New article: Magainin 2 and PGLa in Bacterial Membrane Mimics II: Membrane Fusion and Sponge Phase Formation.
We addressed the synergistic activity of the two well-studied antimicrobial peptides magainin 2 (MG2a) and PGLa using lipid-only mimics of Gram-negative cytoplasmic membranes. Specifically, we combined computer simulations, small-angle X-ray and neutron scattering experiments, cryo-EM, and differential scanning calorimetry to investigate the behavior of peptides in the synergistic regime,i.e. at elevated peptide concentrations which cause enahnced membrane leakage. We found that peptides aggregate into fibril-like structures, inducing cross-links between proximate bilayers and leading to the occurrence of fusion stalks. This turn unilamellar vesicles into multilamellar vesicles with a collapsed interbilayer, which evolved over time into a sponge phase correlating it with synergistic leakage of the vesicles.
You can find the article in Biophysical Journal.