This protein of 154 residues consists of a unit of helices and beta sheets that crystallises into a beautiful asymmetrical dodecameric barrel-structure, of two six-membered rings one on top of the other. It is expressed in bacteria but is of viral origin as it is found in phage BcepMu and is probably a pathogenesis factor [1].

1: Burkholderia cenocepacia phage BcepMu and a family of Mu-like phages encoding potential pathogenesis factors. Summer EJ, Gonzalez CF, Carlisle T, Mebane LM, Cass AM, Savva CG, LiPuma J, Young R; J Mol Biol. 2004;340:49-65. PMID:15184022