Fig. 1. C-terminal amino acid directs handedness of β-sheet twist.

Chemical structures (a) showing the replacement of E with V on the C-termini. TEM images (b) of peptides assembled in 40% ACN, 0.1% TFA for 2 weeks (representative of 3 independent assemblies, scale bars = 500 nm). Electron diffraction (c) (scale bars = 2 nm⁻¹) and schematics showing the twist angle of the tube (representative image of diffraction patterns taken on 3 different areas of the grid). FT-IR (d) of KLVFFAE and KLVFFAV peptides assembled in 40% ACN, 0.1% TFA for 2 weeks showing anti-parallel β-sheet signal. CD spectra (e) of KLVFFAE and KLVFFAV peptides assembled in 40% ACN, 0.1% TFA for 2 weeks. In schematics and graphs, KLVFFA-E = black/gray, KLVFFA-V = pink.