Effect of N-terminal acetylation on lytic activity and lipid-packing perturbation induced in model membranes by a mastoparan-like peptide

Autor(es)

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

Afiliação do(s) autor(es)

^[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, Cordoba - Argentina

• Tipo de documento: Artigo Científico
• Fonte: BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES; v. 1860, n. 3, p. 737-748, MAR 2018.
• Citações Web of Science: 2

Resumo

L1A (IDGLKAIWKKVADLLKNT-NH2) is a peptide that displays a selective antibacterial activity to Gram-negative bacteria without being hemolytic. Its lytic activity in anionic lipid vesicles was strongly enhanced when its N terminus was acetylated (ac-L1A). This modification seems to favor the perturbation of the lipid core of the bilayer by the peptide, resulting in higher membrane lysis. In the present study, we used lipid monolayers and bilayers as membrane model systems to explore the impact of acetylation on the L1A lytic activity and its correlation with lipid-packing perturbation. The lytic activity investigated in giant unilamellar vesicles (GUVs) revealed that the acetylated peptide permeated the membrane at higher rates compared with L1A, and modified the membrane's mechanical properties, promoting shape changes. The peptide secondary structure and the changes in the environment of the tryptophan upon adsorption to large unilamellar vesicles (LUVs) were monitored by circular dichroism (CD) and red-edge excitation shift experiments (REES), respectively. These experiments showed that the N-terminus acetylation has an important effect on both, peptide secondary structure and peptide insertion into the bilayer. This was also confirmed by experiments of insertion into lipid monolayers. Compression isotherms for peptide/lipid mixed films revealed that ac-L1A dragged lipid molecules to the more disordered phase, generating a more favorable environment and preventing the lipid molecules from forming stiff films. Enthalpy changes in the main phase transition of the lipid membrane upon peptide insertion suggested that the acetylated peptide induced higher impact than the non-acetylated one on the thermotropic behavior of anionic vesicles. (AU)

• Processo FAPESP: 15/25619-9 - Efeito de aminofosfolípides e do pH na atividade interfacial do peptídeo anticâncer Polybia-MP1 e análogos em membranas modelo
• Beneficiário: João Ruggiero Neto
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 15/25620-7 - Interação membrana/peptídeo: propriedades mecânica e eletrostática em sistemas com domínios lipídicos
• Beneficiário: Dayane dos Santos Alvares
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado