1
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Zhao D, Liu Y, Fan W. Role of the intermolecular hydrogen bond in microsolvated of a kind of PRODAN derivative with methanol on excited state. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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2
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Tarif E, Saha B, Mukherjee K, De P, Biswas R. Exploring Aqueous Solution Dynamics of an Amphiphilic Diblock Copolymer: Dielectric Relaxation and Time-Resolved Fluorescence Measurements. J Phys Chem B 2019; 123:5892-5901. [DOI: 10.1021/acs.jpcb.9b00889] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ejaj Tarif
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Biswajit Saha
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, West Bengal, India
| | - Kallol Mukherjee
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
| | - Priyadarsi De
- Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, West Bengal, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India
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3
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Biswas S, Mukherjee SK, Chowdhury PK. Crowder-Induced Rigidity in a Multidomain Protein: Insights from Solvation. J Phys Chem B 2016; 120:12501-12510. [DOI: 10.1021/acs.jpcb.6b10478] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Saikat Biswas
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sanjib Kumar Mukherjee
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Pramit Kumar Chowdhury
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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4
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Sonu, Kumari S, Saha SK. Effect of Polymethylene Spacer of Cationic Gemini Surfactants on Solvation Dynamics and Rotational Relaxation of Coumarin 153 in Aqueous Micelles. J Phys Chem B 2015; 119:9751-63. [PMID: 26107156 DOI: 10.1021/acs.jpcb.5b03081] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The present work demonstrates the solvation dynamics and rotational relaxation of Coumarin 153 (C-153) in the micelles of a series of cationic gemini surfactants, 12-s-12, 2Br(-) containing a hydrophobic polymethylene spacer with s = 3, 4, 6, 8, 12. Steady-state and time-correlated single-photon counting (TCSPC) fluorescence spectroscopic techniques have been used to carry out this study. Steady-state and TCSPC fluorescence data suggest that C-153 molecules are located at the Stern layer of micelles. While probe molecules feel more or less the same micropolarity in the micellar phase, the microviscosity of micelles decreases with spacer chain length. Solvation dynamics at the Stern layer is bimodal in nature with fast solvation as a major component. Counter ions and water molecules bonded with the polar headgroups of surfactant molecules are responsible for the slow component. Average solvation time increases with spacer chain length because of the increased degree of counter ion dissociation. Some water molecules are involved in the solvation of counter ions themselves, resulting in the decrease in "free" water molecules to be available for the solvation of C-153. The hydrophobic spacer chain also has an effect on increasing the solvation time with increasing chain length. The average rotational relaxation time for C-153 decreases with spacer chain length with a rapid decrease at s > 4. The anisotropy decay of C-153 in micelles is biexponential in nature. The slow rotational relaxation is due to the lateral diffusion of C-153 in micelles. Lateral diffusion is much faster than the rotational motion of a micelle as a whole. The rotational motion of the micelle as a whole becomes faster with the decreasing size of micelles.
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5
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Först G, Cwiklik L, Jurkiewicz P, Schubert R, Hof M. Interactions of beta-blockers with model lipid membranes: Molecular view of the interaction of acebutolol, oxprenolol, and propranolol with phosphatidylcholine vesicles by time-dependent fluorescence shift and molecular dynamics simulations. Eur J Pharm Biopharm 2014; 87:559-69. [DOI: 10.1016/j.ejpb.2014.03.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 03/07/2014] [Accepted: 03/20/2014] [Indexed: 01/05/2023]
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6
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Vazdar M, Wernersson E, Khabiri M, Cwiklik L, Jurkiewicz P, Hof M, Mann E, Kolusheva S, Jelinek R, Jungwirth P. Aggregation of Oligoarginines at Phospholipid Membranes: Molecular Dynamics Simulations, Time-Dependent Fluorescence Shift, and Biomimetic Colorimetric Assays. J Phys Chem B 2013; 117:11530-40. [DOI: 10.1021/jp405451e] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Mario Vazdar
- Division
of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, P.O.B.
180, HR-10002 Zagreb, Croatia
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Erik Wernersson
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Morteza Khabiri
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Lukasz Cwiklik
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- J. Heyrovský
Institute of Physical Chemistry, Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8, Czech Republic
| | - Piotr Jurkiewicz
- J. Heyrovský
Institute of Physical Chemistry, Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8, Czech Republic
| | - Martin Hof
- J. Heyrovský
Institute of Physical Chemistry, Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8, Czech Republic
| | - Ella Mann
- Department
of Chemistry and the Ilse Katz Institute for Nanoscale Science and
Technology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Sofiya Kolusheva
- Department
of Chemistry and the Ilse Katz Institute for Nanoscale Science and
Technology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Raz Jelinek
- Department
of Chemistry and the Ilse Katz Institute for Nanoscale Science and
Technology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Pavel Jungwirth
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Department
of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
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Barucha-Kraszewska J, Kraszewski S, Ramseyer C. Will C-Laurdan dethrone Laurdan in fluorescent solvent relaxation techniques for lipid membrane studies? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:1174-82. [PMID: 23311388 DOI: 10.1021/la304235r] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Development of fluorescence methods involves the necessity of understanding the fluorescent probes behavior in their ground and excited states. In the case of biological membranes, the position of the dyes in the lipid bilayer and their response after excitation are necessary parameters to correctly analyze the experiments. In the present work, we focus on two fluorescent markers, Laurdan (6-lauroyl-2-(N,N-dimethylamino)naphthalene) and its derivative C-Laurdan (6-dodecanoyl-2-[N-methyl-N-(carboxymethyl)amino]naphthalene), recently proposed for lipid raft visualization [Kim, H. M.; et al. ChemBioChem 2007, 8, 553]. C-Laurdan, by the presence of an additional carboxyl group, has an advantage over Laurdan since it has a higher sensitivity to the membrane polarity at the lipid headgroup region and a higher water solubility. This theoretical study, based on quantum mechanical (QM) and molecular dynamics (MD) simulations in a fully hydrated lipid membrane model, compare the equilibrium and dynamic properties of both probes taking into account their fluorescence lifetimes. C-Laurdan is found to be more stable than Laurdan in the headgroup region of the membrane and also much more aligned with the lipids. This study suggests that, besides the lipid raft imaging, the C-Laurdan marker can considerably extend the capabilities of fluorescent solvent relaxation method.
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Affiliation(s)
- Justyna Barucha-Kraszewska
- Laboratoire de Nanomédecine, Imagerie et Thérapeutique, EA4662, Université de Franche-Comté, Centre Hospitalier Universitaire de Besançon, 16 Route de Gray, 25000 Besançon, France.
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8
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Vazdar M, Jurkiewicz P, Hof M, Jungwirth P, Cwiklik L. Behavior of 4-hydroxynonenal in phospholipid membranes. J Phys Chem B 2012; 116:6411-5. [PMID: 22577896 DOI: 10.1021/jp3044219] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Under conditions of oxidative stress, 4-hydroxy-2-nonenal (4-HNE) is commonly present in vivo. This highly reactive and cytotoxic compound is generated by oxidation of lipids in membranes and can be easily transferred from a membrane to both cytosol and the extracellular space. Employing time-dependent fluorescence shift (TDFS) method and molecular dynamics simulations, we found that 4-HNE is stabilized in the carbonyl region of a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer. 4-HNE is thus able to react with cell membrane proteins and lipids. Stabilization in the membrane is, however, moderate and a transfer of 4-HNE to either extra- or intracellular space occurs on a microsecond time scale. These molecular-level details of 4-HNE behavior in the lipid membrane rationalize the experimentally observed reactivity of 4-HNE with proteins inside and outside the cell. Furthermore, these results support the view that 4-HNE may play an active role in cell signaling pathways.
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Affiliation(s)
- Mario Vazdar
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, 16610 Prague 6, Czech Republic
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Beranová L, Humpolíčková J, Sýkora J, Benda A, Cwiklik L, Jurkiewicz P, Gröbner G, Hof M. Effect of heavy water on phospholipid membranes: experimental confirmation of molecular dynamics simulations. Phys Chem Chem Phys 2012; 14:14516-22. [DOI: 10.1039/c2cp41275f] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Laurdan and di-4-ANEPPDHQ do not respond to membrane-inserted peptides and are good probes for lipid packing. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:298-306. [DOI: 10.1016/j.bbamem.2010.10.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 09/24/2010] [Accepted: 10/05/2010] [Indexed: 11/22/2022]
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11
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Barucha-Kraszewska J, Kraszewski S, Jurkiewicz P, Ramseyer C, Hof M. Numerical studies of the membrane fluorescent dyes dynamics in ground and excited states. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1724-34. [PMID: 20510669 DOI: 10.1016/j.bbamem.2010.05.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 05/17/2010] [Accepted: 05/19/2010] [Indexed: 11/18/2022]
Abstract
Fluorescence methods are widely used in studies of biological and model membranes. The dynamics of membrane fluorescent markers in their ground and excited electronic states and correlations with their molecular surrounding within the fully hydrated phospholipid bilayer are still not well understood. In the present work, Quantum Mechanical (QM) calculations and Molecular Dynamics (MD) simulations are used to characterize location and interactions of two membrane polarity probes (Prodan; 6-propionyl-2-dimethylaminonaphthalene and its derivative Laurdan; 2-dimethylamino-6-lauroylnaphthalene) with the dioleoylphosphatidylcholine (DOPC) lipid bilayer model. MD simulations with fluorophores in ground and excited states are found to be a useful tool to analyze the fluorescent dye dynamics and their immediate vicinity. The results of QM calculations and MD simulations are in excellent agreement with available experimental data. The calculation shows that the two amphiphilic dyes initially placed in bulk water diffuse within 10 ns towards their final location in the lipid bilayer. Analysis of solvent relaxation process in the aqueous phase occurs on the picoseconds timescale whereas it takes nanoseconds at the lipid/water interface. Four different relaxation time constants, corresponding to different relaxation processes, where observed when the dyes were embedded into the membrane.
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12
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Jesenská A, Sýkora J, Olzyńska A, Brezovský J, Zdráhal Z, Damborský J, Hof M. Nanosecond time-dependent Stokes shift at the tunnel mouth of haloalkane dehalogenases. J Am Chem Soc 2009; 131:494-501. [PMID: 19113888 DOI: 10.1021/ja804020q] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The tunnel mouths are evolutionally the most variable regions in the structures of haloalkane dehalogenases originating from different bacterial species, suggesting their importance for adaptation of enzymes to various substrates. We decided to monitor the dynamics of this particular region by means of time-resolved fluorescence spectroscopy and molecular dynamic simulations. To label the enzyme specifically, we adapted a novel procedure that utilizes a coumarin dye containing a halide-hydrocarbon linker, which serves as a substrate for enzymatic reaction. The procedure leads to a coumarin dye covalently attached and specifically located in the tunnel mouth of the enzyme. In this manner, we stained two haloalkane dehalogenase mutants, DbjA-H280F and DhaA-H272F. The measurements of time-resolved fluorescence anisotropy, acrylamide quenching, and time-resolved emission spectra reveal differences in the polarity, accessibility and mobility of the dye and its microenvironment for both of the mutants. The obtained experimental data are consistent with the results obtained by molecular dynamics calculations and correlate with the anatomy of the tunnel mouths, which were proposed to have a strong impact on the catalytic activity and specificity of the examined mutants. Interestingly, the kinetics of the recorded time-dependent Stokes shift is unusual slow; it occurs on the nanosecond time-scale, suggesting that the protein dynamics is extremely slowed down at the region involved in the exchange of ligands between the active-site cavity and bulk solvent.
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Affiliation(s)
- Andrea Jesenská
- Loschmidt Laboratories, Institute of Experimental Biology and National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5/A4, 625 00 Brno, Czech Republic
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Moyano F, Biasutti MA, Silber JJ, Correa NM. New insights on the behavior of PRODAN in homogeneous media and in large unilamellar vesicles. J Phys Chem B 2007; 110:11838-46. [PMID: 16800486 DOI: 10.1021/jp057208x] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The behavior of 6-propionyl-2-dimethylaminonaphthalene (PRODAN) was studied in homogeneous media and in large unilamellar vesicles (LUVs) of the phospholipid 1,2-di-oleoyl-sn-glycero-3-phosphatidylcholine (DOPC), using absorption, emission, depolarization, and time-resolved spectroscopies. In homogeneous media, the Kamlet and Taft solvatochromic comparison method quantified solute-solvent interactions from the absorption and emission PRODAN bands. These studies demonstrate that the absorption band is sensitive to the polarity-polarizability (pi) and the hydrogen bond donor ability (alpha) parameters of the media. PRODAN in the excited state is even more sensitive to these parameters and to the hydrogen bond acceptor ability (beta) of the media. The transition energy (expressed in kcal/mol) for both absorption and emission bands gives a linear correlation with the well-known polarity parameter E(T30). The results from the absorption and emission bands also reveal that PRODAN aggregates in water. The monomer has two fluorescence lifetimes, 2.27 and 0.65 ns, while the aggregate has a lifetime of 14.6 ns. Using steady-state anisotropy measurements, the calculated volumes of the aggregate and the monomer are 5590 and 222 mL mol(-1), respectively. In DOPC LUVs, PRODAN undergoes a partition process between the water bulk and the DOPC bilayer. We show that the partition constant (K(p)) value is large enough that only at [DOPC] below 0.15 mg/mL PRODAN in water can be detected. PRODAN dissolved in LUVs at [DOPC] > 1 mg/mL exists completely incorporated in its monomer form and senses two different microenvironments within the bilayer: a polar region in the interface near the water and a less polar and also less viscous environment, between the phospholipid tails. These environments were characterized by their fluorescence lifetimes (tau), showing that PRODAN in the polar microenvironment has a tau value of approximately 4 ns while in the less polar region gives a value of 1.2 ns. Moreover, this probe also senses the micropolarity of these two different regions of the bilayer and yields values similar to that of methanol and tetrahydrofuran.
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Affiliation(s)
- Fernando Moyano
- Departamento de Química, Universidad Nacional de Río Cuarto, Agencia Postal # 3, X5804ZAB Río Cuarto, Argentina
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Rieber K, Sýkora J, Olzyńska A, Jelinek R, Cevc G, Hof M. The use of solvent relaxation technique to investigate headgroup hydration and protein binding of simple and mixed phosphatidylcholine/surfactant bilayer membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1050-8. [PMID: 17300743 DOI: 10.1016/j.bbamem.2006.12.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 12/19/2006] [Accepted: 12/22/2006] [Indexed: 10/23/2022]
Abstract
The subject of this report was to investigate headgroup hydration and mobility of two types of mixed lipid vesicles, containing nonionic surfactants; straight chain Brij 98, and polysorbat Tween 80, with the same number of oxyethylene units as Brij, but attached via a sorbitan ring to oleic acid. We used the fluorescence solvent relaxation (SR) approach for the purpose and revealed differences between the two systems. Fluorescent solvent relaxation probes (Prodan, Laurdan, Patman) were found to be localized in mixed lipid vesicles similarly as in pure phospholipid bilayers. The SR parameters (i.e. dynamic Stokes shift, Deltanu, and the time course of the correlation function, C(t)) of such labels are in the same range in both kinds of systems. Each type of the tested surfactants has its own impact on water organization in the bilayer headgroup region probed by Patman. Brij 98 does not modify the solvation characteristics of the dye. In contrast, Tween 80 apparently dehydrates the headgroup and decreases its mobility. The SR data measured in lipid bilayers in presence of Interferon alfa-2b reveal that this protein, a candidate for non-invasive delivery, affects the bilayer in a different way than the peptide melittin. Interferon alfa-2b binds to mixed lipid bilayers peripherally, whereas melittin is deeply inserted into lipid membranes and affects their headgroup hydration and mobility measurably.
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Affiliation(s)
- K Rieber
- IDEA AG, Frankfurter Ring 193 a, 80807 Munich, Germany
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15
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Jurkiewicz P, Sýkora J, Olzyńska A, Humpolícková J, Hof M. Solvent relaxation in phospholipid bilayers: principles and recent applications. J Fluoresc 2006; 15:883-94. [PMID: 16328702 DOI: 10.1007/s10895-005-0013-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Although there exist a number of methods, such as NMR, X-ray, e.g., which explore the hydration of phospholipid bilayers, the solvent relaxation (SR) method has the advantage of simple instrumentation, easy data treatment and possibility of measuring fully hydrated samples. The main information gained from SR by the analysis of recorded "time-resolved emission spectra" (TRES) is micro-viscosity and micro-polarity of the dye microenvironment. Based on these parameters, one can draw conclusions about water structure in the bilayer. In this review, we focus on physical background of this method, on all the procedures that are needed in order to obtain relevant parameters, and on the requirements on the fluorescence dyes. Furthermore, a few recent applications (the effect of curvature, binding of antibacterial peptides and phase transition) illustrating the versatility of this method are mentioned. Moreover, limitations and potential problems are discussed.
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Affiliation(s)
- Piotr Jurkiewicz
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-18223, Prague 8, Czech Republic
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Pedersen UR, Leidy C, Westh P, Peters GH. The effect of calcium on the properties of charged phospholipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:573-82. [PMID: 16730642 DOI: 10.1016/j.bbamem.2006.03.035] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 03/08/2006] [Accepted: 03/14/2006] [Indexed: 11/28/2022]
Abstract
We have performed molecular dynamics simulations to investigate the structure and dynamics of charged bilayers as well as the distribution of counterions at the bilayer interface. For this, we have considered the negatively charged di-myristoyl-phosphatidyl-glycerol (DMPG) and di-myristoyl-phosphatidyl-serine (DMPS) bilayers as well as a protonated di-myristoyl-phosphatidyl-serine (DMPSH) bilayer. We were particularly interested in calcium ions due to their important role in biological systems. Simulations performed in the presence of calcium ions (DMPG, DMPS) or sodium ions (DMPS) were run for 45-60 ns. Simulation results for DMPG are compared with fluorescence measurements. The average areas per molecule were 47.4+/-0.5 A2 (DMPG with calcium), 47.3+/-0.5 A2 (DMPS with calcium), 51.3+/-1.0 A2 (DMPS with sodium) and 45.3+/-0.5 A2 (DMPSH). The structure of the negatively charged lipids is significantly affected by the counterions, where calcium ions have a more pronounced effect than sodium ions. Calcium ions were found to be tightly bound to the anionic groups of the lipid molecules and as such appear to constitute an integral part of the membrane interface on nanoseconds time scales. In contrast to sodium ions, calcium ions are localised in a narrow (approximately 10 A) band around the phosphate group. The interaction of calcium with the lipid molecules enhances the molecular packing of the PG and PS lipids. This observation is in good agreement with emission spectra of the membrane partitioning probe Laurdan in DMPG multilamellar vesicles that indicate an increase in the ordering of the DMPG bilayer due to the presence of calcium. Our results indicate that calcium ions, which often function as a second messengers in living cells have a pronounced effect on membrane structures, which may have implications during signal transduction events.
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Affiliation(s)
- Ulf R Pedersen
- Department of Life Science and Chemistry, Roskilde University, MEMPHYS-Center for Biomembrane Physics, 1 Universitetsvej, DK-4000 Roskilde, Denmark
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Chakraborty A, Seth D, Chakrabarty D, Setua P, Sarkar N. Dynamics of Solvent and Rotational Relaxation of Coumarin 153 in Room-Temperature Ionic Liquid 1-Butyl-3-methylimidazolium Hexafluorophosphate Confined in Brij-35 Micelles: A Picosecond Time-Resolved Fluorescence Spectroscopic Study. J Phys Chem A 2005; 109:11110-6. [PMID: 16331893 DOI: 10.1021/jp053981g] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dynamics of solvent and rotational relaxation of Coumarin 153 (C-153) in ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and in the ionic liquid confined in Brij-35 micellar aggregates have been investigated using steady-state and time-resolved fluorescence spectroscopy. We observed slower dynamics in the presence of micellar aggregates as compared to the pure IL. However, the slowing down in the solvation time on going from neat IL to IL-confined micelles is much smaller compared to that on going from water to water-confined micellar aggregates. The increase in solvation and rotational time in micelles is attributed to the increase in viscosity of the medium. The slow component is assumed to be dependent on the viscosity of the solution and involves large-scale rearrangement of the anions and cations while fast component is assumed to originate from the initial response of the anions during excitation. The slow component increases due to the increase in the viscosity of the medium and increase in fast component is probably due to the hydrogen bonding between the anions and polar headgroup of the surfactant. The dynamics of solvent relaxation was affected to a small extent due to the micelle formation.
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Affiliation(s)
- Anjan Chakraborty
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India
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Humpolícková J, Stepánek M, Procházka K, Hof M. Solvent Relaxation Study of pH-Dependent Hydration of Poly(oxyethylene) Shells in Polystyrene-block-poly(2-vinylpyridine)-block-poly(oxyethylene) Micelles in Aqueous Solutions. J Phys Chem A 2005; 109:10803-12. [PMID: 16331923 DOI: 10.1021/jp053348v] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hydration of the poly(oxyethylene) shell in polystyrene-block-poly(2-vinylpyridine)-block-poly(oxyethylene) micelles was investigated by monitoring the solvent relaxation response of a solvent-sensitive fluorophore (patman). It has been found that the relaxation occurs on the nanosecond time scale. Results for triblock copolymer micelles have been compared with those obtained for polystyrene-block-poly(2-vinylpyridine) micelles in order to evaluate the effect of the outer polyoxyethylene layer. Considerable pH-dependent changes in the hydration of poly(oxyethylene) units at the poly(2-vinylpyridine)/polyoxyethylene interface were observed. Additionally, the paper shows that the solvent relaxation technique is a suitable tool for studying polymeric nanoparticles and that the measurement of time-dependent half-width of the emission spectrum allows for estimation of the extent of relaxation process observed by a given experimental setup.
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Affiliation(s)
- Jana Humpolícková
- Department of Physical and Macromolecular Chemistry and Laboratory of Specialty Polymers, School of Science, Charles University in Prague, Albertov 2030, 128 40 Prague 2, Czech Republic
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Chakrabarty D, Chakraborty A, Seth D, Hazra P, Sarkar N. Binding and relaxation behavior of Coumarin-153 in lecithin–taurocholate mixed micelles: A time resolved fluorescence spectroscopic study. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.06.098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sheynis T, Sykora J, Benda A, Kolusheva S, Hof M, Jelinek R. Bilayer localization of membrane-active peptides studied in biomimetic vesicles by visible and fluorescence spectroscopies. ACTA ACUST UNITED AC 2003; 270:4478-87. [PMID: 14622276 DOI: 10.1046/j.1432-1033.2003.03840.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Depth of bilayer penetration and effects on lipid mobility conferred by the membrane-active peptides magainin, melittin, and a hydrophobic helical sequence KKA(LA)7KK (denoted KAL), were investigated by colorimetric and time-resolved fluorescence techniques in biomimetic phospholipid/poly(diacetylene) vesicles. The experiments demonstrated that the extent of bilayer permeation and peptide localization within the membrane was dependent upon the bilayer composition, and that distinct dynamic modifications were induced by each peptide within the head-group environment of the phospholipids. Solvent relaxation, fluorescence correlation spectroscopy and fluorescence quenching analyses, employing probes at different locations within the bilayer, showed that magainin and melittin inserted close to the glycerol residues in bilayers incorporating negatively charged phospholipids, but predominant association at the lipid-water interface occurred in bilayers containing zwitterionic phospholipids. The fluorescence and colorimetric analyses also exposed the different permeation properties and distinct dynamic influence of the peptides: magainin exhibited the most pronounced interfacial attachment onto the vesicles, melittin penetrated more into the bilayers, while the KAL peptide inserted deepest into the hydrophobic core of the lipid assemblies. The solvent relaxation results suggest that decreasing the lipid fluidity might be an important initial factor contributing to the membrane activity of antimicrobial peptides.
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Affiliation(s)
- Tanya Sheynis
- Department of Chemistry and the Stadler Minerva Center for Mesoscopic Macromolecular Engineering, Ben Gurion University of the Negev, Beersheva, Israel
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Hutterer R, Hof M. Probing Ethanol-Induced Phospholipid Phase Transitions by the Polarity Sensitive Fluorescence Probes Prodan and Patman. ACTA ACUST UNITED AC 2002. [DOI: 10.1524/zpch.2002.216.3.333] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The emission behaviour of the two polarity sensitive probes Prodan and Patman in phospholipid vesicles was studied as a function of the concentration of ethanol. Comparing the spectral shifts in both the symmetric lipid 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) showing a phase transition from a normal to a fully interdigitated gel phase and the strongly asymmetric lipid 1-stearoyl-2-lauroyl-sn-glycero-3-phosphatidylcholine (C(18):C(12)-PC) favouring a mixed interdigitated gel phase we show that the huge red shifts of Prodan in presence of higher ethanol concentrations cannot be easily attributed to a specific lipid phase transition. Rather, probe relocation and a pronounced increase in solvent relaxation (SR) as monitored by time-resolved emission spectra (TRES) in presence of ethanol contribute to the large shifts observable in both lipid systems in case of Prodan. While Patman exhibits a red shift caused by increased SR due to the ethanol induced formation of a fully interdigitated phase in DPPC, hardly any shift occurs in C(18):C(12)-PC, which is supposed not to undergo an ethanol-induced phase transition.
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Samanta A, Fessenden RW. Excited State Dipole Moment of PRODAN as Determined from Transient Dielectric Loss Measurements. J Phys Chem A 2000. [DOI: 10.1021/jp0009960] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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