1
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Ivanova AA, Phan CM, Cheremisin AN, Barifcani A. Molecular behaviour of a surfactant layer under an external electrostatic field. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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2
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Electric Field Effects on Photoelectrochemical Water Splitting: Perspectives and Outlook. ENERGIES 2022. [DOI: 10.3390/en15041553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The grand challenges in renewable energy lie in our ability to comprehend efficient energy conversion systems, together with dealing with the problem of intermittency via scalable energy storage systems. Relatively little progress has been made on this at grid scale and two overriding challenges still need to be addressed: (i) limiting damage to the environment and (ii) the question of environmentally friendly energy conversion. The present review focuses on a novel route for producing hydrogen, the ultimate clean fuel, from the Sun, and renewable energy source. Hydrogen can be produced by light-driven photoelectrochemical (PEC) water splitting, but it is very inefficient; rather, we focus here on how electric fields can be applied to metal oxide/water systems in tailoring the interplay with their intrinsic electric fields, and in how this can alter and boost PEC activity, drawing both on experiment and non-equilibrium molecular simulation.
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3
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Wu H, Ghaani MR, Nandi PK, English NJ. Investigation of Dipolar Response of the Hydrated Hen-Egg White Lysozyme Complex under Externally Applied Electric Fields: Insights from Non-equilibrium Molecular Dynamics. J Phys Chem B 2022; 126:858-868. [PMID: 35060735 PMCID: PMC8819654 DOI: 10.1021/acs.jpcb.1c07096] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- HaoLun Wu
- School of Chemical & Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Mohammad Reza Ghaani
- School of Chemical & Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Prithwish K. Nandi
- School of Chemical & Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
- Irish Centre for High-End Computing, Trinity Enterprise Centre, Pearse Street, Dublin 2, Ireland
| | - Niall J. English
- School of Chemical & Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
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4
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Marracino P, Caramazza L, Montagna M, Ghahri R, D'Abramo M, Liberti M, Apollonio F. Electric-driven membrane poration: A rationale for water role in the kinetics of pore formation. Bioelectrochemistry 2021; 143:107987. [PMID: 34794113 DOI: 10.1016/j.bioelechem.2021.107987] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 11/26/2022]
Abstract
Electroporation is a well-established technique used to stimulate cells, enhancing membrane permeability by inducing reversible membrane pores. In the absence of experimental observation of the dynamics of pore creation, molecular dynamics studies provide the molecular-level evidence that the electric field promotes pore formation. Although single steps in the pore formation process are well assessed, a kinetic model representing the mathematical description of the electroporation process, is lacking. In the present work we studied the basis of the pore formation process, providing a rationale for the definition of a first-order kinetic scheme. Here, authors propose a three-state kinetic model for the process based on the assessed mechanism of water defects intruding at the water/lipid interface, when applying electric field intensities at the edge of the linear regime. The methodology proposed is based on the use of two robust biophysical quantities analyzed for the water molecules intruding at the water/lipid interface: (i) number of hydrogen bonds; (ii) number of contacts. The final model, sustained by a robust statistical sampling, provides kinetic constants for the transitions from the intact bilayer state to the hydrophobic pore state.
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Affiliation(s)
- Paolo Marracino
- Rise Technology S.r.l., L.re Paolo Toscanelli 170, 00121 Rome, Italy
| | - Laura Caramazza
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy; Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Maria Montagna
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy; Department of Chemistry, Sapienza Sapienza University of Rome, Rome, Italy
| | - Ramin Ghahri
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy
| | - Marco D'Abramo
- Department of Chemistry, Sapienza Sapienza University of Rome, Rome, Italy
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy; Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy; Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy.
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5
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Baruah I, Borgohain G. Structural and functional changes of the protein β-lactoglobulin under thermal and electrical processing conditions. Biophys Chem 2020; 267:106479. [PMID: 33027745 DOI: 10.1016/j.bpc.2020.106479] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 09/15/2020] [Accepted: 09/15/2020] [Indexed: 10/23/2022]
Abstract
In the present study we have tried to explore the effect of static external electric field of strength 3.0 V/nm on the conformational changes adopted by the protein β-lactoglobulin. We have chosen different temperatures viz. 300 K, 400 K and 450 K to evaluate the temperature dependent effect of electric field. We have observed that combined effect of high temperature and static external electric field show significant changes on the structural conformation of the protein which in turn may affect the functional properties of the protein. Calculations of root mean square deviations reveal that both helical and β-sheet regions of the protein are noticeably affected at high temperature. We have used solvent accessible surface area (SASA) and dipole moment values to explain that there is changes in hydrophobicity of the protein surface due to presence of external electric field. The study reveals that electric field in combination with high temperature can be used to alter the conformation of the protein and the effect of external electric field is more pronounced at high temperature than that of low temperature. The study provides a better understanding of the conformational changes adopted by the protein under the stress of external electric field and high temperature and provide guidance to choose optimum conditions for processing without loss of nutritional properties.
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Affiliation(s)
- Indrani Baruah
- Department of Chemistry, Cotton University, Guwahati, Assam 781001, India
| | - Gargi Borgohain
- Department of Chemistry, Cotton University, Guwahati, Assam 781001, India.
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6
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Marracino P, Caramazza L, Liberti M, Apollonio F. Electroporation Mechanisms: The Role of Lipid Orientation in the Kinetics of Pore Formation .. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:2235-2238. [PMID: 33018452 DOI: 10.1109/embc44109.2020.9175706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Electroporation is a well-established technique used to stimulate cells, enhancing membrane permeability. Although the biological phenomena occurring after the poration process have been widely studied, the physical mechanisms of pore formation are not clearly understood. In this work we investigated by means of molecular dynamics simulations the kinetics of pore formation, linking the different stages of poration to specific arrangements of lipid membrane domains.Clinical Relevance-The approach followed in this study aims to shed light on the molecular mechanisms at the basis of the electroporation technique, nowadays used to enhance the entrance of poorly permeant anticancer drugs into tumor cells, for gene electrotransfer and all the other applications exploiting the modulation of cell membrane properties.
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7
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Průša J, Cifra M. Molecular dynamics simulation of the nanosecond pulsed electric field effect on kinesin nanomotor. Sci Rep 2019; 9:19721. [PMID: 31873109 PMCID: PMC6928163 DOI: 10.1038/s41598-019-56052-3] [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: 06/17/2019] [Accepted: 11/18/2019] [Indexed: 12/23/2022] Open
Abstract
Kinesin is a biological molecular nanomotor which converts chemical energy into mechanical work. To fulfill various nanotechnological tasks in engineered environments, the function of biological molecular motors can be altered by artificial chemical modifications. The drawback of this approach is the necessity of designing and creating a new motor construct for every new task. We propose that intense nanosecond-scale pulsed electric field could modify the function of nanomotors. To explore this hypothesis, we performed molecular dynamics simulation of a kinesin motor domain docked on a subunit of its microtubule track - a single tubulin heterodimer. In the simulation, we exposed the kinesin motor domain to intense (100 MV/m) electric field up to 30 ns. We found that both the magnitude and angle of the kinesin dipole moment are affected. Furthermore, we found that the electric field affects contact surface area between kinesin and tubulin, the structure and dynamics of the functionally important kinesin segments, including microtubule binding motifs as well as nucleotide hydrolysis site which power the nanomotor. These findings indicate that external intense nanosecond-scale electric field could alter kinesin behavior. Our results contribute to developing novel electromagnetic methods for modulating the function of biomolecular matter at the nanoscale.
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Affiliation(s)
- Jiří Průša
- Institute of Photonics and Electronics of the Czech Academy of Sciences, Chaberska 1014/57, Prague, 18251, Czech Republic.,Faculty of Chemical Engineering, University of Chemistry and Technology Prague, Technicka 5, Prague, 16628, Czech Republic
| | - Michal Cifra
- Institute of Photonics and Electronics of the Czech Academy of Sciences, Chaberska 1014/57, Prague, 18251, Czech Republic.
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8
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della Valle E, Marracino P, Pakhomova O, Liberti M, Apollonio F. Nanosecond pulsed electric signals can affect electrostatic environment of proteins below the threshold of conformational effects: The case study of SOD1 with a molecular simulation study. PLoS One 2019; 14:e0221685. [PMID: 31454403 PMCID: PMC6711501 DOI: 10.1371/journal.pone.0221685] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 08/13/2019] [Indexed: 12/19/2022] Open
Abstract
Electric fields can be a powerful tool to interact with enzymes or proteins, with an intriguing perspective to allow protein manipulation. Recently, researchers have focused the interest on intracellular enzyme modifications triggered by the application of nanosecond pulsed electric fields. These findings were also supported by theoretical predictions from molecular dynamics simulations focussing on significant variations in protein secondary structures. In this work, a theoretical study utilizing molecular dynamics simulations is proposed to explore effects of electric fields of high intensity and very short nanosecond duration applied to the superoxide dismutase (Cu/Zn-SOD or SOD-1), an important enzyme involved in the cellular antioxidant defence mechanism. The effects of 100-nanosecond pulsed electric fields, with intensities ranging from 108 to 7x108 V/m, on a single SOD1 enzyme are presented. We demonstrated that the lowest intensity of 108 V/m, although not inducing structural changes, can produce electrostatic modifications on the reaction centre of the enzyme, as apparent from the dipolar response and the electric field distribution of the protein active site. Electric pulses above 5x108 V/m produced a fast transition between the folded and a partially denatured state, as inferred by the secondary structures analysis. Finally, for the highest field intensity used (7x108 V/m), a not reversible transition toward an unfolded state was observed.
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Affiliation(s)
- Elena della Valle
- BioElectronic Vision Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | | | - Olga Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia, United States of America
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Rome, Italy
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9
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Tubulin response to intense nanosecond-scale electric field in molecular dynamics simulation. Sci Rep 2019; 9:10477. [PMID: 31324834 PMCID: PMC6642143 DOI: 10.1038/s41598-019-46636-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 06/18/2019] [Indexed: 12/12/2022] Open
Abstract
Intense pulsed electric fields are known to act at the cell membrane level and are already being exploited in biomedical and biotechnological applications. However, it is not clear if electric pulses within biomedically-attainable parameters could directly influence intra-cellular components such as cytoskeletal proteins. If so, a molecular mechanism of action could be uncovered for therapeutic applications of such electric fields. To help clarify this question, we first identified that a tubulin heterodimer is a natural biological target for intense electric fields due to its exceptional electric properties and crucial roles played in cell division. Using molecular dynamics simulations, we then demonstrated that an intense - yet experimentally attainable - electric field of nanosecond duration can affect the bβ-tubulin’s C-terminus conformations and also influence local electrostatic properties at the GTPase as well as the binding sites of major tubulin drugs site. Our results suggest that intense nanosecond electric pulses could be used for physical modulation of microtubule dynamics. Since a nanosecond pulsed electric field can penetrate the tissues and cellular membranes due to its broadband spectrum, our results are also potentially significant for the development of new therapeutic protocols.
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10
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Elgabarty H, Kaliannan NK, Kühne TD. Enhancement of the local asymmetry in the hydrogen bond network of liquid water by an ultrafast electric field pulse. Sci Rep 2019; 9:10002. [PMID: 31292493 PMCID: PMC6620291 DOI: 10.1038/s41598-019-46449-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 06/27/2019] [Indexed: 11/18/2022] Open
Abstract
Condensed phase electron decomposition analysis based on density functional theory has recently revealed an asymmetry in the hydrogen-bond network in liquid water, in the sense that a significant population of water molecules are simultaneously donating and accepting one strong hydrogen-bond and another substantially weaker one. Here we investigate this asymmetry, as well as broader structural and energetic features of water's hydrogen-bond network, following the application of an intense electric field square pulse that invokes the ultrafast reorientation of water molecules. We find that the necessary field-strength required to invoke an ultrafast alignment in a picosecond time window is on the order of 108 Vm-1. The resulting orientational anisotropy imposes an experimentally measurable signature on the structure and dynamics of the hydrogen-bond network, including its asymmetry, which is strongly enhanced. The dependence of the molecular reorientation dynamics on the field-strength can be understood by relating the magnitude of the water dipole-field interaction to the rotational kinetic energy, as well as the hydrogen-bond energy.
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Affiliation(s)
- Hossam Elgabarty
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Warburger Str. 100, D-33098, Paderborn, Germany
| | - Naveen Kumar Kaliannan
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Warburger Str. 100, D-33098, Paderborn, Germany
| | - Thomas D Kühne
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Warburger Str. 100, D-33098, Paderborn, Germany.
- Paderborn Center for Parallel Computing and Institute for Lightweight Design, University of Paderborn, Warburger Str. 100, D-33098, Paderborn, Germany.
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11
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Garate JA, Bernardin A, Escalona Y, Yanez C, English NJ, Perez-Acle T. Orientational and Folding Thermodynamics via Electric Dipole Moment Restraining. J Phys Chem B 2019; 123:2599-2608. [PMID: 30831028 DOI: 10.1021/acs.jpcb.8b09374] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The projection of molecular processes onto a small set of relevant descriptors, the so-called reaction coordinates or collective variables (CVs), is a technique nowadays routinely employed by the biomolecular simulation community. In this work, we implemented two CVs to manipulate the orientation (i.e., angle) (μ⃗a) and magnitude (|μ⃗|) of the electric dipole moment. In doing so, we studied the thermodynamics of water orientation under the application of external voltages and the folding of two polypeptides at zero-field conditions. The projection of the free-energy [potential of mean force (PMF)] along water orientation defined an upper limit of around 0.3 V for irrelevant thermodynamic effects. On the other hand, sufficiently strong μ⃗a restraints applied on 12-alanine (Ala12) triggered structural effects because of the alignment of local dipoles; for lower restraints, a full-body rotation is achieved. The manipulation of |μ⃗| produced strong perturbations on the secondary structure of Ala12, promoting an enhanced sampling to its configurational space. Rigorous free-energy calculations in the form of 2-D PMFs for deca-alanine showed the utility of |μ⃗| as a reaction coordinate to study folding in small α helices. As a whole, we propose that the manipulation of both components of the dipole moment, μ⃗a and |μ⃗|, provides thermodynamics insights into the structural conformation and stability of biomolecules. These new CVs are implemented in the Colvars module, available for NAMD and LAMMPS.
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Affiliation(s)
- Jose Antonio Garate
- Centro Interdisciplinario de Neurociencia de Valparaiso , Universidad de Valparaiso , Pasaje Harrington 287 , Playa Ancha, Valparaiso 2381850 , Chile
| | - Alejandro Bernardin
- Centro Interdisciplinario de Neurociencia de Valparaiso , Universidad de Valparaiso , Pasaje Harrington 287 , Playa Ancha, Valparaiso 2381850 , Chile.,Computational Biology Lab , Fundacion Ciencia & Vida , Avenida Zanartu 1482, Nunoa , Santiago 7780272 , Chile
| | - Yerko Escalona
- Institute for Molecular Modeling and Simulation , Muthgasse 18 , Vienna 1190 , Austria
| | - Carlos Yanez
- Computational Biology Lab , Fundacion Ciencia & Vida , Avenida Zanartu 1482, Nunoa , Santiago 7780272 , Chile
| | - Niall J English
- School of Chemical and Bioprocess Engineering , University College Dublin , Belfield, Dublin 4 , Ireland
| | - Tomas Perez-Acle
- Centro Interdisciplinario de Neurociencia de Valparaiso , Universidad de Valparaiso , Pasaje Harrington 287 , Playa Ancha, Valparaiso 2381850 , Chile.,Computational Biology Lab , Fundacion Ciencia & Vida , Avenida Zanartu 1482, Nunoa , Santiago 7780272 , Chile
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12
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Bernardi M, Marracino P, Ghaani MR, Liberti M, Del Signore F, Burnham CJ, Gárate JA, Apollonio F, English NJ. Human aquaporin 4 gating dynamics under axially oriented electric-field impulses: A non-equilibrium molecular-dynamics study. J Chem Phys 2019; 149:245102. [PMID: 30599740 DOI: 10.1063/1.5044665] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Human aquaporin 4 has been studied using non-equilibrium molecular dynamics simulations in the absence and presence of pulses of external electric fields. The pulses were 100 ns in duration and 0.005-0.015 V/Å in intensity acting along the pores' axes. Water diffusivity and the dipolar response of various residues of interest within the pores have been studied. Results show relatively little change in levels of water permeability per se within aquaporin channels during axially oriented field impulses, although care must be taken with regard to statistical certainty. However, the spatial variation of water permeability vis-à-vis electric-field intensity within the milieu of the channels, as revealed by heterogeneity in diffusivity-map gradients, indicates the possibility of somewhat enhanced diffusivity, owing to several residues being affected substantially by external fields, particularly for HIS 201 and 95 and ILE 93. This has the effect of increasing slightly intra-pore water diffusivity in the "pore-mouths" locale, albeit rendering it more spatially uniform overall vis-à-vis zero-field conditions (via manipulation of the selectivity filter).
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Affiliation(s)
- Mario Bernardi
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy
| | - Paolo Marracino
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy
| | - Mohammad Reza Ghaani
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin, D4, Ireland
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy
| | - Federico Del Signore
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy
| | - Christian J Burnham
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin, D4, Ireland
| | - José-Antonio Gárate
- Centro Interdisciplinario de neurociencia de Valparaíso, CINV, Universidad de Valparaíso, 05101 Valparaíso, Chile
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy
| | - Niall J English
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin, D4, Ireland
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13
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Aryal D, Ganesan V. Diffusivity of Mono- and Divalent Salts and Water in Polyelectrolyte Desalination Membranes. J Phys Chem B 2018; 122:8098-8110. [DOI: 10.1021/acs.jpcb.8b05979] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dipak Aryal
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Venkat Ganesan
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
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14
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Marracino P, Castellani F, Vernier PT, Liberti M, Apollonio F. Geometrical Characterization of an Electropore from Water Positional Fluctuations. J Membr Biol 2016; 250:11-19. [PMID: 27435217 DOI: 10.1007/s00232-016-9917-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 07/06/2016] [Indexed: 11/30/2022]
Abstract
We present here a new method for calculating the radius of a transmembrane pore in a phospholipid bilayer. To compare size-related properties of pores in bilayers of various compositions, generated and maintained under different physical and chemical conditions, reference metrics are needed. Operational metrics can be associated with some observed behavior. For example, pore size can be defined by the largest object that will pass through the length of the pore. The novelty of the present approach resides in the characterization of electropore geometry via a statistical approach, based on essential dynamics rules. We define the pore size geometrically with an algorithm for determining the pore radius. In particular, we extract the radius from the tri-dimensional surface of a defined pore region. The method is applied to a pore formed in a phospholipid bilayer by application of an external electric field. Although the details described here are specific for lipid pores in molecular dynamics simulations, the method can be generalized for any kind of pores for which appropriate structural information is available.
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Affiliation(s)
- P Marracino
- Department of Information Engineering, Electronics, and Telecommunications, Sapienza University of Rome, Rome, Italy.
| | - F Castellani
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Biomedical Engineering Institute, Frank Batten College of Engineering and Technology, Old Dominion University, Norfolk, VA, 23529, USA
| | - P T Vernier
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - M Liberti
- Department of Information Engineering, Electronics, and Telecommunications, Sapienza University of Rome, Rome, Italy
| | - F Apollonio
- Department of Information Engineering, Electronics, and Telecommunications, Sapienza University of Rome, Rome, Italy
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15
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Marracino P, Liberti M, Trapani E, Burnham CJ, Avena M, Garate JA, Apollonio F, English NJ. Human Aquaporin 4 Gating Dynamics under Perpendicularly-Oriented Electric-Field Impulses: A Molecular Dynamics Study. Int J Mol Sci 2016; 17:E1133. [PMID: 27428954 PMCID: PMC4964506 DOI: 10.3390/ijms17071133] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/01/2016] [Accepted: 07/04/2016] [Indexed: 12/25/2022] Open
Abstract
Human aquaporin 4 has been studied using molecular dynamics (MD) simulations in the absence and presence of pulses of external static electric fields. The pulses were 10 ns in duration and 0.012-0.065 V/Å in intensity acting along both directions perpendicular to the pores. Water permeability and the dipolar response of all residues of interest (including the selectivity filter) within the pores have been studied. Results showed decreased levels of water osmotic permeability within aquaporin channels during orthogonally-oriented field impulses, although care must be taken with regard to statistical certainty. This can be explained observing enhanced "dipolar flipping" of certain key residues, especially serine 211, histidine 201, arginine 216, histidine 95 and cysteine 178. These residues are placed at the extracellular end of the pore (serine 211, histidine 201, and arginine 216) and at the cytoplasm end (histidine 95 and cysteine 178), with the key role in gating mechanism, hence influencing water permeability.
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Affiliation(s)
- Paolo Marracino
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy.
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy.
| | - Erika Trapani
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy.
| | - Christian J Burnham
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, D4 Dublin, Ireland.
| | - Massimiliano Avena
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy.
| | - José-Antonio Garate
- Computational Biology Laboratory, Life Sciences Foundation, 7750000 Santiago, Chile.
- Centro Interdisciplinario de neurociencia de Valparaiso, Universidad de Valparaiso, 05101 Valparaiso, Chile.
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications, La Sapienza University, 00184 Rome, Italy.
| | - Niall J English
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, D4 Dublin, Ireland.
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16
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Avena M, Marracino P, Liberti M, Apollonio F, English NJ. Communication: Influence of nanosecond-pulsed electric fields on water and its subsequent relaxation: Dipolar effects and debunking memory. J Chem Phys 2015; 142:141101. [DOI: 10.1063/1.4917024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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17
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Amadei A, Marracino P. Theoretical–computational modelling of the electric field effects on protein unfolding thermodynamics. RSC Adv 2015. [DOI: 10.1039/c5ra15605j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this paper we present a general theoretical–computational approach to model the protein unfolding thermodynamics response to intense electric fields.
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Affiliation(s)
- A. Amadei
- Dipartimento di Scienze e Tecnologie Chimiche
- Università degli studi di Roma Tor Vergata
- 00031 Rome
- Italy
| | - P. Marracino
- Dipartimento di Ingegneria dell'Informazione
- Elettronica e Telecomunicazioni
- Sapienza Universitaà di Roma
- 00184 Rome
- Italy
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