1
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Nan Y, MacKerell AD. Balancing Group I Monatomic Ion-Polar Compound Interactions for Condensed Phase Simulation in the Polarizable Drude Force Field. J Chem Theory Comput 2024; 20:3242-3257. [PMID: 38588064 PMCID: PMC11039353 DOI: 10.1021/acs.jctc.3c01380] [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] [Indexed: 04/10/2024]
Abstract
Molecular dynamics (MD) simulations are a commonly used method for investigating molecular behavior at the atomic level. Achieving reliable MD simulation results necessitates the use of an accurate force field. In the present work, we present a protocol to enhance the quality of group 1 monatomic ions (specifically Li+, Na+, K+, Rb+, and Cs+) with respect to their interactions with common polar model compounds in biomolecules in condensed phases in the context of the Drude polarizable force field. Instead of adjusting preexisting individual parameters for ions, model compounds, and water, we employ atom-pair specific Lennard-Jones (LJ) (known as NBFIX in CHARMM) and through-space Thole dipole screening (NBTHOLE) terms to fine-tune the balance of ion-model compound, ion-water, and model compound-water interactions. This involved establishing a protocol for the optimization of NBFIX and NBTHOLE parameters targeting the difference between molecular mechanical (MM) and quantum mechanical (QM) potential energy scans (PES). It is shown that targeting PES involving complexes that include multiple model compounds and/or ions as trimers and tetramers yields parameters that produce condensed phase properties in agreement with experimental data. Validation of this protocol involved the reproduction of experimental thermodynamic benchmarks, including solvation free energies of ions in methanol and N-methylacetamide, osmotic pressures, ionic conductivities, and diffusion coefficients within the condensed phase. These results show the importance of including more complex ion-model compound complexes beyond dimers in the QM target data to account for many-body effects during parameter fitting. The presented parameters represent a significant refinement of the Drude polarizable force field, which will lead to improved accuracy for modeling ion-biomolecular interactions.
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Affiliation(s)
- Yiling Nan
- University of Maryland Computer-Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201 MD
| | - Alexander D. MacKerell
- University of Maryland Computer-Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201 MD
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2
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Betrie AH, Abdul-Ridha A, Hartono H, Chalmers DK, Wright CE, Scott DJ, Angus JA, Ayton S. The 8-hydroxyquinoline derivative, clioquinol, is an alpha-1 adrenoceptor antagonist. Biochem Pharmacol 2024; 222:116092. [PMID: 38408679 DOI: 10.1016/j.bcp.2024.116092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/21/2023] [Accepted: 02/23/2024] [Indexed: 02/28/2024]
Abstract
Clioquinol (5-chloro-7-iodo-8-hydroxyquinoline) is an antimicrobial agent whose actions as a zinc or copper ionophore and an iron chelator revived the interest in similar compounds for the treatment of fungal and bacterial infections, neurodegeneration and cancer. Recently, we reported zinc ionophores, including clioquinol, cause vasorelaxation in isolated arteries through mechanisms that involve sensory nerves, endothelium and vascular smooth muscle. Here, we report that clioquinol also uniquely acts as a competitive alpha-1 (α1) adrenoceptor antagonist. We employed ex vivo functional vascular contraction and pharmacological techniques in rat isolated mesenteric arteries, receptor binding assays using stabilized solubilized α1 receptor variants, or wild-type human α1-adrenoceptors transfected in COS-7 cells (African green monkey kidney fibroblast-like cells), and molecular dynamics homology modelling based on the recently published α1A adrenoceptor cryo-EM and α1B crystal structures. At higher concentrations, all ionophores including clioquinol cause a non-competitive antagonism of agonist-mediated contraction due to intracellular zinc delivery, as reported previously. However, at lower concentration ranges, clioquinol has an additional mechanism of competitively inhibiting α1-adrenoceptors that contributes to decreasing vascular contractility. Molecular dynamic simulation showed that clioquinol binds stably to the orthosteric binding site (Asp106) of the receptor, confirming the structural basis for competitive α1-adrenoceptor antagonism by clioquinol.
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Affiliation(s)
- Ashenafi H Betrie
- Translational Neurodegeneration Laboratory, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia; Translational Cardiovascular and Renal Research Group, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Alaa Abdul-Ridha
- Drug Discovery Innovation Group, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Herodion Hartono
- Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria, Australia
| | - David K Chalmers
- Faculty of Pharmacy and Pharmaceutical Sciences, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria, Australia
| | - Christine E Wright
- Department of Biochemistry and Pharmacology, The University of Melbourne, Victoria, Australia
| | - Daniel J Scott
- Drug Discovery Innovation Group, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - James A Angus
- Department of Biochemistry and Pharmacology, The University of Melbourne, Victoria, Australia
| | - Scott Ayton
- Translational Neurodegeneration Laboratory, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.
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3
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Yesylevskyy S, Martinez-Seara H, Jungwirth P. Curvature Matters: Modeling Calcium Binding to Neutral and Anionic Phospholipid Bilayers. J Phys Chem B 2023; 127:4523-4531. [PMID: 37191140 DOI: 10.1021/acs.jpcb.3c01962] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In this work, the influence of membrane curvature on the Ca2+ binding to phospholipid bilayers is investigated by means of molecular dynamics simulations. In particular, we compared Ca2+ binding to flat, elastically buckled, or uniformly bent zwitterionic and anionic phospholipid bilayers. We demonstrate that Ca2+ ions bind preferably to the concave membrane surfaces in both types of bilayers. We also show that the membrane curvature leads to pronounced changes in Ca2+ binding including differences in free ion concentrations, lipid coordination distributions, and the patterns of ion binding to different chemical groups of lipids. Moreover, these effects differ substantially for the concave and convex membrane monolayers. Comparison between force fields with either full or scaled charges indicates that charge scaling results in reduction of the Ca2+ binding to curved phosphatidylserine bilayers, while for phosphatidylcholine membranes, calcium binds only weakly for both force fields.
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Affiliation(s)
- Semen Yesylevskyy
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Nauky Avenue 46, 03038 Kyiv, Ukraine
- Receptor.AI Incorporated, 20-22 Wenlock Road, N1 7GU London, U.K
| | - Hector Martinez-Seara
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
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4
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Nuñez E, Jones F, Muguruza-Montero A, Urrutia J, Aguado A, Malo C, Bernardo-Seisdedos G, Domene C, Millet O, Gamper N, Villarroel A. Redox regulation of K V7 channels through EF3 hand of calmodulin. eLife 2023; 12:e81961. [PMID: 36803414 PMCID: PMC9988260 DOI: 10.7554/elife.81961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
Neuronal KV7 channels, important regulators of cell excitability, are among the most sensitive proteins to reactive oxygen species. The S2S3 linker of the voltage sensor was reported as a site-mediating redox modulation of the channels. Recent structural insights reveal potential interactions between this linker and the Ca2+-binding loop of the third EF-hand of calmodulin (CaM), which embraces an antiparallel fork formed by the C-terminal helices A and B, constituting the calcium responsive domain (CRD). We found that precluding Ca2+ binding to the EF3 hand, but not to EF1, EF2, or EF4 hands, abolishes oxidation-induced enhancement of KV7.4 currents. Monitoring FRET (Fluorescence Resonance Energy Transfer) between helices A and B using purified CRDs tagged with fluorescent proteins, we observed that S2S3 peptides cause a reversal of the signal in the presence of Ca2+ but have no effect in the absence of this cation or if the peptide is oxidized. The capacity of loading EF3 with Ca2+ is essential for this reversal of the FRET signal, whereas the consequences of obliterating Ca2+ binding to EF1, EF2, or EF4 are negligible. Furthermore, we show that EF3 is critical for translating Ca2+ signals to reorient the AB fork. Our data are consistent with the proposal that oxidation of cysteine residues in the S2S3 loop relieves KV7 channels from a constitutive inhibition imposed by interactions between the EF3 hand of CaM which is crucial for this signaling.
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Affiliation(s)
| | - Frederick Jones
- School of Biomedical Sciences, Faculty of Biological Sciences, University of LeedsLeedsUnited Kingdom
| | | | | | | | | | | | - Carmen Domene
- Department of Chemistry, University of BathBathUnited Kingdom
- Department of Chemistry, University of OxfordOxfordUnited Kingdom
| | - Oscar Millet
- Protein Stability and Inherited Disease Laboratory, CIC bioGUNEDerioSpain
| | - Nikita Gamper
- School of Biomedical Sciences, Faculty of Biological Sciences, University of LeedsLeedsUnited Kingdom
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5
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El Harrar T, Gohlke H. Cumulative Millisecond-Long Sampling for a Comprehensive Energetic Evaluation of Aqueous Ionic Liquid Effects on Amino Acid Interactions. J Chem Inf Model 2023; 63:281-298. [PMID: 36520535 DOI: 10.1021/acs.jcim.2c01123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The interactions of amino acid side-chains confer diverse energetic contributions and physical properties to a protein's stability and function. Various computational tools estimate the effect of changing a given amino acid on the protein's stability based on parametrized (free) energy functions. When parametrized for the prediction of protein stability in water, such energy functions can lead to suboptimal results for other solvents, such as ionic liquids (IL), aqueous ionic liquids (aIL), or salt solutions. However, to our knowledge, no comprehensive data are available describing the energetic effects of aIL on intramolecular protein interactions. Here, we present the most comprehensive set of potential of mean force (PMF) profiles of pairwise protein-residue interactions to date, covering 50 relevant interactions in water, the two biotechnologically relevant aIL [BMIM/Cl] and [BMIM/TfO], and [Na/Cl]. These results are based on a cumulated simulation time of >1 ms. aIL and salt ions can weaken, but also strengthen, specific residue interactions by more than 3 kcal mol-1, depending on the residue pair, residue-residue configuration, participating ions, and concentration, necessitating considering such interactions specifically. These changes originate from a complex interplay of competitive or cooperative noncovalent ion-residue interactions, changes in solvent structural dynamics, or unspecific charge screening effects and occur at the contact distance but also at larger, solvent-separated distances. This data provide explanations at the atomistic and energetic levels for complex IL effects on protein stability and should help improve the prediction accuracies of computational tools that estimate protein stability based on (free) energy functions.
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Affiliation(s)
- Till El Harrar
- Institute of Biotechnology, RWTH Aachen University, 52074 Aachen, Germany.,John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Biochemistry), and Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - Holger Gohlke
- John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Biochemistry), and Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.,Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
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6
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Koskamp JA, Ruiz Hernandez SE, de Leeuw NH, Wolthers M. Recalibrating the calcium trap in amino acid carboxyl groups via classical molecular dynamics simulations. Phys Chem Chem Phys 2023; 25:1220-1235. [PMID: 36524712 PMCID: PMC9811642 DOI: 10.1039/d2cp02879d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In order to use classical molecular dynamics to complement experiments accurately, it is important to use robust descriptions of the system. The interactions between biomolecules, like aspartic and glutamic acid, and dissolved ions are often studied using standard biomolecular force-fields, where the interactions between biomolecules and cations are often not parameterized explicitly. In this study, we have employed metadynamics simulations to investigate different interactions of Ca with aspartic and glutamic acid and constructed the free energy profiles of Ca2+-carboxylate association. Starting from a generally accepted, AMBER-based force field, the association was substantially over and under-estimated, depending on the choice of water model (TIP3P and SPC/fw, respectively). To rectify this discrepancy, we have replaced the default calcium parameters. Additionally, we modified the σij value in the hetero-atomic Lennard-Jones interaction by 0.5% to further improve the interaction between Ca and carboxylate, based on comparison with the experimentally determined association constant for Ca with the carboxylate group of L-aspartic acid. The corrected description retrieved the structural properties of the ion pair in agreement with the original biomolecule - Ca2+ interaction in AMBER, whilst also producing an association constant comparable to experimental observations. This refined force field was then used to investigate the interactions between amino acids, calcium and carbonate ions during biogenic and biomimetic calcium carbonate mineralisation.
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Affiliation(s)
- Janou A. Koskamp
- Department of Earth Sciences, Utrecht University3584 CB UtrechtThe Netherlands+31302535042
| | | | - Nora H. de Leeuw
- Department of Earth Sciences, Utrecht University3584 CB UtrechtThe Netherlands+31302535042,School of Chemistry, University of LeedsLeeds LS2 9JTUK
| | - Mariette Wolthers
- Department of Earth Sciences, Utrecht University3584 CB UtrechtThe Netherlands+31302535042
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7
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Berselli A, Benfenati F, Maragliano L, Alberini G. Multiscale modelling of claudin-based assemblies: a magnifying glass for novel structures of biological interfaces. Comput Struct Biotechnol J 2022; 20:5984-6010. [DOI: 10.1016/j.csbj.2022.10.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/24/2022] [Accepted: 10/24/2022] [Indexed: 11/03/2022] Open
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8
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Comparison of the ionic effects of Ca2+ and Mg2+ on nucleic acids in liquids. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Zlobin A, Diankin I, Pushkarev S, Golovin A. Probing the Suitability of Different Ca 2+ Parameters for Long Simulations of Diisopropyl Fluorophosphatase. Molecules 2021; 26:5839. [PMID: 34641383 PMCID: PMC8510429 DOI: 10.3390/molecules26195839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 11/16/2022] Open
Abstract
Organophosphate hydrolases are promising as potential biotherapeutic agents to treat poisoning with pesticides or nerve gases. However, these enzymes often need to be further engineered in order to become useful in practice. One example of such enhancement is the alteration of enantioselectivity of diisopropyl fluorophosphatase (DFPase). Molecular modeling techniques offer a unique opportunity to address this task rationally by providing a physical description of the substrate-binding process. However, DFPase is a metalloenzyme, and correct modeling of metal cations is a challenging task generally coming with a tradeoff between simulation speed and accuracy. Here, we probe several molecular mechanical parameter combinations for their ability to empower long simulations needed to achieve a quantitative description of substrate binding. We demonstrate that a combination of the Amber19sb force field with the recently developed 12-6 Ca2+ models allows us to both correctly model DFPase and obtain new insights into the DFP binding process.
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Affiliation(s)
- Alexander Zlobin
- Faculty of Bioengineering, Lomonosov Moscow State University, 119234 Moscow, Russia; (I.D.); (S.P.)
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Sirius University of Science and Technology, 354340 Sochi, Russia
| | - Igor Diankin
- Faculty of Bioengineering, Lomonosov Moscow State University, 119234 Moscow, Russia; (I.D.); (S.P.)
- Sirius University of Science and Technology, 354340 Sochi, Russia
| | - Sergey Pushkarev
- Faculty of Bioengineering, Lomonosov Moscow State University, 119234 Moscow, Russia; (I.D.); (S.P.)
| | - Andrey Golovin
- Faculty of Bioengineering, Lomonosov Moscow State University, 119234 Moscow, Russia; (I.D.); (S.P.)
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Sirius University of Science and Technology, 354340 Sochi, Russia
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10
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Navarro-Retamal C, Schott-Verdugo S, Gohlke H, Dreyer I. Computational Analyses of the AtTPC1 (Arabidopsis Two-Pore Channel 1) Permeation Pathway. Int J Mol Sci 2021; 22:ijms221910345. [PMID: 34638686 PMCID: PMC8508871 DOI: 10.3390/ijms221910345] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/14/2021] [Accepted: 09/21/2021] [Indexed: 12/26/2022] Open
Abstract
Two Pore Channels (TPCs) are cation-selective voltage- and ligand-gated ion channels in membranes of intracellular organelles of eukaryotic cells. In plants, the TPC1 subtype forms the slowly activating vacuolar (SV) channel, the most dominant ion channel in the vacuolar membrane. Controversial reports about the permeability properties of plant SV channels fueled speculations about the physiological roles of this channel type. TPC1 is thought to have high Ca2+ permeability, a conclusion derived from relative permeability analyses using the Goldman–Hodgkin–Katz (GHK) equation. Here, we investigated in computational analyses the properties of the permeation pathway of TPC1 from Arabidopsis thaliana. Using the crystal structure of AtTPC1, protein modeling, molecular dynamics (MD) simulations, and free energy calculations, we identified a free energy minimum for Ca2+, but not for K+, at the luminal side next to the selectivity filter. Residues D269 and E637 coordinate in particular Ca2+ as demonstrated in in silico mutagenesis experiments. Such a Ca2+-specific coordination site in the pore explains contradicting data for the relative Ca2+/K+ permeability and strongly suggests that the Ca2+ permeability of SV channels is largely overestimated from relative permeability analyses. This conclusion was further supported by in silico electrophysiological studies showing a remarkable permeation of K+ but not Ca2+ through the open channel.
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Affiliation(s)
- Carlos Navarro-Retamal
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Campus Talca, Universidad de Talca, Talca 346000, Chile
- Correspondence: (C.N.-R.); (H.G.); (I.D.)
| | - Stephan Schott-Verdugo
- John von Neumann Institute for Computing (NIC), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany;
- Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Institute of Biological Information Processing (IBI-7: Structural Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Holger Gohlke
- John von Neumann Institute for Computing (NIC), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany;
- Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Institute of Biological Information Processing (IBI-7: Structural Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- Correspondence: (C.N.-R.); (H.G.); (I.D.)
| | - Ingo Dreyer
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Campus Talca, Universidad de Talca, Talca 346000, Chile
- Correspondence: (C.N.-R.); (H.G.); (I.D.)
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11
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Mohanty P, Chatterjee KS, Das R. NEDD8 Deamidation Inhibits Cullin RING Ligase Dynamics. Front Immunol 2021; 12:695331. [PMID: 34489942 PMCID: PMC8418054 DOI: 10.3389/fimmu.2021.695331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/29/2021] [Indexed: 11/15/2022] Open
Abstract
Cullin-RING ligases (CRLs) are a significant subset of Ubiquitin E3 ligases that regulate multiple cellular substrates involved in innate immunity, cytoskeleton modeling, and cell cycle. The glutamine deamidase Cycle inhibitory factor (Cif) from enteric bacteria inactivates CRLs to modulate these processes in the host cell. The covalent attachment of a Ubiquitin-like protein NEDD8 catalytically activates CRLs by driving conformational changes in the Cullin C-terminal domain (CTD). NEDDylation results in a shift from a compact to an open CTD conformation through non-covalent interactions between NEDD8 and the WHB subdomain of CTD, eliminating the latter’s inhibitory interactions with the RING E3 ligase-Rbx1/2. It is unknown whether the non-covalent interactions are sufficient to stabilize Cullin CTD’s catalytic conformation. We studied the dynamics of Cullin-CTD in the presence and absence of NEDD8 using atomistic molecular dynamics (MD) simulations. We uncovered that NEDD8 engages in non-covalent interactions with 4HB/αβ subdomains in Cullin-CTD to promote open conformations. Cif deamidates glutamine 40 in NEDD8 to inhibit the conformational change in CRLs by an unknown mechanism. We investigated the effect of glutamine deamidation on NEDD8 and its interaction with the WHB subdomain post-NEDDylation using MD simulations and NMR spectroscopy. Our results suggest that deamidation creates a new intramolecular salt bridge in NEDD8 to destabilize the NEDD8/WHB complex and reduce CRL activity.
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Affiliation(s)
- Priyesh Mohanty
- National Center for Biological Sciences, Tata Institute of Fundamental Research (TIFR), Bangalore, India
| | - Kiran Sankar Chatterjee
- National Center for Biological Sciences, Tata Institute of Fundamental Research (TIFR), Bangalore, India
| | - Ranabir Das
- National Center for Biological Sciences, Tata Institute of Fundamental Research (TIFR), Bangalore, India
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12
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Shi R, Zhao Z, Huang X, Wang P, Su Y, Sai L, Liang X, Han H, Zhao J. Ground-State Structures of Hydrated Calcium Ion Clusters From Comprehensive Genetic Algorithm Search. Front Chem 2021; 9:637750. [PMID: 34277560 PMCID: PMC8277924 DOI: 10.3389/fchem.2021.637750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 06/02/2021] [Indexed: 12/03/2022] Open
Abstract
We searched the lowest-energy structures of hydrated calcium ion clusters Ca2+(H2O)n (n = 10-18) in the whole potential energy surface by the comprehensive genetic algorithm (CGA). The lowest-energy structures of Ca2+(H2O)10-12 clusters show that Ca2+ is always surrounded by six H2O molecules in the first shell. The number of first-shell water molecules changes from six to eight at n = 12. In the range of n = 12-18, the number of first-shell water molecules fluctuates between seven and eight, meaning that the cluster could pack the water molecules in the outer shell even though the inner shell is not full. Meanwhile, the number of water molecules in the second shell and the total hydrogen bonds increase with an increase in the cluster size. The distance between Ca2+ and the adjacent water molecules increases, while the average adjacent O-O distance decreases as the cluster size increases, indicating that the interaction between Ca2+ and the adjacent water molecules becomes weaker and the interaction between water molecules becomes stronger. The interaction energy and natural bond orbital results show that the interaction between Ca2+ and the water molecules is mainly derived from the interaction between Ca2+ and the adjacent water molecules. The charge transfer from the lone pair electron orbital of adjacent oxygen atoms to the empty orbital of Ca2+ plays a leading role in the interaction between Ca2+ and water molecules.
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Affiliation(s)
- Ruili Shi
- School of Mathematics and Physics, Hebei University of Engineering, Handan, China
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian, China
| | - Zhi Zhao
- School of Mathematics and Physics, Hebei University of Engineering, Handan, China
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian, China
| | - Xiaoming Huang
- School of Ocean Science and Technology, Dalian University of Technology, Panjin Campus, Panjin, China
| | - Pengju Wang
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian, China
| | - Yan Su
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian, China
| | - Linwei Sai
- Department of Mathematics and Physics, Hohai University, Changzhou, China
| | - Xiaoqing Liang
- School of Electronics and Information Engineering, Taizhou University, Taizhou, China
| | - Haiyan Han
- School of Mathematics and Physics, Hebei University of Engineering, Handan, China
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian, China
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13
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Guvench O, Whitmore EK. Sulfation and Calcium Favor Compact Conformations of Chondroitin in Aqueous Solutions. ACS OMEGA 2021; 6:13204-13217. [PMID: 34056470 PMCID: PMC8158799 DOI: 10.1021/acsomega.1c01071] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/28/2021] [Indexed: 06/01/2023]
Abstract
The effects of sulfation and calcium cations (Ca2+) on the atomic-resolution conformational properties of chondroitin carbohydrate polymers in aqueous solutions are not well studied owing to experimental challenges. Here, we compare all-atom explicit-solvent molecular dynamics simulations results for pairs of O-type (nonsulfated) and A-type (GlcNAc 4-O-sulfated) chondroitin 20-mers in 140 mM NaCl with and without Ca2+ and find that both sulfation and Ca2+ favor more compact polymer conformations. We also show that subtle differences in force-field parametrization can have dramatic effects on Ca2+ binding to chondroitin carboxylate and sulfate functional groups and thereby determine Ca2+-mediated intra- and interstrand association. In addition to providing an atomic-resolution picture of the interaction of Ca2+ with sulfated and nonsulfated chondroitin polymers, the molecular dynamics data emphasize the importance of careful force-field parametrization to balance ion-water and ion-chondroitin interactions and suggest additional parametrization efforts to tune interactions involving sulfate.
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Affiliation(s)
- Olgun Guvench
- Department
of Pharmaceutical Sciences and Administration, School of Pharmacy, Westbrook College of Health Professions, University
of New England, 716 Stevens
Avenue, Portland, Maine 04103, United States
- Graduate
School of Biomedical Science and Engineering, University of Maine, 5775 Stodder Hall, Orono, Maine 04469, United
States
| | - Elizabeth K. Whitmore
- Department
of Pharmaceutical Sciences and Administration, School of Pharmacy, Westbrook College of Health Professions, University
of New England, 716 Stevens
Avenue, Portland, Maine 04103, United States
- Graduate
School of Biomedical Science and Engineering, University of Maine, 5775 Stodder Hall, Orono, Maine 04469, United
States
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14
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The molecular basis for the pH-dependent calcium affinity of the pattern recognition receptor langerin. J Biol Chem 2021; 296:100718. [PMID: 33989634 PMCID: PMC8219899 DOI: 10.1016/j.jbc.2021.100718] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/12/2021] [Accepted: 04/27/2021] [Indexed: 02/07/2023] Open
Abstract
The C-type lectin receptor langerin plays a vital role in the mammalian defense against invading pathogens. Langerin requires a Ca2+ cofactor, the binding affinity of which is regulated by pH. Thus, Ca2+ is bound when langerin is on the membrane but released when langerin and its pathogen substrate traffic to the acidic endosome, allowing the substrate to be degraded. The change in pH is sensed by protonation of the allosteric pH sensor histidine H294. However, the mechanism by which Ca2+ is released from the buried binding site is not clear. We studied the structural consequences of protonating H294 by molecular dynamics simulations (total simulation time: about 120 μs) and Markov models. We discovered a relay mechanism in which a proton is moved into the vicinity of the Ca2+-binding site without transferring the initial proton from H294. Protonation of H294 unlocks a conformation in which a protonated lysine side chain forms a hydrogen bond with a Ca2+-coordinating aspartic acid. This destabilizes Ca2+ in the binding pocket, which we probed by steered molecular dynamics. After Ca2+ release, the proton is likely transferred to the aspartic acid and stabilized by a dyad with a nearby glutamic acid, triggering a conformational transition and thus preventing Ca2+ rebinding. These results show how pH regulation of a buried orthosteric binding site from a solvent-exposed allosteric pH sensor can be realized by information transfer through a specific chain of conformational arrangements.
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15
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Duboué-Dijon E, Javanainen M, Delcroix P, Jungwirth P, Martinez-Seara H. A practical guide to biologically relevant molecular simulations with charge scaling for electronic polarization. J Chem Phys 2021; 153:050901. [PMID: 32770904 DOI: 10.1063/5.0017775] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Molecular simulations can elucidate atomistic-level mechanisms of key biological processes, which are often hardly accessible to experiment. However, the results of the simulations can only be as trustworthy as the underlying simulation model. In many of these processes, interactions between charged moieties play a critical role. Current empirical force fields tend to overestimate such interactions, often in a dramatic way, when polyvalent ions are involved. The source of this shortcoming is the missing electronic polarization in these models. Given the importance of such biomolecular systems, there is great interest in fixing this deficiency in a computationally inexpensive way without employing explicitly polarizable force fields. Here, we review the electronic continuum correction approach, which accounts for electronic polarization in a mean-field way, focusing on its charge scaling variant. We show that by pragmatically scaling only the charged molecular groups, we qualitatively improve the charge-charge interactions without extra computational costs and benefit from decades of force field development on biomolecular force fields.
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Affiliation(s)
- E Duboué-Dijon
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - M Javanainen
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, Prague 6 166 10, Czech Republic
| | - P Delcroix
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, Prague 6 166 10, Czech Republic
| | - P Jungwirth
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, Prague 6 166 10, Czech Republic
| | - H Martinez-Seara
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, Prague 6 166 10, Czech Republic
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16
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Zheng W, Wen H. Investigating dual Ca 2+ modulation of the ryanodine receptor 1 by molecular dynamics simulation. Proteins 2020; 88:1528-1539. [PMID: 32557910 DOI: 10.1002/prot.25971] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 05/26/2020] [Accepted: 06/14/2020] [Indexed: 11/09/2022]
Abstract
The ryanodine receptors (RyR) are essential to calcium signaling in striated muscles. A deep understanding of the complex Ca2+ -activation/inhibition mechanism of RyRs requires detailed structural and dynamic information for RyRs in different functional states (eg, with Ca2+ bound to activating or inhibitory sites). Recently, high-resolution structures of the RyR isoform 1 (RyR1) were solved by cryo-electron microscopy, revealing the location of a Ca2+ binding site for activation. Toward elucidating the Ca2+ -modulation mechanism of RyR1, we performed extensive molecular dynamics simulation of the core RyR1 structure in the presence and absence of activating and solvent Ca2+ (total simulation time is >5 μs). In the presence of solvent Ca2+ , Ca2+ binding to the activating site enhanced dynamics of RyR1 with higher inter-subunit flexibility, asymmetric inter-subunit motions, outward domain motions and partial pore dilation, which may prime RyR1 for subsequent channel opening. In contrast, the solvent Ca2+ alone reduced dynamics of RyR1 and led to inward domain motions and pore contraction, which may cause inhibition. Combining our simulation with the map of disease mutation sites in RyR1, we constructed a wiring diagram of key domains coupled via specific hydrogen bonds involving the mutation sites, some of which were modulated by Ca2+ binding. The structural and dynamic information gained from this study will inform future mutational and functional studies of RyR1 activation and inhibition by Ca2+ .
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Affiliation(s)
- Wenjun Zheng
- Department of Physics, University at Buffalo, Buffalo, New York, USA
| | - Han Wen
- Department of Physics, University at Buffalo, Buffalo, New York, USA
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17
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Tolmachev D, Lukasheva N, Mamistvalov G, Karttunen M. Influence of Calcium Binding on Conformations and Motions of Anionic Polyamino Acids. Effect of Side Chain Length. Polymers (Basel) 2020; 12:E1279. [PMID: 32503199 PMCID: PMC7362111 DOI: 10.3390/polym12061279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 11/21/2022] Open
Abstract
Investigation of the effect of CaCl2 salt on conformations of two anionic poly(amino acids) with different side chain lengths, poly-(α-l glutamic acid) (PGA) and poly-(α-l aspartic acid) (PASA), was performed by atomistic molecular dynamics (MD) simulations. The simulations were performed using both unbiased MD and the Hamiltonian replica exchange (HRE) method. The results show that at low CaCl2 concentration adsorption of Ca2+ ions lead to a significant chain size reduction for both PGA and PASA. With the increase in concentration, the chains sizes partially recover due to electrostatic repulsion between the adsorbed Ca2+ ions. Here, the side chain length becomes important. Due to the longer side chain and its ability to distance the charged groups with adsorbed ions from both each other and the backbone, PGA remains longer in the collapsed state as the CaCl2 concentration is increased. The analysis of the distribution of the mineral ions suggests that both poly(amino acids) should induce the formation of mineral with the same structure of the crystal cell.
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Affiliation(s)
- Dmitry Tolmachev
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, 199004 St. Petersburg, Russia;
| | - Natalia Lukasheva
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, 199004 St. Petersburg, Russia;
| | - George Mamistvalov
- Faculty of Physics, St. Petersburg State University, Petrodvorets, 198504 St. Petersburg, Russia;
| | - Mikko Karttunen
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, 199004 St. Petersburg, Russia;
- Department of Chemistry, the University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Department of Applied Mathematics, the University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- The Centre of Advanced Materials and Biomaterials Research, the University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
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18
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Prajapati JD, Mele C, Aksoyoglu MA, Winterhalter M, Kleinekathöfer U. Computational Modeling of Ion Transport in Bulk and through a Nanopore Using the Drude Polarizable Force Field. J Chem Inf Model 2020; 60:3188-3203. [DOI: 10.1021/acs.jcim.0c00389] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
| | - Crystal Mele
- Department of Physics and Earth Sciences, Jacobs University Bremen, 28759 Bremen, Germany
| | | | - Mathias Winterhalter
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, 28759 Bremen, Germany
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19
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Bradley RP, Slochower DR, Janmey PA, Radhakrishnan R. Divalent cations bind to phosphoinositides to induce ion and isomer specific propensities for nano-cluster initiation in bilayer membranes. ROYAL SOCIETY OPEN SCIENCE 2020; 7:192208. [PMID: 32537210 PMCID: PMC7277276 DOI: 10.1098/rsos.192208] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/14/2020] [Indexed: 05/22/2023]
Abstract
We report all-atom molecular dynamics simulations of asymmetric bilayers containing phosphoinositides in the presence of monovalent and divalent cations. We have characterized the molecular mechanism by which these divalent cations interact with phosphoinositides. Ca2+ desolvates more readily, consistent with single-molecule calculations, and forms a network of ionic-like bonds that serve as a 'molecular glue' that allows a single ion to coordinate with up to three phosphatidylinositol-(4,5)-bisphosphate (PI(4, 5)P2) lipids. The phosphatidylinositol-(3,5)-bisphosphate isomer shows no such effect and neither does PI(4, 5)P2 in the presence of Mg2+. The resulting network of Ca2+-mediated lipid-lipid bonds grows to span the entire simulation space and therefore has implications for the lateral distribution of phosophoinositides in the bilayer. We observe context-specific differences in lipid diffusion rates, lipid surface densities and bilayer structure. The molecular-scale delineation of ion-lipid arrangements reported here provides insight into similar nanocluster formation induced by peripheral proteins to regulate the formation of functional signalling complexes on the membrane.
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Affiliation(s)
- Ryan P. Bradley
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David R. Slochower
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paul A. Janmey
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ravi Radhakrishnan
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Author for correspondence: Ravi Radhakrishnan e-mail:
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20
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Long MP, Alland S, Martin ME, Isborn CM. Molecular dynamics simulations of alkaline earth metal ions binding to DNA reveal ion size and hydration effects. Phys Chem Chem Phys 2020; 22:5584-5596. [DOI: 10.1039/c9cp06844a] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Classical molecular dynamics simulations reveal size-dependent trends of alkaline earth metal ions binding to DNA are due to ion size and hydration behavior.
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Affiliation(s)
| | - Serra Alland
- Department of Chemistry and Biochemistry
- University of Central Arkansas
- Arkansas 72035
- USA
| | - Madison E. Martin
- Department of Chemistry and Biochemistry
- University of Central Arkansas
- Arkansas 72035
- USA
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21
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Nikitin A, Del Frate G. Development of Nonbonded Models for Metal Cations Using the Electronic Continuum Correction. J Comput Chem 2019; 40:2464-2472. [PMID: 31301182 DOI: 10.1002/jcc.26021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/14/2019] [Accepted: 06/06/2019] [Indexed: 12/24/2022]
Abstract
The parametrization of classical nonbonded models of metal ions has been widely addressed in the recent years. Despite the continuous development of novel and more physically inspired functional forms, the 12-6 Lennard-Jones plus Coulomb potential is still the most adopted force field in molecular dynamics (MD) codes, owing to its simple form and easy implementation. However, due to the integer formal charge, unpolarizable force fields of ions may suffer from overestimated interatomic electrostatic interactions, leading to nonphysical clustering or repulsion between such full charges. The electronic continuum correction (ECC) can fix this problem through a simple inclusion of solvent polarization effects via ionic charge rescaling. In this work, the development of novel nonbonded models for mono, divalent, and highly charged metal ions is presented. For each metal species, the ionic charge has been scaled, according to the ECC. Lennard-Jones parameters have been optimized using experimental structural and thermodynamic properties as target quantities. Performances of the proposed models are discussed and compared with the literature data, while transferability attitudes among different and well-known water models are evaluated. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexei Nikitin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russian Federation.,Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126, Pisa, Italy
| | - Gianluca Del Frate
- IMT School for Advanced Studies Lucca, Piazza S. Francesco 19, I-55100, Lucca, Italy
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22
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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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23
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Nieto-Draghi C, Rousseau B. Thermodynamically Consistent Force Field for Coarse-Grained Modeling of Aqueous Electrolyte Solution. J Phys Chem B 2019; 123:2424-2431. [DOI: 10.1021/acs.jpcb.8b11190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Carlos Nieto-Draghi
- IFP Energies nouvelles, 1-4 Avenue de Bois Préau, 92852 Rueil-Malmaison, France
| | - Bernard Rousseau
- Laboratoire de Chimie Physique, UMR 8000 CNRS, Université Paris-Sud, 91405 Orsay, France
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24
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Abstract
Complex carbohydrates are ubiquitous in nature, and together with proteins and nucleic acids they comprise the building blocks of life. But unlike proteins and nucleic acids, carbohydrates form nonlinear polymers, and they are not characterized by robust secondary or tertiary structures but rather by distributions of well-defined conformational states. Their molecular flexibility means that oligosaccharides are often refractory to crystallization, and nuclear magnetic resonance (NMR) spectroscopy augmented by molecular dynamics (MD) simulation is the leading method for their characterization in solution. The biological importance of carbohydrate-protein interactions, in organismal development as well as in disease, places urgency on the creation of innovative experimental and theoretical methods that can predict the specificity of such interactions and quantify their strengths. Additionally, the emerging realization that protein glycosylation impacts protein function and immunogenicity places the ability to define the mechanisms by which glycosylation impacts these features at the forefront of carbohydrate modeling. This review will discuss the relevant theoretical approaches to studying the three-dimensional structures of this fascinating class of molecules and interactions, with reference to the relevant experimental data and techniques that are key for validation of the theoretical predictions.
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Affiliation(s)
- Robert J Woods
- Complex Carbohydrate Research Center and Department of Biochemistry and Molecular Biology , University of Georgia , 315 Riverbend Road , Athens , Georgia 30602 , United States
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25
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Naleem N, Bentenitis N, Smith PE. A Kirkwood-Buff derived force field for alkaline earth halide salts. J Chem Phys 2018; 148:222828. [PMID: 29907021 DOI: 10.1063/1.5019454] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The activity and function of many macromolecules in cellular environments are coupled with the binding of divalent ions such as calcium or magnesium. In principle, computer simulations can be used to understand the molecular level aspects of how many important macromolecules interact with ions. However, most of the force fields currently available often fail to accurately reproduce the properties of divalent ions in aqueous environments. Here we develop classical non-polarizable force fields for the aqueous alkaline earth metal halides (MX2), where M = Mg2+, Ca2+, Sr2+, Ba2+ and X = Cl-, Br-, I-, which can be used in bimolecular simulations and which are compatible with the Simple Point Charge/Extended (SPC/E) water model. The force field parameters are specifically developed to reproduce the experimental Kirkwood-Buff integrals for aqueous solutions and thereby the experimental activity derivatives, partial molar volumes, and excess coordination numbers. This ensures that a reasonable balance between ion-ion, ion-water, and water-water distributions is obtained. However, this requires a scaling of the cation to water oxygen interaction strength in order to accurately reproduce the integrals. The scaling factors developed for chloride salts are successfully transferable to the bromide and iodide salts. Use of these new models leads to reasonable diffusion constants and dielectric decrements. However, the performance of the models decreases with increasing salt concentration (>4m), and simulations of the pure crystals exhibited unstable behavior.
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Affiliation(s)
- Nawavi Naleem
- Department of Chemistry, Kansas State University, 213 CBC Building, 1212 Mid Campus Dr. North, Manhattan, Kansas 66506-0401, USA
| | - Nikolaos Bentenitis
- Department of Chemistry, Kansas State University, 213 CBC Building, 1212 Mid Campus Dr. North, Manhattan, Kansas 66506-0401, USA
| | - Paul E Smith
- Department of Chemistry, Kansas State University, 213 CBC Building, 1212 Mid Campus Dr. North, Manhattan, Kansas 66506-0401, USA
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26
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Abstract
Microtubules, constituted by end-to-end negatively charged α- and β-tubulin dimers, are long, hollow, pseudohelical cylinders with internal and external diameters of about 16 and 26 nm, respectively, and widely exist in cell cytoplasm, neuron axons, and dendrites. Although their structural functions in physiological processes, such as cell mitosis, cell motility, and motor protein transport, have been widely accepted, their role in neuron activity remains attractively elusive. Here we show a new function of microtubules: they can generate instant response to a calcium pulse because of their specific permeability for ions. Our comprehensive simulations from all-atom molecular dynamics to potential of mean force and continuum modeling reveal that K+ and Na+ ions can permeate through the nanopores in the microtubule wall easily, while Ca2+ ions are blocked by the wall with a much higher free energy barrier. These cations are adsorbed to the surfaces of the wall with affinity decreasing in the sequence Ca2+, Na+, and K+. As a result, when the concentration of Ca2+ ions increases outside the microtubule during neuronal excitation, K+ and Na+ ions will be driven into the microtubule, triggering subsequent axial ion redistribution within the microtubule. The results shed light on the possibility of the ion-permeable microtubules being involved in neural signal processing.
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Affiliation(s)
- Chun Shen
- State Key Laboratory of Mechanics and Control of Mechanical Structure and Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, and Institute of Nanoscience , Nanjing University of Aeronautics and Astronautics , Nanjing 210016 , China
| | - Wanlin Guo
- State Key Laboratory of Mechanics and Control of Mechanical Structure and Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, and Institute of Nanoscience , Nanjing University of Aeronautics and Astronautics , Nanjing 210016 , China
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27
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Yoo J, Aksimentiev A. New tricks for old dogs: improving the accuracy of biomolecular force fields by pair-specific corrections to non-bonded interactions. Phys Chem Chem Phys 2018; 20:8432-8449. [PMID: 29547221 DOI: 10.1039/c7cp08185e] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In contrast to ordinary polymers, the vast majority of biological macromolecules adopt highly ordered three-dimensional structures that define their functions. The key to folding of a biopolymer into a unique 3D structure or to an assembly of several biopolymers into a functional unit is a delicate balance between the attractive and repulsive forces that also makes such self-assembly reversible under physiological conditions. The all-atom molecular dynamics (MD) method has emerged as a powerful tool for studies of individual biomolecules and their functional assemblies, encompassing systems of ever increasing complexity. However, advances in parallel computing technology have outpaced the development of the underlying theoretical models-the molecular force fields, pushing the MD method into an untested territory. Recent tests of the MD method have found the most commonly used molecular force fields to be out of balance, overestimating attractive interactions between charged and hydrophobic groups, which can promote artificial aggregation in MD simulations of multi-component protein, nucleic acid, and lipid systems. One route towards improving the force fields is through the NBFIX corrections method, in which the intermolecular forces are calibrated against experimentally measured quantities such as osmotic pressure by making atom pair-specific adjustments to the non-bonded interactions. In this article, we review development of the NBFIX (Non-Bonded FIX) corrections to the AMBER and CHARMM force fields and discuss their implications for MD simulations of electrolyte solutions, dense DNA systems, Holliday junctions, protein folding, and lipid bilayer membranes.
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Affiliation(s)
- Jejoong Yoo
- Center for the Physics of Living Cells, Department of Physics and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801, USA. and Center for Self-assembly and Complexity, Institute for Basic Science, Pohang, 37363, Republic of Korea
| | - Aleksei Aksimentiev
- Center for the Physics of Living Cells, Department of Physics and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801, USA.
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28
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Sauter J, Grafmüller A. Efficient Osmotic Pressure Calculations Using Coarse-Grained Molecular Simulations. J Chem Theory Comput 2018; 14:1171-1176. [PMID: 29401374 DOI: 10.1021/acs.jctc.7b01220] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Osmotic pressure data is increasingly used to parametrize all-atom simulation Force Fields (FFs), leading to large computational cost for larger molecules. Here, we show that the osmotic pressure can be calculated precisely using transferable coarse-grained FFs obtained from short atomistic simulations using an inhomogeneously regularized coarse-graining procedure. This is demonstrated for carbohydrates, where compared to the equivalent atomistic system, an increase of the computational efficiency by a factor of ≈500 is achieved.
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Affiliation(s)
- Jörg Sauter
- Department of Theory and Biosystems , Max Planck Institute of Colloids and Interfaces , Potsdam 14424 , Germany
| | - Andrea Grafmüller
- Department of Theory and Biosystems , Max Planck Institute of Colloids and Interfaces , Potsdam 14424 , Germany
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29
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Jacobson DR, Saleh OA. Counting the ions surrounding nucleic acids. Nucleic Acids Res 2017; 45:1596-1605. [PMID: 28034959 PMCID: PMC5389524 DOI: 10.1093/nar/gkw1305] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/21/2016] [Indexed: 01/29/2023] Open
Abstract
Nucleic acids are strongly negatively charged, and thus electrostatic interactions—screened by ions in solution—play an important role in governing their ability to fold and participate in biomolecular interactions. The negative charge creates a region, known as the ion atmosphere, in which cation and anion concentrations are perturbed from their bulk values. Ion counting experiments quantify the ion atmosphere by measuring the preferential ion interaction coefficient: the net total number of excess ions above, or below, the number expected due to the bulk concentration. The results of such studies provide important constraints on theories, which typically predict the full three-dimensional distribution of the screening cloud. This article reviews the state of nucleic acid ion counting measurements and critically analyzes their ability to test both analytical and simulation-based models.
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Affiliation(s)
- David R Jacobson
- Department of Physics, University of California, Santa Barbara, CA 93106, USA
| | - Omar A Saleh
- Materials Department and BMSE Program, University of California, Santa Barbara, CA 93106, USA
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30
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Lay WK, Miller MS, Elcock AH. Reparameterization of Solute-Solute Interactions for Amino Acid-Sugar Systems Using Isopiestic Osmotic Pressure Molecular Dynamics Simulations. J Chem Theory Comput 2017; 13:1874-1882. [PMID: 28437100 PMCID: PMC5844349 DOI: 10.1021/acs.jctc.7b00194] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
AMBER/GLYCAM and CHARMM are popular force fields for simulations of amino acids and sugars. Here we report excessively attractive amino acid-sugar interactions in both force fields, and corrections to nonbonded interactions that match experimental osmotic pressures of mixed aqueous solutions of diglycine and sucrose. The modified parameters also improve the ΔGtrans of diglycine from water to aqueous sucrose and, with AMBERff99SB/GLYCAM06, eliminate a caging effect seen in previous simulations of the protein ubiquitin with glucose.
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Affiliation(s)
- Wesley K Lay
- Department of Biochemistry, University of Iowa , Iowa City, Iowa 52242, United States
| | - Mark S Miller
- Department of Biochemistry, University of Iowa , Iowa City, Iowa 52242, United States
| | - Adrian H Elcock
- Department of Biochemistry, University of Iowa , Iowa City, Iowa 52242, United States
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31
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Joshi H, Bhatia D, Krishnan Y, Maiti PK. Probing the structure and in silico stability of cargo loaded DNA icosahedra using MD simulations. NANOSCALE 2017; 9:4467-4477. [PMID: 28304019 DOI: 10.1039/c6nr08036g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Platonic solids such as polyhedra based on DNA have been deployed for multifarious applications such as RNAi delivery, biological targeting and bioimaging. All of these applications hinge on the capability of DNA polyhedra for molecular display with high spatial precision. Therefore high resolution structural models of such polyhedra are critical to widen their applications in both materials and biology. Here, we present an atomistic model of a well-characterized DNA icosahedron, with demonstrated versatile functionalities in biological systems. We study the structure and dynamics of this DNA icosahedron using fully atomistic molecular dynamics (MD) simulation in explicit water and ions. The major modes of internal motion have been identified using principal component analysis. We provide a quantitative estimate of the radius of gyration (Rg), solvent accessible surface area (SASA) and volume of the icosahedron which is essential to estimate its maximal cargo carrying capacity. Importantly, our simulation of gold nanoparticles (AuNPs) encapsulated within DNA icosahedra revealed enhanced stability of the AuNP loaded DNA icosahedra compared to empty icosahedra. This is consistent with the experimental results that show high yields of cargo-encapsulated DNA icosahedra that have led to its diverse applications for precision targeting. These studies reveal that the stabilizing interactions between the cargo and the DNA scaffold powerfully position DNA polyhedra as targetable nanocapsules for payload delivery. These insights can be exploited for precise molecular display for diverse biological applications.
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Affiliation(s)
- Himanshu Joshi
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| | - Dhiraj Bhatia
- Institut Curie, PSL Research University, Chemical Biology of Membranes and Therapeutic Delivery unit, INSERM, U 1143, CNRS, UMR 3666, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Yamuna Krishnan
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA and Grossman Institute of Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, Illinois 60637, USA
| | - Prabal K Maiti
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
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Yoo J, Aksimentiev A. Refined Parameterization of Nonbonded Interactions Improves Conformational Sampling and Kinetics of Protein Folding Simulations. J Phys Chem Lett 2016; 7:3812-3818. [PMID: 27617340 DOI: 10.1021/acs.jpclett.6b01747] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Recent advances in computational technology have enabled brute-force molecular dynamics (MD) simulations of protein folding using physics-based molecular force fields. The extensive sampling of protein conformations afforded by such simulations revealed, however, considerable compaction of the protein conformations in the unfolded state, which is inconsistent with experiment. Here, we show that a set of surgical corrections to nonbonded interactions between amine nitrogen-carboxylate oxygen and aliphatic carbon-carbon atom pairs can considerably improve the realism of protein folding simulations. Specifically, we show that employing our corrections in ∼500 μs all-atom replica-exchange MD simulations of the WW domain and villin head piece proteins increases the size of the denatured proteins' conformations and does not destabilize the native conformations of the proteins. In addition to making the folded conformations a global minimum of the respective free energy landscapes at room temperature, our corrections also make the free energy landscape smoother, considerably accelerating the folding kinetics and, hence, reducing the computational expense of a protein folding simulation.
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Affiliation(s)
- Jejoong Yoo
- Center for the Physics of Living Cells, Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801, United States
| | - Aleksei Aksimentiev
- Center for the Physics of Living Cells, Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801, United States
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33
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Sauter J, Grafmüller A. Predicting the Chemical Potential and Osmotic Pressure of Polysaccharide Solutions by Molecular Simulations. J Chem Theory Comput 2016; 12:4375-84. [PMID: 27529356 DOI: 10.1021/acs.jctc.6b00295] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Jörg Sauter
- Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces , 14424 Potsdam, Germany
| | - Andrea Grafmüller
- Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces , 14424 Potsdam, Germany
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Boiteux C, Allen TW. Understanding Sodium Channel Function and Modulation Using Atomistic Simulations of Bacterial Channel Structures. CURRENT TOPICS IN MEMBRANES 2016; 78:145-82. [PMID: 27586284 DOI: 10.1016/bs.ctm.2016.07.002] [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: 12/19/2022]
Abstract
Sodium channels are chief proteins involved in electrical signaling in the nervous system, enabling critical functions like heartbeat and brain activity. New high-resolution X-ray structures for bacterial sodium channels have created an opportunity to see how these proteins operate at the molecular level. An important challenge to overcome is establishing relationships between the structures and functions of mammalian and bacterial channels. Bacterial sodium channels are known to exhibit the main structural features of their mammalian counterparts, as well as several key functional characteristics, including selective ion conduction, voltage-dependent gating, pore-based inactivation and modulation by local anesthetic, antiarrhythmic and antiepileptic drugs. Simulations have begun to shed light on each of these features in the past few years. Despite deviations in selectivity signatures for bacterial and mammalian channels, simulations have uncovered the nature of the multiion conduction mechanism associated with Na(+) binding to a high-field strength site established by charged glutamate side chains. Simulations demonstrated a surprising level of flexibility of the protein, showing that these side chains are active participants in the permeation process. They have also uncovered changes in protein structure, leading to asymmetrical collapses of the activation gate that have been proposed to correspond to inactivated structures. These observations offer the potential to examine the mechanisms of state-dependent drug activity, focusing on pore-blocking and pore-based slow inactivation in bacterial channels, without the complexities of inactivation on multiple timescales seen in eukaryotic channels. Simulations have provided molecular views of the interactions of drugs, consistent with sites predicted in mammalian channels, as well as a wealth of other sites as potential new drug targets. In this chapter, we survey the new insights into sodium channel function that have emerged from studies of simpler bacterial channels, which provide an excellent learning platform, and promising avenues for mechanistic discovery and pharmacological development.
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Affiliation(s)
- C Boiteux
- RMIT University, Melbourne, VIC, Australia
| | - T W Allen
- RMIT University, Melbourne, VIC, Australia; University of California Davis, Davis, CA, United States
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Catte A, Girych M, Javanainen M, Loison C, Melcr J, Miettinen MS, Monticelli L, Määttä J, Oganesyan VS, Ollila OHS, Tynkkynen J, Vilov S. Molecular electrometer and binding of cations to phospholipid bilayers. Phys Chem Chem Phys 2016; 18:32560-32569. [DOI: 10.1039/c6cp04883h] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The molecular electrometer – reorientation of lipid head due to bound charge – allows direct quantitative vetting of simulations against noninvasive NMR experiments; most simulation models overestimated lipid–cation affinities.
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