Figure 1. Nanodiscs modulate the kinetics of hIAPP aggregation.

(a) Thioflavin T (ThT) was determined to have no interactions with nanodiscs which could significantly alter the dye’s fluorescent properties (20 mM PO₄ pH 7.4, 50 mM NaCl, 25°C). (b) ThT fluorescence was monitored as hIAPP (5 μM) was incubated with increasing concentration of ND1 under different conditions (either 20 mM PO₄ pH 7.4 or 30 mM acetate pH 5.3, both with 50 mM NaCl at either 25 or 35°C). Solid curves represent the average of three independent trials while the shaded regions represent the standard deviations of those measurements. (c) Lag times were calculated for each individual kinetic trace for hIAPP incubated with ND1, ND2, and ND3 (Figure 2). The fold change in the lag time compared to untreated hIAPP are plotted with respect to both nanodisc concentration and sample conditions. (d) TEM was used to image samples of hIAPP (50 μM) fiber prepared in the absence of nanodisc, freshly prepared ND1 (50 μM), and hIAPP monomer (50 μM) incubated with ND1 (50 μM). All samples were prepared in 30 mM acetate pH 5.3 at 35°C. (e) The overall signal intensities measured from 2D ¹H-¹⁵N HMQC spectra of hIAPP backbone amides in the absence or presence of ND1 were monitored over time. Peptide was prepared via both a monomeric and oligomeric methods (see Materials and methods for details) prior to treating with ND1.