Cryo-TEM images of MPX peptide and POPC/POPG (3:1) lipid aggregates vitrified at 25°C. (A and B) Uni- and multilamellar liposomes with an average size of ∼100 nm are shown at P/L = 0, Clip = 7.5 mM (A) and P/L = 0.025, Clip = 7.5 mM (B). (C and D) The presence of membrane pores is observed at P/L = 0.06, Clip = 7.5 mM (C) and P/L = 0.12, Clip = 7.5 mM (D), where fenestration of the liposome membrane and patterning of the liposome interior can be seen. (E and F) At higher peptide/lipid ratios, the peptide-lipid aggregates change morphology from lamellar to networks of wormlike micelles (E) (P/L = 0.24, Clip = 7.5 mM) or globular micelles (F) (P/L = 0.60, Clip = 7.5 mM). (G) A fenestrated multilamellar membrane system can be seen at P/L = 0.24, Clip = 0.75 mM. (H and I) Magnifications of the vesicles imaged in D and A, respectively. Arrows in H point to positions on the membrane with diminished contrast, attributed to aqueous pores spanning the membrane.