Fork sensing and strand switching control antagonistic activities of RecQ helicases
| Autor: | Daniel Klaue, Felix E. Kemmerich, Ralf Seidel, Alicja Kozikowska, Daniela Kobbe, Holger Puchta |
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| Rok vydání: | 2012 |
| Předmět: |
DNA Replication
Magnetic tweezers DNA Plant Arabidopsis General Physics and Astronomy DNA Single-Stranded Models Biological General Biochemistry Genetics and Molecular Biology Article 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Arabidopsis thaliana 030304 developmental biology Genetics 0303 health sciences Multidisciplinary biology RecQ Helicases Arabidopsis Proteins DNA replication Helicase General Chemistry biology.organism_classification Cell biology enzymes and coenzymes (carbohydrates) chemistry biology.protein Nucleic Acid Conformation Homologous recombination 030217 neurology & neurosurgery DNA |
| Zdroj: | Nature Communications |
| ISSN: | 2041-1723 |
| Popis: | RecQ helicases have essential roles in maintaining genome stability during replication and in controlling double-strand break repair by homologous recombination. Little is known about how the different RecQ helicases found in higher eukaryotes achieve their specialized and partially opposing functions. Here, we investigate the DNA unwinding of RecQ helicases from Arabidopsis thaliana, AtRECQ2 and AtRECQ3 at the single-molecule level using magnetic tweezers. Although AtRECQ2 predominantly unwinds forked DNA substrates in a highly repetitive fashion, AtRECQ3 prefers to rewind, that is, to close preopened DNA forks. For both enzymes, this process is controlled by frequent strand switches and active sensing of the unwinding fork. The relative extent of the strand switches towards unwinding or towards rewinding determines the predominant direction of the enzyme. Our results provide a simple explanation for how different biological activities can be achieved by rather similar members of the RecQ family. RecQ helicases are enzymes that play a central role in maintaining genome stability in the DNA repair cascade. Klaue et al. show that RecQ2 and RecQ3 from Arabidopsis thaliana process DNA by, respectively, unwinding and rewinding forked DNA substrates, using a frequent strand switching mechanism. |
| Databáze: | OpenAIRE |
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