PMID:10454599
| Citation |
McGlynn, P and Lloyd, RG (1999) RecG helicase activity at three- and four-strand DNA structures. Nucleic Acids Res. 27:3049-56 |
|---|---|
| Abstract |
The RecG helicase of Escherichia coli is necessary for efficient recombination and repair of DNA in vivo and has been shown to catalyse the unwinding of DNA junctions in vitro. Despite these findings, the precise role of RecG remains elusive. However, models have been proposed in which RecG promotes the resolution of linked duplexes by targeting three-strand junctions present at D-loops. One such model postulates that RecG catalyses the formation of four-strand (Holliday) junctions from three-strand junctions. To test this model, the DNA binding and unwinding activities of RecG were analysed using synthetic three- and four-strand junctions. The substrate specificity of RecG was found to depend critically on the concentrations of ATP and MgCl(2)and under certain conditions RecG preferentially unwound three-strand junction DNA. This was at least partly due to the larger inhibitory effect of MgCl(2)on the binding of four-strand as opposed to three-strand junctions by RecG. Thus RecG may be targeted to three-strand junctions in vivo whilst still being able to branch migrate the four-strand junctions formed as a result of the initial helicase reaction. The increase in the dissociation constant of RecG on conversion of a three-strand into a four-strand junction may also facilitate resolution of the four-strand junction by the RuvABC complex. |
| Links | |
| Keywords |
Adenosine Triphosphate/pharmacology; Bacterial Proteins/metabolism; DNA/chemistry; DNA/genetics; DNA/metabolism; DNA Helicases/metabolism; DNA-Binding Proteins/metabolism; Dose-Response Relationship, Drug; Escherichia coli/enzymology; Escherichia coli/genetics; Escherichia coli Proteins; G-Quadruplexes; Kinetics; Magnesium Chloride/pharmacology; Models, Genetic; Recombination, Genetic/genetics; Substrate Specificity/drug effects |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.