Figure 2
IAPP forms an α-helix upon interaction with phosphatidic acid containing LUVs before transitioning into a β-sheet structure.
(a–c) Representative circular dichroism spectra are shown. The secondary structure of 25 μM IAPP was first determined in 10 mM phosphate buffer, pH 7.4 (—). (a) minimum at 202 nm suggests a mostly disordered structure. LUVs composed of 66 (a), 25 (b) and 10 mol% (c) POPA were added and the structure was immediately measured (•••). Minima at 208 nm and 222 nm indicate a transition into an α-helix upon interaction with LUVs. After incubation at room temperature, the samples were measured a final time (— —). A minimum near 218 nm is most consistent with a β-sheet structure. D) Initial spectra of IAPP upon addition of 66 (— • —), 25 (— —) and 10 mol% (•••) PA-LUVs are overlaid with the disordered structure in buffer (—), provided for reference.
