Effect of a laminin amphiphatic sequence on DPPC ordered bilayers.
A peptide sequence, stearoyl-GESIKVAVS(NH2), related to a laminin fragment, has been synthesized. Formation of aggregates was controlled by titrating a sodium anilinonaphthalene sulphonate (ANS) solution with peptide and recording fluorescence intensity increases. The results show that this system experiences a sudden increase in fluorescence at peptide concentrations around 2.5 x 10(-4) mol/L. The interaction of this hydrophobic peptide with DPPC vesicles has been studied using fluorescence techniques. Its influence on the microviscosity of bilayers was determined by studying polarization/temperature dependence for ANS and diphenyl hexatriene (DPH) fluorescent probes. With both markers the presence of peptide promotes a clear increase in anisotropy values. This indicates a rigidifying effect. Leakage studies carried out with liposomes loaded with carboxyfluorescein (CF) indicate a stabilizing effect of the peptide on bilayers, in agreement with results obtained with fluorescent probes.
Reig
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F
Peptides Department, Institute for Environmental and Biological Chemistry, CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
Juvé
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A
Ortiz
A
A
Sospedra
P
P
Alsina
M A
MA
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000595:Amino Acid Sequence; D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D005452:Fluoresceins; D057927:Hydrophobic and Hydrophilic Interactions; D007797:Laminin / Q000737:chemistry* / Q000494:pharmacology*; D008051:Lipid Bilayers / Q000737:chemistry*; D008567:Membranes, Artificial; D010455:Peptides / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013696:Temperature
D000817:Anilino Naphthalenesulfonates; D005452:Fluoresceins; D007797:Laminin; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010455:Peptides; D015060:1,2-Dipalmitoylphosphatidylcholine; C024098:6-carboxyfluorescein