Calcium-induced aggregation and fusion of mixed phosphatidylcholine-phosphatidic acid vesicles as studied by 31P NMR.
Biochim Biophys Acta
; 514(2): 255-63, 1978 Dec 19.
Article
em En
| MEDLINE
| ID: mdl-737172
ABSTRACT
1. The transbilayer distribution of the phospholipids in sonicated egg phosphatidylcholine-phosphatidic acid vesicles and the interaction of Ca2+ with these vesicles was studied by 31P NMR. 2. Over a wide composition range the bilayer of these vesicles has a symmetrical phospholipid composition. 3. With ratios of Ca2+ to phosphatidic acid in the outer monolayer of the vesicles up to 0.3, Ca2+ induces vesicle aggregation. The extent of aggregation is increased by the Ca2+ concentration in the medium and the outer monolayer concentration of phosphatidic acid. The vesicle aggregation can be fully reversed by chelating Ca2+. 4. When the ratio exceeds 0.5 Ca2+ induces vesicle fusion. The fusion is maximal for vesicles containing both phosphatidylcholine and phosphatidic acid. The data suggest that Ca2+-induced lateral phase separations make the bilayer more susceptible to fusion.
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01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ácidos Fosfatídicos
/
Fosfatidilcolinas
/
Cálcio
/
Membranas Artificiais
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1978
Tipo de documento:
Article