Interaction of the cationic peptide bactenecin with mixed phospholipid monolayers at the air-water interface

Ana B. López-Oyama, Pablo Taboada, María G. Burboa, Ezequiel Rodríguez, Víctor Mosquera, Miguel A. Valdez*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

The initial mechanism by which antimicrobial peptides target microbes occurs via electrostatic interactions; however, the mechanism is not well understood. We investigate the interaction of the antimicrobial peptide bactenecin with a 50:50. w:w% 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DMPG) phospholipid mixture at the air-water interface with different NaCl concentrations (0.01, 0.05, 0.1, 0.5. M) in the subphase. A larger shift of DPPC:DMPG isotherms was obtained for 0.1. M salt concentration at lower and higher pressures, demonstrating the influence of the negative charge of DMPG molecules and the screening of the electrostatic interaction by the salt concentration. Raman spectroscopy of monolayers demonstrated the presence of cysteine-cysteine bridges in bactenecin loops. The peptide adsorption in DPPC:DMPG monolayers observed by AFM images suggests a self-assembled aggregation process, starting with filament-like networks. Domains similar to carpets were formed and pore structures were obtained after a critical peptide concentration, according to the carpet model.

Original languageEnglish
Pages (from-to)279-288
Number of pages10
JournalJournal of Colloid and Interface Science
Volume359
Issue number1
DOIs
StatePublished - 1 Jul 2011

Bibliographical note

Funding Information:
The Consejo Nacional de Ciencia y Tecnologìa (CONACyT) is gratefully acknowledged for grants Apoy-Compl-2008-90345 and 83191. A.B.L.O. acknowledges a Ph.D. scholarship from CONACYT. We appreciate the technical assistance of Teresita Pesqueira to obtain Raman spectra and helpful discussions with Josué Juárez.

Keywords

  • AFM
  • Antimicrobial peptides
  • Bactenecin
  • Carpet model
  • Isotherms
  • Raman spectroscopy

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