Ca2+ adsorption to lipid membranes and the effect of cholesterol in their composition

Iraolagoitia, Ximena L. Raffo; Martini, M. Florencia

doi:10.1016/j.colsurfb.2009.10.037

Cited by 36 publications

(26 citation statements)

References 43 publications

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“…Both peptides caused a much greater disruption of DMPC/DMPG than DMPC alone. However, DMPC/DMPG/cholesterol and DMPE/DMPG were both resistant to full lysis by either peptide which has been recently observed by others and related to the influence of these lipids on bilayer rigidity and membrane packing383940. Understanding the process leading to membrane disintegration is at the core of designing selective antimicrobial agents and requires consideration of the extent of membrane structural changes for a particular peptide.…”

Section: Discussionmentioning

confidence: 83%

Real-time Measurement of Membrane Conformational States Induced by Antimicrobial Peptides: Balance Between Recovery and Lysis

Hall

Lee

Mechler

et al. 2014

Sci Rep

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The disruption of membranes by antimicrobial peptides is a multi-state process involving significant structural changes in the phospholipid bilayer. However, direct measurement of these membrane structural changes is lacking. We used a combination of dual polarisation interferometry (DPI), surface plasmon resonance spectroscopy (SPR) and atomic force microscopy (AFM) to measure the real-time changes in membrane structure through the measurement of birefringence during the binding of magainin 2 (Mag2) and a highly potent analogue in which Ser8, Gly13 and Gly18 has been replaced with alanine (Mag-A). We show that the membrane bilayer undergoes a series of structural changes upon peptide binding before a critical threshold concentration is reached which triggers a significant membrane disturbance. We also propose a detailed model for antimicrobial peptide action as a function of the degree of bilayer disruption to provide an unprecedented in-depth understanding of the membrane lysis in terms of the interconversion of different membrane conformational states in which there is a balance between recovery and lysis.

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Section: Discussionmentioning

confidence: 83%

Real-time Measurement of Membrane Conformational States Induced by Antimicrobial Peptides: Balance Between Recovery and Lysis

Hall

Lee

Mechler

et al. 2014

Sci Rep

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“…The slight shift to the aqueous region is indicative of a preference to interact with the phosphate moiety rather than with the carbonyl groups. 61 It is worth to notice that due to the relatively small size of the molecular systems, only 2 Ca 2+ ions are present within the extracellular space. Hence, the statistical significance of the Ca 2+ binding event is limited.…”

Section: System I: Non-raft Plasma Membranementioning

confidence: 99%

Structure and dynamics of nano-sized raft-like domains on the plasma membrane

Herrera

Pantano

2012

The Journal of Chemical Physics

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Cell membranes are constitutively composed of thousands of different lipidic species, whose specific organization leads to functional heterogeneities. In particular, sphingolipids, cholesterol and some proteins associate among them to form stable nanoscale domains involved in recognition, signaling, membrane trafficking, etc. Atomic-detail information in the nanometer/second scale is still elusive to experimental techniques. In this context, molecular simulations on membrane systems have provided useful insights contributing to bridge this gap. Here we present the results of a series of simulations of biomembranes representing non-raft and raft-like nano-sized domains in order to analyze the particular structural and dynamical properties of these domains. Our results indicate that the smallest (5 nm) raft domains are able to preserve their distinctive structural and dynamical features, such as an increased thickness, higher ordering, lower lateral diffusion, and specific lipid-ion interactions. The insertion of a transmembrane protein helix into non-raft, extended raft-like, and raft-like nanodomain environments result in markedly different protein orientations, highlighting the interplay between the lipid-lipid and lipid-protein interactions.

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“…A special role plays calcium Ca ?2 cations causing modulation of the insertion of proteins. Moreover, the cations adsorb not only by electrostatic interaction to the charged anionic phospholipids but also to zwitterionic lipid and polar heads (Raffo Iraolagoitia and Florencia Martini 2010). Among other applications, liposomes are used for gene transfection (Takeuchi et al 1996) and targeted encapsulated drug delivery where they have to cross several cell membranes.…”

Section: Introductionmentioning

confidence: 99%

Zeta potential and surface charge of DPPC and DOPC liposomes in the presence of PLC enzyme

2016

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Zeta potential of liposomes is often measured in studies of their properties and/or applications. However, there are not many papers published in which zeta potential was determined during enzymatic reaction of a lipid. Therefore in this paper size, polydispersity index, and zeta potentials of 1,2-dipalmitoylsn-glycero-3-phosphatidylcholine (DPPC) and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) liposomes were investigated in 1 mM NaCl (pH 6.2) and phosphate buffer (pH 8.1) during 60 min of phospholipase C action at 20 and 37°C. The hydrocarbon chains saturation differ these two phospholipids what appears in some differences in the zeta potential changes during the hydrolysis reaction run. The polydispersity index of the liposomes indicates that they are relatively stable and monodisperse, except for DPPC in phosphate buffer where up to 30 % of the initial amount forms larger size moieties, possibly aggregates of the liposomes, enzyme and the hydrolysis products. However, in this buffer zeta potential of the liposomes practically does not change during PLC action. Also the changes of zeta potential of DOPC liposomes are minor, although their negative values are much smaller than those of DPPC at both temperatures. These small changes of the potential may be due to compression of the diffuse double layer by present phosphate buffer. However, distinct changes of the zeta potentials in the presence of PLC take place in NaCl solution. The observed changes can be explained by reorientation of the phospholipid polar heads and their different density on DPPC and DOPC surface of the liposomes. Although it appeared that the zeta potential is not a very sensitive parameter for tracking the hydrolysis reaction in phosphate buffer, generally zeta potential enables the characterization of such reactions through determination of electrokinetic properties of liposomes as well as the polydispersity and size distribution of the liposomes do.

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Ca2+ adsorption to lipid membranes and the effect of cholesterol in their composition

Cited by 36 publications

References 43 publications

Real-time Measurement of Membrane Conformational States Induced by Antimicrobial Peptides: Balance Between Recovery and Lysis

Real-time Measurement of Membrane Conformational States Induced by Antimicrobial Peptides: Balance Between Recovery and Lysis

Structure and dynamics of nano-sized raft-like domains on the plasma membrane

Zeta potential and surface charge of DPPC and DOPC liposomes in the presence of PLC enzyme

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