Revealing the Lytic Mechanism of the Antimicrobial Peptide Gomesin by Observing Giant Unilamellar Vesicles

Revealing the Lytic Mechanism of the Antimicrobial Peptide Gomesin by Observing Giant Unilamellar Vesicles

Author Domingues, Tatiana Moreira Autor UNIFESP Google Scholar
Riske, Karin A. Autor UNIFESP Google Scholar
Miranda, Antonio Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract Gomesin (Gm) is a potent cationic antimicrobial peptide from a Brazilian spider. Here we use optical and fluorescence microscopy to study the interaction of Gm, its low active linear analogue, [Ser(2.6,11,15)]-Gm (GmL), and a fluorescent labeled analogue. Gm-Rh, with giant unilamellar vesicles (GUVs) composed of mixtures of the neutral lipid palmitoyloleoyl phosphatidylcholine (POPC) with the negatively charged lipid palmitoyloleoyl phosphatidylglycerol (POPG) or cholesterol, so as to mimic bacterial and mammalian cell membranes, respectively. We observed the effect of injecting a peptide solution with a micropipet close to GUVs. As a result of peptide-lipid interaction, GUVs burst suddenly. Stable pores, which result in leaky vesicles, were not observed. Fluorescence microscopy of Gm-Rh injected on GUVs confirmed the high peptide/lipid affinity. These facts lead us to suggest that Gm and GmL disrupt the membrane via the carpet model. in order to quantify the lytic activity of both peptides against different membrane composition, a solution of GUVs was diluted in increasing concentration of peptides and the fraction of burst GM's was measured as a function of time. the lytic activity of both peptides was enhanced by the presence of POPG and decreased upon addition of cholesterol, GmL exhibited lower lytic activity as compared to Gm, but this difference vanished at high POPG molar fraction.
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Date 2010-07-06
Published in Langmuir. Washington: Amer Chemical Soc, v. 26, n. 13, p. 11077-11084, 2010.
ISSN 0743-7463 (Sherpa/Romeo, impact factor)
Publisher Amer Chemical Soc
Extent 11077-11084
Access rights Closed access
Type Article
Web of Science ID WOS:000279239900091

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