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Conti Nibali V, Sacchetti F, Paciaroni A, Petrillo C, Tarek M, D'Angelo G. Intra-protein interacting collective modes in the terahertz frequency region. J Chem Phys 2023; 159:161101. [PMID: 37870134 DOI: 10.1063/5.0142381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 09/25/2023] [Indexed: 10/24/2023] Open
Abstract
Understanding how proteins work requires a thorough understanding of their internal dynamics. Proteins support a wide range of motions, from the femtoseconds to seconds time scale, relevant to crucial biological functions. In this context, the term "protein collective dynamics" refers to the complex patterns of coordinated motions of numerous atoms throughout the protein in the sub-picosecond time scale (terahertz frequency region). It is hypothesized that these dynamics have a substantial impact on the regulation of functional dynamical mechanisms, including ligand binding and allosteric signalling, charge transport direction, and the regulation of thermodynamic and thermal transport properties. Using the theoretical framework of hydrodynamics, the collective dynamics of proteins had previously been described in a manner akin to that of simple liquids, i.e. in terms of a single acoustic-like excitation, related to intra-protein vibrational motions. Here, we employ an interacting-mode model to analyse the results from molecular dynamics simulations and we unveil that the vibrational landscape of proteins is populated by multiple acoustic-like and low-frequency optic-like modes, with mixed symmetry and interfering with each other. We propose an interpretation at the molecular level of the observed scenario that we relate to the side-chains and the hydrogen-bonded networks dynamics. The present insights provide a perspective for understanding the molecular mechanisms underlying the energy redistribution processes in the interior of proteins.
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Affiliation(s)
- Valeria Conti Nibali
- Department of Mathematical and Computational Sciences, Physical Science and Earth Science, Messina University, Viale Ferdinando Stagno D'Alcontres 31, 98166 Messina, Italy
| | - Francesco Sacchetti
- Department of Physics and Geology, Perugia University, Via Alessandro Pascoli, I-06123 Perugia, Italy
| | - Alessandro Paciaroni
- Department of Physics and Geology, Perugia University, Via Alessandro Pascoli, I-06123 Perugia, Italy
| | - Caterina Petrillo
- Department of Physics and Geology, Perugia University, Via Alessandro Pascoli, I-06123 Perugia, Italy
| | - Mounir Tarek
- Université de Lorraine, CNRS, LPCT, F-54000 Nancy, France
| | - Giovanna D'Angelo
- Department of Mathematical and Computational Sciences, Physical Science and Earth Science, Messina University, Viale Ferdinando Stagno D'Alcontres 31, 98166 Messina, Italy
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Dobrynina EA, Zykova VA, Surovtsev NV. In-plane and out-of-plane gigahertz sound velocities of saturated and unsaturated phospholipid bilayers from cryogenic to room temperatures. Chem Phys Lipids 2023; 256:105335. [PMID: 37579988 DOI: 10.1016/j.chemphyslip.2023.105335] [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: 03/31/2023] [Revised: 06/23/2023] [Accepted: 08/11/2023] [Indexed: 08/16/2023]
Abstract
Here, we examined the gigahertz sound velocities of hydrated multibilayers of saturated (1,2-dimyristoyl-sn-glycero-3-phosphocholine, DMPC) and unsaturated (1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC) phospholipids by Brillouin spectroscopy. Out-of-plane and in-plane (lateral) phonons were studied independently of each other. Similar strong temperature dependences of the sound velocities were found for phonons of both types. The sound velocities in the low-temperature limit were two-fold higher than that at physiological temperatures; a significant part of the changes in sound velocity occurs in the solid-like gel phase. The factors that may be involved in the peculiar behavior of sound velocity include changes in the chain conformational state, relaxation susceptibility, changes in the elastic modulus at infinite frequencies, and lateral packing of molecules.
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Affiliation(s)
- E A Dobrynina
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - V A Zykova
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - N V Surovtsev
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia.
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Bolmatov D, Collier CP, Zav’yalov D, Egami T, Katsaras J. Real Space and Time Imaging of Collective Headgroup Dipole Motions in Zwitterionic Lipid Bilayers. MEMBRANES 2023; 13:442. [PMID: 37103869 PMCID: PMC10142431 DOI: 10.3390/membranes13040442] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/05/2023] [Accepted: 04/14/2023] [Indexed: 06/19/2023]
Abstract
Lipid bilayers are supramolecular structures responsible for a range of processes, such as transmembrane transport of ions and solutes, and sorting and replication of genetic materials, to name just a few. Some of these processes are transient and currently, cannot be visualized in real space and time. Here, we developed an approach using 1D, 2D, and 3D Van Hove correlation functions to image collective headgroup dipole motions in zwitterionic phospholipid bilayers. We show that both 2D and 3D spatiotemporal images of headgroup dipoles are consistent with commonly understood dynamic features of fluids. However, analysis of the 1D Van Hove function reveals lateral transient and re-emergent collective dynamics of the headgroup dipoles-occurring at picosecond time scales-that transmit and dissipate heat at longer times, due to relaxation processes. At the same time, the headgroup dipoles also generate membrane surface undulations due a collective tilting of the headgroup dipoles. A continuous intensity band of headgroup dipole spatiotemporal correlations-at nanometer length and nanosecond time scales-indicates that dipoles undergo stretching and squeezing elastic deformations. Importantly, the above mentioned intrinsic headgroup dipole motions can be externally stimulated at GHz-frequency scale, enhancing their flexoelectric and piezoelectric capabilities (i.e., increased conversion efficiency of mechanical energy into electric energy). In conclusion, we discuss how lipid membranes can provide molecular-level insights about biological learning and memory, and as platforms for the development of the next generation of neuromorphic computers.
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Affiliation(s)
- Dima Bolmatov
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - C. Patrick Collier
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Dmitry Zav’yalov
- Department of Physics, Volgograd State Technical University, Volgograd 400005, Russia
| | - Takeshi Egami
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37916, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - John Katsaras
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Sample Environment Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Bolmatov D. The Phonon Theory of Liquids and Biological Fluids: Developments and Applications. J Phys Chem Lett 2022; 13:7121-7129. [PMID: 35950307 DOI: 10.1021/acs.jpclett.2c01779] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Among the three basic states of matter (solid, liquid, and gas), the liquid state has always eluded general theoretical approaches for describing liquid energy and heat capacity. In this Viewpoint, we derive the phonon theory of liquids and biological fluids stemming from Frenkel's microscopic picture of the liquid state. Specifically, the theory predicts the existence of phonon gaps in vibrational spectra of liquids and a thermodynamic boundary in the supercritical state. Direct experimental evidence reaffirming these theoretical predictions was achieved through a combination of techniques using static compression X-ray diffraction and inelastic X-ray scattering on deeply supercritical argon in a diamond anvil cell. Furthermore, these findings inspired and then led to the discovery of phonon gaps in liquid crystals (mesogens), block copolymers, and biological membranes. Importantly, phonon gaps define viscoelastic crossovers in cellular membranes responsible for lipid self-diffusion, lateral molecular-level stress propagation, and passive transmembrane transport of small molecules and solutes. Finally, molecular interactions mediated by external stimuli result in synaptic activity controlling biological membranes' plasticity resulting in learning and memory. Therefore, we also discuss learning and memory effects─equally important for neuroscience as well as for the development of neuromorphic devices─facilitated in biological membranes by external stimuli.
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Affiliation(s)
- Dima Bolmatov
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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Surovtsev NV, Adichtchev SV. Dynamic response on a nanometer scale of binary phospholipid-cholesterol vesicles: Low-frequency Raman scattering insight. Phys Rev E 2021; 104:054406. [PMID: 34942765 DOI: 10.1103/physreve.104.054406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/18/2021] [Indexed: 11/07/2022]
Abstract
Low-frequency Raman spectroscopy was used to study the dynamic response on a nanometer scale of aqueous suspensions of two-component lipid vesicles. Binary mixtures of saturated phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC) and cholesterol are interesting for possible coexistence of solidlike and liquid-ordered phases, while the phase coexistence was not reported for unsaturated phospholipid (1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC) and cholesterol mixtures. The DOPC-DPPC mixtures represent the well-documented case of coexisting domains of solidlike and liquid-disordered phases. These three series of lipid mixtures are studied here. A broad peak with the maximum in the range of 30-50cm^{-1} and a narrow peak near 10cm^{-1} are observed in the Raman susceptibility of the binary mixtures and attributed to the acousticlike vibrational density of states and layer modes, respectively. Parameters of the broad and narrow peaks are sensitive to lateral and conformational hydrocarbon chain ordering. It was also demonstrated that the low-frequency Raman susceptibility of multicomponent lipid bilayers allows one to determine the phase state of lipid bilayers and distinguish the homogeneous distribution of molecular complexes from coexisting domains with sizes above several nanometers. Thus, the low-frequency Raman spectroscopy provides unique information in studying phase coexistence in lipid bilayers.
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Affiliation(s)
- N V Surovtsev
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - S V Adichtchev
- Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia
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Petrillo C, Sacchetti F. Future applications of the high-flux thermal neutron spectroscopy: the ever-green case of collective excitations in liquid metals. ADVANCES IN PHYSICS: X 2021. [DOI: 10.1080/23746149.2021.1871862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Caterina Petrillo
- Department of Physics & Earth Science, University of Perugia, Perugia, Italy
| | - Francesco Sacchetti
- Department of Physics & Earth Science, University of Perugia, Perugia, Italy
- National Research Council, Institute IOM-CNR, Perugia, Italy
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Mondal D, Malik S, Banerjee P, Kundu N, Debnath A, Sarkar N. Modulation of Membrane Fluidity to Control Interfacial Water Structure and Dynamics in Saturated and Unsaturated Phospholipid Vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12423-12434. [PMID: 33035065 DOI: 10.1021/acs.langmuir.0c02736] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The structure and dynamics of interfacial water in biological systems regulate the biochemical reactions. But, it is still enigmatic how the behavior of the interfacial water molecule is controlled. Here, we have investigated the effect of membrane fluidity on the structure and dynamics of interfacial water molecules in biologically relevant phopholipid vesicles. This study delineates that modulation of membrane fluidity through interlipid separation and unsaturation not only mitigate membrane rigidity but also disrupt the strong hydrogen bond (H-bond) network around the lipid bilayer interface. As a result, a disorder in H-bonding between water molecules arises several layers beyond the first hydration shell of the polar headgroup, which essentially modifies the interfacial water structure and dynamics. Furthermore, we have also provided evidence of increasing transportation through these modulated membranes, which enhance the membrane mediated isomerization reaction rate.
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Affiliation(s)
- Dipankar Mondal
- Department of Chemistry, Indian Institute of Technology Kharagpur Kharagpur 721302, West Bengal, India
| | - Sheeba Malik
- Department of Chemistry, Indian Institute of Technology Jodhpur, Jodhpur 342037, Rajasthan, India
| | - Pavel Banerjee
- Department of Chemistry, Indian Institute of Technology Kharagpur Kharagpur 721302, West Bengal, India
| | - Niloy Kundu
- Department of Chemistry, Indian Institute of Technology Kharagpur Kharagpur 721302, West Bengal, India
- Environment Research Group, R&D and Scientific Services Department, Tata Steel Ltd., Jamshedpur 831007, India
| | - Ananya Debnath
- Department of Chemistry, Indian Institute of Technology Jodhpur, Jodhpur 342037, Rajasthan, India
| | - Nilmoni Sarkar
- Department of Chemistry, Indian Institute of Technology Kharagpur Kharagpur 721302, West Bengal, India
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Bolmatov D, Kinnun JJ, Katsaras J, Lavrentovich MO. Phonon-mediated lipid raft formation in biological membranes. Chem Phys Lipids 2020; 232:104979. [PMID: 32980352 DOI: 10.1016/j.chemphyslip.2020.104979] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/21/2020] [Accepted: 09/21/2020] [Indexed: 10/23/2022]
Abstract
Short-wavelength collective molecular motions, also known as phonons, have recently attracted much interest in revealing dynamic properties of biological membranes through the use of neutron and X-ray scattering, infrared and Raman spectroscopies, and molecular dynamics simulations. Experimentally detecting unique vibrational patterns such as, shear phonon excitations, viscoelastic crossovers, transverse acoustic phonon gaps, and continuous and truncated optical phonon modes in cellular membranes, to name a few, has proven non-trivial. Here, we review recent advances in liquid thermodynamics that have resulted in the development of the phonon theory of liquids. The theory has important predictions regarding the shear vibrational spectra of fluids, namely the emergence of viscoelastic crossovers and transverse acoustic phonon gaps. Furthermore, we show that these vibrational patterns are common in soft (non-crystalline) materials, including, but not limited to liquids, colloids, liquid crystals (mesogens), block copolymers, and biological membranes. The existence of viscoelastic crossovers and acoustic phonon gaps define the self-diffusion properties of cellular membranes and provide a molecular picture of the transient nature of lipid rafts (Bolmatov et al., 2020). Importantly, the timescales (picoseconds) for the formation and dissolution of transient lipid rafts match the lifetime of the formation and breakdown of interfacial water hydrogen bonds. Apart from acoustic propagating phonon modes, biological membranes can also support more energetic non-propagating optical phonon excitations, also known as standing waves or breathing modes. Importantly, optical phonons can be truncated due to the existence of finite size nanodomains made up of strongly correlated lipid-cholesterol molecular pairs. These strongly coupled molecular pairs can serve as nucleation centers for the formation of stable rafts at larger length scales, due to correlations of spontaneous fluctuations (Onsager's regression hypothesis). Finally and importantly, molecular level viscoelastic crossovers, acoustic phonon gaps, and continuous and truncated optical phonon modes may offer insights as to how lipid-lipid and lipid-protein interactions enable biological function.
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Affiliation(s)
- Dima Bolmatov
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States.
| | - Jacob J Kinnun
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
| | - John Katsaras
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States; Sample Environment Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
| | - Maxim O Lavrentovich
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States.
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Bolmatov D, Soloviov D, Zhernenkov M, Zav'yalov D, Mamontov E, Suvorov A, Cai YQ, Katsaras J. Molecular Picture of the Transient Nature of Lipid Rafts. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4887-4896. [PMID: 32259453 DOI: 10.1021/acs.langmuir.0c00125] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In biological membranes, lipid rafts are now thought to be transient and nanoscopic. However, the mechanism responsible for these nanoscopic assemblies remains poorly understood, even in the case of model membranes. As a result, it has proven extremely challenging to probe the physicochemical properties of lipid rafts at the molecular level. Here, we use all-atom molecular dynamics (MD) simulations and inelastic X-ray scattering (IXS), an intrinsically nanoscale technique, to directly probe the energy transfer and collective short-wavelength dynamics (phonons) of biologically relevant model membranes. We show that the nanoscale propagation of stress in lipid rafts takes place in the form of collective motions made up of longitudinal (compression waves) and transverse (shear waves) molecular vibrations. Importantly, we provide a molecular picture for the so-called van der Waals mediated "force from lipid" [Anishkin, A. et al. Proc. Natl. Acad. Sci. U.S.A. 2014, 111, 7898], a key parameter for the ionic channel mechano-transduction and the mechanism for the lipid transfer of molecular level stress [Aponte-Santamarı́a, C. et al. J. Am. Chem. Soc. 2017, 139, 13588]. Specifically, we describe how lipid rafts are formed and maintained through the propagation of molecular stress, lipid raft rattling dynamics, and a relaxation process. Eventually, the rafts dissipate through the self-diffusion of lipids making up the rafts. We also show that the molecular stress and viscoelastic properties of transient lipid rafts can be modulated through the use of hydrophobic biomolecules such as melatonin and tryptophan. Ultimately, the herein proposed mechanism describing the molecular interactions for the formation and dissolution of lipid rafts may offer insights as to how lipid rafts enable biological function.
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Affiliation(s)
- Dima Bolmatov
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Dmytro Soloviov
- Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia
- Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, Kyiv 03680, Ukraine
| | - Mikhail Zhernenkov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | | | - Eugene Mamontov
- Spectroscopy Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexey Suvorov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Yong Q Cai
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - John Katsaras
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
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Soloviov D, Cai YQ, Bolmatov D, Suvorov A, Zhernenkov K, Zav'yalov D, Bosak A, Uchiyama H, Zhernenkov M. Functional lipid pairs as building blocks of phase-separated membranes. Proc Natl Acad Sci U S A 2020; 117:4749-4757. [PMID: 32071249 PMCID: PMC7060688 DOI: 10.1073/pnas.1919264117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Biological membranes exhibit a great deal of compositional and phase heterogeneity due to hundreds of chemically distinct components. As a result, phase separation processes in cell membranes are extremely difficult to study, especially at the molecular level. It is currently believed that the lateral membrane heterogeneity and the formation of domains, or rafts, are driven by lipid-lipid and lipid-protein interactions. Nevertheless, the underlying mechanisms regulating membrane heterogeneity remain poorly understood. In the present work, we combine inelastic X-ray scattering with molecular dynamics simulations to provide direct evidence for the existence of strongly coupled transient lipid pairs. These lipid pairs manifest themselves experimentally through optical vibrational (a.k.a. phononic) modes observed in binary (1,2-dipalmitoyl-sn-glycero-3-phosphocholine [DPPC]-cholesterol) and ternary (DPPC-1,2-dioleoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-glycero-3-phosphocholine [DOPC/POPC]-cholesterol) systems. The existence of a phononic gap in these vibrational modes is a direct result of the finite size of patches formed by these lipid pairs. The observation of lipid pairs provides a spatial (subnanometer) and temporal (subnanosecond) window into the lipid-lipid interactions in complex mixtures of saturated/unsaturated lipids and cholesterol. Our findings represent a step toward understanding the lateral organization and dynamics of membrane domains using a well-validated probe with a high spatial and temporal resolution.
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Affiliation(s)
- Dmytro Soloviov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
- Frank Laboratory for Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia
- Department of Physics, Taras Shevchenko National University of Kyiv, Kyiv 01601, Ukraine
- Nuclear Facility Safety Department, Institute for Safety Problems of Nuclear Power Plants of National Academy of Science of Ukraine, Chornobyl 07270, Ukraine
| | - Yong Q Cai
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973
| | - Dima Bolmatov
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996
| | - Alexey Suvorov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973
| | - Kirill Zhernenkov
- Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, 85748 Garching, Germany
- Frank Laboratory for Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - Dmitry Zav'yalov
- Department of Physics, Volgograd State Technical University, Volgograd 400005, Russia
| | - Alexey Bosak
- Experiments Division, European Synchrotron Radiation Facility, 38043 Grenoble, France
| | - Hiroshi Uchiyama
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan
| | - Mikhail Zhernenkov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973;
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Zakhvataev VE. Dynamic structure factor of a lipid bilayer in the presence of a high electric field. J Chem Phys 2019; 151:234902. [PMID: 31864280 DOI: 10.1063/1.5123786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The influence of a high average electric field (∼1 V/nm) in the hydrophobic interior of a bilayer lipid membrane on short-wavelength in-plane phononic motions of lipid chains is considered. The average electric field is assumed to be nearly constant on a picosecond time scale and a nanometer length scale. This field may be induced, for instance, by externally applied subnanosecond electric pulses or the membrane dipole potential. Using a generalized hydrodynamic approach, we derive a corresponding electrohydrodynamic model generalized to high wave numbers. In the considered approximation, all electric field effects are reduced only to a constant contribution to the generalized isothermal compressibility modulus. The corresponding dynamic structure factor for a lipid bilayer is derived. We show that due to polarization effects, the high field can critically impact the dynamics of longitudinal acousticlike modes at wave numbers near the major peak of the static structure factor. We estimate quantitatively that for typical lipid bilayers, transverse high electric fields can cause strong phonon energy softening, enhancement of phonon population, and formation of a gap in the dispersion of excitation frequency. The results obtained agree with simulations of the initiation of lipid bilayer electropores, suggesting that the proposed model reproduces the essential features of the field's impact on atomic density fluctuations. The proposed mechanism may have significant implications for the understanding of electroporation, passive molecular transport, and spontaneous pore formation in lipid bilayers.
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Affiliation(s)
- V E Zakhvataev
- Federal Research Center "Krasnoyarsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences", Krasnoyarsk 660036 Russia and Siberian Federal University, Krasnoyarsk 660041 Russia
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