Illustration of the symbolic representation of edge-face nomenclature for T-shaped interactions, using examples from different geometrical families (Table 1). PDB code, crystallographic resolution, and interaction code (horizontal base–vertical base) are provided for each interaction. The interacting atom of the horizontal base and the participating edge of the vertical base are indicated for each annotation. The distance between the interacting atom (heavy atom for the C-H group) of the vertical base and the center of the interacting ring of the horizontal base is provided. Although in some cases, one atom belonging to the interacting edge may visually appear closer than the other atom of the same edge, the interacting atom is identified using a quantitative method according to the algorithm described in the Materials and Methods section. Note that including the information on the ring identity of the horizontal base and the interacting atom/group of the vertical base is optional and can be removed in ambiguous cases.
