Molecular Structures of Fluid Phosphatidylethanolamine Bilayers Obtained from Simulation-to-Experiment Comparisons and Experimental Scattering Density Profiles

Abstract

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1021/jp511159qAccess and use of this website and the material on it are subject to the Terms and Conditions set forth at NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=9f16af25-9d91-47f7-b19b-387fe4c4022b http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=9f16af25-9d91-47f7-b19b-387fe4c4022b ABSTRACT: Following our previous efforts in determining the structures of commonly used PC, PG, and PS bilayers, we continue our studies of fully hydrated, fluid phase PE bilayers. The newly designed parsing scheme for PE bilayers was based on extensive MD simulations, and is utilized in the SDP analysis of both X-ray and neutron (contrast varied) scattering measurements. Obtained experimental scattering form factors are directly compared to our simulation results, and can serve as a benchmark for future developed force fields. Among the evaluated structural parameters, namely, area per lipid A, overall bilayer thickness D B , and hydrocarbon region thickness 2D C , the PE bilayer response to changing temperature is similar to previously studied bilayers with different headgroups. On the other hand, the reduced hydration of PE headgroups, as well as the strong hydrogen bonding between PE headgroups, dramatically affects lateral packing within the bilayer. Despite sharing the same glycerol backbone, a markedly smaller area per lipid distinguishes PE from other bilayers (i.e., PC, PG, and PS) studied to date. Overall, our data are consistent with the notion that lipid headgroups govern bilayer packing, while hydrocarbon chains dominate the bilayer's response to temperature changes. ■ INTRODUCTIONMembranes that surround cells and separate their contents from the external environment are ubiquitous in nature. Biological membranes consist mainly of lipids and proteins, where it is widely accepted that the membrane's underlying structure is imparted by the lipid bilayer. As such, tremendous effort has been expe...

Lipid Extraction by α-Synuclein Generates Semi-Transmembrane Defects and Lipoprotein Nanoparticles

“…70,71 A structural manifestation of the hydrogen-bonding is that PE lipids have smaller areas per lipid than those of PC counterparts. 72 Hydrogen-bonding renders PE-containing membranes more resilient to perturbations imparted by external agents. For example, PE lipids are less susceptible to ethanol-facilitated lipid desorption.…”

Lipid based drug delivery systems: Kinetics by SANS

“…The polar head group of phosphatidylethanolamines is smaller in comparison to that bulky in phosphatidylcholines and also the headgroup region is thinner. For example, at the lipid bilayer thickness d L =40.5 Å of POPE (palmitoyl-oleoylphosphatidylethanolamine) in liquid-crystalline phase (at 35 o C) the thickness of hydrophobic region d C = 32.1 Å was determined by [31], meaning that, the obtained lipid bilayer thickness d L = 30.3±0.1 Å for vesicles of C 12 NO/DOPE=1 mol/mol sounds reasonable. At low q values ( Figure 3A), we see a clear discrepancy between experimental data and the full line represented by the model.…”

“…Full lines in Figure 3 represent the best fits of experimental data applying this paracrystal lamellar model using SasView fitting software [29]. The average excess of scattering length density per unit mass (∆ρ) of the solute was calculated from known C 12 NO/DOPE molar ratio using the appropriate molecular volumes and molecular weights [30,31]. The ideal model scattering curves were smeared by the instrument resolution ~10 %.…”

Cation-containing lipid membranes – experiment and md simulations

“…The accuracy of MD simulations is known to vary from study to study, depending on the force field used and the treatment of the electrostatics (Pan et al, 2012). The most difficult aspect for simulations is in reproducing the global membrane parameters due to an imbalance of long range interactions and their approximations, and truncations in the calculations (Kučerka et al, 2015b). As a result, many simulations require an extra variable parameter (e.g., temperature, partial charges, area or surface tension) in order to converge with experiment.…”