These repeats were first identified in many cyanobacterial proteins but they are also found in bacterial as well as in plant proteins [<cite idref="PUB00001717"/>]. The repeats were first identified in hglK [<cite idref="PUB00002283"/>]. The function of these repeats is unknown. The structure of this repeat has been predicted to be a beta-helix [<cite idref="PUB00005053"/>]. The repeat can be approximately described as A(D/N)LXX, where X can be any amino acid. Pentapeptide repeat