Interaction of a synthetic antimicrobial peptide with model membrane by fluorescence spectroscopy

Author(s)

Puia Zanin, Luciana Moro ^[1] ; Alvares, Dayane dos Santos ^[1] ; Juliano, Maria Aparecida ^[1] ; Pazin, Wallance Moreira ^[1] ; Ito, Amando Siuiti ^[1] ; Ruggiero Neto, Joo ^[1]

Affiliation

^[1] Sao Paulo State Univ, Dept Phys, IBILCE, UNESP, BR-15054000 Sao Jose Do Rio Preto, SP - Brazil

• Document type: Journal article
• Source: EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS; v. 42, n. 11-12, p. 819-831, DEC 2013.
• Web of Science Citations: 10

Abstract

Static and time-resolved fluorescence of tryptophan and ortho-aminobenzoic acid was used to investigate the interaction of the synthetic antimicrobial peptide L1A (IDGLKAIWKKVADLLKNT-NH2) with POPC and POPC:POPG. N-acetylated (Ac-L1A) and N-terminus covalently bonded ortho-aminobenzoic acid (Abz-L1A-W8V) were also used. Static fluorescence and quenching by acrylamide showed that the peptides adsorption to the lipid bilayers was accompanied by spectral blue shift and by a decrease in fluorescence quenching, indicating that the peptides moved to a less polar environment probably buried in the lipidic phase of the vesicles. These results also suggest that the loss of the N-terminus charge allowed deeper fluorophore insertion in the bilayer. Despite the local character of spectroscopic information, conclusions can be drawn about the peptides as a whole. The dynamic behaviors of the peptides are such that the mean intensity lifetimes, the long correlation time and the residual anisotropy at long times increased when the peptides adsorb in lipid vesicles, being larger in anionic vesicles. From the steady-state increase in fluorescence intensity and anisotropy, we observed that the partition coefficient of peptides L1A and its Abz analog in both types of vesicles are higher than the acetylated analog; moreover, the affinity to the anionic vesicle is higher than to the zwitterionic. (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