Multi-protein complexes are emerging as important entities of biological activity inside cells that serve to create func-tional diversity by contextual combination of gene products and, at the same time, organize the large number of different proteins into functional units. Many a time, when studying protein complexes rather than individual proteins, the bio-logical insight gained has been fundamental, particularly in cases in which proteins with no previous functional anno-tation couldbe placed intoa functional context derived from their molecular environment . .
