FIGURE 9.

Preliminary structural modeling of medin fibrils. A, scheme of the proposed hairpin topology of the medin monomer constrained by a Asp²⁵-Lys³⁰ salt bridge. Residues Ala¹⁰, Trp¹¹, Val¹², Trp²¹, Thr³³, Ile³⁴, and Thr³⁷ (highlighted in red) are discussed under “Results.” B, a DARR NMR spectrum of uniformly ¹³C-labeled fibrils (black) superimposed with a simulated spectrum (red) calculated from average chemical shifts for the amino acids in the model. All chemical shift values for the amino acids outside the β-sheet regions were taken from tabulated random coil values (39).