Lipid-Induced Organization of a Primary Amphipathic Peptide: A Coupled AFM-Monolayer Study

Abstract. To better understand the nature of the mechanism involved in the membrane uptake of a vector peptide, the interactions between dioleoylphosphatidylcholine and a primary amphipathic peptide containing a signal peptide associated with a nuclear localization sequence have been studied by isotherms analysis of mixed monolayers spread at the air-water interface. The peptide and the lipid interact through strong hydrophobic interactions with expansion of the mean molecular area that resulted from a lipid-induced modification of the organization of the peptide at the interface. In addition, a phase separation occurs for peptide molar fraction ranging from about 0.08 to 0.4 Atomic force microscopy observations made on transferred monolayers confirm the existence of phase separation and further reveal that mixed lipid-peptide particles are formed, the size and shape of which depend on the peptide molar fraction. At low peptide contents, round-shaped particles are observed and an increase of the peptide amount, simultaneously to the lipidic phase separation, induces morphological changes from bowls to filamentous particles. Fourier transform infrared spectra (FTIR) obtained on transferred monolayers indicate that the peptide adopts a β-like structure for high peptide molar fractions. Such an approach involving complementary methods allows us to conclude that the lipid and the peptide have a nonideal miscibility and form mixed particles which phase separate.

[1]  M Edidin,et al.  Lipid microdomains in cell surface membranes. , 1997, Current opinion in structural biology.

[2]  Y. Choo,et al.  Distribution of ganglioside GM3 in the rat ovary after gonadotropin stimulation. , 1999, Molecules and cells.

[3]  N. Thompson,et al.  Imaging fluorescence correlation spectroscopy: nonuniform IgE distributions on planar membranes. , 1996, Biophysical journal.

[4]  Solid‐phase Synthesis and Cellular Localization of a C‐ and/or N‐terminal Labelled Peptide , 1996, Journal of peptide science : an official publication of the European Peptide Society.

[5]  Z. Shao,et al.  Gramicidin A aggregation in supported gel state phosphatidylcholine bilayers. , 1996, Biochemistry.

[6]  K. Keough,et al.  Pulmonary surfactant proteins SP-B and SP-C in spread monolayers at the air-water interface: II. Monolayers of pulmonary surfactant protein SP-C and phospholipids. , 1994, Biophysical journal.

[7]  Roger D. Kornberg,et al.  Synthetic peptides as nuclear localization signals , 1986, Nature.

[8]  Eric Lesniewska,et al.  Distribution of ganglioside GM1 between two-component, two-phase phosphatidylcholine monolayers , 1998 .

[9]  M. Seul,et al.  Lateral diffusion of specific antibodies bound to lipid monolayers on alkylated substrates. , 1986, Proceedings of the National Academy of Sciences of the United States of America.

[10]  H. Rahmann,et al.  Surface potentials and electric dipole moments of ganglioside and phospholipid bilayers: contribution of the polar headgroup at the water/lipid interface. , 1989, Biochimica et biophysica acta.

[11]  L. Gierasch,et al.  Conformations of signal peptides induced by lipids suggest initial steps in protein export. , 1986, Science.

[12]  L. Chaloin,et al.  Design of carrier peptide-oligonucleotide conjugates with rapid membrane translocation and nuclear localization properties. , 1998, Biochemical and biophysical research communications.

[13]  N. Thompson,et al.  Fluorescence correlation spectroscopy for detecting submicroscopic clusters of fluorescent molecules in membranes. , 1989, Chemistry and physics of lipids.

[14]  C. le Grimellec,et al.  Imaging of the membrane surface of MDCK cells by atomic force microscopy. , 1994, Biophysical journal.

[15]  J. Ruysschaert,et al.  Properties of mixed monolayers of lecithin and spin probe: I. Study of the interactions at the air—water interface , 1979 .

[16]  L. Chaloin,et al.  A new peptide vector for efficient delivery of oligonucleotides into mammalian cells. , 1997, Nucleic acids research.

[17]  K. Keough,et al.  Pulmonary surfactant proteins SP-B and SP-C in spread monolayers at the air-water interface: I. Monolayers of pulmonary surfactant protein SP-B and phospholipids. , 1994, Biophysical journal.

[18]  J. Garnaes,et al.  Langmuir-Blodgett films. , 1994, Science.

[19]  Pierre Vidal,et al.  Nouvelle stratégie pour vectorisation d'ARN dans des cellules de mammifères. Utilisation d'un vecteur peptidique , 1997 .

[20]  L. Gierasch,et al.  Molecular mechanisms of protein secretion: the role of the signal sequence. , 1986, Advances in protein chemistry.

[21]  M. Ptak,et al.  Penetration of the insect defensin A into phospholipid monolayers and formation of defensin A-lipid complexes. , 1997, Biophysical journal.

[22]  L. Chaloin,et al.  Conformations of primary amphipathic carrier peptides in membrane mimicking environments. , 1997, Biochemistry.

[23]  B. Roelofsen,et al.  Relation between various phospholipase actions on human red cell membranes and the interfacial phospholipid pressure in monolayers. , 1975, Biochimica et biophysica acta.

[24]  M. Ptak,et al.  Interactions of surfactin with membrane models. , 1995, Biophysical journal.

[25]  K. B. Blodgett.  Films Built by Depositing Successive Monomolecular Layers on a Solid Surface , 1935 .

[26]  J. Bouwstra,et al.  Phase behavior of stratum corneum lipids in mixed Langmuir-Blodgett monolayers. , 1996, Biophysical journal.

[27]  F. Goñi,et al.  Quantitative studies of the structure of proteins in solution by Fourier-transform infrared spectroscopy. , 1993, Progress in biophysics and molecular biology.

[28]  W. Richardson,et al.  Sequence requirements for nuclear location of simian virus 40 large-T antigen , 1984, Nature.