The ankyrin repeat: a diversity of interactions on a common structural framework.

The ankyrin repeat is one of the most common protein sequence motifs. Recent X-ray and NMR structures of ankyrin-repeat proteins and their complexes have provided invaluable insights into the molecular basis of the extraordinary variety of biological activities of these molecules. In particular, they have begun to reveal how a large family of structurally related proteins can interact specifically with such a diverse array of macromolecular targets.