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Biophys J. 1997 Apr;72(4):1762-6.

Sizing membrane pores in lipid vesicles by leakage of co-encapsulated markers: pore formation by melittin.

Author information

1
Department of Physiology and Biophysics, University of California, Irvine 92717-4560, USA.

Abstract

Many toxins and antimicrobial peptides permeabilize membrane vesicles by forming multimeric pores. Determination of the size of such pores is an important first step for understanding their structure and the mechanism of their self-assembly. We report a simple method for sizing pores in vesicles based on the differential release of co-encapsulated fluorescently labeled dextran markers of two different sizes. The method was tested using the bee venom peptide melittin, which was found to form pores of 25-30 A diameter in palmitoyloleoylphosphatidylcholine (POPC) vesicles at a lipid-to-peptide ratio of 50. This result is consistent with observations on melittin pore formation in erythrocytes (Katsu, T., C. Ninomiya, M. Kuroko, H. Kobayashi, T. Hirota, and Y. Fujita 1988. Action mechanism of amphipathic peptides gramicidin S and melittin on erythrocyte membrane Biochim. Biophys. Acta. 939:57-63).

PMID:
9083680
PMCID:
PMC1184370
DOI:
10.1016/S0006-3495(97)78822-2
[Indexed for MEDLINE]
Free PMC Article

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