The interfacial properties of the peptide Polybia-MP1 and its interaction with DPPC are modulated by lateral electrostatic attractions

Author(s)

Alvares, Dayane S. ^[1] ; Laura Fanani, Maria ^[2] ; Ruggiero Neto, Joao ^[1] ; Wilke, Natalia ^[2]

Affiliation

^[1] UNESP Sao Paulo State Univ, IBILCE, Dept Phys, Sao Jose Do Rio Preto, SP - Brazil

^[2] Univ Nacl Cordoba, Fac Ciencias Quim, Dept Quim Biol, Ctr Invest Quim Biol Cordoba CIQUIBIC, CONICET, RA-5000 Cordoba - Argentina

• Document type: Journal article
• Source: BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES; v. 1858, n. 2, p. 393-402, FEB 2016.
• Web of Science Citations: 12

Abstract

Polybia-MP1 (IDWKKLLDAAKQIL-NH2), extracted from the Brazilian wasp Polybia paulista, exhibits a broad-spectrum bactericidal activity without being hemolytic and cytotoxic. In the present study, we analyzed the surface properties of the peptide and its interaction with DPPC in Langmuir monolayers. Polybia-MP1 formed stable monolayers, with lateral areas and surface potential values suggesting a mostly alpha-helical structure oriented near perpendicular to the membrane plane. In DPPC-peptide mixed monolayers, MP1 co-crystallized with the lipid forming branched domains only when the subphase was pure water. On subphases with high salt concentrations or at acidic or basic conditions, the peptide formed less densely packed films and was excluded from the domains, indicating the presence of attractive electrostatic interactions between peptides, which allow them to get closer to each other and to interact with DPPC probably as a consequence of a particular peptide arrangement. The residues responsible of the peptide-peptide attraction are suggested to be the anionic aspartic acids and the cationic lysines, which form a salt bridge, leading to oriented interactions in the crystal and thereby to branched domains. For this peptide, the balance between total attractive and repulsive interactions may be finely tuned by the aqueous ionic strength and pH, and since this effect is related with lysines and aspartic acids, similar effects may also occur in other peptides containing these residues in their sequences. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/08147-8 - Study of domains formation in model membranes induced by antimicrobial peptides and their action interfacial
• Grantee: Dayane dos Santos Alvares
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 11/11640-5 - Interaction of lytic peptides and model membranes: intefacial action and induction of lipid domains
• Grantee: João Ruggiero Neto
• Support Opportunities: Regular Research Grants