating structural and dynamic coupling between the selectivity filter and intracellular constriction point in the bacterial nonselective cation channel, NaK. This transmembrane allosteric communication must be structurally different from KcsA because the NaK selectivity filter does not collapse under low-cation conditions. Comparison of NMR spectra of the nonselective NaK and potassium-selective NaK2K indicates that the number of ion binding sites in the selectivity filter shifts the equilibrium distribution of structural states throughout the channel. This finding was unexpected given the nearly identical crystal structure of NaK and NaK2K outside the immediate vicinity of the selectivity filter. Our results highlight the tight structural and dynamic coupling between the selectivity filter and the channel scaffold, which has significant implications for channel function. NaK offers a distinct model to study the physiologically essential connection between ion conduction and channel gating.
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Affiliation(s)
- Joshua B Brettmann
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110
| | - Darya Urusova
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO 63130
| | - Marco Tonelli
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO 63130
| | - Katherine A Henzler-Wildman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
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19
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Sadhu B, Sundararajan M, Bandyopadhyay T. Selectivity of a Singly Permeating Ion in Nonselective NaK Channel: Combined QM and MD Based Investigations. J Phys Chem B 2015; 119:12783-97. [DOI: 10.1021/acs.jpcb.5b05996] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Biswajit Sadhu
- Radiation Safety Systems Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Mahesh Sundararajan
- Radiation Safety Systems Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Tusar Bandyopadhyay
- Radiation Safety Systems Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
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20
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Li Y, Gong H. Theoretical and simulation studies on voltage-gated sodium channels. Protein Cell 2015; 6:413-22. [PMID: 25894089 PMCID: PMC4444806 DOI: 10.1007/s13238-015-0152-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/05/2015] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium (Nav) channels are indispensable membrane elements for the generation and propagation of electric signals in excitable cells. The successes in the crystallographic studies on prokaryotic Nav channels in recent years greatly promote the mechanistic investigation of these proteins and their eukaryotic counterparts. In this paper, we mainly review the progress in computational studies, especially the simulation studies, on these proteins in the past years.
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Affiliation(s)
- Yang Li
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Haipeng Gong
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084 China
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21
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Effects of the protonation state of the EEEE motif of a bacterial Na(+)-channel on conduction and pore structure. Biophys J 2014; 106:2175-83. [PMID: 24853746 DOI: 10.1016/j.bpj.2014.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 03/25/2014] [Accepted: 04/03/2014] [Indexed: 11/20/2022] Open
Abstract
A distinctive feature of prokaryotic Na(+)-channels is the presence of four glutamate residues in their selectivity filter. In this study, how the structure of the selectivity filter, and the free-energy profile of permeating Na(+) ions are altered by the protonation state of Glu177 are analyzed. It was found that protonation of a single glutamate residue was enough to modify the conformation of the selectivity filter and its conduction properties. Molecular dynamics simulations revealed that Glu177 residues may adopt two conformations, with the side chain directed toward the extracellular entrance of the channel or the intracellular cavity. The likelihood of the inwardly directed arrangement increases when Glu177 residues are protonated. The presence of one glutamate residue with its chain directed toward the intracellular cavity increases the energy barrier for translocation of Na(+) ions. These higher-energy barriers preclude Na(+) ions to permeate the selectivity filter of prokaryotic Na(+)-channels when one or more Glu177 residues are protonated.
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22
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Horn R, Roux B, Åqvist J. Permeation redux: thermodynamics and kinetics of ion movement through potassium channels. Biophys J 2014; 106:1859-63. [PMID: 24806917 DOI: 10.1016/j.bpj.2014.03.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/14/2014] [Accepted: 03/27/2014] [Indexed: 10/25/2022] Open
Abstract
The fundamental biophysics underlying the selective movement of ions through ion channels was launched by George Eisenman in the 1960s, using glass electrodes. This minireview examines the insights from these early studies and the explosive progress made since then.
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Affiliation(s)
- Richard Horn
- Department of Molecular Physiology and Biophysics, Jefferson Medical College, Philadelphia, Pennsylvania.
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois
| | - Johan Åqvist
- Department of Cell & Molecular Biology, Uppsala University, Biomedical Center, Uppsala, Sweden
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23
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Darré L, Furini S, Domene C. Permeation and dynamics of an open-activated TRPV1 channel. J Mol Biol 2014; 427:537-49. [PMID: 25479373 DOI: 10.1016/j.jmb.2014.11.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 09/28/2014] [Accepted: 11/20/2014] [Indexed: 10/24/2022]
Abstract
Transient receptor potential (TRP) ion channels constitute a large and diverse protein family, found in yeast and widespread in the animal kingdom. TRP channels work as sensors for a wide range of cellular and environmental signals. Understanding how these channels respond to physical and chemical stimuli has been hindered by the limited structural information available until now. The three-dimensional structure of the vanilloid receptor 1 (TRPV1) was recently determined by single particle electron cryo-microscopy, offering for the first time the opportunity to explore ionic conduction in TRP channels at atomic detail. In this study, we present molecular dynamics simulations of the open-activated pore domain of TRPV1 in the presence of three cationic species: Na(+), Ca(2+) and K(+). The dynamics of these ions while interacting with the channel pore allowed us to rationalize their permeation mechanism in terms of a pathway involving three binding sites at the intracellular cavity, as well as the extracellular and intracellular entrance of the selectivity filter. Furthermore, conformational analysis of the pore in the presence of these ions reveals specific ion-mediated structural changes in the selectivity filter, which influences the permeability properties of the TRPV1 channel.
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Affiliation(s)
- Leonardo Darré
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, UK
| | - Simone Furini
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, UK; Department of Medical Biotechnologies, University of Siena, Viale Mario Bracci 16, I-53100 Siena, Italy
| | - Carmen Domene
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, UK; Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK.
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24
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Berti C, Furini S, Gillespie D, Boda D, Eisenberg RS, Sangiorgi E, Fiegna C. Three-Dimensional Brownian Dynamics Simulator for the Study of Ion Permeation through Membrane Pores. J Chem Theory Comput 2014; 10:2911-26. [DOI: 10.1021/ct4011008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Claudio Berti
- Department
of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago,Illinois, United States
- ARCES
and DEI, University of Bologna and IUNET, Cesena, Italy
| | - Simone Furini
- Department
of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Dirk Gillespie
- Department
of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago,Illinois, United States
| | - Dezső Boda
- Department
of Physical Chemistry, University of Pannonia, Veszprém, Hungary
| | - Robert S. Eisenberg
- Department
of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago,Illinois, United States
| | | | - Claudio Fiegna
- ARCES
and DEI, University of Bologna and IUNET, Cesena, Italy
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25
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Ke S, Timin EN, Stary-Weinzinger A. Different inward and outward conduction mechanisms in NaVMs suggested by molecular dynamics simulations. PLoS Comput Biol 2014; 10:e1003746. [PMID: 25079564 PMCID: PMC4117422 DOI: 10.1371/journal.pcbi.1003746] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 06/13/2014] [Indexed: 01/03/2023] Open
Abstract
Rapid and selective ion transport is essential for the generation and regulation of electrical signaling pathways in living organisms. Here, we use molecular dynamics (MD) simulations with an applied membrane potential to investigate the ion flux of bacterial sodium channel NaVMs. 5.9 µs simulations with 500 mM NaCl suggest different mechanisms for inward and outward flux. The predicted inward conductance rate of ∼27±3 pS, agrees with experiment. The estimated outward conductance rate is 15±3 pS, which is considerably lower. Comparing inward and outward flux, the mean ion dwell time in the selectivity filter (SF) is prolonged from 13.5±0.6 ns to 20.1±1.1 ns. Analysis of the Na+ distribution revealed distinct patterns for influx and efflux events. In 32.0±5.9% of the simulation time, the E53 side chains adopted a flipped conformation during outward conduction, whereas this conformational change was rarely observed (2.7±0.5%) during influx. Further, simulations with dihedral restraints revealed that influx is less affected by the E53 conformational flexibility. In contrast, during outward conduction, our simulations indicate that the flipped E53 conformation provides direct coordination for Na+. The free energy profile (potential of mean force calculations) indicates that this conformational change lowers the putative barriers between sites SCEN and SHFS during outward conduction. We hypothesize that during an action potential, the increased Na+ outward transition propensities at depolarizing potentials might increase the probability of E53 conformational changes in the SF. Subsequently, this might be a first step towards initiating slow inactivation.
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Affiliation(s)
- Song Ke
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - E. N. Timin
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
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