Nucleic Acids Research Advance Access originally published online on April 21, 2009
Nucleic Acids Research 2009 37(10):3125-3133; doi:10.1093/nar/gkp250
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Nucleic Acids Research, 2009, Vol. 37, No. 10 3125-3133
© 2009 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Theoretical models of DNA topology simplification by type IIA DNA topoisomerases
Department of Chemistry, New York University, New York, NY 10003, USA
*To whom correspondence should be addressed. Tel: 212 998 3599; Fax: 212 260 7905; Email: alex.vologodskii{at}nyu.edu
Received September 30, 2008. Revised March 31, 2009. Accepted April 1, 2009.
It was discovered 12 years ago that type IIA topoisomerases can simplify DNA topology—the steady-state fractions of knots and links created by the enzymes are many times lower than the corresponding equilibrium fractions. Though this property of the enzymes made clear biological sense, it was not clear how small enzymes could selectively change the topology of very large DNA molecules, since topology is a global property and cannot be determined by a local DNA–protein interaction. A few models, suggested to explain the phenomenon, are analyzed in this review. We also consider experimental data that both support and contravene these models.