51
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Liu J, Conboy JC. Structure of a gel phase lipid bilayer prepared by the Langmuir-Blodgett/Langmuir-Schaefer method characterized by sum-frequency vibrational spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:9091-7. [PMID: 16171337 DOI: 10.1021/la051500e] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The structure of a planar supported lipid bilayer (PSLB) prepared by the Langmuir-Blodgett (LB)/Langmuir-Schaefer (LS) method was investigated by sum-frequency vibrational spectroscopy (SFVS). By using asymmetric lipid bilayers composed of selectively deuterated 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) lipids, the orientation of the fatty acid chains and phosphocholine headgroups has been determined independently for both leaflets of the bilayer. The alkyl chains of the lipids were found to be orientated approximately 13 degrees +/- 4 degrees from the surface normal for both leaflets. The lipid chains in both leaflets also contain some gauche content, which is consistent with previous NMR and FTIR studies of similar lipid systems. More importantly, the relative number of gauche defects does not seem to be influenced by the deposition method, LB versus LS. The headgroup orientation for the lipid film in contact with the silica support was determined to be 69 degrees +/- 3 degrees , whereas that in contact with the aqueous phase was 66 degrees +/- 4 degrees from the surface normal. The SFVS results indicate that the structure of the DSPC lipid film in contact with the solid support and the film adjacent to the aqueous phase are nearly identical in structure. These results suggesting the LB/LS deposition method do indeed produce symmetric lipid bilayers. These studies further add to the growing information on the efficacy of PSLBs as suitable models for biological membrane studies.
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Affiliation(s)
- Jin Liu
- Department of Chemistry, University of Utah, 315 S. 1400 E. RM 2020, Salt Lake City, UT 84112, USA
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52
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Patel RY, Balaji PV. Effect of the Choice of the Pressure Coupling Method on the Spontaneous Aggregation of DPPC Molecules. J Phys Chem B 2005; 109:14667-74. [PMID: 16852851 DOI: 10.1021/jp052697m] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The self-assembly of DPPC molecules starting from a random, solution-like configuration in the presence of water molecules is described in the present MD simulation study. Simulations were performed with either anisotropic or isotropic pressure coupling. Use of anisotropic pressure coupling led to the formation of a bilayer/bilayerlike aggregate; the features of the bilayer are in agreement with those reported from earlier simulation and experimental studies. In contrast, simulating the same system with isotropic pressure coupling led to the formation of a cylindrical micelle/lamellar structure with a large water hole. The formation of micelles seems unrealistic since diacylphosphatidylcholines having hydrocarbon tails with nine or more carbon atoms have been shown to form only bilayers. Simulations were also performed with preformed bilayerlike configurations with either anisotropic or isotropic pressure coupling. The bilayer characteristics deduced from simulations using anisotropic pressure coupling are in better agreement with those reported from earlier experimental and simulation studies. Thus, the choice of the pressure coupling method has a significant effect on the spontaneous aggregation of DPPC molecules but makes relatively lesser effect if the bilayer has formed already.
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Affiliation(s)
- Ronak Y Patel
- School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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53
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Zaraiskaya T, Jeffrey KR. Molecular dynamics simulations and 2H NMR study of the GalCer/DPPG lipid bilayer. Biophys J 2005; 88:4017-31. [PMID: 15764671 PMCID: PMC1305633 DOI: 10.1529/biophysj.104.054601] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 02/28/2005] [Indexed: 01/25/2023] Open
Abstract
Molecular dynamics simulations were performed on a two-component lipid bilayer system in the liquid crystalline phase at constant pressure and constant temperature. The lipid bilayers were composed of a mixture of neutral galactosylceramide (GalCer) and charged dipalmitoylphosphatidylglycerol (DPPG) lipid molecules. Two lipid bilayer systems were prepared with GalCer:DPPG ratio 9:1 (10%-DPPG system) and 3:1 (25%-DPPG system). The 10%-DPPG system represents a collapsed state lipid bilayer, with a narrow water space between the bilayers, and the 25%-DPPG system represents an expanded state with a fluid space of approximately 10 nm. The number of lipid molecules used in each simulation was 1024, and the length of the production run simulation was 10 ns. The simulations were validated by comparing the results with experimental data for several important aspects of the bilayer structure and dynamics. Deuterium order parameters obtained from (2)H NMR experiments for DPPG chains are in a very good agreement with those obtained from molecular dynamics simulations. The surface area per GalCer lipid molecule was estimated to be 0.608 +/- 0.011 nm(2). From the simulated electron density profiles, the bilayer thickness defined as the distance between the phosphorus peaks across the bilayer was calculated to be 4.21 nm. Both simulation systems revealed a tendency for cooperative bilayer undulations, as expected in the liquid crystalline phase. The interaction of water with the GalCer and DPPG oxygen atoms results in a strong water ordering in a spherical hydration shell and the formation of hydrogen bonds (H-bonds). Each GalCer lipid molecule makes 8.6 +/- 0.1 H-bonds with the surrounding water, whereas each DPPG lipid molecule makes 8.3 +/- 0.1 H-bonds. The number of water molecules per GalCer or DPPG in the hydration shell was estimated to be 10-11 from an analysis of the radial distribution functions. The formation of the intermolecular hydrogen bonds was observed between hydroxyl groups from the opposing GalCer sugar headgroups, giving an energy of adhesion in the range between -1.0 and -3.4 erg/cm(2). We suggest that this value is the contribution of the hydrogen-bond component to the net adhesion energy between GalCer bilayers in the liquid crystalline phase.
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Affiliation(s)
- T Zaraiskaya
- Department of Physics, University of Guelph, Ontario, Canada
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54
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Gauger DR, Pohle W. FT-IR spectroscopy for exposing the CH vibrational bands from the polar parts of phospholipids. J Mol Struct 2005. [DOI: 10.1016/j.molstruc.2004.10.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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55
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Srinivasan G, Neumann-Singh S, Müller K. Conformational order of n-alkyl modified silica gels as evaluated by Fourier transform infrared spectroscopy. J Chromatogr A 2005; 1074:31-41. [PMID: 15941036 DOI: 10.1016/j.chroma.2005.03.056] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The conformational behaviour of non-deuterated and selectively deuterated alkyl modified silica gels in the dry state is examined by variable temperature FT IR spectroscopy. In the present study, three systems are considered, which are distinguished by the length of the tethered alkyl chains (C9Hl9-, C18H37-, C22H45-). The desired information is obtained by the analysis of various conformational-sensitive IR bands, including CH2 wagging, CD2 stretching and CD2 rocking bands. The analysis of the CH2 wagging bands provides the relative amounts (i.e., integral numbers over the whole chain) of the kink/gauche-trans-gauche, double-gauche and end-gauche conformers in the tethered alkyl chains. From the analysis of the CD2 stretching and CD2 rocking bands information about the conformational order at a specific deuterated methylene segment is available. Here, the CD2 rocking band data are used to determine the amount of gauche conformers at the deuterated carbon positions C-4 and C-6, and C-12. It is found that the conformational order critically depends on the actual alkyl chain length, chain position and sample temperature. Particular emphasis is given to the impact of the external pressure during sample preparation on the alkyl chain conformations, about which so far no information is available. It is observed that the samples prepared as KBr pellets, which experienced a pressure of about 10 kbar, are characterised by a lower amount of gauche conformers. This substantial increase of conformational order is attributed to better alkyl chain packing along with a gain of intermolecular chain interactions.
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Affiliation(s)
- Gokulakrishnan Srinivasan
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Baden-Wuertemburg, Germany
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56
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Lehnert R, Eibl HJ, Müller K. Order and Dynamics in Lipid Bilayers from 1,2-Dipalmitoyl-sn-glycero-phospho-diglycerol as Studied by NMR Spectroscopy. J Phys Chem B 2004. [DOI: 10.1021/jp048738g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- René Lehnert
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany, and Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, D-37070 Göttingen, Germany
| | - Hans-Jörg Eibl
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany, and Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, D-37070 Göttingen, Germany
| | - Klaus Müller
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany, and Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, D-37070 Göttingen, Germany
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57
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Huffman SW, Schlücker S, Levin IW. Reorganizational dynamics of multilamellar lipid bilayer assemblies using continuously scanning Fourier transform infrared spectroscopic imaging. Chem Phys Lipids 2004; 130:167-74. [PMID: 15172833 DOI: 10.1016/j.chemphyslip.2004.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 03/02/2004] [Accepted: 03/02/2004] [Indexed: 11/15/2022]
Abstract
We employ an implementation of rapid-scan Fourier transform infrared (FT-IR) microspectroscopic imaging to acquire time-resolved images for assessing the non-repetitive reorganizational dynamics of aqueous dispersions of multilamellar lipid vesicles (MLVs) derived from distearoylphosphatidylcholine (DSPC). The spatially and temporally resolved images allow direct and simultaneous determinations of various physical and chemical properties of the MLVs, including the main thermal gel to liquid crystalline phase transition, comparisons of vesicle diffusion rates in both phases and the variation in lipid bilayer packing properties between the inner and outer lamellae defining the vesicle. Specifically, in the lipid liquid crystalline phase, the inner bilayers of the MLVs are more intermolecularly ordered than the outer regions, while the intramolecular acyl chain order/disorder parameters, reflecting the overall characteristics of the fluid phase, remain uniform across the vesicle diameter. In contrast, the lipid vesicle gel phase displays no intermolecular or intramolecular dependence as a function of distance from the MLV center.
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Affiliation(s)
- Scott W Huffman
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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58
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Neumann-Singh S, Villanueva-Garibay J, Müller K. Variable Temperature 2H NMR and FT IR Studies of n-Alkyl Modified Silica Gels. J Phys Chem B 2004. [DOI: 10.1021/jp036098w] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shashikala Neumann-Singh
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Jorge Villanueva-Garibay
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Klaus Müller
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
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59
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Shinoda W, Mikami M, Baba T, Hato M. Molecular Dynamics Study on the Effect of Chain Branching on the Physical Properties of Lipid Bilayers: Structural Stability. J Phys Chem B 2003. [DOI: 10.1021/jp035493j] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wataru Shinoda
- Research Institute for Computational Sciences (RICS), National Institute of Advanced Industrial Science and Technology (AIST), Central-2, Umezono 1-1-1, Tsukuba 305-8568, Japan, and Nanotechnology Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Central-5, Higashi 1-1-1, Tsukuba 305-8565, Japan
| | - Masuhiro Mikami
- Research Institute for Computational Sciences (RICS), National Institute of Advanced Industrial Science and Technology (AIST), Central-2, Umezono 1-1-1, Tsukuba 305-8568, Japan, and Nanotechnology Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Central-5, Higashi 1-1-1, Tsukuba 305-8565, Japan
| | - Teruhiko Baba
- Research Institute for Computational Sciences (RICS), National Institute of Advanced Industrial Science and Technology (AIST), Central-2, Umezono 1-1-1, Tsukuba 305-8568, Japan, and Nanotechnology Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Central-5, Higashi 1-1-1, Tsukuba 305-8565, Japan
| | - Masakatsu Hato
- Research Institute for Computational Sciences (RICS), National Institute of Advanced Industrial Science and Technology (AIST), Central-2, Umezono 1-1-1, Tsukuba 305-8568, Japan, and Nanotechnology Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Central-5, Higashi 1-1-1, Tsukuba 305-8565, Japan
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60
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Wolfangel P, Müller K. Chain Order in Lipid Bilayers: FTIR and Solid State NMR Studies on Bilayer Membranes from 1,2-Dimyristoyl-sn-glycero-3-phosphoglucose. J Phys Chem B 2003. [DOI: 10.1021/jp0346920] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter Wolfangel
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Klaus Müller
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
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61
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Denich TJ, Beaudette LA, Lee H, Trevors JT. Effect of selected environmental and physico-chemical factors on bacterial cytoplasmic membranes. J Microbiol Methods 2003; 52:149-82. [PMID: 12459238 DOI: 10.1016/s0167-7012(02)00155-0] [Citation(s) in RCA: 277] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Membranes lipids are one of the most adaptable molecules in response to perturbations. Even subtle changes of the composition of acyl chains or head groups can alter the packing arrangements of lipids within the bilayer. This changes the balance between bilayer and nonbilayer lipids, serving to affect bilayer stability and fluidity, as well as altering lipid-protein interactions. External factors can also change membrane fluidity and lipid composition; including temperature, chemicals, ions, pressure, nutrients and the growth phase of the microbial culture. Various biophysical techniques have been used to monitor fluidity changes within the bacterial membrane. In this review, bacterial cytoplasmic membrane changes and related functional effects will be examined as well as the use of fluorescence polarization methods and examples of data obtained from research with bacteria.
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Affiliation(s)
- T J Denich
- Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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62
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Braun CS, Jas GS, Choosakoonkriang S, Koe GS, Smith JG, Middaugh CR. The structure of DNA within cationic lipid/DNA complexes. Biophys J 2003; 84:1114-23. [PMID: 12547792 PMCID: PMC1302688 DOI: 10.1016/s0006-3495(03)74927-3] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The structure of DNA within CLDCs used for gene delivery is controversial. Previous studies using CD have been interpreted to indicate that the DNA is converted from normal B to C form in complexes. This investigation reexamines this interpretation using CD of model complexes, FTIR as well as Raman spectroscopy and molecular dynamics simulations to address this issue. CD spectra of supercoiled plasmid DNA undergo a significant loss of rotational strength in the signal near 275 nm upon interaction with either the cationic lipid dimethyldioctadecylammonium bromide or 1,2-dioleoyltrimethylammonium propane. This loss of rotational strength is shown, however, by both FTIR and Raman spectroscopy to occur within the parameters of the B-type conformation. Contributions of absorption flattening and differential scattering to the CD spectra of complexes are unable to account for the observed spectra. Model studies of the CD of complexes prepared from synthetic oligonucleotides of varying length suggest that significant reductions in rotational strength can occur within short stretches of DNA. Furthermore, some alteration in the hydrogen bonding of bases within CLDCs is indicated in the FTIR and Raman spectroscopy results. In addition, alterations in base stacking interactions as well as hydrogen bonding are suggested by molecular dynamics simulations. A global interpretation of all of the data suggests the DNA component of CLDCs remains in a variant B form in which base/base interactions are perturbed.
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Affiliation(s)
- Chad S Braun
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, USA
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63
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Lehnert R, Eibl HJ, Müller K. FT-IR and NMR Studies on the Conformational and Structural Properties of 1,2-Dipalmitoyl-sn-glycero-3-phosphatidyloligoglycerols. J Phys Chem B 2002. [DOI: 10.1021/jp026509t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- René Lehnert
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D- 70569 Stuttgart, Germany
| | - Hans-Jörg Eibl
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D- 70569 Stuttgart, Germany
| | - Klaus Müller
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D- 70569 Stuttgart, Germany
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64
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Snyder RG, Tu K, Klein ML, Mendelssohn R, Strauss HL, Sun W. Acyl Chain Conformation and Packing in Dipalmitoylphosphatidylcholine Bilayers from MD Simulation and IR Spectroscopy. J Phys Chem B 2002. [DOI: 10.1021/jp012145d] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert G. Snyder
- Department of Chemistry, University of California, Berkeley, California 94720-1460, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, Newark, New Jersey 07102
| | - Kechuan Tu
- Department of Chemistry, University of California, Berkeley, California 94720-1460, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, Newark, New Jersey 07102
| | - Michael L. Klein
- Department of Chemistry, University of California, Berkeley, California 94720-1460, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, Newark, New Jersey 07102
| | - Richard Mendelssohn
- Department of Chemistry, University of California, Berkeley, California 94720-1460, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, Newark, New Jersey 07102
| | - Herbert L. Strauss
- Department of Chemistry, University of California, Berkeley, California 94720-1460, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, Newark, New Jersey 07102
| | - Wenjun Sun
- Department of Chemistry, University of California, Berkeley, California 94720-1460, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, Newark, New Jersey 07102
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65
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Sun F. Constant normal pressure, constant surface tension, and constant temperature molecular dynamics simulation of hydrated 1,2-dilignoceroylphosphatidylcholine monolayer. Biophys J 2002; 82:2511-9. [PMID: 11964239 PMCID: PMC1302041 DOI: 10.1016/s0006-3495(02)75594-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
A constant normal pressure, constant surface tension, and constant temperature (NP(N)gammaT) molecular dynamics (MD) simulation of the liquid condensed phase of a 1,2-dilignoceroylphosphatidylcholine (DLGPC) monolayer has been performed at 293.15 K. A DLGPC molecule has two saturated 24-carbon acyl chains, giving the hydrocarbon core thickness of the monolayer approximately 28 A, which is close to the hydrocarbon core thickness of a membrane of a living system. NP(N)gammaT ensemble was used to reproduce the experimental observations, such as area/lipid, because surface tension is an essential factor in determining the monolayer structure. Data analysis on DLGPC/water monolayer shows that various liquid condensed-phase properties of the monolayer have been well reproduced from the simulation, indicating that surface tension 22.9 mN/M used in the simulation is an appropriate condition for the condensed-phase NP(N)gammaT simulation. The simulation results suggest that this long-chain phospholipid monolayer shares many structural characteristics with typical short-chain 1,2-diacylphosphatidylcholine systems, such as DPPC/water monolayer in the condensed phase and DPPC/water bilayer in the gel phase. Furthermore, it was found that DLGPC/water monolayer has almost completely rotationally disordered acyl chains, which have not been observed so far in short-chain 1,2-diacylphosphatidylcholine/water bilayers. This study indicates the good biological relevance of the DLGPC/water monolayer which might be useful in protein/lipid studies to reveal protein structure and protein/lipid interactions in a membrane environment.
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Affiliation(s)
- Feng Sun
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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66
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Singh S, Wegmann J, Albert K, Müller K. Variable Temperature FT-IR Studies of n-Alkyl Modified Silica Gels. J Phys Chem B 2002. [DOI: 10.1021/jp012979w] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Shashikala Singh
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany, and Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Jürgen Wegmann
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany, and Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Klaus Albert
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany, and Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Klaus Müller
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany, and Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
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67
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Elmore DL, Shanmukh S, Dluhy RA. A Study of Binary Phospholipid Mixtures at the Air−Water Interface Using Infrared Reflection−Absorption Spectroscopy and 2D IR βν Correlation Analysis. J Phys Chem A 2001. [DOI: 10.1021/jp0124948] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Douglas L. Elmore
- University of Georgia, Department of Chemistry, Athens, Georgia 30602-2556
| | | | - Richard A. Dluhy
- University of Georgia, Department of Chemistry, Athens, Georgia 30602-2556
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68
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Murzyn K, Róg T, Jezierski G, Takaoka Y, Pasenkiewicz-Gierula M. Effects of phospholipid unsaturation on the membrane/water interface: a molecular simulation study. Biophys J 2001; 81:170-83. [PMID: 11423404 PMCID: PMC1301501 DOI: 10.1016/s0006-3495(01)75689-5] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Molecular dynamics (MD) simulations of fully hydrated bilayers in the liquid-crystalline state made of 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) or 1-palmitoyl-2-elaidoyl-phosphatidylcholine (PEPC) were carried out to investigate the effect of the incorporation of a double bond in the phosphatidylcholine (PC) beta-chain (cis or trans) on the membrane/water interface. The bilayers reached thermal equilibrium after 3 and 1 ns of MD simulations, respectively, and productive runs were carried out for 3 ns for each bilayer. As reference systems, the 1,2-dimyristoyl-phosphatidylcholine (DMPC) bilayer (M. Pasenkiewicz-Gierula, Y. Takaoka, H. Miyagawa, K. Kitamura, and A. Kusumi, 1999, Biophys. J. 76:1228-1240) and DMPC-cholesterol (Chol) bilayer containing 22 mol % Chol (M. Pasenkiewicz-Gierula, T. Róg, K. Kitamura, A. and Kusumi, 2000, Biophys. J. 78:1376-1389) were used. The study shows that at the interface of POPC, PEPC, and DMPC-Chol bilayers, average numbers of PC-water and PC-PC interactions are similar and, respectively, greater and smaller than in the DMPC bilayer. The average area/PC in mono-unsaturated bilayers is approximately 4 A(2) larger than in the DMPC bilayer; nevertheless, a strong correlation was found between a single molecular area (SMA) of a PC and the number of interactions this PC makes; i.e., PCs (either saturated or unsaturated) with the same SMA form similar numbers of intermolecular links. The numbers and corresponding SMAs are distributed about averages pertinent to each bilayer. No significant difference between cis and trans bonds was found.
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Affiliation(s)
- K Murzyn
- Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Kraków 31-120, Poland
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69
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Choosakoonkriang S, Wiethoff CM, Anchordoquy TJ, Koe GS, Smith JG, Middaugh CR. Infrared spectroscopic characterization of the interaction of cationic lipids with plasmid DNA. J Biol Chem 2001; 276:8037-43. [PMID: 11118456 DOI: 10.1074/jbc.m010592200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fourier transform infrared spectroscopy was used to characterize the interaction of the cationic lipids 1,2-dioleoyl-3-trimethylammonium-propane and dioctadecyldimethylammonium bromide with plasmid DNA. The effect of incorporating the neutral colipids cholesterol and dioleoylphosphatidylethanolamine on this interaction was also examined. Additionally, dynamic and phase analysis light scattering were used to monitor the size and zeta potential of the resulting complexes under conditions similar to the Fourier transform infrared measurements. Results suggest that upon interaction of cationic lipids with DNA, the DNA remains in the B form. Distinct changes in the frequency of several infrared bands arising from the DNA bases, however, suggest perturbation of their hydration upon interaction with cationic lipids. A direct interaction of the lipid ammonium headgroup with and dehydration of the DNA phosphate is observed when DNA is complexed with these lipids. Changes in the apolar regions of the lipid bilayer are minimal, whereas the interfacial regions of the membrane show changes in hydration or molecular packing. Incorporation of helper lipids into the cationic membranes results in increased conformational disorder of the apolar region and further dehydration of the interfacial region. Changes in the hydration of the DNA bases were also observed as the molar ratio of helper lipid in the membranes was increased.
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Affiliation(s)
- S Choosakoonkriang
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, USA
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70
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Höltje M, Förster T, Brandt B, Engels T, von Rybinski W, Höltje HD. Molecular dynamics simulations of stratum corneum lipid models: fatty acids and cholesterol. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1511:156-67. [PMID: 11248214 DOI: 10.1016/s0005-2736(01)00270-x] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the results of an investigation on stratum corneum lipids, which present the main barrier of the skin. Molecular dynamics simulations, thermal analysis and FTIR measurements were applied. The primary objective of this work was to study the effect of cholesterol on skin structure and dynamics. Two molecular models were constructed, a free fatty acid bilayer (stearic acid, palmitic acid) and a fatty acid/cholesterol mixture at a 1:1 molar ratio. Our simulations were performed at constant pressure and temperature on a nanosecond time scale. The resulting model structures were characterized by calculating surface areas per headgroup, conformational properties, atom densities and order parameters of the fatty acids. Analysis of the simulations indicates that the free fatty acid fraction of stratum corneum lipids stays in a highly ordered crystalline state at skin temperatures. The phase behavior is strongly influenced when cholesterol is added. Cholesterol smoothes the rigid phases of the fatty acids: the order of the hydrocarbon tails (mainly of the last eight bonds) is reduced, the area per molecule becomes larger, the fraction of trans dihedrals is lower and the hydrophobic thickness is reduced. The simulation results are in good agreement with our experimental data from FTIR analysis and NIR-FT Raman spectroscopy.
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Affiliation(s)
- M Höltje
- Jülich Research Center, Germany.
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71
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Mendelsohn R, Moore DJ. Infrared determination of conformational order and phase behavior in ceramides and stratum corneum models. Methods Enzymol 2001; 312:228-47. [PMID: 11070876 DOI: 10.1016/s0076-6879(00)12913-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- R Mendelsohn
- Department of Chemistry, Rutgers University, Newark College of Arts and Science, New Jersey 07102, USA
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72
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Shinoda W, Okazaki S. Molecular dynamics study of the dipalmitoyl phosphatidylcholine bilayer in the liquid crystal phase: an effect of the potential force fields on the membrane structure. J Mol Liq 2001. [DOI: 10.1016/s0167-7322(01)00111-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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73
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Chen L, Johnson ML, Biltonen RL. A macroscopic description of lipid bilayer phase transitions of mixed-chain phosphatidylcholines: chain-length and chain-asymmetry dependence. Biophys J 2001; 80:254-70. [PMID: 11159399 PMCID: PMC1301230 DOI: 10.1016/s0006-3495(01)76011-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A macroscopic model is presented to quantitatively describe lipid bilayer gel to fluid phase transitions. In this model, the Gibbs potential of the lipid bilayer is expressed in terms of a single order parameter q, the average chain orientational order parameter. The Gibbs potential is based on molecular mean-field and statistical mechanical calculations of inter and intrachain interactions. Chain-length and chain-asymmetry are incorporated into the Gibbs potential so that one equation provides an accurate description of mixed-chain phosphatidylcholines of a single class. Two general classes of lipids are studied in this work: lipid bilayers of partially or noninterdigitated gel phases, and bilayers of mixed interdigitated gel phases. The model parameters are obtained by fitting the transition temperature and enthalpy data of phosphatidylcholines to the model. The proposed model provides estimates for the transition temperature and enthalpy, van der Waals energy, number of gauche bonds, chain orientational order parameter, and bond rotational and excluded volume entropies, achieving excellent agreement with existing data obtained with various techniques.
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Affiliation(s)
- L Chen
- Department of Pharmacology and the Biophysics Program, University of Virginia Health System, Charlottesville, Virginia 22908, USA
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74
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Petrache HI, Dodd SW, Brown MF. Area per lipid and acyl length distributions in fluid phosphatidylcholines determined by (2)H NMR spectroscopy. Biophys J 2000; 79:3172-92. [PMID: 11106622 PMCID: PMC1301193 DOI: 10.1016/s0006-3495(00)76551-9] [Citation(s) in RCA: 528] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Deuterium ((2)H) NMR spectroscopy provides detailed information regarding the structural fluctuations of lipid bilayers, including both the equilibrium properties and dynamics. Experimental (2)H NMR measurements for the homologous series of 1, 2-diacyl-sn-glycero-3-phosphocholines with perdeuterated saturated chains (from C12:0 to C18:0) have been performed on randomly oriented, fully hydrated multilamellar samples. For each lipid, the C-D bond order parameters have been calculated from de-Paked (2)H NMR spectra as a function of temperature. The experimental order parameters were analyzed using a mean-torque potential model for the acyl chain segment distributions, and comparison was made with the conventional diamond lattice approach. Statistical mechanical principles were used to relate the measured order parameters to the lipid bilayer structural parameters: the hydrocarbon thickness and the mean interfacial area per lipid. At fixed temperature, the area decreases with increasing acyl length, indicating increased van der Waals attraction for longer lipid chains. However, the main effect of increasing the acyl chain length is on the hydrocarbon thickness rather than on the area per lipid. Expansion coefficients of the structural parameters are reported and interpreted using an empirical free energy function that describes the force balance in fluid bilayers. At the same absolute temperature, the phosphatidylcholine (PC) series exhibits a universal chain packing profile that differs from that of phosphatidylethanolamines (PE). Hence, the lateral packing of phospholipids is more sensitive to the headgroup methylation than to the acyl chain length. A fit to the area per lipid for the PC series using the empirical free energy function shows that the PE area represents a limiting value for the packing of fluid acyl chains.
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Affiliation(s)
- H I Petrache
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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75
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Belohorcová K, Qian J, Davis JH. Molecular dynamics and (2)H-NMR study of the influence of an amphiphilic peptide on membrane order and dynamics. Biophys J 2000; 79:3201-16. [PMID: 11106624 PMCID: PMC1301195 DOI: 10.1016/s0006-3495(00)76553-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A molecular dynamics simulation of a fully hydrated model membrane consisting of 12 molecules of 1, 2-dimyristoyl-sn-glycero-3-phosphocholine, one amphiphilic peptide with the sequence acetyl-Lys-Lys-Gly-Leu(16)-Lys-Lys-Ala-amide, and 593 water molecules was performed for 1.06 ns (Belohorcova, K., J. H. Davis, T. B. Woolf, and B. Roux. 1997. Biophys. J. 73:3039-3055). The analysis presented here is primarily focused on the phospholipid component and the results are compared with experimental (2)H-NMR studies of the lipid component of mixtures of the same peptide and lipid at a molar ratio of 1:32, and with earlier studies of closely related peptide/lipid mixtures. The phospholipid chain and headgroup isomer populations and isomerization rates compare favorably with previous simulations and experimental measurements. Of particular interest is the effect of the peptide on the phospholipid headgroup and hydrocarbon chain orientational order calculated from the simulation, which also agree well with experimental measurements performed on this and closely related systems. Comparison of the experimental results with the simulations not only shows that there is significant agreement between the two methods, but also provides new insight into the effect of the peptide on the lipid dynamics. In particular, these results confirm that a membrane spanning peptide has little effect on lipid chain order, and bilayer thickness if its hydrophobic length closely matches the lipid hydrocarbon thickness. In addition, we find that the peptide can have a strong ordering effect if it is longer than the lipid hydrophobic thickness.
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Affiliation(s)
- K Belohorcová
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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76
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Lindahl E, Edholm O. Spatial and energetic-entropic decomposition of surface tension in lipid bilayers from molecular dynamics simulations. J Chem Phys 2000. [DOI: 10.1063/1.1287423] [Citation(s) in RCA: 212] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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77
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Feller SE, MacKerell AD. An Improved Empirical Potential Energy Function for Molecular Simulations of Phospholipids. J Phys Chem B 2000. [DOI: 10.1021/jp0007843] [Citation(s) in RCA: 660] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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78
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Yan WH, Strauss HL, Snyder RG. Conformation of the Acyl Chains in Diacylphospholipid Gels by IR Spectroscopy. J Phys Chem B 2000. [DOI: 10.1021/jp993944n] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Wen-Hong Yan
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Herbert L. Strauss
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Robert G. Snyder
- Department of Chemistry, University of California, Berkeley, California 94720-1460
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79
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Venable RM, Brooks BR, Pastor RW. Molecular dynamics simulations of gel (LβI) phase lipid bilayers in constant pressure and constant surface area ensembles. J Chem Phys 2000. [DOI: 10.1063/1.481085] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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80
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SHINODA W, OKAZAKI S. 分子動力学シミュレーションによる脂質二重層膜の構造と動力学. ELECTROCHEMISTRY 2000. [DOI: 10.5796/electrochemistry.68.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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81
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Bardeau JF, Parikh AN, Beers JD, Swanson BI. Phase Behavior of a Structurally Constrained Organic−Inorganic Crystal: Temperature-Dependent Infrared Spectroscopy of Silver n-Dodecanethiolate. J Phys Chem B 1999. [DOI: 10.1021/jp992156v] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Atul N. Parikh
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Jaime D. Beers
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Basil I. Swanson
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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82
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Gliss C, Randel O, Casalta H, Sackmann E, Zorn R, Bayerl T. Anisotropic motion of cholesterol in oriented DPPC bilayers studied by quasielastic neutron scattering: the liquid-ordered phase. Biophys J 1999; 77:331-40. [PMID: 10388761 PMCID: PMC1300333 DOI: 10.1016/s0006-3495(99)76893-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Quasielastic neutron scattering (QENS) at two energy resolutions (1 and 14 microeV) was employed to study high-frequency cholesterol motion in the liquid ordered phase (lo-phase) of oriented multilayers of dipalmitoylphosphatidylcholine at three temperatures: T = 20 degrees C, T = 36 degrees C, and T = 50 degrees C. We studied two orientations of the bilayer stack with respect to the incident neutron beam. This and the two energy resolutions for each orientation allowed us to determine the cholesterol dynamics parallel to the normal of the membrane stack and in the plane of the membrane separately at two different time scales in the GHz range. We find a surprisingly high, model-independent motional anisotropy of cholesterol within the bilayer. The data analysis using explicit models of molecular motion suggests a superposition of two motions of cholesterol: an out-of-plane diffusion of the molecule parallel to the bilayer normal combined with a locally confined motion within the bilayer plane. The rather high amplitude of the out-of-plane diffusion observed at higher temperatures (T >/= 36 degrees C) strongly suggests that cholesterol can move between the opposite leaflets of the bilayer while it remains predominantly confined within its host monolayer at lower temperatures (T = 20 degrees C). The locally confined in-plane cholesterol motion is dominated by discrete, large-angle rotational jumps of the steroid body rather than a quasicontinous rotational diffusion by small angle jumps. We observe a significant increase of the rotational jump rate between T = 20 degrees C and T = 36 degrees C, whereas a further temperature increase to T = 50 degrees C leaves this rate essentially unchanged.
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Affiliation(s)
- C Gliss
- Institut für Experimentelle Physik, V, Universität Würzburg, 97074 Würzburg, Germany
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83
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Coles SE, Chetty MC, Ho MM, Nicolaou A, Kearney JW, Wright SD, Stewart GW. Two British families with variants of the 'cryohydrocytosis' form of hereditary stomatocytosis. Br J Haematol 1999; 105:1055-65. [PMID: 10554820 DOI: 10.1046/j.1365-2141.1999.01444.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We describe two British families with similar, dominantly-inherited, temperature-related variants of hereditary stomatocytosis, consistent with the original description of 'cryohydrocytosis'. The cells show a 5-6-fold increase in passive permeability at 37 degrees C with abnormal intracellular Na and K levels at 15-20 and 60-65 mmol/(l cells) respectively. Marked temperature effects were evident: lysis of red cells on storage in the cold was blatant and when whole heparinized blood was stored at room temperature, K accumulated in the plasma, producing 'pseudohyperkalaemia'. Studies of the temperature dependence of passive permeability showed that the minimum in the passive permeability, which is seen in normal cells at 8-10 degrees C, was shifted up to 23 degrees C in these abnormal cells, such that the permeability at 0 degrees C exceeded that at 37 degrees C. The abnormal temperature dependence in these genetically abnormal red cells strongly resembles that seen in normal cells when suspended in media in which either Na or Cl has been replaced by an organic cation or anion: it could be said these cells had a genetic mutation that somehow rendered the cell resistant to the stabilizing action of NaCl at low temperatures.
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Affiliation(s)
- S E Coles
- Department of Medicine, University College London, Rayne Institute
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84
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Arrondo JL, Goñi FM. Infrared studies of protein-induced perturbation of lipids in lipoproteins and membranes. Chem Phys Lipids 1998; 96:53-68. [PMID: 9871982 DOI: 10.1016/s0009-3084(98)00080-2] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The paper reviews the main recent publications concerning infrared (IR) spectroscopy as applied to the study of lipid-protein interactions in model and cell membranes, lipoproteins, and related systems (e.g. lung surfactant). The review focuses mainly on transmission IR. Based on the available data, a number of general conclusions are presented on the perturbations caused by proteins on either the hydrocarbon chains, the polar headgroups or the interface region. Lipid-protein interactions in native cell membranes do not reveal significant differences from what is observed in semisynthetic model systems.
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Affiliation(s)
- J L Arrondo
- Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
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85
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Nzai JM, Proctor A. Determination of phospholipids in vegetable oil by fourier transform infrared spectroscopy. J AM OIL CHEM SOC 1998. [DOI: 10.1007/s11746-998-0173-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- J. M. Nzai
- ; Department of Food Science; University of Arkansas; 272 Young Ave. 72704 Fayetteville AR
| | - A. Proctor
- ; Department of Food Science; University of Arkansas; 272 Young Ave. 72704 Fayetteville AR
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86
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Marrink SJ, Berger O, Tieleman P, Jähnig F. Adhesion forces of lipids in a phospholipid membrane studied by molecular dynamics simulations. Biophys J 1998; 74:931-43. [PMID: 9533704 PMCID: PMC1302572 DOI: 10.1016/s0006-3495(98)74016-0] [Citation(s) in RCA: 169] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Lipid adhesion forces can be measured using several experimental techniques, but none of these techniques provide insight on the atomic level. Therefore, we performed extensive nonequilibrium molecular dynamics simulations of a phospholipid membrane in the liquid-crystalline phase out of which individual lipid molecules were pulled. In our method, as an idealization of the experimental setups, we have simply attached a harmonic spring to one of the lipid headgroup atoms. Upon retraction of the spring, the force needed to drag the lipid out of the membrane is recorded. By simulating different retraction rates, we were able to investigate the high pull rate part of the dynamical spectrum of lipid adhesion forces. We find that the adhesion force increases along the unbinding path, until the point of rupture is reached. The maximum value of the adhesion force, the rupture force, decreases as the pull rate becomes slower, and eventually enters a friction-dominated regime. The computed bond lengths depend on the rate of rupture, and show some scatter due to the nonequilibrium nature of the experiment. On average, the bond length increases from approximately 1.7 nm to 2.3 nm as the rates go down. Conformational analyses elucidate the detailed mechanism of lipid-membrane bond rupture. We present results of over 15 ns of membrane simulations. Implications for the interpretation and understanding of experimental rupture data are discussed.
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Affiliation(s)
- S J Marrink
- Max-Planck-Institut für Biologie, Abteilung Membranbiochemie, Tübingen, Germany
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87
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Hyvönen MT, Rantala TT, Ala-Korpela M. Structure and dynamic properties of diunsaturated 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphatidylcholine lipid bilayer from molecular dynamics simulation. Biophys J 1997; 73:2907-23. [PMID: 9414205 PMCID: PMC1181196 DOI: 10.1016/s0006-3495(97)78319-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Unsaturated fatty acid chains are known to be an essential structural part of biomembranes, but only monounsaturated chains have been included in the molecular dynamics (MD) simulations of membrane systems. Here we present a 1-ns MD simulation for a diunsaturated 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphatidylcholine (PLPC; 16:0/18:2[delta9,12]) bilayer. The structural behavior of the phosphatidylcholine headgroup, the glycerol backbone, and the hydrating water were assessed and found to be consistent with the existing information about similar systems from both experimental and computational studies. Further analysis was focused on the structure of the double bond region and the effects of the diunsaturation on the bilayer interior. The behavior of the diunsaturated sn-2 chains is affected by the tilted beginning of the chain and the four main conformations of the double bond region. The double bonds of the sn-2 chains also influenced the characteristics of the saturated chains in the sn-1 position. Furthermore, extreme conformations of the sn-2 chains existed that are likely to be related to the functional role of the double bonds. The results here point out the importance of polyunsaturation for the biological interpretations deduced from the membrane MD simulations.
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Affiliation(s)
- M T Hyvönen
- NMR Research Group, Department of Physical Sciences, University of Oulu, Finland
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88
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Pasenkiewicz-Gierula M, Takaoka Y, Miyagawa H, Kitamura K, Kusumi A. Hydrogen Bonding of Water to Phosphatidylcholine in the Membrane As Studied by a Molecular Dynamics Simulation: Location, Geometry, and Lipid−Lipid Bridging via Hydrogen-Bonded Water. J Phys Chem A 1997. [DOI: 10.1021/jp962099v] [Citation(s) in RCA: 207] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marta Pasenkiewicz-Gierula
- Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Krakow, Poland, Department of Molecular Science, Research Center, Taisho Pharmaceutical Co. Ltd., Omiya, Saitama 330, Japan, and Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153, Japan
| | - Yuji Takaoka
- Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Krakow, Poland, Department of Molecular Science, Research Center, Taisho Pharmaceutical Co. Ltd., Omiya, Saitama 330, Japan, and Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153, Japan
| | - Hiroo Miyagawa
- Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Krakow, Poland, Department of Molecular Science, Research Center, Taisho Pharmaceutical Co. Ltd., Omiya, Saitama 330, Japan, and Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153, Japan
| | - Kunihiro Kitamura
- Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Krakow, Poland, Department of Molecular Science, Research Center, Taisho Pharmaceutical Co. Ltd., Omiya, Saitama 330, Japan, and Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153, Japan
| | - Akihiro Kusumi
- Department of Biophysics, Institute of Molecular Biology, Jagiellonian University, Krakow, Poland, Department of Molecular Science, Research Center, Taisho Pharmaceutical Co. Ltd., Omiya, Saitama 330, Japan, and Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153, Japan
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89
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Shinoda W, Namiki N, Okazaki S. Molecular dynamics study of a lipid bilayer: Convergence, structure, and long-time dynamics. J Chem Phys 1997. [DOI: 10.1063/1.473592] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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90
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Badia A, Cuccia L, Demers L, Morin F, Lennox RB. Structure and Dynamics in Alkanethiolate Monolayers Self-Assembled on Gold Nanoparticles: A DSC, FT-IR, and Deuterium NMR Study. J Am Chem Soc 1997. [DOI: 10.1021/ja963571t] [Citation(s) in RCA: 298] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Antonella Badia
- Contribution from the Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
| | - Louis Cuccia
- Contribution from the Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
| | - Linette Demers
- Contribution from the Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
| | - Fred Morin
- Contribution from the Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
| | - R. Bruce Lennox
- Contribution from the Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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91
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Obst S, Kastowsky M, Bradaczek H. Molecular dynamics simulations of six different fully hydrated monomeric conformers of Escherichia coli re-lipopolysaccharide in the presence and absence of Ca2+. Biophys J 1997; 72:1031-46. [PMID: 9138554 PMCID: PMC1184491 DOI: 10.1016/s0006-3495(97)78755-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Six previously published conformational models of Escherichia coli Re lipopolysaccharide (ReLPS) were subjected to molecular dynamics simulations using the CHARMM force field. The monomers of ReLPS were completely immersed in a water box. The dynamic behavior of the solvated models in the presence and absence of calcium cations was compared. The structure of the solvent shell was analyzed in terms of radial distribution functions. Diffusion coefficients and mean residence times were analyzed to characterize the dynamic behavior of the solvent. Order parameters and number of gauche defects were used for the description of the dynamics of the acyl chains. The cations are preferentially located between the carboxylate and phosphate groups of the headgroup. Their presence leads to a rigidification of the headgroup structure and alters the conformation of the backbone, thus influencing the structure and flexibility of the hydrophobic region as well. The effect of calcium on the backbone flexibility was measured in terms of glycosidic torsion angles. The six fatty acid chains of each ReLPS monomer adopt a highly ordered micromembrane structure. The packing parameter indicates that aggregation of these ReLPS monomers will lead to lamellar structures. Evaluation of all data enables us to present one conformation, C, which is thought to best represent the average structure of the ReLPS conformers.
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Affiliation(s)
- S Obst
- Freie Universität Berlin, Institut für Kristallographie, Germany.
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92
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Chapter 3 NMR Studies of Membrane Lipid Properties. CURRENT TOPICS IN MEMBRANES 1997. [DOI: 10.1016/s0070-2161(08)60207-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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93
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Bittman R. Has nature designed the cholesterol side chain for optimal interaction with phospholipids? Subcell Biochem 1997; 28:145-71. [PMID: 9090294 DOI: 10.1007/978-1-4615-5901-6_6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- R Bittman
- Department of Chemistry and Biochemistry, Queens College of The City University of New York, Flushing 11367-1597, USA
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94
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Hazel J. Thermal Adaptation in Biological Membranes: Beyond Homeoviscous Adaptation. THERMOBIOLOGY 1997. [DOI: 10.1016/s1569-2558(08)60075-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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95
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Clavell-Grunbaum D, Strauss HL, Snyder RG. Structure of Model Waxes: Conformational Disorder and Chain Packing in Crystalline Multicomponentn-Alkane Solid Solutions. J Phys Chem B 1997. [DOI: 10.1021/jp962616+] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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96
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Qin D, Byun HS, Bittman R. Synthesis of Half-Deuterated Palmitic and Palmitoleic Acids from THF-d8. J Org Chem 1996. [DOI: 10.1021/jo961423f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Donghui Qin
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, Flushing, New York 11367-1597
| | - Hoe-Sup Byun
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, Flushing, New York 11367-1597
| | - Robert Bittman
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, Flushing, New York 11367-1597
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97
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Gabdoulline RR, Vanderkooi G, Zheng C. Comparison of the Structures of Dimyristoylphosphatidylcholine in the Presence and Absence of Cholesterol by Molecular Dynamics Simulations. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9614456] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Garret Vanderkooi
- Department of Chemistry, Northern Illinois University, DeKalb, Illinois 60115
| | - Chong Zheng
- Department of Chemistry, Northern Illinois University, DeKalb, Illinois 60115
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98
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Xie X, Lin S, Moring J, Makriyannis A. Interdigitation of bilayers from ether lipid analogs: (R)-PAF, (R)-Lyso-PAF and the antineoplastic (R)-ET-18-OMe. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1283:111-8. [PMID: 8765102 DOI: 10.1016/0005-2736(96)00085-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The ether lipid analogs (R)-PAF, (R)-ET-18-OMe and (R)-Lyso-PAF can form bilayers. Using differential scanning calorimetry (DSC) and small angle X-ray diffraction, we have investigated bilayers formed entirely of these molecules. Small angle X-ray diffraction experiments strongly indicated that these bilayers are interdigitated at 98% relative humidity in the gel phase. The slight differences in the structures of the ether lipids affect their thermal behavior and packing properties. Of the three, (R)-Lyso-PAF shows the highest phase transition temperature, broadest phase transition peak and smallest enthalpy change. These characteristics may be attributed to hydrogen bonding of the -OH group at sn-2 position of its glycerol backbone to water or to other (R)-Lyso-PAF molecules. The interdigitated structure shows that these bilayers are similar to lipid bilayers and suggests that these molecules could easily insert themselves into membranes to reach their respective active sites or to perturb the membranes. The packing and thermal characteristics of (R)-Lyso-PAF may help explain its biological inactivity.
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Affiliation(s)
- X Xie
- Institute of Materials Science, University of Connecticut, Storrs 06269, USA
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99
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Gericke A, Moore DJ, Erukulla RK, Bittman R, Mendelsohn R. Partially deuterated phospholipids as IR structure probes of conformational order in bulk and monolayer phases. J Mol Struct 1996. [DOI: 10.1016/0022-2860(95)09201-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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100
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Reis O, Winter R, Zerda TW. The effect of high external pressure on DPPC-cholesterol multilamellar vesicles: a pressure-tuning Fourier transform infrared spectroscopy study. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1279:5-16. [PMID: 8624361 DOI: 10.1016/0005-2736(95)00233-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have investigated the effect of incorporation of cholesterol on the barotropic phase behavior of aqueous dispersions of 1,2-dipalmitoylphosphatidylcholine (DPPC) using Fourier-transform infrared spectroscopy (FTIR) in combination with the diamond anvil technique. Infrared spectral parameters, such as the frequencies, intensities, bandshapes and band splittings have been used to detect structural and dynamical changes upon incorporation of cholesterol into the DPPC bilayer. Analysis of these spectral parameters yields information on conformer population, reorientational fluctuations, interchain interaction, hydrogen bonding, interdigitation packing, and phase transformations of the DPPC/cholesterol mixtures. We present FTIR data of aqueous DPPC dispersions at 0, 10, 20, 30, 40, and 50 mol% cholesterol in the pressure range from 0.001 to 20 kbar at two temperatures, 25 degrees C and 55 degrees C. In addition, comprehensive temperature dependent measurements in the range from 20 degrees C to 80 degrees C were performed at ambient pressure. Analysis of the CH2 symmetric and antisymmetric stretching modes yields information of the effect of cholesterol concentration on the phase transition phenomena occurring in the lipid bilayer. Observation of the correlation field splittings of the CH2 bending and rocking modes monitors structural changes and dynamical properties of the lipid mixtures. Cholesterol induces more orientational disorder of the lipid molecules in terms of an increase of the reorientational fluctuations of the molecules and twisting/torsion motions of the acyl chains in the gel phase even at elevated pressures. It therefore appears that one important role of cholesterol is to make the membrane insensitive to changes in external environment, such as high hydrostatic pressure. Increase of pressure leads to a decrease in half width of the C = O band contour of pure DPPC and of DPPC/cholesterol mixtures, especially for cholesterol concentrations equal and higher than 30 mol%, which might be due to a marked increase in free carbonyl groups. At high pressure part of the bound water from the interfacial zone of the membrane is withdrawn. Increase of the cholesterol concentration and increase in pressure have opposite effects on the population of free and hydrated carbonyl ester groups of DPPC in the gel phases.
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Affiliation(s)
- O Reis
- University of Dortmund, Institute of Physical Chemistry, Germany
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