The ssNMR structural model of amylin fibrils [<b>10</b>].

<p>The long axis of the fibrils runs in and out of the plane of the page. (<b>A</b>) Backbone hydrogen bonding between two adjacent amylin monomers in the fibril. Amide protons involved in intermolecular β-sheet hydrogen bonds are labeled alternatively in the blue and gray monomers. Note that the β-sheet hydrogen bonding is continuous along the length of the fibril, so that the amide proton of T36 in the blue monomer is a hydrogen bond donor for the carbonyl of S35 in the next monomer below (not shown). (<b>B</b>) In the ssNMR model of amylin fibrils two columns of amylin β-hairpins stack against each other with C₂ symmetry to form a protofilament <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056467#pone.0056467-Luca1" target="_blank">[10]</a>. The C-terminal strands (red and orange) constitute the packing interface between the two layers of β-sheets, whereas the N-terminal strands (green) are on the surface. Residues I26-L27 which were not assigned to strand β2 in the ssNMR model but which nevertheless show strong qHX protection are colored in light blue. The drawings were rendered in PyMOL <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056467#pone.0056467-deLano1" target="_blank">[39]</a>.