Operationally, topoisomerase IV is a type II topoisomerase required for the decatenation of chromosome segregation. Not every bacterium has both a topo II and a topo IV. The topo IV families of the Gram-positive bacteria and the Gram-negative bacteria appear not to represent a single clade among the type II topoisomerases, and are represented by separate models for this reason. This protein is active as an alpha(2)beta(2) heterotetramer. [DNA metabolism, DNA replication, recombination, and repair]
Jiyao W et al.(2023). "The conserved domain database in 2023.",