Electrophoretic and Dynamic Light Scattering Study of the Interaction of Cytochromecwith Dimyristoylphosphatidylglycerol, Dimyristoylphosphatidylcholine, and Intramembranously Mixed Liposomes

Meulenaer, Bruno De; Meeren, Paul Van der; Cuyper, Marcel De; Vanderdeelen, Jean; Baert, L.

doi:10.1006/jcis.1997.4789

Cited by 14 publications

(16 citation statements)

References 16 publications

(2 reference statements)

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“…Previous studies suggest that electrostatic interactions govern/regulate the interaction of the positively charged cyt c with membranes containing the negatively charged CL [30], [31], [32], [33]. To probe this further, we examined the influence of ionic strength on the permeability behavior of these membrane systems by varying salt concentrations from 50 mM to 3 M KCl.…”

Section: Resultsmentioning

confidence: 99%

Lytic and Non-Lytic Permeabilization of Cardiolipin-Containing Lipid Bilayers Induced by Cytochrome c

Vanderlick

Beales

2013

PLoS ONE

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The release of cytochrome c (cyt c) from mitochondria is an important early step during cellular apoptosis, however the precise mechanism by which the outer mitochondrial membrane becomes permeable to these proteins is as yet unclear. Inspired by our previous observation of cyt c crossing the membrane barrier of giant unilamellar vesicle model systems, we investigate the interaction of cyt c with cardiolipin (CL)-containing membranes using the innovative droplet bilayer system that permits electrochemical measurements with simultaneous microscopy observation. We find that cyt c can permeabilize CL-containing membranes by induction of lipid pores in a dose-dependent manner, with membrane lysis eventually observed at relatively high (µM) cyt c concentrations due to widespread pore formation in the membrane destabilizing its bilayer structure. Surprisingly, as cyt c concentration is further increased, we find a regime with exceptionally high permeability where a stable membrane barrier is still maintained between droplet compartments. This unusual non-lytic state has a long lifetime (>20 h) and can be reversibly formed by mechanically separating the droplets before reforming the contact area between them. The transitions between behavioural regimes are electrostatically driven, demonstrated by their suppression with increasing ionic concentrations and their dependence on CL composition. While membrane permeability could also be induced by cationic PAMAM dendrimers, the non-lytic, highly permeable membrane state could not be reproduced using these synthetic polymers, indicating that details in the structure of cyt c beyond simply possessing a cationic net charge are important for the emergence of this unconventional membrane state. These unexpected findings may hold significance for the mechanism by which cyt c escapes into the cytosol of cells during apoptosis.

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Section: Resultsmentioning

confidence: 99%

Lytic and Non-Lytic Permeabilization of Cardiolipin-Containing Lipid Bilayers Induced by Cytochrome c

Vanderlick

Beales

2013

PLoS ONE

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“…In addition to altering surface charge density upon adsorption to the membrane, peptides dehydrate lipid head groups and induce aggregation of phospholipid vesicles. Reducing charge density also reduces peptide–peptide long-distance repulsion, which facilitates the formation of hydrophobic interactions between peptides associated with adjacent bilayers (De Meulenaer et al 1997). Other studies found that more highly charged residues, and neutralization of those charges may be required to induce fusion between giant liposomes (Nomura et al 2004).…”

Section: Discussionmentioning

confidence: 99%

Effect of repetitive lysine–tryptophan motifs on the bactericidal activity of antimicrobial peptides

et al. 2012

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Previous studies identified lysine- and tryptophan-rich sequences within various cationic antimicrobial peptides. In the present study, we synthesized a series of peptides composed of lysine (K)-tryptophan (W) repeats (KW)n (where n equals 2, 3, 4 or 5) with amidation of the C-terminal to increase cationicity. We found that increases in chain length up to (KW)4 enhanced the peptides’ antibacterial activity; (KW)5 exhibited somewhat less bactericidal activity than (KW)4. Cytotoxicity, measured as lysis of human red blood cells, also increased with increasing chain length. With (KW)5, reduced antibacterial activity and increased cytotoxicity correlated with greater hydrophobicity and self-aggregation in the aqueous environment. The peptides acted by inducing rapid collapse of the bacterial transmembrane potential and induction of membrane permeability. The mode of interaction of the peptides and the phosphate groups of lipopolysaccharide was dependent upon the peptides’ ability to permeate the membrane. Longer peptides [(KW)4 and (KW)5] but not shorter peptides [(KW)2 and (KW)3] strongly bound and partially inserted into negatively charged, anionic lipid bilayers. These longer peptides also induced membrane permeabilization and aggregation of lipid vesicles. The peptides had a disordered structure in aqueous solution, and only (KW)4 and (KW)5 displayed a folded conformation on lipid membranes. Moreover, (KW)4 destroyed and agglutinated bacterial cells, demonstrating its potential as an antimicrobial agent. Collectively, the results show (KW)4 to be the most efficacious peptide in the (KW)n series, exhibiting strong antibacterial activity with little cytotoxicity.Electronic supplementary materialThe online version of this article (doi:10.1007/s00726-012-1388-6) contains supplementary material, which is available to authorized users.

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“…In addition, the adsorption of LSZ and CC induces PC liposome bridging flocculation (11,12). The activation energy and the rate of the protein-induced liposome flocculation (PILF) depend strongly on the protein/lipid concentration ratio, ionic strength (12), and ambient temperature (13).…”

Section: Introductionmentioning

confidence: 99%

Size Dependence of Protein-Induced Flocculation of Phosphatidylcholine Liposomes

Dimitrova

Tsekov

Matsumura

et al. 2000

Journal of Colloid and Interface Science

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Electrophoretic and Dynamic Light Scattering Study of the Interaction of Cytochromecwith Dimyristoylphosphatidylglycerol, Dimyristoylphosphatidylcholine, and Intramembranously Mixed Liposomes

Cited by 14 publications

References 16 publications

Lytic and Non-Lytic Permeabilization of Cardiolipin-Containing Lipid Bilayers Induced by Cytochrome c

Lytic and Non-Lytic Permeabilization of Cardiolipin-Containing Lipid Bilayers Induced by Cytochrome c

Effect of repetitive lysine–tryptophan motifs on the bactericidal activity of antimicrobial peptides

Size Dependence of Protein-Induced Flocculation of Phosphatidylcholine Liposomes

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