Adenosine 5'-O-(3-thio)triphosphate (ATPgammaS) promotes positive supercoiling of DNA by T. maritima reverse gyrase

Jungblut, S. P. and Klostermeier, D.. (2007) Adenosine 5'-O-(3-thio)triphosphate (ATPgammaS) promotes positive supercoiling of DNA by T. maritima reverse gyrase. Journal of molecular biology, Vol. 371, H. 1. pp. 197-209.

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Official URL: http://edoc.unibas.ch/dok/A5259708

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Reverse gyrases are topoisomerases that catalyze ATP-dependent positive supercoiling of circular covalently closed DNA. They consist of an N-terminal helicase-like domain, fused to a C-terminal topoisomerase I-like domain. Most of our knowledge on reverse gyrase-mediated positive DNA supercoiling is based on studies of archaeal enzymes. To identify general and individual properties of reverse gyrases, we set out to characterize the reverse gyrase from a hyperthermophilic eubacterium. Thermotoga maritima reverse gyrase relaxes negatively supercoiled DNA in the presence of ADP or the non-hydrolyzable ATP-analog ADPNP. Nucleotide binding is necessary, but not sufficient for the relaxation reaction. In the presence of ATP, positive supercoils are introduced at temperatures above 50 degrees C. However, ATP hydrolysis is stimulated by DNA already at 37 degrees C, suggesting that reverse gyrase is not frozen at this temperature, but capable of undergoing inter-domain communication. Positive supercoiling by reverse gyrase is strictly coupled to ATP hydrolysis. At the physiological temperature of 75 degrees C, reverse gyrase binds and hydrolyzes ATPgammaS. Surprisingly, ATPgammaS hydrolysis is stimulated by DNA, and efficiently promotes positive DNA supercoiling, demonstrating that inter-domain communication during positive supercoiling is fully functional with both ATP and ATPgammaS. These findings support a model for communication between helicase-like and topoisomerase domains in reverse gyrase, in which an ATP and DNA-induced closure of the cleft in the helicase-like domain initiates a cycle of conformational changes that leads to positive DNA supercoiling.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Biophysical Chemistry (Klostermeier)
UniBasel Contributors:Klostermeier, Dagmar
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
Last Modified:22 Mar 2012 14:21
Deposited On:22 Mar 2012 13:23

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