ANK REPEAT

Amino acid motif found in diverse proteins including ankyrin (hence the name), the Notch product, transcriptional regulators, cell cycle regulatory proteins and a toxin produced by the black widow spider. The motif is about 33 amino acids long and is generally found as a tandem array of 2-7 repeats, though ankyrins contain 24 repeats. Their role is not established, but they may be involved in protein-protein binding.