826706.fig.007a
(a)
826706.fig.007b
(b)
Figure 7: Diagram showing how (a) unmodified amino acids can form β-sheet structures via hydrogen bonding (represented as - - -) and how (b) N-methylation (expressed as dark circles) replaces hydrogen in a polypeptide and thus preventing β-sheet stacking. R1–R4 represent the side groups of the amino acids. Adapted from Rijkers et al. [116].