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Chem Phys Lipids. 1999 Dec;103(1-2):11-20.

Interbilayer lipid mixing induced by the human immunodeficiency virus type-1 fusion peptide on large unilamellar vesicles: the nature of the nonlamellar intermediates.

Author information

1
Unidad de Biofísica (CSIC-EHU/UPV), Universidad del País Vasco, Bilbao, Spain.

Abstract

A peptide corresponding to the 23 N-terminal amino acid residues of the human immunodeficiency virus type-1 (HIV-1) gp41 has the capacity to induce intervesicular lipid mixing in large unilamellar liposomes composed of dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylethanolamine (DOPE) and cholesterol (CHOL) (molar ratio, 1:1:1). Cryo-transmission electron microscopy (cryo-TEM) of diluted vesicles to which peptides has been externally added reveals a morphology that is compatible with the formation of nonlamellar lipidic aggregates during the time-course of lipid mixing. 31P-nuclear magnetic resonance and 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (TMADPH) steady-state anisotropy data at equilibrium indicate that the peptide is able to modulate the lipid polymorphism in pelletted membranes by: (i) promoting the thermotropic formation of inverted phases; and (ii) driving the lamellar-to-nonlamellar transition towards the formation of isotropic phases. Therefore, our combined morphological and spectroscopic data reveal the existence of a direct correlation between the ability of the externally added peptide to induce lipid-mixing in dilute liposome samples and its capacity to modulate lipid polymorphism in stacked bilayers.

PMID:
10701076
DOI:
10.1016/s0009-3084(99)00087-0
[Indexed for MEDLINE]

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