Mitochondria and plasma membrane permeabilization by polycationic peptides derived from Cry‐protoxins

Abstract

Polycationic peptides hold a promise as antitumoral and antimicrobial agents. Many natural and artificially designed polycationic peptides demonstrate high activity in permeabilization of biological membranes. In this work, several peptides composed of 20 amino acid residues were designed on the bases of amino acid sequences of some Cry‐protoxins. The effects of these peptides on the rat liver mitochondria were evaluated using the measurement of mitochondrial swelling and pyridine nucleotide fluorescence, as endogenous indirect indicator of the inner membrane potential changes. To study plasma membrane permeabilization by these peptides, the rat red blood cells with normal and artificially generated high membrane potentials were used (Lemeshko VV, Arch. Biochem. Biophys., 2010). Most of the designed peptides caused mitochondria permeabilization at the concentration of 4 ug/ml or less. The effect of the peptides on the red blood cell swelling was strongly potentiated by the artificially generated membrane potential (up to −200 mV, in the presence of valinomycin). The peptides with significant mitochondria permeabilizing effects and relatively low capacity to induce hemolysis were selected for further modifications to obtain peptide properties essential for antitumoral activity. (Supported by Colciencias grant #111840820380).