Figure 1.

(A) The 16 protein blocks (PBs) represented in balls with carbon atoms in gray, oxygen atoms in red and nitrogen atoms in purple (hydrogen atoms are not represented). (B) The barstar protein (PDB ID 1AY7 (Sevcík et al., 1998)) represented in cartoon with alpha-helices in blue, beta-strands in red and coil in pink. These representations were generated using PyMOL software (DeLano, 2002) (C) PBs sequence obtained from PBs assignment. Z is a dummy PB, meaning that no PB can be assigned to this position.