The ankyrin repeat is one of the most common protein-protein interaction motifs in nature. Ankyrin repeats are tandemly repeated modules of about 33 amino acids. They occur in a large number of functionally diverse proteins mainly from eukaryotes. The few known examples from prokaryotes and viruses may be the result of horizontal gene transfers. The repeat has been found in proteins of diverse … expand

The ankyrin repeat is one of the most common protein-protein interaction motifs in nature. Ankyrin repeats are tandemly repeated modules of about 33 amino acids. They occur in a large number of functionally diverse proteins mainly from eukaryotes. The few known examples from prokaryotes and viruses may be the result of horizontal gene transfers. The repeat has been found in proteins of diverse function such as transcriptional initiators, cell-cycle regulators [ PUBMED:31000436 ], cytoskeletal, ion transporters and signal transducers [ PUBMED:29769718 PUBMED:8108379 ]. The ankyrin fold appears to be defined by its structure rather than its function since there is no specific sequence or structure which is universally recognised by it.

The conserved fold of the ankyrin repeat unit is known from several crystal and solution structures [ PUBMED:8875926 PUBMED:9353127 PUBMED:9461436 PUBMED:9865693 ]. Each repeat folds into a helix-loop-helix structure with a β-hairpin/loop region projecting out from the helices at a 90 ^o angle. The repeats stack together to form an L-shaped structure [ PUBMED:8875926 PUBMED:12461176 ].