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Effect of Anionic Lipids on Mammalian Plasma Cell Membrane Properties.

ABSTRACT: The effect of lipid composition on models of the inner leaflet of mammalian cell membranes has been investigated. Grazing incidence X-ray diffraction and X-ray and neutron reflectivity have been used to characterize lipid packing and solvation, while electrochemical and infrared spectroscopic methods have been employed to probe phase behavior in an applied electric field. Introducing a small quantity of the anionic lipid dimyristoylphosphatidylserine (DMPS) into bilayers of zwitterionic dimyristoylphosphatidylethanolamine (DMPE) results in a significant change in the bilayer response to an applied field: the tilt of the hydrocarbon chains increases before returning to the original tilt angle on detachment of the bilayer. Equimolar mixtures, with slightly closer chain packing, exhibit a similar but weaker response. The latter also tend to incorporate more solvent during this electrochemical phase transition, at levels similar to those of pure DMPS. Reflectivity measurements reveal greater solvation of lipid layers for DMPS > 30 mol %, matching the greater propensity for DMPS-rich bilayers to incorporate water. Taken together, the data indicate that the range of 10-35 mol % DMPS provides optimum bilayer properties (in flexibility and function as a barrier), which may explain why the DMPS content of cell membranes tends to be found within this range.

SUBMITTER: Martin AL

PROVIDER: S-EPMC9948536 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature

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Effect of Anionic Lipids on Mammalian Plasma Cell Membrane Properties.

Martin Alexandra L AL Jemmett Philip N PN Howitt Thomas T Wood Mary H MH Burley Andrew W AW Cox Liam R LR Dafforn Timothy R TR Welbourn Rebecca J L RJL Campana Mario M Skoda Maximilian W A MWA Thompson Joseph J JJ Hussain Hadeel H Rawle Jonathan L JL Carlà Francesco F Nicklin Christopher L CL Arnold Thomas T Horswell Sarah L SL

Langmuir : the ACS journal of surfaces and colloids 20230209 7

The effect of lipid composition on models of the inner leaflet of mammalian cell membranes has been investigated. Grazing incidence X-ray diffraction and X-ray and neutron reflectivity have been used to characterize lipid packing and solvation, while electrochemical and infrared spectroscopic methods have been employed to probe phase behavior in an applied electric field. Introducing a small quantity of the anionic lipid dimyristoylphosphatidylserine (DMPS) into bilayers of zwitterionic dimyrist ...[more]

PMID: 36757323

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Project description:To investigate the effect of lipid structure upon the membrane topography of hydrophobic helices, the behavior of hydrophobic peptides was studied in model membrane vesicles. To define topography, fluorescence and fluorescence quenching methods were used to determine the location of a Trp at the center of the hydrophobic sequence. For peptides with cationic residues flanking the hydrophobic sequence, the stability of the transmembrane (TM) configuration (relative to a membrane-bound non-TM state) increased as a function of lipid composition on the order: 1:1 (mol:mol) 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC):1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine approximately 6:4 POPC:cholesterol<POPC approximately dioleoylphosphatidylcholine (DOPC)<1,2-dioleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] sodium salt (DOPG)</=1,2-dioleoyl-sn-glycero-3-[phospho-l-serine] sodium salt (DOPS), indicating that the anionic lipids DOPG and DOPS most strongly stabilized the TM configuration. TM stabilization was near maximal at 20-30 mol% anionic lipid, which are physiologically relevant values. TM stabilization by anionic lipid was observed for hydrophobic sequences with a diverse set of sequences (including polyAla), diverse lengths (from 12 to 22 residues), and various cationic flanking residues (H, R, or K), but not when the flanking residues were uncharged. TM stabilization by anionic lipid was also dependent on the number of cationic residues flanking the hydrophobic sequence, but was still significant with only one cationic residue flanking each end of the peptide. These observations are consistent with TM-stabilizing effects being electrostatic in origin. However, Trp located more deeply in DOPS vesicles relative to DOPG vesicles, and peptides in DOPS vesicles showed increased helix formation relative to DOPG and all other lipid compositions. These observations fit a model in which DOPS anchors flanking residues near the membrane surface more strongly than does DOPG and/or increases the stability of the TM state to a greater degree than DOPG. We conclude that anionic lipids can have significant and headgroup structure-specific effects upon membrane protein topography.

Dataset Information

Effect of Anionic Lipids on Mammalian Plasma Cell Membrane Properties.

Publications

Effect of Anionic Lipids on Mammalian Plasma Cell Membrane Properties.

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