Matched and unmatched contacts.

<p>Mean of the percentage of buried atoms per molecule engaged in successful interactions (Matched contacts, left chart) and mean of the percentage of buried atoms without an appropriate partner in the other side of the interface (Unmatched contacts, right chart). The percentage is divided into polar (red) and apolar (blue) contribution. Each set has two bars, one on the left for the atoms in the protein and one on the right for the atoms in the ligand or smaller protein in the case of protein complexes. Error bars denote the standard error of the mean. Sets are ordered from left to right: Synthetic small molecules, approved drugs, oral drugs, protein-protein interaction small molecule inhibitors, natural molecules, natural molecules without phosphor, small peptides, obligate protein-protein dimers, transient protein-protein dimers, homo quaternary protein-protein interfaces and hetero quaternary protein-protein interfaces.