Unravel the interactions of ?de novo? antimicrobial peptide P1 with model and bacterial membranes

ESPECHE, JUAN; MATURANA PATRICIA; MARTINEZ, M; MAFFIA, PABLO; ANDREA C. CUTRÓ; HOLLMANN, AXEL

La Plata

Congreso; Reunión Anual de la Sociedad Biofísica Argentina; 2018

Sociedad Argentina de Biofísica

In the present work, we evaluate the interaction of the antimicrobial peptide 1 (P1)with model and bacterial membranes. P1 is a cationic peptide with 21 amino acids(WPKWWKWKRRWGRKKAKKRRG), designed identifying short putative activeregions from AMP databases.First, we evaluated the interaction of P1 with model membranes (i.e. liposomes ofDMPC:DMPG 5:1) by using Zeta Potential. Then fluorescence quenching wasapplied to dissect the ability of the peptide to insert into the lipid bilayer. Bothexperiments confirm the interaction of P1 with this model membrane showing adepth insertion of the Trp residues in the hydrophobic core of the bilayer.In order to evaluate the effect of the peptide in more physiologic scenery, weevaluate also by zeta potential the ability of P1 to interact with Escherichia coliand Staphylococcus aureus. In both cases, zeta potential becomes less negativeafter peptide incubation confirm the ability of the peptides to bound into the cellenvelope. However, the effect becomes more noticeable in S. aureus.Finally, the ability of the peptide to permeabilize the inner and outer membrane ofE. coli was assessed. The results obtained confirm that P1 is able to disrupt bothmembranes, showing a much faster kinetics in the disruption of the outermembrane as expected.All the data put together allows proposing a model where the insertion of the ofthe peptide, stabilized by Trp residues depth inserted in hydrocarbon region,promotes changes in the lipids organization following a carpet-like mechanism thatresults in a permeabilization of the membrane triggering the antimicrobial activity.