<p><sup>1</sup>H-NMR spectra derived from the N<sup>+</sup>(CH<sub>3</sub>)<sub>3</sub> groups of PC in large unilamellar liposomes composed of PC+ 10 mol% CL (<b>A</b> and <b>B</b>) or in PC+ 10 mol% PS (<b>C</b> and <b>D</b>) in the presence of potassium ferricyanide at 18°C and in the presence of CTII (<b>A</b> and <b>C,</b> top spectra) or of CTI (<b>B</b> and <b>D,</b> top spectra) at a cytotoxin/lipid molar ratio of 0.02. This figure shows a representative <sup>1</sup>H-NMR traces from three independent experiments that showed similar results. Each sample (<b>A-D</b>) was measured in triplicate.</p