Physical principles of membrane organization

Israelachvili, Jacob N.; Marčelja, S.; Horn, Roger G.

doi:10.1017/s0033583500001645

Cited by 1,357 publications

(767 citation statements)

References 194 publications

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“…3 The relationship between lipid molecular geometries and structure of the aggregates. See details on lipid molecular geometries in [11]. Inset: The formation of bilayer structures combining lipids with opposite (complementary) non-bilayer geometries approximately 20 min.…”

Section: Resultsmentioning

confidence: 99%

“…DOPE, however, does not form bilayers spontaneously under many conditions [15], and sterols are never found to form bilayers spontaneously. Israelachvili et al [11] proposed that the molecular geometry of the lipid molecules dictates the structure of the lipid aggregates. Phosphatidylcholine (PC) molecules would have a "cylinder shape" (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, we show that these binary mixtures give rise to vesicles and that the corresponding bilayers act as edelfosine reservoirs, from which it is slowly released. The behaviour of these non-haemolytic edelfosine preparations can be explained on the basis of the Israelachvili's lipid shape hypothesis [11].…”

Section: Introductionmentioning

confidence: 99%

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Combination of the anti-tumour cell ether lipid edelfosine with sterols abolishes haemolytic side effects of the drug

et al. 2008

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Edelfosine (1-O-octadecyl-2-O-methyl-racglycero-3-phosphocholine) is an anti-tumour cell ether lipid with surface-active properties. Pure edelfosine can be dispersed in aqueous media in the form of micelles. One important, negative side effect of edelfosine is that it is highly haemolytic. In this paper, we show that edelfosine can be co-dispersed in water with certain lipids (particularly cholesterol, campesterol or β-sitosterol) so that it gives rise to liposomes. Surface pressure measurements demonstrate that edelfosine is slowly released from these liposomes. In liposomal form, edelfosine remains apoptogenic for a variety of leukemia cell lines, while its haemolytic effect is abolished. The phenomenon is explained on the basis of the complementarity of the molecular geometries of sterols and edelfosine.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Combination of the anti-tumour cell ether lipid edelfosine with sterols abolishes haemolytic side effects of the drug

et al. 2008

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“…If pK3pH = 3, this term amounts to vG d = 25^30 kJ/mole, a value that is considerably smaller than the corresponding Born energy of transferring a charge from a high to a low dielectric environment (estimated as 50^200 kJ/ mole [19]). …”

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confidence: 91%

Solid‐state NMR investigations of interaction contributions that determine the alignment of helical polypeptides in biological membranes

Bechinger¹

2001

FEBS Letters

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Helical peptides reconstituted into oriented phospholipid bilayers were studied by proton-decoupled 15 N solid-state NMR spectroscopy. Whereas hydrophobic channel peptides, such as the N-terminal region of Vpu of HIV-1, adopt transmembrane orientations, amphipathic peptide antibiotics are oriented parallel to the bilayer surface. The interaction contributions that determine the alignment of helical peptides in lipid membranes were analysed using model sequences, and peptides that change their topology in a pH-dependent manner have been designed. The energy contributions of histidines, lysines, leucines and alanines as well as the alignment of peptides and phospholipids under conditions of hydrophobic mismatch have been investigated in considerable detail. ß 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.Key words: Oriented bilayer ; Transmembrane polypeptide; Amphipathic peptide; Membrane equilibrium; Hydrophobicity scale; Interface Although membrane proteins constitute about one third of the expressed reading frames, only a few high-resolution structures of this important class of proteins have become available [1,2]. This lack of conformational information is due to the di¤culties encountered during the expression and puri¢cation of hydrophobic proteins and their resistance to crystallization, which would be necessary for X-ray or electron di¡raction. The organization of integral membrane proteins is characterized by the separation of hydrophobic membrane-spanning and hydrophilic membrane-£anking regions (reviewed in [13 ]) with two major motifs, i.e. helical domains and, for proteins of the bacterial outer membranes, L-barrel structures being observed [1].At the same time DNA sequence analysis is fast and routine; therefore, structure prediction algorithms identifying membrane-spanning domains remain an important source of information. These protocols involve a ¢rst step in which the primary sequence is searched for hydrophobic, putatively transmembrane helical domains [4^6]. Clearly the accuracy of these predictions is strongly dependent on the quality of the underlying data base which assigns hydrophobicity values to individual amino acids.An accurate knowledge of the interaction contributions that determine the alignment of membrane-associated helices is of great importance not only for the prediction of membrane protein structure, but also for our understanding of the functional mechanisms of smaller single helical domain polypeptides. Hydrophobic or amphipathic helical peptides exhibit a multitude of functional properties, including antibiotic, fusogenic and channel activities [7,8]. However, due to the multitude of conformations and the dynamic properties of these sequences in the presence of lipid bilayers, it is often di¤cult to directly correlate structural data with functional aspects [9,10]. For example, it has been suggested that the membrane-permeabilizing properties of magainin/PGS-type antibiotic peptides are caused by transmem...

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“…The studies on micellar organization and dynamics assume special significance in light of the fact that the general principles underlying the formation of micelles are common to other related assemblies such as reverse micelles, bilayers, liposomes, and biological membranes (Tanford 1978;Israelachvili et al 1980). Micelles have also been applied as membrane mimetics to characterize membrane proteins and peptides (Franklin et al 1994;Lenz et al 1995;Sham et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Effect of micellar charge on the conformation and dynamics of melittin

Raghuraman

Chattopadhyay

2004

Eur Biophys J

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Electrostatic interactions play a crucial role in modulating and stabilizing molecular interactions in membranes and membrane-mimetic systems such as micelles. We have monitored the change in the conformation and dynamics of the cationic hemolytic peptide melittin bound to micelles of various charge types, utilizing fluorescence and circular dichroism (CD) spectroscopy. The sole tryptophan of melittin displays a red-edge excitation shift (REES) of 3-6 nm when bound to anionic, nonionic, and zwitterionic micelles. This suggests that melittin is localized in a restricted environment, probably in the interfacial region of the micelles, and this region offers considerable restriction to the reorientational motion of the solvent dipoles around the excited state tryptophan in melittin. Further, the rotational mobility of melittin is considerably reduced in these micelles and is found to be dependent on the surface charge of micelles. Interestingly, our results show that melittin does not partition into cetyltrimethylammonium bromide (CTAB) micelles owing to electrostatic repulsion between melittin and CTAB micelles, both of which carry a positive charge. In addition, the fluorescence lifetime of melittin is modulated in micelles of different charge types. The lowest mean fluorescence lifetime is observed in the case of melittin bound to anionic sodium dodecyl sulfate (SDS) micelles. CD spectroscopy shows that micelles induce significant helicity to melittin, with maximum helicity being induced in the case of melittin bound to SDS micelles. Fluorescence quenching measurements using the neutral aqueous quencher acrylamide show differential accessibility of melittin in various types of micelles. Taken together, our results show that micellar surface charge can modulate the conformation and dynamics of melittin. These results could be relevant to understanding the role of the surface charge of membranes in the interaction of membrane-active, amphiphilic peptides with membranes.

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Physical principles of membrane organization

Cited by 1,357 publications

References 194 publications

Combination of the anti-tumour cell ether lipid edelfosine with sterols abolishes haemolytic side effects of the drug

Combination of the anti-tumour cell ether lipid edelfosine with sterols abolishes haemolytic side effects of the drug

Solid‐state NMR investigations of interaction contributions that determine the alignment of helical polypeptides in biological membranes

Effect of micellar charge on the conformation and dynamics of melittin

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