Class of enzymes that control the number and topology of supercoils in DNA. Type I enzymes cut one DNA strand, rotate it about the other, and reseal the ends. Type II enzymes cut and reseal both DNA strands.
Enzyme that makes reversible cuts in a double helical DNA molecule for the purpose of removing knots or unwinding excessive twists.
An enzyme that can mediate transitions in the structures of DNA and chromatin by its ability to break and rejoin single or double strands of DNA.