Linked Life Data

17560602

Source:http://linkedlifedata.com/resource/pubmed/id/17560602

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2007-7-13
pubmed:abstractText
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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
371
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
197-209
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Adenosine 5'-O-(3-thio)triphosphate (ATPgammaS) promotes positive supercoiling of DNA by T. maritima reverse gyrase.
pubmed:affiliation
University of Basel, Biozentrum, Dept. of Biophysical Chemistry, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't