Class I topoisomerasePDB ID: 1A36
Class I topoisomerases bind to DNA and release tension caused by winding or unwinding of the double helix. This structure includes the enzyme and a short piece of DNA captured before the cleavage reaction that relaxes the DNA.
A model for the mechanism of human topoisomerase I.
Stewart, L., Redinbo, M.R., Qiu, X., Hol, W.G., Champoux, J.J.
Journal: (1998) Science 279: 1534-1541