Members of this family adopt a structure consisting of afour-stranded beta-sheet backed by three alpha-helices, the lastof which is over 50 amino acids long and extends from the bodyof the protein by several turns. This domain has been proposedto mediate intersubunit communication by structurallytransducing signals from the ATP binding and hydrolysis domainsto the DNA binding and cleavage domains of the gyrase holoenzyme[1]. Topoisomerase VI B subunit, transducer Topo-VIb_trans