Peptide:lipid ratio and membrane surface charge determine the mechanism of action of the antimicrobial peptide BP100. Conformational and functional studies

Peptide:lipid ratio and membrane surface charge determine the mechanism of action of the antimicrobial peptide BP100. Conformational and functional studies

Author Manzini, Mariana C. Google Scholar
Perez, Katia Regina Autor UNIFESP Google Scholar
Riske, Karin Amaral Autor UNIFESP Google Scholar
Bozelli, Jose C. Google Scholar
Santos, Talita L. Google Scholar
Silva, Marcia A. da Google Scholar
Saraiva, Greice Kelle Viegas Google Scholar
Politi, Mario J. Google Scholar
Valente, Ana P. Google Scholar
Almeida, Fabio C. L. Google Scholar
Chaimovich, Hernan Google Scholar
Rodrigues, Magali A. Google Scholar
Bemquerer, Marcelo P. Google Scholar
Schreier, Shirley Google Scholar
Cuccovia, Iolanda M. Google Scholar
Institution Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Universidade Federal do Rio de Janeiro (UFRJ)
Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)
Abstract The cecropin-melittin hybrid antimicrobial peptide BP100 (H-KKLFKKILKYL-NH2) is selective for Gram-negative bacteria, negatively charged membranes, and weakly hemolytic. We studied BP100 conformational and functional properties upon interaction with large unilamellar vesicles, LUVs, and giant unilamellar vesicles, GUVs, containing variable proportions of phosphatidylcholine (PC) and negatively charged phosphatidylglycerol (PG). CD and NMR spectra showed that upon binding to PG-containing LUVs BP100 acquires a-helical conformation, the helix spanning residues 3-11. Theoretical analyses indicated that the helix is amphipathic and surface-seeking. CD and dynamic light scattering data evinced peptide and/or vesicle aggregation, modulated by peptide: lipid ratio and PG content. BP100 decreased the absolute value of the zeta potential () of LUVs with low PG contents; for higher PG, binding was analyzed as an ion-exchange process. At high salt, BP100-induced LUVS leakage requires higher peptide concentration, indicating that both electrostatic and hydrophobic interactions contribute to peptide binding. While a gradual release took place at low peptide:lipid ratios, instantaneous loss occurred at high ratios, suggesting vesicle disruption. Optical microscopy of GUVs confirmed BP100-promoted disruption of negatively charged membranes. the mechanism of action of BP100 is determined by both peptide:lipid ratio and negatively charged lipid content While gradual release results from membrane perturbation by a small number of peptide molecules giving rise to changes in acyl chain packing, lipid clustering (leading to membrane defects), and/or membrane thinning, membrane disruption results from a sequence of events large-scale peptide and lipid clustering, giving rise to peptide-lipid patches that eventually would leave the membrane in a carpet-like mechanism. (C) 2014 Elsevier B.V. All rights reserved.
Keywords BP100
Antimicrobial peptide
CD
NMR
Zeta potential
Model membrane leakage
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Institut Nacional de Ciencia e Tecnologia de fluidos complexos (INCTFCx)
Nude de Apoio Pesquisa de Fluidos Complexos (NAPFCx)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Grant number FAPESP: 2007/50970-5
FAPESP: 2013/08166-5
Date 2014-07-01
Published in Biochimica Et Biophysica Acta-biomembranes. Amsterdam: Elsevier B.V., v. 1838, n. 7, p. 1985-1999, 2014.
ISSN 0005-2736 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 1985-1999
Origin http://dx.doi.org/10.1016/j.bbamem.2014.04.004
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000336695300034
URI http://repositorio.unifesp.br/handle/11600/37884

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