Quaternary changes in topoisomerase II may direct orthogonal movement of two DNA strands.

摘要: Type II DNA topoisomerases mediate the passage of one duplex through a transient break in another, an event essential for chromosome segregation and cell viability. The active sites type topoisomerase dimer associate covalently with break-points must separate by at least width second to accommodate transport. A new structure Saccharomyces cerevisiae DNA-binding cleavage core suggests that addition conformational changes DNA-opening platform, dramatic reorganization accessory domains may occur during catalysis. These differences have implications both DNA-breaking duplex-transport events topo reaction mechanism, suggest mechanism which two distinct drug-resistance loci interact, illustrate scope structural cycling molecular machines.