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Membrane fusion induced by a lipopeptidic epitope from VP3 capside protein of hepatitis A virus
Author(s) -
Chávez Abelardo,
Pujol Montserrat,
Alsina M. Asunción,
Cajal Yolanda
Publication year - 2001
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.629
Subject(s) - lipopeptide , chemistry , vesicle , phosphatidylethanolamine , phosphatidylcholine , liposome , epitope , biophysics , membrane , lipid bilayer , phospholipid , biochemistry , biology , antigen , genetics , bacteria
Abstract Palmitoyl‐VP3(110–121) (PVP3) is a synthetic lipopeptide derivative of a continuous epitope from the VP3 capsid protein of hepatitis A virus, and it is highly immunogenic in vivo . We have investigated the interaction of PVP3 with lipid model membranes of varying surface charge. Binding of PVP3 to anionic vesicles of PC/SM/PE/PS; (PC) 1‐palmitoyl‐2‐oleoyl‐phosphatidylcholine, (SM) sphingomyelin, (PE) 1,2‐dipalmitoyl‐phosphatidylethanolamine and (PS) L ‐α‐phosphatidyl‐ L ‐serine, a composition that mimics the lipid component of natural membranes, was determined by tryptophan fluorescence and quenching experiments. In addition, and given the anionic net charge of the lipopeptide, binding to zwitterionic (PC/SM/PE) and cationic PC/SM/PE/DOTAP (DOTAP) 1,2‐dioleoyl‐3‐trimethylammonium‐propane mixtures was also determined. PVP3 binds to all three types of vesicles, but it adopts different forms depending on the electrical charge of the interface. This conclusion is supported by the insertion of PVP3 into lipid monolayers of the same charges spread at the air–water interface. The bound lipopeptide has membrane‐destabilizing effects in all three vesicle compositions, as demonstrated by leakage of vesicle contents, whereas lipid mixing only occurs in cationic liposomes. Our results provide useful information for the design of a liposomal system that promotes a direct delivery of the membrane‐incorporated immunogen to the immunocompetent cells, potentially increasing the immune response from the host. Copyright © 2001 John Wiley & Sons, Ltd.