1
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Shikata K, Kasahara K, Watanabe NM, Umakoshi H, Kim K, Matubayasi N. Influence of cholesterol on hydrogen-bond dynamics of water molecules in lipid-bilayer systems at varying temperatures. J Chem Phys 2024; 161:015102. [PMID: 38958163 DOI: 10.1063/5.0208008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 06/17/2024] [Indexed: 07/04/2024] Open
Abstract
Cholesterol (Chol) plays a crucial role in shaping the intricate physicochemical attributes of biomembranes, exerting a considerable influence on water molecules proximal to the membrane interface. In this study, we conducted molecular dynamics simulations on the bilayers of two lipid species, dipalmitoylphosphatidylcholine (DPPC) and palmitoyl sphingomyelin; they are distinct with respect to the structures of the hydrogen-bond (H-bond) acceptors. Our investigation focuses on the dynamic properties and H-bonds of water molecules in the lipid-membrane systems, with a particular emphasis on the influence of Chol at varying temperatures. Notably, in the gel phase at 303 K, the presence of Chol extends the lifetimes of H-bonds of the oxygen atoms acting as H-bond acceptors within DPPC with water molecules by a factor of 1.5-2.5. In the liquid-crystalline phase at 323 K, on the other hand, H-bonding dynamics with lipid membranes remain largely unaffected by Chol. This observed shift in H-bonding states serves as a crucial key to unraveling the subtle control mechanisms governing water dynamics in lipid-membrane systems.
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Affiliation(s)
- Kokoro Shikata
- Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kento Kasahara
- Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Nozomi Morishita Watanabe
- Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hiroshi Umakoshi
- Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kang Kim
- Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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2
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Schlaich A, Daldrop JO, Kowalik B, Kanduč M, Schneck E, Netz RR. Water Structuring Induces Nonuniversal Hydration Repulsion between Polar Surfaces: Quantitative Comparison between Molecular Simulations, Theory, and Experiments. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:7896-7906. [PMID: 38578930 PMCID: PMC11025125 DOI: 10.1021/acs.langmuir.3c03656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/13/2024] [Accepted: 03/15/2024] [Indexed: 04/07/2024]
Abstract
Polar surfaces in water typically repel each other at close separations, even if they are charge-neutral. This so-called hydration repulsion balances the van der Waals attraction and gives rise to a stable nanometric water layer between the polar surfaces. The resulting hydration water layer is crucial for the properties of concentrated suspensions of lipid membranes and hydrophilic particles in biology and technology, but its origin is unclear. It has been suggested that surface-induced molecular water structuring is responsible for the hydration repulsion, but a quantitative proof of this water-structuring hypothesis is missing. To gain an understanding of the mechanism causing hydration repulsion, we perform molecular simulations of different planar polar surfaces in water. Our simulated hydration forces between phospholipid bilayers agree perfectly with experiments, validating the simulation model and methods. For the comparison with theory, it is important to split the simulated total surface interaction force into a direct contribution from surface-surface molecular interactions and an indirect water-mediated contribution. We find the indirect hydration force and the structural water-ordering profiles from the simulations to be in perfect agreement with the predictions from theoretical models that account for the surface-induced water ordering, which strongly supports the water-structuring hypothesis for the hydration force. However, the comparison between the simulations for polar surfaces with different headgroup architectures reveals significantly different decay lengths of the indirect water-mediated hydration-force, which for laterally homogeneous water structuring would imply different bulk-water properties. We conclude that laterally inhomogeneous water ordering, induced by laterally inhomogeneous surface structures, shapes the hydration repulsion between polar surfaces in a decisive manner. Thus, the indirect water-mediated part of the hydration repulsion is caused by surface-induced water structuring but is surface-specific and thus nonuniversal.
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Affiliation(s)
- Alexander Schlaich
- Stuttgart
Center for Simulation Science (SC SimTech), University of Stuttgart, 70569 Stuttgart, Germany
- Institute
for Computational Physics, University of
Stuttgart, 70569 Stuttgart, Germany
| | - Jan O. Daldrop
- Fachbereich
Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Bartosz Kowalik
- Fachbereich
Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Matej Kanduč
- Department
of Theoretical Physics, Jožef Stefan
Institute, SI-1000 Ljubljana, Slovenia
| | - Emanuel Schneck
- Institut
für Physik Kondensierter Materie, Technische Universität Darmstadt, Hochschulstrasse 8, Darmstadt 64289, Germany
| | - Roland R. Netz
- Fachbereich
Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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3
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Chandra A, Kayal A, Das B, Chandra A. Dynamical Crossover of Interfacial Water upon Melting of a Lipid Bilayer: Influence of Different Parts of the Headgroups. J Phys Chem B 2023. [PMID: 38032152 DOI: 10.1021/acs.jpcb.3c04792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
All-atom molecular dynamics simulations of a 1,2-dimyristoyl-sn-glycero-3-phosphocholine bilayer in contact with liquid water were performed at different temperatures ranging from 285 to 320 K. We have investigated the heterogeneity and dynamical transitions in interfacial water as the lipid bilayer undergoes a melting transition. Results are obtained for water at the outer surface of the bilayer and for those buried more deeply in the lipid chains of the bilayer. It is found that lipid bilayer melting influences both the structure and dynamics of interfacial water. The number of interfacial water molecules shows a jump in the melting of the bilayer. The temperature dependence of the diffusivity and orientational relaxation of interfacial water molecules exhibits a dynamical crossover upon melting of the bilayer. The extent of dynamical crossover is found to be rather strong with significant changes in activation barriers for interfacial water around the carbonyl groups, which are deeply buried toward the lipid chains of the bilayer. The dynamical crossover gradually decreases as one moves further away from the outer surface, and it essentially vanishes for water in the region of 5-10 Å from the outer surface. It is found that the lipid melting-induced dynamical crossover of interfacial water is significant only for water that is in close proximity to the bilayer surface or deeply buried into it. The current results reveal that water molecules in different parts of the interface respond differently on melting of the bilayer. The current study also shows that the carbonyl-bound water molecules can play an important role in the phase transition of the bilayer as the temperature is raised through its melting point.
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Affiliation(s)
- Abhilash Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India
| | - Abhijit Kayal
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India
| | - Banshi Das
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India
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4
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Şahin Bektay H, Sağıroğlu AA, Bozali K, Güler EM, Güngör S. The Design and Optimization of Ceramide NP-Loaded Liposomes to Restore the Skin Barrier. Pharmaceutics 2023; 15:2685. [PMID: 38140026 PMCID: PMC10747297 DOI: 10.3390/pharmaceutics15122685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/08/2023] [Accepted: 10/25/2023] [Indexed: 12/24/2023] Open
Abstract
The impairment of skin integrity derived from derangement of the orthorhombic lateral organization is mainly caused by dysregulation of ceramide amounts in the skin barrier. Ceramides, fatty acids, and cholesterol-containing nano-based formulations have been used to impair the skin barrier. However, there is still a challenge to formulate novel formulations consisting of ceramides due to their chemical structure, poor aqueous solubility, and high molecular weight. In this study, the design and optimization of Ceramide 3 (CER-NP)-loaded liposomes are implemented based on response surface methodology (RSM). The optimum CER-NP-loaded liposome was selected based on its particle size (PS) and polydispersity index (PDI). The optimum CER-NP-loaded liposome was imagined by observing the encapsulation by using a confocal laser scanning microscope (CLSM) within fluorescently labeled CER-NP. The characteristic liquid crystalline phase and lipid chain conformation of CER-NP-loaded liposomes were determined using attenuated total reflectance infrared spectroscopy (ATR-IR). The CER-NP-loaded liposomes were imagined using a field emission scanning electron microscope (FE-SEM). Finally, the in vitro release of CER-NP from liposomes was examined using modified Franz Cells. The experimental and predicted results were well correlated. The CLSM images of optimized liposomes were conformable with the other studies, and the encapsulation efficiency of CER-NP was 93.84 ± 0.87%. ATR-IR analysis supported the characteristics of the CER-NP-loaded liposome. In addition, the lipid chain conformation shows similarity with skin barrier lipid organization. The release pattern of CER-NP liposomes was fitted with the Korsmeyer-Peppas model. The cytotoxicity studies carried out on HaCaT keratinocytes supported the idea that the liposomes for topical administration of CER-NP could be considered relatively safe. In conclusion, the optimized CER-NP-loaded liposomes could have the potential to restore the skin barrier function.
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Affiliation(s)
- Hümeyra Şahin Bektay
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Istanbul University, Istanbul 34116, Türkiye
- Health Science Institute, Istanbul University, Istanbul 34126, Türkiye
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Bezmialem Vakıf University, Istanbul 34093, Türkiye
| | - Ali Asram Sağıroğlu
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Bezmialem Vakıf University, Istanbul 34093, Türkiye
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Istanbul University-Cerrahpaşa, Istanbul 34500, Türkiye
| | - Kübra Bozali
- Department of Medical Biochemistry, Faculty of Hamidiye Medicine, University of Health Science, Istanbul 34668, Türkiye
| | - Eray Metin Güler
- Department of Medical Biochemistry, Faculty of Hamidiye Medicine, University of Health Science, Istanbul 34668, Türkiye
| | - Sevgi Güngör
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Istanbul University, Istanbul 34116, Türkiye
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5
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Miyajima A, Nakao H, Ikeda K, Nakano M. The Nanometer-Scale Proximity of Bilayers Facilitates Intermembrane Lipid Transfer. J Phys Chem Lett 2023; 14:4172-4178. [PMID: 37114850 DOI: 10.1021/acs.jpclett.3c00154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Biological membranes approach one another in various biological phenomena, such as lipid transport at membrane contact sites and membrane fusion. The proximity of two bilayers may cause environmental changes in the interbilayer space and alter the dynamics of lipid molecules. Here, we investigate the structure and dynamics of vesicles aggregated due to the depletion attraction caused by polyethylene glycol (PEG) through static and dynamic small-angle neutron scattering. Manipulation of the interbilayer distance using PEG-conjugated lipids reveals that lipid molecules rapidly transfer between vesicles when the opposing bilayers are within ∼2 nm of each other. This distance corresponds to a region in which water molecules are more structured than in bulk water. Kinetic analysis suggests that the decrease in water entropy is responsible for the progression of lipid transfer. These results provide a basis for understanding the dynamic function of biomembranes in confined regions.
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Affiliation(s)
- Ayari Miyajima
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Hiroyuki Nakao
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Keisuke Ikeda
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Minoru Nakano
- Department of Biointerface Chemistry, Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
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6
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Aghaaminiha M, Farnoud AM, Sharma S. Interdependence of cholesterol distribution and conformational order in lipid bilayers. Biointerphases 2023; 18:2887740. [PMID: 37125848 DOI: 10.1116/6.0002489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 04/11/2023] [Indexed: 05/02/2023] Open
Abstract
We show, via molecular simulations, that not only does cholesterol induce a lipid order, but the lipid order also enhances cholesterol localization within the lipid leaflets. Therefore, there is a strong interdependence between these two phenomena. In the ordered phase, cholesterol molecules are predominantly present in the bilayer leaflets and orient themselves parallel to the bilayer normal. In the disordered phase, cholesterol molecules are mainly present near the center of the bilayer at the midplane region and are oriented orthogonal to the bilayer normal. At the melting temperature of the lipid bilayers, cholesterol concentration in the leaflets and the bilayer midplane is equal. This result suggests that the localization of cholesterol in the lipid bilayers is mainly dictated by the degree of ordering of the lipid bilayer. We validate our findings on 18 different lipid bilayer systems, obtained from three different phospholipid bilayers with varying concentrations of cholesterol. To cover a large temperature range in simulations, we employ the Dry Martini force field. We demonstrate that the Dry and the Wet Martini (with polarizable water) force fields produce comparable results.
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Affiliation(s)
| | - Amir M Farnoud
- Department of Chemical and Biomolecular Engineering, Ohio University, Athens, Ohio 45701
| | - Sumit Sharma
- Department of Chemical and Biomolecular Engineering, Ohio University, Athens, Ohio 45701
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7
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Rivera-Sanchez SP, Ocampo-Ibáñez ID, Liscano Y, Martínez N, Muñoz I, Manrique-Moreno M, Martinez-Martinez L, Oñate-Garzon J. Integrating In Vitro and In Silico Analysis of a Cationic Antimicrobial Peptide Interaction with Model Membranes of Colistin-Resistant Pseudomonas aeruginosa Strains. Pharmaceutics 2022; 14:pharmaceutics14061248. [PMID: 35745820 PMCID: PMC9230736 DOI: 10.3390/pharmaceutics14061248] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/03/2022] [Accepted: 06/08/2022] [Indexed: 02/04/2023] Open
Abstract
Bacterial antibiotic resistance is a serious global public health concern. Infections caused by colistin-resistant Pseudomonas aeruginosa (CRPa) strains represent a serious threat due to their considerable morbidity and mortality rates, since most of the current empirical antibiotic therapies are ineffective against these strains. Accordingly, cationic antimicrobial peptides (CAMPs) have emerged as promising alternatives to control resistant bacteria. In this study, the interaction of a CAMP derived from cecropin D-like (∆M2) with model membranes mimicking bacterial biomembranes of wild-type (WTPa) strains of P. aeruginosa and CRPa was evaluated through in vitro and in silico approaches. In vitro interaction was determined by infrared spectroscopy, whereas in silico molecular dynamics was performed to predict specific interactions between amino acids of ∆M2 and lipids of model membrane systems. Experimental analysis showed this peptide interacted with the lipids of bacterial-like model membranes of WTPa and CRPa. In both cases, an increase in the concentration of peptides induced an increase in the phase transition temperature of the lipid systems. On the other hand, the peptides in solution underwent a transition from a random to a helical secondary structure after interacting with the membranes mostly favored in the CRPa system. The α-helix structure percentage for ΔM2 interacting with WTPa and CRPa lipid systems was 6.4 and 33.2%, respectively. Finally, molecular dynamics showed ∆M2 to have the most affinities toward the phospholipids palmitoyl-oleyl-phosphatidylglycerol (POPG) and palmitoyl-oleoyl-phosphatidylethanolamine (POPE) that mimic membranes of WTPa and CRPa, respectively. This work provides clues for elucidating the membrane-associated mechanism of action of ∆M2 against colistin-susceptible and -resistant strains of Pseudomonas aeruginosa.
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Affiliation(s)
- Sandra Patricia Rivera-Sanchez
- Research Group of Microbiology, Industry and Environment, Faculty of Basic Sciences, Universidad Santiago of Cali, Cali 760035, Colombia; (I.D.O.-I.); (N.M.); (I.M.)
- Transnational Research Group on Infectious Diseases, PhD School of Biomedicine, University of Córdoba, 14071 Córdoba, Spain
- Correspondence: (S.P.R.-S.); (J.O.-G.)
| | - Iván Darío Ocampo-Ibáñez
- Research Group of Microbiology, Industry and Environment, Faculty of Basic Sciences, Universidad Santiago of Cali, Cali 760035, Colombia; (I.D.O.-I.); (N.M.); (I.M.)
| | - Yamil Liscano
- Research Group of Comprehensive Health (GISI), Department Faculty of Health, Universidad Santiago de Cali, Cali 760035, Colombia;
| | - Natalia Martínez
- Research Group of Microbiology, Industry and Environment, Faculty of Basic Sciences, Universidad Santiago of Cali, Cali 760035, Colombia; (I.D.O.-I.); (N.M.); (I.M.)
| | - Isamar Muñoz
- Research Group of Microbiology, Industry and Environment, Faculty of Basic Sciences, Universidad Santiago of Cali, Cali 760035, Colombia; (I.D.O.-I.); (N.M.); (I.M.)
| | - Marcela Manrique-Moreno
- Chemistry Institute, Faculty of Exact and Natural Sciences, University of Antioquia, Medellin 050010, Colombia;
| | - Luis Martinez-Martinez
- Microbiology Unit, Reina Sofía University Hospital, 14008 Córdoba, Spain;
- Maimonides Institute for Biomedical Research of Córdoba, 14008 Córdoba, Spain
- Department of Agricultural Chemistry, Soil Sciencies and Microbiology, University of Córdoba, 14071 Córdoba, Spain
| | - José Oñate-Garzon
- Research Group of Chemistry and Biotechnology, Faculty of Basic Sciences, Universidad Santiago of Cali, Cali 760035, Colombia
- Correspondence: (S.P.R.-S.); (J.O.-G.)
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8
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Karathanou K, Bondar AN. Algorithm to catalogue topologies of dynamic lipid hydrogen-bond networks. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183859. [PMID: 34999081 DOI: 10.1016/j.bbamem.2022.183859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/21/2021] [Accepted: 12/31/2021] [Indexed: 06/14/2023]
Abstract
Lipid membrane interfaces host reactions essential for the functioning of cells. The hydrogen-bonding environment at the membrane interface is particularly important for binding of proteins, drug molecules, and ions. We present here the implementation and applications of a depth-first search algorithm that analyzes dynamic lipid interaction networks. Lipid hydrogen-bond networks sampled transiently during simulations of lipid bilayers are clustered according to main types of topologies that characterize three-dimensional arrangements of lipids connected to each other via short water bridges. We characterize the dynamics of hydrogen-bonded lipid clusters in simulations of model POPE and POPE:POPG membranes that are often used for bacterial membrane proteins, in a model of the Escherichia coli membrane with six different lipid types, and in POPS membranes. We find that all lipids sample dynamic hydrogen-bonded networks with linear, star, or circular arrangements of the lipid headgroups, and larger networks with combinations of these three types of topologies. Overall, linear lipid-water bridges tend to be short. Water-mediated lipid clusters in all membranes with PE lipids tend to be somewhat small, with about four lipids in all membranes studied here. POPS membranes allow circular arrangements of three POPS lipids to be sampled frequently, and complex arrangements of linear, star, and circular paths may also be sampled. These findings suggest a molecular picture of the membrane interface whereby lipid molecules transiently connect in clusters with somewhat small spatial extension.
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Affiliation(s)
- Konstantina Karathanou
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany; University of Bucharest, Faculty of Physics, Str. Atomiştilor 405, Bucharest-Măgurele 077125, Romania; Institute for Neuroscience and Medicine and Institute for Advanced Simulations (IAS-5/INM-9), Computational Biomedicine, Forschungszentrum Jülich, 52425 Jülich, Germany.
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9
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Rajasekaran M, Ayappa G. Influence of the extent of hydrophobicity on water organization and dynamics on 2D graphene oxide surfaces. Phys Chem Chem Phys 2022; 24:14909-14923. [DOI: 10.1039/d1cp03962h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Graphene oxide (GO) nanomaterials are being extensively explored for a wide spectrum of applications, ranging from water desalination to fuel cell applications due to their tunable mechanical, thermal, and electrical...
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10
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Gonzalez MA, Zaragoza A, Lynch CI, Sansom MSP, Valeriani C. Influence of water models on water movement through AQP1. J Chem Phys 2021; 155:154502. [PMID: 34686053 DOI: 10.1063/5.0063986] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Water diffusion through membrane proteins is a key aspect of cellular function. Essential processes of cellular metabolism are driven by osmotic pressure, which depends on water channels. Membrane proteins such as aquaporins (AQPs) are responsible for enabling water permeation through the cell membrane. AQPs are highly selective, allowing only water and relatively small polar molecules to cross the membrane. Experimentally, estimation of water flux through membrane proteins is still a challenge, and hence, accurate simulations of water permeation are of particular importance. We present a numerical study of water diffusion through AQP1 comparing three water models: TIP3P, OPC, and TIP4P/2005. Bulk diffusion, diffusion permeability, and osmotic permeability are computed and compared among all models. The results show that there are significant differences between TIP3P (a particularly widespread model for simulations of biological systems) and the more recently developed TIP4P/2005 and OPC models. We demonstrate that OPC and TIP4P/2005 reproduce protein-water interactions and dynamics in very good agreement with experimental data. From this study, we find that the choice of the water model has a significant effect on the computed water dynamics as well as its molecular behavior within a biological nanopore.
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Affiliation(s)
| | - Alberto Zaragoza
- Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112-0850, USA
| | - Charlotte I Lynch
- Department of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, United Kingdom
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, United Kingdom
| | - Chantal Valeriani
- Universidad Complutense de Madrid, Facultad de Ciencias Fícias, Departamento de Estructura de la Materia, Física Térmica y Electrónica, 28040 Madrid, Spain
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11
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Hossain SI, Saha SC, Deplazes E. Phenolic compounds alter the ion permeability of phospholipid bilayers via specific lipid interactions. Phys Chem Chem Phys 2021; 23:22352-22366. [PMID: 34604899 DOI: 10.1039/d1cp03250j] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This study aims to understand the role of specific phenolic-lipid interactions in the membrane-altering properties of phenolic compounds. We combine tethered lipid bilayer (tBLM) electrical impedance spectroscopy (EIS) with all-atom molecular dynamics (MD) simulations to study the membrane interactions of six phenolic compounds: caffeic acid methyl ester, caffeic acid, 3,4 dihydroxybenzoic acid, chlorogenic acid, syringic acid and p-coumaric acid. tBLM/EIS experiments showed that caffeic acid methyl ester, caffeic acid and 3,4 dihydroxybenzoic acid significantly increase the permeability of phospholipid bilayers to Na+ ions. In contrast, chlorogenic acid, syringic acid and p-coumaric acid showed no effect. Experiments with lipids lacking the phosphate group show a significant decrease in the membrane-altering effects indicating that specific phenolic-lipid interactions are critical in altering ion permeability. MD simulations confirm that compounds that alter ion permeability form stable interactions with the phosphate oxygen. In contrast, inactive phenolic compounds are superficially bound to the membrane surface and primarily interact with interfacial water. Our combined results show that compounds with similar structures can have very different effects on ion permeability in membranes. These effects are governed by specific interactions at the water-lipid interface and show no correlation with lipophilicity. Furthermore, none of the compounds alter the overall structure of the phospholipid bilayer as determined by area per lipid and order parameters. Based on data from this study and previous findings, we propose that phenolic compounds can alter membrane ion permeability by causing local changes in lipid packing that subsequently reduce the energy barrier for ion-induced pores.
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Affiliation(s)
- Sheikh I Hossain
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia.
| | - Suvash C Saha
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Evelyne Deplazes
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia. .,School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia
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12
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Chattopadhyay M, Krok E, Orlikowska H, Schwille P, Franquelim HG, Piatkowski L. Hydration Layer of Only a Few Molecules Controls Lipid Mobility in Biomimetic Membranes. J Am Chem Soc 2021; 143:14551-14562. [PMID: 34342967 PMCID: PMC8447254 DOI: 10.1021/jacs.1c04314] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
![]()
Self-assembly of
biomembranes results from the intricate interactions
between water and the lipids’ hydrophilic head groups. Therefore,
the lipid–water interplay strongly contributes to modulating
membrane architecture, lipid diffusion, and chemical activity. Here,
we introduce a new method of obtaining dehydrated, phase-separated,
supported lipid bilayers (SLBs) solely by controlling the decrease
of their environment’s relative humidity. This facilitates
the study of the structure and dynamics of SLBs over a wide range
of hydration states. We show that the lipid domain structure of phase-separated
SLBs is largely insensitive to the presence of the hydration layer.
In stark contrast, lipid mobility is drastically affected by dehydration,
showing a 6-fold decrease in lateral diffusion. At the same time,
the diffusion activation energy increases approximately 2-fold for
the dehydrated membrane. The obtained results, correlated with the
hydration structure of a lipid molecule, revealed that about six to
seven water molecules directly hydrating the phosphocholine moiety
play a pivotal role in modulating lipid diffusion. These findings
could provide deeper insights into the fundamental reactions where
local dehydration occurs, for instance during cell–cell fusion,
and help us better understand the survivability of anhydrobiotic organisms.
Finally, the strong dependence of lipid mobility on the number of
hydrating water molecules opens up an application potential for SLBs
as very precise, nanoscale hydration sensors.
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Affiliation(s)
- Madhurima Chattopadhyay
- Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Piotrowo 3, 60-965 Poznan, Poland
| | - Emilia Krok
- Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Piotrowo 3, 60-965 Poznan, Poland
| | - Hanna Orlikowska
- Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Piotrowo 3, 60-965 Poznan, Poland
| | - Petra Schwille
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Henri G Franquelim
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Lukasz Piatkowski
- Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Piotrowo 3, 60-965 Poznan, Poland
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13
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Wang D, Tian Y, Jiang L. Abnormal Properties of Low-Dimensional Confined Water. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2100788. [PMID: 34176214 DOI: 10.1002/smll.202100788] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/25/2021] [Indexed: 06/13/2023]
Abstract
Water molecules confined to low-dimensional spaces exhibit unusual properties compared to bulk water. For example, the alternating hydrophilic and hydrophobic nanodomains on flat silicon wafer can induce the abnormal spreading of water (contact angles near 0°) which is caused by the 2D capillary effect. Hence, exploring the physicochemical properties of confined water from the nanoscale is of great value for understanding the challenges in material science and promoting the applications of nanomaterials in the fields of mass transport, nanofluidic designing, and fuel cell. The knowledge framework of confined water can also help to better understand the complex functions of the hydration layer of biomolecules, and even trace the origin of life. In this review, the physical properties, abnormal behaviors, and functions of the confined water are mainly summarized through several common low-dimensional water formats in the fields of solid/air-water interface, nanochannel confinement, and biological hydration layer. These researches indicate that the unusual behaviors of the confined water depend strongly on the confinement size and the interaction between the molecules and confining surface. These diverse properties of confined water open a new door to materials science and may play an important role in the future development of biology.
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Affiliation(s)
- Dianyu Wang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Ye Tian
- Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
- Key Laboratory of Bioinspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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14
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Voloshin VP, Medvedev NN. ORIENTATION OF WATER MOLECULES NEAR A GLOBULAR PROTEIN. J STRUCT CHEM+ 2021. [DOI: 10.1134/s002247662105005x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Abstract
Water determines the properties of biological systems. Therefore, understanding the nature of the mutual interaction between water and biosystems is of primary importance for a proper assessment of any biological activity, e.g., the efficacy of new drugs or vaccines. A convenient way to characterize the interactions between biosystems and water is to analyze their impact on water density and dynamics in the proximity of the interfaces. It is commonly accepted that water bulk density and dynamical properties are recovered at distances of the order of 1 nm away from the surface of biological systems. This notion leads to the definition of hydration or biological water as the nanoscopic layer of water covering the surface of biosystems and to the expectation that all the effects of the water-interface interaction are limited to this thin region. Here, we review some of our latest contributions, showing that phospholipid membranes affect the water dynamics, structural properties, and hydrogen bond network at a distance that is more than twice as large as the commonly evoked ∼1nm thick layer and of the order of 2.4 nm. Furthermore, we unveil that at a shorter distance ∼0.5nm from the membrane, instead, there is an additional interface between lipid-bound and unbound water. Bound water has a structural role in the stability of the membrane. Our results imply that the concept of hydration water should be revised or extended and pave the way to a deeper understanding of the mutual interactions between water and biological systems.
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16
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Valentine ML, Waterland MK, Fathizadeh A, Elber R, Baiz CR. Interfacial Dynamics in Lipid Membranes: The Effects of Headgroup Structures. J Phys Chem B 2021; 125:1343-1350. [DOI: 10.1021/acs.jpcb.0c08755] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Mason L. Valentine
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712-1224, United States
| | - Maya K. Waterland
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712-1224, United States
| | - Arman Fathizadeh
- Oden Institute for Computational Science and Engineering, Austin, Texas 78712, United States
| | - Ron Elber
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712-1224, United States
- Oden Institute for Computational Science and Engineering, Austin, Texas 78712, United States
| | - Carlos R. Baiz
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712-1224, United States
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17
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Martelli F, Crain J, Franzese G. Network Topology in Water Nanoconfined between Phospholipid Membranes. ACS NANO 2020; 14:8616-8623. [PMID: 32578978 DOI: 10.1021/acsnano.0c02984] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Water provides the driving force for the assembly and stability of many cellular components. Despite its impact on biological functions, a nanoscale understanding of the relationship between its structure and dynamics under soft confinement has remained elusive. As expected, water in contact with biological membranes recovers its bulk density and dynamics at ∼1 nm from phospholipid headgroups but surprisingly enhances its intermediate range order (IRO) over a distance, at least, twice as large. Here, we explore how the IRO is related to the water's hydrogen-bond network (HBN) and its coordination defects. We characterize the increased IRO by an alteration of the HBN up to more than eight coordination shells of hydration water. The HBN analysis emphasizes the existence of a bound-unbound water interface at ∼0.8 nm from the membrane. The unbound water has a distribution of defects intermediate between bound and bulk water, but with density and dynamics similar to bulk, while bound water has reduced thermal energy and many more HBN defects than low-temperature water. This observation could be fundamental for developing nanoscale models of biological interactions and for understanding how alteration of the water structure and topology, for example, due to changes in extracellular ions concentration, could affect diseases and signaling. More generally, it gives us a different perspective to study nanoconfined water.
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Affiliation(s)
- Fausto Martelli
- Hartree Centre, IBM Research Europe, Daresbury WA4 4AD, United Kingdom
| | - Jason Crain
- Hartree Centre, IBM Research Europe, Daresbury WA4 4AD, United Kingdom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Giancarlo Franzese
- Secció de Física Estadística i Interdisciplinària, Departament de Física de la Matèria Condensada, and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, C. Martí i Franquès 1, 08028 Barcelona, Spain
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18
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Venkatraman RK, Baiz CR. Ultrafast Dynamics at the Lipid-Water Interface: DMSO Modulates H-Bond Lifetimes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6502-6511. [PMID: 32423219 DOI: 10.1021/acs.langmuir.0c00870] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Dimethyl sulfoxide (DMSO) is a common cosolvent and cryopreservation agent used to freeze cells and tissues. DMSO alters the H-bond structure of water, but its interactions with biomolecules and, specifically, with biological interfaces remain poorly understood. Here we investigate the effects of DMSO on the H-bond dynamics at the lipid-water interface using a combination of ultrafast two-dimensional infrared (2D IR) spectroscopy and molecular dynamics simulations. Ester carbonyl absorption spectra show that DMSO dehydrates the interface, and simulations show that the area per lipid is decreased. Ultrafast 2D IR spectra measure the time scales of frequency fluctuations at the ester carbonyl positions located precisely between the hydrophobic and hydrophilic regions of the membrane. 2D IR measurements show that low DMSO concentrations (<10 mol %) induce ∼40% faster H-bond dynamics compared with pure water, whereas increased concentrations (>10-20 mol %) once again slow down the dynamics. This slow-fast-slow trend is described in terms of two different solvation regimes. Below 10 mol %, DMSO weakens the interfacial H bond, leading to faster "bulk-like" dynamics, whereas above 10 mol %, water molecules become "relatively immobilized" as the H-bond networks becoming disrupted by the H-bond donor/acceptor imbalance at the interface. These studies are an important step toward characterizing the environments around lipid membranes, which are essential to numerous biological processes.
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Affiliation(s)
- Ravi Kumar Venkatraman
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Carlos R Baiz
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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19
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Dwadasi BS, Goverapet Srinivasan S, Rai B. Interfacial structure in the liquid-liquid extraction of rare earth elements by phosphoric acid ligands: a molecular dynamics study. Phys Chem Chem Phys 2020; 22:4177-4192. [PMID: 32040116 DOI: 10.1039/c9cp05719f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solvent extraction (SX), wherein two immiscible liquids, one containing the extractant molecules and the other containing the solute to be extracted are brought in contact to effect the phase transfer of the solute, underpins metal extraction and recovery processes. The interfacial region is of utmost importance in the SX process, since besides thermodynamics, the physical and chemical heterogeneity at the interface governs the kinetics of the process. Yet, a fundamental understanding of this heterogeneity and its implications for the extraction mechanism are currently lacking. We use molecular dynamics (MD) simulations to study the liquid-liquid interface under conditions relevant to the SX of Rare Earth Elements (REEs) by a phosphoric acid ligand. Simulations revealed that the extractant molecules and varying amounts of acid and metal ions partitioned to the interface. The presence of these species had a significant effect on the interfacial thickness, hydrogen bond life times and orientations of the water molecules at the interface. Deprotonation of the ligands was essential for the adsorption of the metal ions at the interface, with these ions forming a number of different complexes at the interface involving one to three extractant molecules and four to eight water molecules. Although the interface itself was rough, no obvious 'finger-like' water protrusions penetrating the organic phase were seen in our simulations. While the results of our work help us gain fundamental insights into the sequence of events leading to the formation of a variety of interfacial complexes, they also emphasize the need to carry out a more detailed atomic level study to understand the full mechanism of extraction of REEs from the aqueous to organic phases by phosphoric acid ligands.
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Affiliation(s)
- Balarama Sridhar Dwadasi
- TCS Research, Tata Research Development and Design Center, 54-B Hadapsar Industrial Estate, Hadapsar, Pune - 411013, Maharashtra, India.
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20
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Deplazes E, Sarrami F, Poger D. Effect of H3O+ on the Structure and Dynamics of Water at the Interface with Phospholipid Bilayers. J Phys Chem B 2020; 124:1361-1373. [DOI: 10.1021/acs.jpcb.9b10169] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Evelyne Deplazes
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
- School of Pharmacy and Biomedical Sciences, Curtin Institute for Computation, Curtin University, Perth, Western Australia 6845, Australia
| | - Farzaneh Sarrami
- School of Chemistry and Biochemistry, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - David Poger
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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21
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Dalchand N, Doğangün M, Ohno PE, Ma E, Martinson ABF, Geiger FM. Perturbation of Hydrogen-Bonding Networks over Supported Lipid Bilayers by Poly(allylamine hydrochloride). J Phys Chem B 2019; 123:4251-4257. [PMID: 31013086 DOI: 10.1021/acs.jpcb.9b02392] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Water is vital to many biochemical processes and is necessary for driving fundamental interactions of cell membranes with their external environments, yet it is difficult to probe the membrane/water interface directly and without the use of external labels. Here, we employ vibrational sum frequency generation spectroscopy to understand the role of interfacial water molecules above bilayers formed from zwitterionic (phosphatidylcholine) and anionic (phosphatidylglycerol, PG, and phosphatidylserine, PS) lipids as they are exposed to the common polycation poly(allylamine hydrochloride) (PAH) in 100 mM NaCl. We show that as the concentration of PAH is increased, the interfacial water molecules are irreversibly displaced and find that it requires 10 times more PAH to displace interfacial water molecules from membranes formed from purely zwitterionic lipids when compared to membranes that contain the anionic PG and PS lipids. This outcome is likely due to the difference in (1) the energy with which water molecules are bound to the lipid headgroups, (2) the number of water molecules bound to the headgroups, which is related to the headgroup area, and (3) the electrostatic interactions between the PAH molecules and the negatively charged lipids that are favored when compared to the zwitterionic lipid headgroups. The findings presented here contribute to establishing causal relationships in nanotoxicology and to understanding, controlling, and predicting the initial steps that lead to the lysis of cells exposed to membrane-disrupting polycations or to transfection.
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Affiliation(s)
- Naomi Dalchand
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60660 , United States
| | - Merve Doğangün
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60660 , United States
| | - Paul E Ohno
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60660 , United States
| | - Emily Ma
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60660 , United States
| | - Alex B F Martinson
- Materials Science Division , Argonne National Laboratory , 9700 S. Cass Avenue , Argonne, Lemont , Illinois 40439 , United States
| | - Franz M Geiger
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60660 , United States
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22
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M R, Ayappa KG. Enhancing the Dynamics of Water Confined between Graphene Oxide Surfaces with Janus Interfaces: A Molecular Dynamics Study. J Phys Chem B 2019; 123:2978-2993. [DOI: 10.1021/acs.jpcb.8b12341] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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23
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Calero C, Franzese G. Membranes with different hydration levels: The interface between bound and unbound hydration water. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.10.074] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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24
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Dai Z, Shi L, Lu L, Sun Y, Lu X. Unique Structures and Vibrational Spectra of Protic Ionic Liquids Confined in TiO 2 Slits: The Role of Interfacial Hydrogen Bonds. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13449-13458. [PMID: 30350690 DOI: 10.1021/acs.langmuir.8b02527] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The ionic liquid (IL)/titanium dioxide (TiO2) interface exists in many application systems, such as nanomaterial synthesis, catalysis, and electrochemistry systems. The nanoscale interfacial properties in the above systems are a common issue. However, directly detecting the interfacial properties of nanoconfined ILs by experimental methods is still challenging. To help better learn about the interfacial issue, molecular dynamics simulations have been performed to explore the structures, vibration spectra, and hydrogen bond (HB) properties at the IL/TiO2 interface. Ethylammonium nitrate (EAN) ILs confined in TiO2 slit pores with different pore widths were studied. A unique vibrational spectrum appeared for EAN ILs confined in a 0.7 nm TiO2 slit, and this phenomenon is related to interfacial hydrogen bonds (HBs). An analysis of the HB types indicated that the interfacial NH3+ group of the cations was in an asymmetric HB environment in the 0.7 nm TiO2 slit, which led to the disappearance of the symmetric N-H stretching mode. In addition, the significant increase in the HB strength between NH3+ groups and the TiO2 surface slowed down the stretching vibration of the N-H bond, resulting in one peak in the vibrational spectra at a lower frequency. For the first time, our simulation work establishes a molecular-level relationship between the vibrational spectrum and the local HB environment of nanoconfined ILs at the IL/TiO2 interface, and this relationship is helpful for interface design in related systems.
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Affiliation(s)
- Zhongyang Dai
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering , Nanjing Tech University , 5 Xinmofan Road , Nanjing 210009 , P. R. China
| | - Lili Shi
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering , Nanjing Tech University , 5 Xinmofan Road , Nanjing 210009 , P. R. China
| | - Linghong Lu
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering , Nanjing Tech University , 5 Xinmofan Road , Nanjing 210009 , P. R. China
| | - Yunhao Sun
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering , Nanjing Tech University , 5 Xinmofan Road , Nanjing 210009 , P. R. China
| | - Xiaohua Lu
- College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering , Nanjing Tech University , 5 Xinmofan Road , Nanjing 210009 , P. R. China
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25
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Lütgebaucks C, Macias-Romero C, Roke S. Characterization of the interface of binary mixed DOPC:DOPS liposomes in water: The impact of charge condensation. J Chem Phys 2018; 146:044701. [PMID: 28147550 DOI: 10.1063/1.4974084] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Solutions of liposomes composed of binary mixtures of anionic dioleoylphosphatidylserine (DOPS) and zwitterionic dioleoylphosphatidylcholine (DOPC) are investigated with label-free angle-resolved (AR) second harmonic scattering (SHS) and electrophoretic mobility measurements. The membrane surface potential is extracted from the AR-SHS response. The surface potential changes from -10 to -145 mV with varying DOPS content ( from 0% to 100%) and levels off already at ∼ 10 % DOPS content. The ζ-potential shows the same trend but with a drastically lower saturation value (-44 mV). This difference is explained by the formation of a condensed layer of Na+ counterions around the outer leaflet of the liposome as predicted by charge condensation theories for polyelectrolyte systems.
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Affiliation(s)
- Cornelis Lütgebaucks
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Carlos Macias-Romero
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sylvie Roke
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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26
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Dynamic Water Hydrogen-Bond Networks at the Interface of a Lipid Membrane Containing Palmitoyl-Oleoyl Phosphatidylglycerol. J Membr Biol 2018. [DOI: 10.1007/s00232-018-0023-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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Yang D, Fu F, Li L, Yang Z, Wan Z, Luo Y, Hu N, Chen X, Zeng G. Unique orientations and rotational dynamics of a 1-butyl-3-methyl-imidazolium hexafluorophosphate ionic liquid at the gas–liquid interface: the effects of the hydrogen bond and hydrophobic interactions. Phys Chem Chem Phys 2018; 20:12043-12052. [DOI: 10.1039/c8cp00839f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-stage rotational motions of the interfacial [BMIM]+ cations are essentially determined by both hydrophobic and hydrogen-bonding interactions.
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Affiliation(s)
- Deshuai Yang
- Institute of Advanced Materials (IAM), State-Province Joint Engineering Laboratory of Zeolite Membrane Materials, College of Chemistry and Chemical Engineering, Jiangxi Normal University
- Nanchang 330022
- People's Republic of China
- Kuang Yaming Honors School, Nanjing University
- Nanjing 210023
| | - Fangjia Fu
- Institute of Advanced Materials (IAM), State-Province Joint Engineering Laboratory of Zeolite Membrane Materials, College of Chemistry and Chemical Engineering, Jiangxi Normal University
- Nanchang 330022
- People's Republic of China
| | - Li Li
- Institute of Advanced Materials (IAM), State-Province Joint Engineering Laboratory of Zeolite Membrane Materials, College of Chemistry and Chemical Engineering, Jiangxi Normal University
- Nanchang 330022
- People's Republic of China
| | - Zhen Yang
- Institute of Advanced Materials (IAM), State-Province Joint Engineering Laboratory of Zeolite Membrane Materials, College of Chemistry and Chemical Engineering, Jiangxi Normal University
- Nanchang 330022
- People's Republic of China
| | - Zheng Wan
- Institute of Advanced Materials (IAM), State-Province Joint Engineering Laboratory of Zeolite Membrane Materials, College of Chemistry and Chemical Engineering, Jiangxi Normal University
- Nanchang 330022
- People's Republic of China
| | - Yi Luo
- Institute of Advanced Materials (IAM), State-Province Joint Engineering Laboratory of Zeolite Membrane Materials, College of Chemistry and Chemical Engineering, Jiangxi Normal University
- Nanchang 330022
- People's Republic of China
| | - Na Hu
- Institute of Advanced Materials (IAM), State-Province Joint Engineering Laboratory of Zeolite Membrane Materials, College of Chemistry and Chemical Engineering, Jiangxi Normal University
- Nanchang 330022
- People's Republic of China
| | - Xiangshu Chen
- Institute of Advanced Materials (IAM), State-Province Joint Engineering Laboratory of Zeolite Membrane Materials, College of Chemistry and Chemical Engineering, Jiangxi Normal University
- Nanchang 330022
- People's Republic of China
| | - Guixiang Zeng
- Kuang Yaming Honors School, Nanjing University
- Nanjing 210023
- People's Republic of China
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28
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Lee Y, Pincus PA, Hyeon C. Effects of Dimethyl Sulfoxide on Surface Water near Phospholipid Bilayers. Biophys J 2017; 111:2481-2491. [PMID: 27926849 DOI: 10.1016/j.bpj.2016.10.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/14/2016] [Accepted: 10/27/2016] [Indexed: 11/18/2022] Open
Abstract
Despite much effort to probe the properties of dimethyl sulfoxide (DMSO) solution, the effects of DMSO on water, especially near plasma membrane surfaces, still remain elusive. By performing molecular dynamics simulations at varying DMSO concentrations (XDMSO), we study how DMSO affects structural and dynamical properties of water in the vicinity of phospholipid bilayers. As proposed by a number of experiments, our simulations confirm that DMSO induces dehydration from bilayer surfaces and disrupts the H-bond structure of water. However, DMSO-enhanced water diffusivity at solvent-bilayer interfaces, an intriguing discovery reported by a spin-label measurement, is not confirmed in our simulations. To resolve this discrepancy, we examine the location of the spin label (Tempo) relative to the solvent-bilayer interface. In accord with the evidence in the literature, our simulations, which explicitly model Tempo-phosphatidylcholine, find that the Tempo moiety is equilibrated at ∼8-10 Å below the bilayer surface. Furthermore, the DMSO-enhanced surface-water diffusion is confirmed only when water diffusion is analyzed around the Tempo moiety that is immersed below the bilayer surface, which implies that the experimentally detected signal of water using Tempo stems from the interior of bilayers, not from the interface. Our analysis finds that the increase of water diffusion below the bilayer surface is coupled to the increase of area per lipid with an increasing XDMSO(≲10mol%). Underscoring the hydrophobic nature of the Tempo moiety, our study calls for careful re-evaluation of the use of Tempo in measurements on lipid bilayer surfaces.
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Affiliation(s)
- Yuno Lee
- Korea Institute for Advanced Study, Seoul, Republic of Korea
| | - Philip A Pincus
- Physics and Materials Departments, University of California, Santa Barbara, California
| | - Changbong Hyeon
- Korea Institute for Advanced Study, Seoul, Republic of Korea.
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29
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Fábián B, Sega M, Horvai G, Jedlovszky P. Single Particle Dynamics at the Intrinsic Surface of Various Apolar, Aprotic Dipolar, and Hydrogen Bonding Liquids As Seen from Computer Simulations. J Phys Chem B 2017; 121:5582-5594. [PMID: 28498673 DOI: 10.1021/acs.jpcb.7b02220] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigate the single molecule dynamics at the intrinsic liquid/vapor interface of five different molecular liquids (carbon tetrachloride, acetone, acetonitrile, methanol, and water). After assessing that the characteristic residence times in the surface layer are long enough for a meaningful definition of several transport properties within the layer itself, we characterize the dynamics of the individual molecules at the liquid surface by analyzing their normal and lateral mean-square displacements and lateral velocity autocorrelation functions and, in the case of the hydrogen bonding liquids (i.e., water and methanol), also the properties of the hydrogen bonds. Further, dynamical properties as well as the clustering of the molecules residing unusually long in the surface layer are also investigated. The global picture emerging from this analysis is that of a noticeably enhanced dynamics of the molecules at the liquid surface, with diffusion coefficients up to 4 times larger than in the bulk, and the disappearance of the caging effect at the surface of all liquids but water. The dynamics of water is dominated by the strong hydrogen bonding structure also at the liquid surface.
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Affiliation(s)
- Balázs Fábián
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics , Szt. Gellért tér 4, H-1111 Budapest, Hungary.,Institut UTINAM (CNRS UMR 6213), Université Bourgogne Franche-Comté , 16 route de Gray, F-25030 Besançon, France
| | - Marcello Sega
- Faculty of Physics, University of Vienna , Boltzmanngasse 5, A-1090 Vienna, Austria
| | - George Horvai
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics , Szt. Gellért tér 4, H-1111 Budapest, Hungary.,MTA-BME Research Group of Technical Analytical Chemistry, Szt. Gellért tér 4, H-1111 Budapest, Hungary
| | - Pál Jedlovszky
- MTA-BME Research Group of Technical Analytical Chemistry, Szt. Gellért tér 4, H-1111 Budapest, Hungary.,Department of Chemistry, Eszterházy Károly University , Leányka u. 6, H-3300 Eger, Hungary
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30
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Alarcón LM, de Los Angeles Frías M, Morini MA, Belén Sierra M, Appignanesi GA, Anibal Disalvo E. Water populations in restricted environments of lipid membrane interphases. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2016; 39:94. [PMID: 27761781 DOI: 10.1140/epje/i2016-16094-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/20/2016] [Indexed: 06/06/2023]
Abstract
We employ molecular dynamics simulations to study the hydration properties of Dipalmitoylphosphatidylcholine (DPPC) bilayers, both in the gel and the liquid crystalline states. We show that while the tight hydration centers (PO and CO moieties) are significantly hydrated in both phases, the gel-fluid transition involves significant changes at the second hydration shell, particularly at the buried region between the hydrocarbon tails. Thus, while almost no buried water population exists in the gel state below the carbonyls, this hydrophobic region becomes partially water accesible in the liquid crystalline state. We shall also show that such water molecules present a lower H-bond coordination as compared to the molecules at the primary hydration shell. This means that, while the latter are arranged in relatively compact nanoclusters (as already proposed), the buried water molecules tend to organize themselves in less compact structures, typically strings or branched strings, with a scarce population of isolated molecules. This behavior is similar to that observed in other hydration contexts, like water penetrating carbon nanotubes or model hydrophobic channels or pores, and reflects the reluctance of water to sacrifice HB coordination.
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Affiliation(s)
- Laureano M Alarcón
- Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, 8000-Bahía, Blanca, Argentina
| | - M de Los Angeles Frías
- Laboratorio de Biointerfases y Sistemas Biomiméticos, Laboratorios Centrales, CITSE-UNSE, Santiago del Estero, Argentina
| | - Marcela A Morini
- Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, 8000-Bahía, Blanca, Argentina
| | - M Belén Sierra
- Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, 8000-Bahía, Blanca, Argentina
| | - Gustavo A Appignanesi
- Sección Fisicoquímica, INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, 8000-Bahía, Blanca, Argentina.
| | - E Anibal Disalvo
- Laboratorio de Biointerfases y Sistemas Biomiméticos, Laboratorios Centrales, CITSE-UNSE, Santiago del Estero, Argentina
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31
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Halder S, Surolia A, Mukhopadhyay C. Dynamics simulation of soybean agglutinin (SBA) dimer reveals the impact of glycosylation on its enhanced structural stability. Carbohydr Res 2016; 428:8-17. [DOI: 10.1016/j.carres.2016.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/10/2016] [Accepted: 04/08/2016] [Indexed: 10/21/2022]
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Structural Interpretation of the Large Slowdown of Water Dynamics at Stacked Phospholipid Membranes for Decreasing Hydration Level: All-Atom Molecular Dynamics. MATERIALS 2016; 9:ma9050319. [PMID: 28773441 PMCID: PMC5503093 DOI: 10.3390/ma9050319] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/18/2016] [Accepted: 04/21/2016] [Indexed: 11/27/2022]
Abstract
Hydration water determines the stability and function of phospholipid membranes as well as the interaction of membranes with other molecules. Experiments and simulations have shown that water dynamics slows down dramatically as the hydration decreases, suggesting that the interfacial water that dominates the average dynamics at low hydration is slower than water away from the membrane. Here, based on all-atom molecular dynamics simulations, we provide an interpretation of the slowdown of interfacial water in terms of the structure and dynamics of water–water and water–lipid hydrogen bonds (HBs). We calculate the rotational and translational slowdown of the dynamics of water confined in stacked phospholipid membranes at different levels of hydration, from completely hydrated to poorly hydrated membranes. For all hydrations, we analyze the distribution of HBs and find that water–lipids HBs last longer than water–water HBs and that at low hydration most of the water is in the interior of the membrane. We also show that water–water HBs become more persistent as the hydration is lowered. We attribute this effect (i) to HBs between water molecules that form, in turn, persistent HBs with lipids; (ii) to the hindering of the H-bonding switching between water molecules due to the lower water density at the interface; and (iii) to the higher probability of water–lipid HBs as the hydration decreases. Our interpretation of the large dynamic slowdown in water under dehydration is potentially relevant in understanding membrane biophysics at different hydration levels.
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Pasenkiewicz-Gierula M, Baczynski K, Markiewicz M, Murzyn K. Computer modelling studies of the bilayer/water interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2305-2321. [PMID: 26825705 DOI: 10.1016/j.bbamem.2016.01.024] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/18/2016] [Accepted: 01/21/2016] [Indexed: 01/24/2023]
Abstract
This review summarises high resolution studies on the interface of lamellar lipid bilayers composed of the most typical lipid molecules which constitute the lipid matrix of biomembranes. The presented results were obtained predominantly by computer modelling methods. Whenever possible, the results were compared with experimental results obtained for similar systems. The first and main section of the review is concerned with the bilayer-water interface and is divided into four subsections. The first describes the simplest case, where the interface consists only of lipid head groups and water molecules and focuses on interactions between the lipid heads and water molecules; the second describes the interface containing also mono- and divalent ions and concentrates on lipid-ion interactions; the third describes direct inter-lipid interactions. These three subsections are followed by a discussion on the network of direct and indirect inter-lipid interactions at the bilayer interface. The second section summarises recent computer simulation studies on the interactions of antibacterial membrane active compounds with various models of the bacterial outer membrane. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Marta Pasenkiewicz-Gierula
- Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
| | - Krzysztof Baczynski
- Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Michal Markiewicz
- Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Krzysztof Murzyn
- Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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34
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Basu I, Manna M, Mukhopadhyay C. Insights into the behavioral difference of water in the presence of GM1. FEBS Lett 2015; 589:3887-92. [DOI: 10.1016/j.febslet.2015.11.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/16/2015] [Accepted: 11/16/2015] [Indexed: 11/26/2022]
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35
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Benedetto A, Bingham RJ, Ballone P. Structure and dynamics of POPC bilayers in water solutions of room temperature ionic liquids. J Chem Phys 2015; 142:124706. [DOI: 10.1063/1.4915918] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Antonio Benedetto
- School of Physics, University College Dublin, Dublin 4, Ireland
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Richard J. Bingham
- York Centre for Complex Systems Analysis, University of York, York YO10 5GE, United Kingdom
| | - Pietro Ballone
- Center for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia (IIT), 00185 Roma, Italy
- Department of Physics, Università di Roma “La Sapienza,” 00185 Roma, Italy
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36
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Yamamoto E, Akimoto T, Yasui M, Yasuoka K. Origin of 1/f noise in hydration dynamics on lipid membrane surfaces. Sci Rep 2015; 5:8876. [PMID: 25743377 PMCID: PMC4351557 DOI: 10.1038/srep08876] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/09/2015] [Indexed: 12/15/2022] Open
Abstract
Water molecules on lipid membrane surfaces are known to contribute to membrane stability by connecting lipid molecules and acting as a water bridge. Although water structures and diffusivities near the membrane surfaces have been extensively studied, hydration dynamics on the surfaces has remained an open question. Here we investigate residence time statistics of water molecules on the surface of lipid membranes using all-atom molecular dynamics simulations. We show that hydration dynamics on the lipid membranes exhibits 1/f noise. Constructing a dichotomous process for the hydration dynamics, we find that residence times in each state follow a power-law with exponential cutoff and that the process can be regarded as a correlated renewal process where interoccurrence times are correlated. The results imply that the origin of the 1/f noise in hydration dynamics on the membrane surfaces is a combination of a power-law distribution with cutoff of interoccurrence times of switching events and a long-term correlation between the interoccurrence times. These results suggest that the 1/f noise attributed to the correlated renewal process may contribute to the stability of the hydration layers and lipid membranes.
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Affiliation(s)
- Eiji Yamamoto
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Takuma Akimoto
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Masato Yasui
- Department of Pharmacology, School of Medicine, Keio University, 35 Shinanomachi, Shinju-ku, Tokyo 160-8582, Japan
| | - Kenji Yasuoka
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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37
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Pronk S, Lindahl E, Kasson PM. Coupled diffusion in lipid bilayers upon close approach. J Am Chem Soc 2015; 137:708-14. [PMID: 25535654 PMCID: PMC4308745 DOI: 10.1021/ja508803d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Indexed: 11/28/2022]
Abstract
Biomembrane interfaces create regions of slowed water dynamics in their vicinity. When two lipid bilayers come together, this effect is further accentuated, and the associated slowdown can affect the dynamics of larger-scale processes such as membrane fusion. We have used molecular dynamics simulations to examine how lipid and water dynamics are affected as two lipid bilayers approach each other. These two interacting fluid systems, lipid and water, both slow and become coupled when the lipid membranes are separated by a thin water layer. We show in particular that the water dynamics become glassy, and diffusion of lipids in the apposed leaflets becomes coupled across the water layer, while the "outer" leaflets remain unaffected. This dynamic coupling between bilayers appears mediated by lipid-water-lipid hydrogen bonding, as it occurs at bilayer separations where water-lipid hydrogen bonds become more common than water-water hydrogen bonds. We further show that such coupling occurs in simulations of vesicle-vesicle fusion prior to the fusion event itself. Such altered dynamics at membrane-membrane interfaces may both stabilize the interfacial contact and slow fusion stalk formation within the interface region.
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Affiliation(s)
- Sander Pronk
- 'Department
of Theoretical Physics, KTH Royal Institute
of Technology, AlbaNova, 106 91 Stockholm, Sweden
| | - Erik Lindahl
- 'Department
of Theoretical Physics, KTH Royal Institute
of Technology, AlbaNova, 106 91 Stockholm, Sweden
- Science
for Life Laboratory, 171
21 Stockholm, Sweden
| | - Peter M. Kasson
- Department
of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, United States
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38
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Abstract
It is commonly assumed that the structure of water at a lipid-water interface is influenced mostly in the first hydration layer. However, recent results from different experimental methods show that perturbation extends through several hydration layers. Due to its low light penetration depth, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is specifically suited to study interlamellar water structure in multibilayers. Results obtained by this technique confirm the long-range water structure disturbance. Consequently, in confined membrane environments nearly all water molecules can be perturbed. It is important to note that the behavior of confined water molecules differs significantly in samples prepared in excess water and in partially hydrated samples. We show in what manner the interlamellar water perturbation is influenced by the hydration level and how it is sequentially modified with a step-by-step dehydration of samples either by water evaporation or by osmotic pressure. Our results also indicate that besides different levels of hydration the lipid-water interaction is modulated by different lipid headgroups and different lipid phases as well. Therefore, modification of interlamellar water properties may clarify the role of water-mediated effects in biological processes.
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Affiliation(s)
- Zoran Arsov
- Laboratory of Biophysics, Department of Solid State Physics, "Jozef Stefan" Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.
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39
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Abstract
The classical view of a biological membrane is based on the Singer-Nicholson mosaic fluid model in which the lipid bilayer is the structural backbone. Under this paradigm, many studies of biological processes such as, permeability, active transport, enzyme activity and adhesion and fusion processes have been rationalized considering the lipid membrane as a low dielectric slab of hydrocarbon chains with polar head groups exposed to water at each side in which oil/water partition prevails. In spite of several analyses and evidence available in relation to membrane hydration, water is not taken into account as a functional component. For this purpose, new insights in the water organization in restricted environments and the thermodynamical and mechanical properties emerging from them are specifically analysed and correlated.This chapter summarizes the progress of the studies of water in membranes along the book in order to give a more realistic structural and dynamical picture accounting for the membrane functional properties.
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Affiliation(s)
- E Anibal Disalvo
- Laboratorio de Biointerfases y Sistemas Biomimeticos, Centro de Investigacion y Transferencia de Santiago del Estero, Universidad Nacional de Santiago del Estero-Consejo Nacional de Investigaciones Científicas y Técnicas, 4200, Santiago del Estero, Argentina.
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40
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Re S, Nishima W, Tahara T, Sugita Y. Mosaic of Water Orientation Structures at a Neutral Zwitterionic Lipid/Water Interface Revealed by Molecular Dynamics Simulations. J Phys Chem Lett 2014; 5:4343-4348. [PMID: 26273985 DOI: 10.1021/jz502299m] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ordering of water structures near the surface of biological membranes has been recently extensively studied using interface-selective techniques like vibrational sum frequency generation (VSFG) spectroscopy. The detailed structures of interface water have emerged for charged lipids, but those for neutral zwitterionic lipids remain obscure. We analyze an all-atom molecular dynamics (MD) trajectory of a hydrated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer to characterize the orientation of interface waters in different chemical environments. The structure and dynamics of interfacial waters strongly depend on both their vertical position along the bilayer normal as well as vicinal lipid charged groups. Water orientation in the vicinity of phosphate groups is opposite to that around choline groups. The results are consistent with observed VSFG spectra and demonstrate that a mosaic of water orientation structures exists on the surface of a neutral zwitterionic phospholipid bilayer, reflecting rapid water exchange and the influence of local chemical environments.
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Affiliation(s)
- Suyong Re
- †RIKEN Theoretical Molecular Science Laboratory, ‡Molecular Spectroscopy Laboratory, §Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), and ¶RIKEN iTHES, RIKEN , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- #RIKEN Advanced Institute for Computational Science and ⊥RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F, RIKEN, 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Wataru Nishima
- †RIKEN Theoretical Molecular Science Laboratory, ‡Molecular Spectroscopy Laboratory, §Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), and ¶RIKEN iTHES, RIKEN , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- #RIKEN Advanced Institute for Computational Science and ⊥RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F, RIKEN, 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Tahei Tahara
- †RIKEN Theoretical Molecular Science Laboratory, ‡Molecular Spectroscopy Laboratory, §Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), and ¶RIKEN iTHES, RIKEN , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- #RIKEN Advanced Institute for Computational Science and ⊥RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F, RIKEN, 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Yuji Sugita
- †RIKEN Theoretical Molecular Science Laboratory, ‡Molecular Spectroscopy Laboratory, §Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), and ¶RIKEN iTHES, RIKEN , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- #RIKEN Advanced Institute for Computational Science and ⊥RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F, RIKEN, 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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41
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Free energy simulations of amylin I26P mutation in a lipid bilayer. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2014; 44:37-47. [DOI: 10.1007/s00249-014-0999-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 11/06/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
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42
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Yang J, Calero C, Martí J. Diffusion and spectroscopy of water and lipids in fully hydrated dimyristoylphosphatidylcholine bilayer membranes. J Chem Phys 2014; 140:104901. [PMID: 24628199 DOI: 10.1063/1.4867385] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Microscopic structure and dynamics of water and lipids in a fully hydrated dimyristoylphosphatidylcholine phospholipid lipid bilayer membrane in the liquid-crystalline phase have been analyzed with all-atom molecular dynamics simulations based on the recently parameterized CHARMM36 force field. The diffusive dynamics of the membrane lipids and of its hydration water, their reorientational motions as well as their corresponding spectral densities, related to the absorption of radiation, have been considered for the first time using the present force field. In addition, structural properties such as density and pressure profiles, a deuterium-order parameter, surface tension, and the extent of water penetration in the membrane have been analyzed. Molecular self-diffusion, reorientational motions, and spectral densities of atomic species reveal a variety of time scales playing a role in membrane dynamics. The mechanisms of lipid motion strongly depend on the time scale considered, from fast ballistic translation at the scale of picoseconds (effective diffusion coefficients of the order of 10(-5) cm(2)/s) to diffusive flow of a few lipids forming nanodomains at the scale of hundreds of nanoseconds (diffusion coefficients of the order of 10(-8) cm(2)/s). In the intermediate regime of sub-diffusion, collisions with nearest neighbors prevent the lipids to achieve full diffusion. Lipid reorientations along selected directions agree well with reported nuclear magnetic resonance data and indicate two different time scales, one about 1 ns and a second one in the range of 2-8 ns. We associated the two time scales of reorientational motions with angular distributions of selected vectors. Calculated spectral densities corresponding to lipid and water reveal an overall good qualitative agreement with Fourier transform infrared spectroscopy experiments. Our simulations indicate a blue-shift of the low frequency spectral bands of hydration water as a result of its interaction with lipids. We have thoroughly analyzed the physical meaning of all spectral features from lipid atomic sites and correlated them with experimental data. Our findings include a "wagging of the tails" frequency around 30 cm(-1), which essentially corresponds to motions of the tail-group along the instantaneous plane formed by the two lipid tails, i.e., in-plane oscillations are clearly of bigger importance than those along the normal-to-the plane direction.
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Affiliation(s)
- J Yang
- Department of Physics and Nuclear Engineering, Technical University of Catalonia-Barcelona Tech, B4-B5 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia, Spain
| | - C Calero
- Department of Physics and Nuclear Engineering, Technical University of Catalonia-Barcelona Tech, B4-B5 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia, Spain
| | - J Martí
- Department of Physics and Nuclear Engineering, Technical University of Catalonia-Barcelona Tech, B4-B5 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia, Spain
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43
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Disalvo EA, Martini MF, Bouchet AM, Hollmann A, Frías MA. Structural and thermodynamic properties of water-membrane interphases: significance for peptide/membrane interactions. Adv Colloid Interface Sci 2014; 211:17-33. [PMID: 25085854 DOI: 10.1016/j.cis.2014.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 05/16/2014] [Accepted: 05/16/2014] [Indexed: 12/28/2022]
Abstract
Water appears as a common intermediary in the mechanisms of interaction of proteins and polypeptides with membranes of different lipid composition. In this review, how water modulates the interaction of peptides and proteins with lipid membranes is discussed by correlating the thermodynamic response and the structural changes of water at the membrane interphases. The thermodynamic properties of the lipid-protein interaction are governed by changes in the water activity of monolayers of different lipid composition according to the lateral surface pressure. In this context, different water populations can be characterized below and above the phase transition temperature in relation to the CH₂ conformers' states in the acyl chains. According to water species present at the interphase, lipid membrane acts as a water state regulator, which determines the interfacial water domains in the surface. It is proposed that those domains are formed by the contact between lipids themselves and between lipids and the water phase, which are needed to trigger adsorption-insertion processes. The water domains are essential to maintain functional dynamical properties and are formed by water beyond the hydration shell of the lipid head groups. These confined water domains probably carries information in local units in relation to the lipid composition thus accounting for the link between lipidomics and aquaomics. The analysis of these results contributes to a new insight of the lipid bilayer as a non-autonomous, responsive (reactive) structure that correlates with the dynamical properties of a living system.
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Affiliation(s)
- E A Disalvo
- Centro de Investigaciones y Transferencia Santiago del Estero (CITSE), (CONICET-UNSE), Laboratorio de Biointerfases y Sistemas Biomiméticos, Laboratorios Centrales - Ala Norte, Ruta Nacional 9, Km 1125 - Villa El Zanjón, CP 4206 Santiago del Estero, Argentina.
| | - M F Martini
- Department of Pharmaceutical Technology, Universidad de Buenos Aires, Buenos Aires, Argentina and CONICET
| | - A M Bouchet
- Centro de Investigaciones y Transferencia Santiago del Estero (CITSE), (CONICET-UNSE), Laboratorio de Biointerfases y Sistemas Biomiméticos, Laboratorios Centrales - Ala Norte, Ruta Nacional 9, Km 1125 - Villa El Zanjón, CP 4206 Santiago del Estero, Argentina
| | - A Hollmann
- Centro de Investigaciones y Transferencia Santiago del Estero (CITSE), (CONICET-UNSE), Laboratorio de Biointerfases y Sistemas Biomiméticos, Laboratorios Centrales - Ala Norte, Ruta Nacional 9, Km 1125 - Villa El Zanjón, CP 4206 Santiago del Estero, Argentina
| | - M A Frías
- Centro de Investigaciones y Transferencia Santiago del Estero (CITSE), (CONICET-UNSE), Laboratorio de Biointerfases y Sistemas Biomiméticos, Laboratorios Centrales - Ala Norte, Ruta Nacional 9, Km 1125 - Villa El Zanjón, CP 4206 Santiago del Estero, Argentina
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44
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Peters GH, Werge M, Elf-Lind MN, Madsen JJ, Velardez GF, Westh P. Interaction of neurotransmitters with a phospholipid bilayer: a molecular dynamics study. Chem Phys Lipids 2014; 184:7-17. [PMID: 25159594 DOI: 10.1016/j.chemphyslip.2014.08.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 08/14/2014] [Accepted: 08/22/2014] [Indexed: 11/15/2022]
Abstract
We have performed a series of molecular dynamics simulations to study the interactions between the neurotransmitters (NTs) γ-aminobutyrate (GABA), glycine (GLY), acetylcholine (ACH) and glutamate (GLU) as well as the amidated/acetylated γ-aminobutyrate (GABA(neu)) and the osmolyte molecule glycerol (GOL) with a dipalmitoylphosphatidylcholine (DPPC) bilayer. In agreement with previously published experimental data, we found the lowest membrane affinity for the charged molecules and a moderate affinity for zwitterionic and polar molecules. The affinity can be ranked as follows: ACH-GLU<<GABA<GLY<<GABA(neu)<<GOL. The latter three penetrated the bilayer at most with the deepest location being close to the glycerol backbone of the phospholipids. Even at that position, these solutes were noticeably hydrated and carried ∼30-80% of the bulk water along. The mobility of hydration water at the solute is also affected by the penetration into the bilayer. Two time scales of exchanging water molecules could be determined. In the bulk phase, the hydration layer contains ∼20% slow exchanging water molecules which increases 2-3 times as the solutes entered the bilayer. Our results indicate that there is no intermediate exchange of slow moving water molecules from the solutes to the lipid atoms and vice versa. Instead, the exchange relies on the reservoir of unbounded ("free") water molecules in the interfacial bilayer region. Results from the equilibrium simulations are in good agreement with the results from umbrella sampling simulations, which were conducted for the four naturally occurring NTs. Free energy profiles for ACH and GLU show a minimum of ∼2-3 kJ/mol close to the bilayer interface, while for GABA and GLY, a minimum of respectively ∼2 kJ/mol and ∼5 kJ/mol is observed when these NTs are located in the vicinity of the lipid glycerol backbone. The most important interaction of NTs with the bilayer is the charged amino group of NTs with the lipid phosphate group.
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Affiliation(s)
- Günther H Peters
- Department of Chemistry, Technical University of Denmark, Kongens Lyngby 2800, Denmark.
| | - Mikkel Werge
- Department of Chemistry, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | | | - Jesper J Madsen
- Department of Chemistry, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Gustavo F Velardez
- Department of Chemistry, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Peter Westh
- NSM, Research Unit for Functional Biomaterials, Roskilde University, Roskilde 4000, Denmark.
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45
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Gruenbaum SM, Skinner JL. Vibrational spectroscopy of water in hydrated lipid multi-bilayers. III. Water clustering and vibrational energy transfer. J Chem Phys 2014; 139:175103. [PMID: 24206336 DOI: 10.1063/1.4827018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Water clustering and connectivity around lipid bilayers strongly influences the properties of membranes and is important for functions such as proton and ion transport. Vibrational anisotropic pump-probe spectroscopy is a powerful tool for understanding such clustering, as the measured anisotropy depends upon the time-scale and degree of intra- and intermolecular vibrational energy transfer. In this article, we use molecular dynamics simulations and theoretical vibrational spectroscopy to help interpret recent experimental measurements of the anisotropy of water in lipid multi-bilayers as a function of both lipid hydration level and isotopic substitution. Our calculations are in satisfactory agreement with the experiments of Piatkowski, Heij, and Bakker, and from our simulations we can directly probe water clustering and connectivity. We find that at low hydration levels, many water molecules are in fact isolated, although up to 70% of hydration water forms small water clusters or chains. At intermediate hydration levels, water forms a wide range of cluster sizes, while at higher hydration levels, the majority of water molecules are part of a large, percolating water cluster. Therefore, the size, number, and nature of water clusters are strongly dependent on lipid hydration level, and the measured anisotropy reflects this through its dependence on intermolecular energy transfer.
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Affiliation(s)
- S M Gruenbaum
- Theoretical Chemistry Institute and Department of Chemistry, 1101 University Ave., University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Kanduč M, Schlaich A, Schneck E, Netz RR. Hydration repulsion between membranes and polar surfaces: simulation approaches versus continuum theories. Adv Colloid Interface Sci 2014; 208:142-52. [PMID: 24612664 DOI: 10.1016/j.cis.2014.02.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/31/2014] [Accepted: 02/01/2014] [Indexed: 11/28/2022]
Abstract
A review of various computer simulation approaches for the study of the hydration repulsion between lipid membranes and polar surfaces is presented. We discuss different methods and compare their advantages and limitations. We consider interaction pressures, interaction thermodynamics, and interaction mechanisms. We take a close look at the influence of the experimental boundary conditions and at repulsion mechanisms due to the unfavorable overlap of interfacial water layers. To this end, we analyze several distinct water order parameters in simulations of interacting polar surfaces and compare the results to the predictions of simple continuum theories.
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Affiliation(s)
- Matej Kanduč
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany; Department of Theoretical Physics, J. Stefan Institute, SI-1000 Ljubljana, Slovenia.
| | - Alexander Schlaich
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Emanuel Schneck
- Institut Laue-Langevin, 6 Rue Jules Horowitz, 38042 Grenoble, France.
| | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
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Origin of subdiffusion of water molecules on cell membrane surfaces. Sci Rep 2014; 4:4720. [PMID: 24739933 PMCID: PMC5380161 DOI: 10.1038/srep04720] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/31/2014] [Indexed: 12/22/2022] Open
Abstract
Water molecules play an important role in providing unique environments for biological reactions on cell membranes. It is widely believed that water molecules form bridges that connect lipid molecules and stabilize cell membranes. Using all-atom molecular dynamics simulations, we show that translational and rotational diffusion of water molecules on lipid membrane surfaces exhibit subdiffusion and aging. Moreover, we provide evidence that both divergent mean trapping time (continuous-time random walk) and long-correlated noise (fractional Brownian motion) contribute to this subdiffusion. These results suggest that subdiffusion on cell membranes causes the water retardation, an enhancement of cell membrane stability, and a higher reaction efficiency.
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Costard R, Heisler IA, Elsaesser T. Structural Dynamics of Hydrated Phospholipid Surfaces Probed by Ultrafast 2D Spectroscopy of Phosphate Vibrations. J Phys Chem Lett 2014; 5:506-11. [PMID: 26276601 DOI: 10.1021/jz402493b] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The properties of biomembranes depend in a decisive way on interactions of phospholipids with hydrating water molecules. To map structural dynamics of a phospholipid-water interface on the length and time scale of molecular motions, we introduce the phospholipid symmetric and asymmetric phosphate stretch vibrations as probes of interfacial hydrogen bonds and electrostatic interactions. The first two-dimensional infrared spectra of such modes and a line shape analysis by density matrix theory reveal two distinct structural dynamics components; the first 300 fs contribution is related to spatial fluctuations of charged phospholipid head groups with additional water contributions at high hydration levels; the second accounts for water-phosphate hydrogen bonds persisting longer than 10 ps. Our results reveal a relatively rigid hydration shell around phosphate groups, a behavior relevant for numerous biomolecular systems.
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Affiliation(s)
- Rene Costard
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2 a, 12489 Berlin, Germany
| | - Ismael A Heisler
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2 a, 12489 Berlin, Germany
| | - Thomas Elsaesser
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2 a, 12489 Berlin, Germany
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Krylov NA, Pentkovsky VM, Efremov RG. Nontrivial behavior of water in the vicinity and inside lipid bilayers as probed by molecular dynamics simulations. ACS NANO 2013; 7:9428-9442. [PMID: 24070369 DOI: 10.1021/nn4042392] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The atomic-scale diffusion of water in the presence of several lipid bilayers mimicking biomembranes is characterized via unconstrained molecular dynamics (MD) simulations. Although the overall water dynamics corresponds well to literature data, namely, the efficient braking near polar head groups of lipids, a number of interesting and biologically relevant details observed in this work have not been sufficiently discussed so far; for instance, the fact that waters "sense" the membrane unexpectedly early, before water density begins to decrease. In this "transitional zone" the velocity distributions of water and their H-bonding patterns deviate from those in the bulk solution. The boundaries of this zone are well preserved even despite the local (<1 nm size) perturbation of the lipid bilayer, thus indicating a decoupling of the surface and bulk dynamics of water. This is in excellent agreement with recent experimental data. Near the membrane surface, water movement becomes anisotropic, that is, solvent molecules preferentially move outward the bilayer. Deep in the membrane interior, the velocities can even exceed those in the bulk solvent and undergo large-scale fluctuations. The analysis of MD trajectories of individual waters in the middle part of the acyl chain region of lipids reveals a number of interesting rare phenomena, such as the fast (ca. 50 ps) breakthrough across the membrane or long-time (up to 750 ps) "roaming" between lipid leaflets. The analysis of these events was accomplished to delineate the mechanisms of spontaneous water permeation inside the hydrophobic membrane core. It was shown that such nontrivial dynamics of water in an "alien" environment is driven by the dynamic heterogeneities of the local bilayer structure and the formation of transient atomic-scale "defects" in it. The picture observed in lipid bilayers is drastically different from that in a primitive membrane mimic, a hydrated cyclohexane slab. The possible biological impact of such phenomena in equilibrated lipid bilayers is discussed.
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Affiliation(s)
- Nikolay A Krylov
- M.M. Shemyakin & Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences , ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia
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Dzuba SA. Structural studies of biological membranes using ESEEM spectroscopy of spin labels and deuterium substitution. J STRUCT CHEM+ 2013. [DOI: 10.1134/s0022476613070019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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