Structural investigations of basic amphipathic model peptides in the presence of lipid vesicles studied by circular dichroism, fluorescence, monolayer and modeling

Autor: Patrick Tauc, Cécile Mangavel, Denise Sy, Jean Antoine Reynaud, Jean-Claude Brochon, Régine Maget-Dana
Přispěvatelé: Centre de génétique moléculaire (CGM), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), École normale supérieure - Cachan (ENS Cachan)-Centre National de la Recherche Scientifique (CNRS)
Rok vydání: 1998
Předmět:
Models
Molecular
Circular dichroism
MESH: Materials Testing
MESH: Amino Acid Sequence
Biochemistry
MESH: Circular Dichroism
Membrane Potentials
chemistry.chemical_compound
MESH: Nanotechnology
MESH: Crystallization
Transmembrane channels
MESH: Peptides
Chemistry
Circular Dichroism
Vesicle
Bilayer
MESH: Models
Chemical
MESH: Surface-Active Agents
Tryptophan
biolabel
Peptide Conformation
[SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry
Molecular Biology/Biophysics
MESH: Staining and Labeling
Lipid vesicle
Peptide
Phosphatidylcholines
Thermodynamics
photoluminescence
MESH: Membranes
Artificial
MESH: Thermodynamics
MESH: Anions
MESH: Models
Molecular
MESH: Spectrometry
Fluorescence
Protein Binding
Anions
Membrane permeability
MESH: Diamond
Stereochemistry
Molecular Sequence Data
Biophysics
Phospholipid
Fluorescence
Surface-Active Agents
MESH: Nanostructures
diamond
Cations
endocytosis
MESH: Membrane Potentials
MESH: Protein Binding
MESH: Particle Size
Amino Acid Sequence
MESH: Cations
MESH: Tryptophan
MESH: Surface Properties
MESH: Molecular Conformation
MESH: Molecular Sequence Data
MESH: Humans
Modeling
Membranes
Artificial
MESH: Macromolecular Substances
Cell Biology
MESH: Phosphatidylcholines
MESH: Hela Cells
Crystallography
MESH: Luminescent Measurements
Spectrometry
Fluorescence
Models
Chemical
Liposomes
Helix
MESH: Liposomes
nanoparticles
Peptides
Zdroj: Biochimica et Biophysica Acta-Molecular Cell Research
Biochimica et Biophysica Acta-Molecular Cell Research, Elsevier, 1998, 1371 (2), pp.265-83. ⟨10.1021/nn901014j⟩
ISSN: 0005-2736
0167-4889
DOI: 10.1016/s0005-2736(98)00026-1
Popis: International audience; A cationic amphiphilic peptide made of 10 leucine and 10 lysine residues, and four of its fluorescent derivatives in which leucines were substituted by Trp residues at different locations on the primary sequence have been synthesized. The interactions of these five peptides with neutral anionic or cationic vesicles were investigated using circular dichroism, steady state and time-resolved fluorescence with a combination of Trp quenching by brominated lipid probes, monolayers, modeling with minimization and simulated annealing procedures. We show that all the five peptides interact with neutral and anionic DMPC, DMPG, DOPC or egg yolk PC vesicles. The binding takes place whatever the peptide conformation in solution is. In the case of DMPC bilayers the binding free energy DeltaG is estimated at -8 kcal mole-1 and the number of phospholipid molecules involved is about 20-25 per peptide molecule. Peptides are bound as single-stranded alpha helices orientated parallel to the bilayer surface. In the anchoring of phospholipid head groups around the peptides, the lipid molecules are not smeared out in a plane parallel to the membrane surface but are organized around the hydrophilic face of the alpha helices like 'wheat grains around an ear' and protrude outside the bilayer towards the solvent. We suggest that such a lipid arrangement generates transient structural defects responsible for the membrane permeability enhancement. When an electrical potential is applied, the axis of the peptide helices remains parallel to the membrane surface and does not reorient to give rise to a bundle of helix monomers that forms transmembrane channels via a 'barrel stave' mechanism. The penetration depth of alpha helices in relation to the position of phosphorus atoms in the unperturbed lipid leaflet is estimated at 3.2 A.
Databáze: OpenAIRE
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