Amide Proton Solvent Protection in Amylin Fibrils Probed by Quenched Hydrogen Exchange NMR
Figure 1
1H-15N HSQC spectra illustrating hydrogen exchange in amylin fibrils.
(A) Control spectrum of unfibrillized 15N-amylin freshly dissolved in 95% d6-DMSO/5% DCA at 25°C, pH 3.5. Backbone crosspeaks are labeled according to sequence-specific assignments. Residues N3, T4, A5, and A8 are only visible at lower contours than shown. The group of crosspeaks connected by horizontal lines between 109 and 111 ppm (15N) are unassigned sidechain amide groups from the 6 Asn and 1 Gln in amylin. (B)Spectrum of a 15N-amylin after 4 days (99h) of D2O exchange in the fibril state, recorded in 95% d6-DMSO/5% d2-DCA. Strongly protected amide protons are labeled in bold type.