Secondary Structure, a Missing Component of Sequence-Based Minimotif Definitions
A, B. Plot of the number of occurrences of each xYxN lexicon for a β-turn (A), or total number in the PDB (B). The depth and horizontal axes shows the single letter IUPAC code for amino acids in the X1 and X2 positions of the xYxN consensus minimotif, respectively. Colored labeled bars indicate lexica where a known structure of a complex of the Grb2 SH2 domain with this peptide sequence exists in the PDB.