Glycine parameters. (A) The Ramachandran plot in shifted coordinates φ'-ψ'. The dashed lines show the steric clashes that define the boundaries of the observed densities (Figure 2B describes the specific interactions). (B) The distributions of various inter-atomic interactions as a function of ψ'. The dashed line show the limit of the VDW diameters. The grey line gives the model curve calculated with ideal geometry. At the bottom is the frequency distribution of the ψ' angle. (C) Frequency distribution of the inter-atomic distance d(O···H). There are 3 peaks, of which, the smallest at d(O···H) = 2.4 Å, which corresponds to the βS region.