Three aromatic
residues in IAPP interact differently with resveratrol.
Thioflavin-T fluorescence-monitored kinetic experiments with (A) F15L-IAPP,
(B) F23L-IAPP, and (C) Y37L-IAPP in the presence of resveratrol. Experiments
were conducted at 25 °C and pH 7.4 in 20 mM Tris buffer, 16 μM
mutants, and 1% (v/v) DMSO without stirring: (black) peptide alone,
(yellow) peptide with resveratrol at a 1:1 ratio, (green) peptide
with resveratrol at a 1:2 ratio, (pink) peptide with resveratrol at
a 1:5 ratio, (red) peptide with resveratrol at a 1:10 ratio, and (blue)
peptide with resveratrol at a 1:20 ratio. The red and blue curves
overlap in panels A and B. TEM images of (D) F15L-IAPP fibrils after
42 h, (E) F15L-IAPP fibrils with a 20-fold excess of resveratrol after
42 h, (F) F23L-IAPP fibrils, and (G) F23L-IAPP fibrils with a 20-fold
excess of resveratrol. The F23L-IAPP samples were removed from the
kinetic experiments at 96 h for TEM. TEM images of (H) Y37L-IAPP fibrils
and (I) Y37L-IAPP fibrils with a 20-fold excess of resveratrol. The
Y37L-IAPP samples were removed from the kinetic experiments at 96
h for TEM. Scale bars represent 100 nm.