Unknown

Dataset Information

0

Fusion of phospholipid vesicles produced by the anti-tumour protein alpha-sarcin.


ABSTRACT: The anti-tumour protein alpha-sarcin causes fusion of bilayers of phospholipid vesicles at neutral pH. This is demonstrated by measuring the decrease in the efficiency of the fluorescence energy transfer between N-(7-nitro-2-1,3-benzoxadiazol-4-yl)-dimyristoylphosphatidylethano lamine (NDB-PE) (donor) and N-(lissamine rhodamine B sulphonyl)-diacylphosphatidylethanolamine (Rh-PE) (acceptor) incorporated in dimyristoylphosphatidylcholine (DMPG) vesicles. The effect of alpha-sarcin is a maximum at 0.15 M ionic strength and is abolished at basic pH. alpha-Sarcin promotes fusion between 1,6-diphenylhexa-1,3,5-triene (DPH)-labelled DMPG and dipalmitoyl-PG (DPPG) vesicles, resulting in a single thermotropic transition for the population of fused phospholipid vesicles. Bilayers composed of DMPC and DMPG, at different molar ratios in the range 1:1 to 1:10 PC/PG, are also fused by alpha-sarcin. Freeze-fracture electron micrographs corroborate the occurrence of fusion induced by the protein. alpha-Sarcin also modifies the permeability of the bilayers, causing the leakage of calcein in dye-trapped PG vesicles. All of the observed effects reach saturation at a 50:1 phospholipid/protein molar ratio, which is coincident with the binding stoichiometry previously described.

SUBMITTER: Gasset M 

PROVIDER: S-EPMC1133705 | biostudies-other | 1990 Feb

REPOSITORIES: biostudies-other

Similar Datasets

| S-EPMC1138399 | biostudies-other
| S-EPMC1134842 | biostudies-other
| S-EPMC7293039 | biostudies-literature
| S-EPMC3340996 | biostudies-literature
| S-EPMC22992 | biostudies-literature
| S-EPMC2895252 | biostudies-literature
| S-EPMC9950948 | biostudies-literature
| S-EPMC4793259 | biostudies-literature
| S-EPMC6327981 | biostudies-literature
| S-EPMC2224146 | biostudies-literature