Fluorescence Imaging of Disrupted Interfaces between Liquid-Ordered and Liquid-Disordered Domains by a Flavin-Labeled PNA Duplex

[Image: see text] Lipid rafts and membrane-active peptides are attracting attention because they help understand basic membrane functions. In addition, we focus on flavoproteins playing some physiological roles and explore the model compounds. In this study, we demonstrate that a new flavin probe, composed of palmitoylated peptide nucleic acid (PNA) and its complementary PNA labeled with flavin, targets the liquid-ordered (lo) microdomains and disrupts its interfaces to liquid-disordered (ld) microdomains of giant unilamellar vesicles and can be visualized by using confocal laser scanning microscopy. Surprisingly, as shown in time-lapse images, vesiculation and probe aggregations appear in the lo–ld interfaces, which leads to local disruption of the membrane. We discuss a possible interpretation of the data based on a comparison with control experiments.