1
|
Abstract
Lipid membranes are more than just barriers between cell compartments; they provide molecular environments with a finely tuned balance between hydrophilic and hydrophobic interactions that enable proteins to dynamically fold and self-assemble to regulate biological function. Characterizing dynamics at the lipid-water interface is essential to understanding molecular complexities from the thermodynamics of liquid-liquid phase separation down to picosecond-scale reorganization of interfacial hydrogen-bond networks.Ultrafast vibrational spectroscopy, including two-dimensional infrared (2D IR) and vibrational sum-frequency generation (VSFG) spectroscopies, is a powerful tool to examine picosecond interfacial dynamics. Two-dimensional IR spectroscopy provides a bond-centered view of dynamics with subpicosecond time resolutions, as vibrational frequencies are highly sensitive to the local environment. Recently, 2D IR spectroscopy has been applied to carbonyl and phosphate vibrations intrinsically located at the lipid-water interface. Interface-specific VSFG spectroscopy probes the water vibrational modes directly, accessing H-bond strength and water organization at lipid headgroup positions. Signals in VSFG arise from the interfacial dipole contributions, directly probing headgroup ordering and water orientation to provide a structural view of the interface.In this Account we discuss novel applications of ultrafast spectroscopy to lipid membranes, a field that has experienced significant growth over the past decade. In particular, ultrafast experiments now offer a molecular perspective on increasingly complex membranes. The powerful combination of ultrafast, interface-selective spectroscopy and simulations opens up new routes to understanding multicomponent membranes and their function. This Account highlights key prevailing views that have emerged from recent experiments: (1) Water dynamics at the lipid-water interface are slow compared to those of bulk water as a result of disrupted H-bond networks near the headgroups. (2) Peptides, ions, osmolytes, and cosolvents perturb interfacial dynamics, indicating that dynamics at the interface are affected by bulk solvent dynamics and vice versa. (3) The interfacial environment is generally dictated by the headgroup structure and orientation, but hydrophobic interactions within the acyl chains also modulate interfacial dynamics. Ultrafast spectroscopy has been essential to characterizing the biophysical chemistry of the lipid-water interface; however, challenges remain in interpreting congested spectra as well as designing appropriate model systems to capture the complexity of a membrane environment.
Collapse
Affiliation(s)
- Jennifer C. Flanagan
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street Stop A5300, Austin, Texas 78712-1224, United States
| | - Mason L. Valentine
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street Stop A5300, Austin, Texas 78712-1224, United States
| | - Carlos R. Baiz
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street Stop A5300, Austin, Texas 78712-1224, United States
| |
Collapse
|
2
|
Lee E, Kundu A, Jeon J, Cho M. Water hydrogen-bonding structure and dynamics near lipid multibilayer surface: Molecular dynamics simulation study with direct experimental comparison. J Chem Phys 2019; 151:114705. [DOI: 10.1063/1.5120456] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Euihyun Lee
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Republic of Korea
- Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
| | - Achintya Kundu
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Republic of Korea
- Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2a, 12489 Berlin, Germany
| | - Jonggu Jeon
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Republic of Korea
| | - Minhaeng Cho
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Republic of Korea
- Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
| |
Collapse
|
3
|
Gobrogge CA, Kong VA, Walker RA. Temperature-Dependent Partitioning of C152 in Binary Phosphatidylcholine Membranes and Mixed Phosphatidylcholine/Phosphatidylethanolamine Membranes. J Phys Chem B 2017; 121:7889-7898. [DOI: 10.1021/acs.jpcb.7b04831] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Christine A. Gobrogge
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Victoria A. Kong
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Robert A. Walker
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| |
Collapse
|
4
|
Stevenson P, Tokmakoff A. Ultrafast Fluctuations of High Amplitude Electric Fields in Lipid Membranes. J Am Chem Soc 2017; 139:4743-4752. [DOI: 10.1021/jacs.6b12412] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Paul Stevenson
- Department
of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts
Ave., Cambridge, Massachusetts 02139, United States
- Department
of Chemistry, James Frank Institute, and The Institute
for Biophysical Dynamics, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, United States
| | - Andrei Tokmakoff
- Department
of Chemistry, James Frank Institute, and The Institute
for Biophysical Dynamics, The University of Chicago, 929 E 57th Street, Chicago, Illinois 60637, United States
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Pokorna S, Jurkiewicz P, Vazdar M, Cwiklik L, Jungwirth P, Hof M. Does fluoride disrupt hydrogen bond network in cationic lipid bilayer? Time-dependent fluorescence shift of Laurdan and molecular dynamics simulations. J Chem Phys 2014; 141:22D516. [DOI: 10.1063/1.4898798] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sarka Pokorna
- J. Heyrovský Institute of Physical Chemistry of the 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 of the Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8, Czech Republic
| | - Mario Vazdar
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, P.O.B. 180, HR-10002 Zagreb, Croatia
| | - Lukasz Cwiklik
- J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8, Czech Republic
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - 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
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8, Czech Republic
| |
Collapse
|
7
|
|
8
|
Piatkowski L, de Heij J, Bakker HJ. Probing the distribution of water molecules hydrating lipid membranes with ultrafast Förster vibrational energy transfer. J Phys Chem B 2013; 117:1367-77. [PMID: 23360328 DOI: 10.1021/jp310602v] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We determine the relative positioning of water molecules in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) membranes by measuring the rate of vibrational resonant (Förster) energy transfer between the water hydroxyl stretch vibrations. The rate of Förster energy transfer is strongly distance dependent and thus gives detailed information on the relative positioning of the water molecules. We determine the rate of intermolecular Förster energy by measuring the anisotropy dynamics of excited O-D stretch vibrations of HDO and D(2)O molecules with polarization-resolved femtosecond mid-infrared spectroscopy. We study the dynamics for deuterium fractions between 0.1 and 1 and for hydration levels between 2 and 12 water molecules per DOPC lipid molecule. We find that most of the water molecules hydrating the membrane are contained in nanoclusters and have an average intermolecular distance of 3.4 Å. The density of these nanoclusters increases with increasing hydration level of the DOPC membranes.
Collapse
Affiliation(s)
- L Piatkowski
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
| | | | | |
Collapse
|
9
|
Tu K, Matubayasi N, Liang K, Todorov I, Chan S, Chau PL. A possible molecular mechanism for the pressure reversal of general anaesthetics: Aggregation of halothane in POPC bilayers at high pressure. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.06.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
10
|
Mondal JA, Nihonyanagi S, Yamaguchi S, Tahara T. Three Distinct Water Structures at a Zwitterionic Lipid/Water Interface Revealed by Heterodyne-Detected Vibrational Sum Frequency Generation. J Am Chem Soc 2012; 134:7842-50. [DOI: 10.1021/ja300658h] [Citation(s) in RCA: 219] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jahur A. Mondal
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Satoshi Nihonyanagi
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Shoichi Yamaguchi
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| |
Collapse
|
11
|
Mashaghi A, Partovi-Azar P, Jadidi T, Nafari N, Maass P, Tabar MRR, Bonn M, Bakker HJ. Hydration strongly affects the molecular and electronic structure of membrane phospholipids. J Chem Phys 2012; 136:114709. [DOI: 10.1063/1.3694280] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
|
12
|
Woiterski L, Britt DW, Käs JA, Selle C. Oriented confined water induced by cationic lipids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4712-4722. [PMID: 22339557 DOI: 10.1021/la205043x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on attenuated total reflection Fourier-transform infrared (ATR FTIR) spectroscopic measurements on oriented lipid multilayers of N,N-dimethyl-N,N-dioctadecyl-ammonium halides (DODAX, X = F, Cl, Br, I). The main goal of this study is the investigation of the structure and spectroscopic properties of water absorbed to these model membranes. Intensities of the water stretch absorptions were used to determine the amount of bound water. At high water activity, DODAF membranes bind ~11 water molecules/lipid while DODAC and DODAB adsorb 1-2 water/lipid and DODAI was hydrophobic. By adjustment of DODAF hydration to ~2 water molecules, stretching absorptions from water of the first hydration shell were accessible for the fluoride, chloride, and bromide analogs. The polarized measurements demonstrate highly confined and oriented water with infrared (IR) order parameters ranging from 0.2 to -0.4. Resolved IR water band components are attributed to different hydrogen-bonded populations. Complementary molecular dynamics simulations of DODAB strongly support the existence of differently hydrogen-bonded and oriented water within DODAB multilayers. A combination of both techniques was used for an assignment of water stretch band components to structures. The described cationic lipid systems are a prototype for a bottom-up approach to understand the IR spectroscopy of structured water at biological interfaces since they permit a defined increase of hydrophilic water-anionic interactions leading to extended water networks at membranes.
Collapse
Affiliation(s)
- Lydia Woiterski
- Institut für Experimentelle Physik I, Abteilung Physik Weicher Materie, Universität Leipzig, Leipzig, Germany.
| | | | | | | |
Collapse
|
13
|
Bakulin AA, Pshenichnikov MS. Reduced coupling of water molecules near the surface of reverse micelles. Phys Chem Chem Phys 2011; 13:19355-61. [PMID: 21959913 DOI: 10.1039/c1cp22235j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on vibrational dynamics of water near the surface of AOT reverse micelles studied by narrow-band excitation, mid-IR pump-probe spectroscopy. Evidence of OH-stretch frequency splitting into the symmetric and asymmetric modes is clearly observed for the interfacial H(2)O molecules. The polarization memory of interfacial waters is preserved over an exceptionally extended >10 ps timescale which is a factor of 100 longer than in bulk water. These observations point towards negligibly small intermolecular vibrational coupling between the water molecules as well as strongly reduced water rotational mobility within the interfacial water layer.
Collapse
Affiliation(s)
- Artem A Bakulin
- Department of Physical Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | | |
Collapse
|
14
|
Nagata Y, Mukamel S. Spectral diffusion at the water/lipid interface revealed by two-dimensional fourth-order optical spectroscopy: a classical simulation study. J Am Chem Soc 2011; 133:3276-9. [PMID: 21329386 PMCID: PMC3101253 DOI: 10.1021/ja110748s] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using a classical simulation protocol for nonlinear optical signals, we predict the two-dimensional (2D) spectra of water near a monolayer of [1,2-dimytristoyl-sn-glycero-3-phosphatidylcholine] (DMPC) generated by three IR probe pulses followed by one visible probe pulse. Sum-frequency-generation 1D spectra show two peaks of the OH stretch representing two environments: near-bulk water nonadjacent to DMPC and top-layer water adjacent to DMPC. These peaks create a 2D pattern in the fourth-order signal. The asymmetric cross-peak pattern with respect to the diagonal line is a signature of coherence transfer from the higher- to the lower-frequency modes. The nodal lines in the imaginary part of the 2D spectrum show that the near-bulk water has fast spectral diffusion resembling that of bulk water despite the orientation by the strong electrostatic field of DMPC. The top-layer water has slower spectral diffusion.
Collapse
Affiliation(s)
- Yuki Nagata
- Department of Chemistry, University of California, Irvine, California 92697, United States.
| | | |
Collapse
|
15
|
Casillas-Ituarte NN, Chen X, Castada H, Allen HC. Na+ and Ca2+ Effect on the Hydration and Orientation of the Phosphate Group of DPPC at Air−Water and Air−Hydrated Silica Interfaces. J Phys Chem B 2010; 114:9485-95. [PMID: 20614879 DOI: 10.1021/jp1022357] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Xiangke Chen
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Hardy Castada
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Heather C. Allen
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| |
Collapse
|
16
|
Campen RK, Ngo TTM, Sovago M, Ruysschaert JM, Bonn M. Molecular Restructuring of Water and Lipids upon the Interaction of DNA with Lipid Monolayers. J Am Chem Soc 2010; 132:8037-47. [DOI: 10.1021/ja100838q] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- R. Kramer Campen
- FOM Institute for Atomic and Molecular Physics [AMOLF], 104 Science Park, 1098 XG Amsterdam, The Netherlands, and Structure and Function of Biological Membranes (SFMB), Université Libre de Bruxelles (ULB), Boulevard du Triomphe, CP 206/2, B-1050 Brussels, Belgium
| | - Thuy T. M. Ngo
- FOM Institute for Atomic and Molecular Physics [AMOLF], 104 Science Park, 1098 XG Amsterdam, The Netherlands, and Structure and Function of Biological Membranes (SFMB), Université Libre de Bruxelles (ULB), Boulevard du Triomphe, CP 206/2, B-1050 Brussels, Belgium
| | - Maria Sovago
- FOM Institute for Atomic and Molecular Physics [AMOLF], 104 Science Park, 1098 XG Amsterdam, The Netherlands, and Structure and Function of Biological Membranes (SFMB), Université Libre de Bruxelles (ULB), Boulevard du Triomphe, CP 206/2, B-1050 Brussels, Belgium
| | - Jean-Marie Ruysschaert
- FOM Institute for Atomic and Molecular Physics [AMOLF], 104 Science Park, 1098 XG Amsterdam, The Netherlands, and Structure and Function of Biological Membranes (SFMB), Université Libre de Bruxelles (ULB), Boulevard du Triomphe, CP 206/2, B-1050 Brussels, Belgium
| | - Mischa Bonn
- FOM Institute for Atomic and Molecular Physics [AMOLF], 104 Science Park, 1098 XG Amsterdam, The Netherlands, and Structure and Function of Biological Membranes (SFMB), Université Libre de Bruxelles (ULB), Boulevard du Triomphe, CP 206/2, B-1050 Brussels, Belgium
| |
Collapse
|
17
|
Nagata Y, Mukamel S. Vibrational sum-frequency generation spectroscopy at the water/lipid interface: molecular dynamics simulation study. J Am Chem Soc 2010; 132:6434-42. [PMID: 20394423 PMCID: PMC3151577 DOI: 10.1021/ja100508n] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The sum-frequency generation (SFG) spectrum from the water/[1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine] (DMPC) interface in the OH stretching mode region of water is simulated and shows three spectral peaks which are assigned to different environments. The weak 3590 cm(-1) peak is attributed to a few water molecules coupled to the glycerol backbone of DMCP. The 3470 cm(-1) feature comes from the top water layer adjacent to the hydrophilic headgroup of DMPC. The 3290 cm(-1) peak arises from the near-bulk water nonadjacent to DMPC. The stretching mode corresponding to the 3290 cm(-1) peak is strongly coupled to the neighboring water molecules. In contrast, the 3470 cm(-1) mode is decoupled from the surrounding water molecules, and the orientation of water is governed by DMPC. This decoupling explains the slow relaxation dynamics of water measured in the time-resolved SFG experiment. Despite the similarity of the SFG spectra, the peak origins of water/lipid and water/vapor interfaces are different.
Collapse
Affiliation(s)
- Yuki Nagata
- University of California Irvine, Irvine, California, 92617, USA
| | - Shaul Mukamel
- University of California Irvine, Irvine, California, 92617, USA
| |
Collapse
|
18
|
Volkov VV, Righini R. Partitioning of an Anchor Dipeptide in a Phospholipid Membrane. J Phys Chem B 2009; 113:16246-50. [DOI: 10.1021/jp9082536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Victor V. Volkov
- European Laboratory for Nonlinear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
| | - Roberto Righini
- European Laboratory for Nonlinear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
| |
Collapse
|
19
|
Volkov V, Takaoka Y, Righini R. Hydration of phospholipid interface: carbonyl–water hydrogen bond association. Phys Chem Chem Phys 2009; 11:9979-86. [DOI: 10.1039/b914511g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|