Disorder and interfaces in proteins are two sides of the same coin
The importance of unstructured biology has quickly grown during the last decades accompanying the explosion of the number of experimentally resolved structures. The idea that structural disorder might be a novel mechanism of protein interaction is widespread in the literature, although the number of statistically significant structural studies supporting this idea is surprisingly low. In this work, through a large-scale-analysis of all the crystallographic structures of the Protein Data Bank averaged over clusters of homologous sequences, we show clear evidences that both the (experimentally verified) interaction interfaces and the disordered regions are involving roughly the same amino-acids of the protein. And beyond, disordered regions appear to carry information about the location of alternative interfaces when the protein lies within complexes, thus playing an important role in determining the order of assembly of protein complexes.