DNA topoisomerases have evolved as an effective drug target in prokaryotic and eukaryotic systems as these enzyme mediate mechanistic interactions such as supercoiling, relaxation, knotting or catenating of DNA double helices. Based on their mechanism of action, topoisomerases can be classified as type I enzymes, which break a single strand of the DNA helix during the catalytic cycle, and type II enzymes, which make double-stranded breaks. On the basis of primary sequence and reaction mechanism, type I topoisomerases are further subdivided into type IA and type IB.