Type II DNA topoisomerases are ubiquitous enzymes that catalyse the ATP-dependent transport of one DNA duplex through a second DNA segment via a transient double-strand break. Type II DNA topoisomerases are now subdivided into two sub-families, type IIA and IIB DNA topoisomerases. TP6A_N is present in type IIB topoisomerase and is thought to be involved in DNA binding owing to its sequence similarity to E. coli catabolite activator protein (CAP) [1].

1: Structure and function of an archaeal topoisomerase VI subunit with homology to the meiotic recombination factor Spo11. Nichols MD, DeAngelis K, Keck JL, Berger JM; EMBO J 1999;18:6177-6188. PMID:10545127