DNA topoisomerases are a class of enzymes required for the regulation of DNA folding and supercoiling to maintain chromosome integrity and cellular function. They are essential for relaxing entangled DNA and modulating DNA topology by transiently breaking and rejoining DNA single or double strands. Topoisomerases play a key role during DNA replication, transcription, and chromosome segregation. They are also involved in resolving specific DNA structures and intermediates arising from other cellular processes such as DNA repair and recombination.
To fit into the tiny nucleus, cellular DNA, which has a combined length of several meters, is compacted and bound by proteins to form chromatin, which is twisted and folded into a space of only a few microns. However, excess folding of DNA poses a unique challenge to living organisms and generates topological problems when the DNA helix must be unwound to make its genetic information accessible. This highly...