title: Cooperative effects in phospholipid monolayers induced by a peptide from HIV-1 capsid protein.
abstract: The study of interactions between biological molecules and model membranes is essential for the understanding of a number of physiological mechanisms involved in viral infections and dissemination. In this paper, the analysis of the interaction between a peptide from the p24 protein of Human Immunodeficiency Virus type 1 (HIV-1) and a phospholipid monolayer has pointed to a cooperative response in which very small amounts of peptide p24-1 (e.g. 0.05 mol%) can lead to measurable effects. Monolayer surface pressure and surface potential isotherms were affected for peptide concentrations as low as 0.05 mol%, with saturation at 0.5 mol%. The expansion effect from p24-1 is confirmed by changes in morphology of the monolayers using Brewster angle microscopy. Even though p24-1 is disordered in aqueous solutions, the interaction with dipalmitoyl phosphatidylcholine (DPPC) causes it to adopt an alpha-helix structure, as shown by circular dichroism (CD) data for multilamellar vesicles (MLV). The expansion of the phospholipid monolayer in a cooperative way may imply that p24-1 has potential antiviral activity, by participating in the cell rupture, with no need of specific receptors in the membrane.
authors.affiliation: Instituto de Física de São Carlos, USP, CP 369, 13560-970 São Carlos, Brazil.
authors.forename: Marli L
authors.initials: ML
authors.lastname: Moraes
authors.forename: Cláudia
authors.initials: C
authors.lastname: Bonardi
authors.forename: Cleber R
authors.initials: CR
authors.lastname: Mendonça
authors.forename: Patrícia T
authors.initials: PT
authors.lastname: Campana
authors.forename: Javier
authors.initials: J
authors.lastname: Lottersberger
authors.forename: Georgina
authors.initials: G
authors.lastname: Tonarelli
authors.forename: Osvaldo N
authors.initials: ON
authors.lastname: Oliveira
authors.forename: Leila M
authors.initials: LM
authors.lastname: Beltramini
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D002942:Circular Dichroism; D016655:HIV Core Protein p24 / Q000737:chemistry* / Q000378:metabolism; D015497:HIV-1 / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D010715:Phosphatidylglycerols / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary
chemical_list: D016655:HIV Core Protein p24; D010455:Peptides; D010715:Phosphatidylglycerols; D015060:1,2-Dipalmitoylphosphatidylcholine; C030345:1,2-dipalmitoylphosphatidylglycerol