Figure 2.

Case studies of the conservation of charged residue pairs in homologous interfaces. For each case study, the following are shown: (i) the overall structural alignment of the interacting complexes, (ii) the structural alignment of the interaction interfaces, and (ii) the superposed binding sites with the shown positively charged (blue and cyan) and negatively charged (red and magenta) residues delineated. A: Conserved charged residue pairs. B and D: Swapped charged residue pairs. C and E: Charged residue pairs of correlated reappearance. In the first three cases (A–C), each pair of homologous subunits that forms the interaction is from the same SCOP family, while in the last two cases (D and E), at least one pair of the interfaces is from two different families, although within the same SCOP superfamily.