mast-cell-degranulating-peptide and anoplin

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.

Topics: Animals; Antimicrobial Cationic Peptides; Biophysical Phenomena; Cell Degranulation; Circular Dichroism; In Vitro Techniques; Intercellular Signaling Peptides and Proteins; Lipid Bilayers; Mast Cells; Membrane Potentials; Membranes, Artificial; Models, Molecular; Peptides; Protein Conformation; Rats; Rats, Wistar; Wasp Venoms