title: Interactions of mast cell degranulating peptides with model membranes: a comparative biophysical study.
abstract: In the last decade, there has been renewed interest in biologically active peptides in fields like allergy, autoimmune diseases and antibiotic therapy. Mast cell degranulating peptides mimic G-protein receptors, showing different activity levels even among homologous peptides. Another important feature is their ability to interact directly with membrane phospholipids, in a fast and concentration-dependent way. The mechanism of action of peptide HR1 on model membranes was investigated comparatively to other mast cell degranulating peptides (Mastoparan, Eumenitin and Anoplin) to evidence the features that modulate their selectivity. Using vesicle leakage, single-channel recordings and zeta-potential measurements, we demonstrated that HR1 preferentially binds to anionic bilayers, accumulates, folds, and at very low concentrations, is able to insert and create membrane spanning ion-selective pores. We discuss the ion selectivity character of the pores based on the neutralization or screening of the peptides charges by the bilayer head group charges or dipoles.
authors.affiliation: USP - University of São Paulo, Department of Physiology and Biophysics, Biomedical Sciences Institute, São Paulo, SP, Brazil. cabrera.marcia@gmail.com
authors.forename: Marcia Perez
authors.initials: MP
authors.lastname: Dos Santos Cabrera
authors.forename: Manoel
authors.initials: M
authors.lastname: Arcisio-Miranda
authors.forename: Laiana Cristina
authors.initials: LC
authors.lastname: da Costa
authors.forename: Bibiana Monson
authors.initials: BM
authors.lastname: de Souza
authors.forename: Sabrina Thaís
authors.initials: ST
authors.lastname: Broggio Costa
authors.forename: Mario Sérgio
authors.initials: MS
authors.lastname: Palma
authors.forename: João
authors.initials: J
authors.lastname: Ruggiero Neto
authors.forename: Joaquim
authors.initials: J
authors.lastname: Procopio