Type II DNA topoisomerases mediate the passage of one DNA duplex through a transient break in another, an event essential for chromosome segregation and cell viability. The active sites of the type II topoisomerase dimer associate covalently with the DNA break-points and must separate by at least the width of the second DNA duplex to accommodate transport ...
Type II DNA topoisomerases mediate the passage of one DNA duplex through a transient break in another, an event essential for chromosome segregation and cell viability. The active sites of the type II topoisomerase dimer associate covalently with the DNA break-points and must separate by at least the width of the second DNA duplex to accommodate transport. A new structure of the Saccharomyces cerevisiae topoisomerase II DNA-binding and cleavage core suggests that in addition to conformational changes in the DNA-opening platform, a dramatic reorganization of accessory domains may occur during catalysis. These conformational differences have implications for both the DNA-breaking and duplex-transport events in the topo II reaction mechanism, suggest a mechanism by which two distinct drug-resistance loci interact, and illustrate the scope of structural changes in the cycling of molecular machines.
Related Citations:
Structure and Mechanism of DNA Topoisomerase II Berger, J.M., Gamblin, S.J., Harrison, S.C., Wang, J.C. (1996) Nature 379: 225
Erratum. Structure and Mechanism of DNA Topoisomerase II Berger, J.M., Gamblin, S.J., Harrison, S.C., Wang, J.C. (1996) Nature 380: 179
Organizational Affiliation:
Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02140, USA.
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