Fig. 2

Protomer conformation revealed by ss-NMR. a The 2D ¹³C–¹³C proton-driven spin diffusion spectrum shows the cross-peaks between aliphatic carbon atoms. b Backbone model of the cross-β sheet implementing Φ/Ψ angles as predicted by the program TALOS+²⁹ (scale bar, 1 nm). c Averaged parallelograms of morphologies I–V (gray) superimposed with a peptide dimer (green, magenta) as obtained by NMR. The placement of the peptides followed the considerations described previously for morphology I⁸ (scale bar, 1 nm). d Side view and top view of a six-layer stack illustrating the structure of a PF. Side-chain conformations were not determined by experiments and represent only conformations that are compatible with the packing shown here