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dc.contributor.authorYang, Jing
dc.contributor.authorCalero Borrallo, Carles
dc.contributor.authorMartí Rabassa, Jordi
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear
dc.date.accessioned2014-03-11T15:30:00Z
dc.date.available2014-03-11T15:30:00Z
dc.date.created2014-03-10
dc.date.issued2014-03-10
dc.identifier.citationYang, J.; Calero, C.; Marti, J. Diffusion and spectroscopy of water and lipids in fully hydrated dimyristoylphosphatidylcholine bilayer membranes. "Journal of chemical physics", 10 Març 2014, vol. 140, núm. 10, p. 104901-1-104901-13.
dc.identifier.issn0021-9606
dc.identifier.urihttp://hdl.handle.net/2117/21998
dc.description.abstractMicroscopic structure and dynamics of water and lipids in a fully hydrated dimyristoylphosphatidylcholine phospholipid lipid bilayer membrane in the liquid-crystalline phase have been analyzed with all-atom molecular dynamics simulations based on the recently parameterized CHARMM36 force field. The diffusive dynamics of the membrane lipids and of its hydration water, their reorientational motions as well as their corresponding spectral densities, related to the absorption of radiation, have been considered for the first time using the present force field. In addition, structural properties such as density and pressure profiles, a deuterium-order parameter, surface tension, and the extent of water penetration in the membrane have been analyzed. Molecular self-diffusion, reorientational motions, and spectral densities of atomic species reveal a variety of time scales playing a role in membrane dynamics. The mechanisms of lipid motion strongly depend on the time scale considered, from fast ballistic translation at the scale of picoseconds (effective diffusion coefficients of the order of 10-5 cm2/s) to diffusive flow of a few lipids forming nanodomains at the scale of hundreds of nanoseconds (diffusion coefficients of the order of 10-8 cm2/s). In the intermediate regime of sub-diffusion, collisions with nearest neighbors prevent the lipids to achieve full diffusion. Lipid reorientations along selected directions agree well with reported nuclear magnetic resonance data and indicate two different time scales, one about 1 ns and a second one in the range of 2–8 ns. We associated the two time scales of reorientational motions with angular distributions of selected vectors. Calculated spectral densities corresponding to lipid and water reveal an overall good qualitative agreement with Fourier transform infrared spectroscopy experiments. Our simulations indicate a blue-shift of the low frequency spectral bands of hydration water as a result of its interaction with lipids. We have thoroughly analyzed the physical meaning of all spectral features from lipid atomic sites and correlated them with experimental data. Our findings include a “wagging of the tails” frequency around 30 cm-1, which essentially corresponds to motions of the tail-group along the instantaneous plane formed by the two lipid tails, i.e., in-plane oscillations are clearly of bigger importance than those along the normal-to-the plane direction.
dc.language.isoeng
dc.rightsAttribution-NonCommercial-NoDerivs 3.0 Spain
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/es/
dc.subjectÀrees temàtiques de la UPC::Física
dc.subject.lcshBilayer lipid membranes
dc.subject.lcshMolecular dynamics
dc.subject.otherlipid bilayer membrane
dc.subject.othermolecular dynamics
dc.subject.otherdynamics (diffusion
dc.subject.otherspectroscopy)
dc.titleDiffusion and spectroscopy of water and lipids in fully hydrated dimyristoylphosphatidylcholine bilayer membranes
dc.typeArticle
dc.subject.lemacDinàmica molecular
dc.contributor.groupUniversitat Politècnica de Catalunya. SIMCON - First-principles approaches to condensed matter physics: quantum effects and complexity
dc.identifier.doi10.1063/1.4867385
dc.relation.publisherversionhttp://scitation.aip.org/content/aip/journal/jcp/140/10/10.1063/1.4867385
dc.rights.accessOpen Access
local.identifier.drac13434987
dc.description.versionPostprint (published version)
local.citation.authorYang, J.; Calero, C.; Marti, J.
local.citation.publicationNameJournal of chemical physics
local.citation.volume140
local.citation.number10
local.citation.startingPage104901-1
local.citation.endingPage104901-13


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