"Introduction of positive supercoils requires the cooperation of both domains. The helicase-like domain probably does not directly unwind DNA, but more likely acts by driving ATP-dependent conformational changes within the whole enzyme. A beta hairpin in the 'latch' region of the N-terminal domain plays a regulatory role in the enzyme, repressing topoisomerase activity in the absence of ATP and preventing the enzyme from acting as an ATP-independent relaxing enzyme; it also helps to coordinate nucleotide hydrolysis by the ATPase domain with the supercoiling activity of the topoisomerase domain."xsd:string