Biochemical characterization of Srs2 helicase
| Authors | |
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| Year of publication | 2008 |
| Type | R&D Presentation |
| MU Faculty or unit | |
| Citation | |
| Description | DNA double-strand breaks (DSBs) are induced by a large number of endogenous and exogenous agents, as genotoxic chemicals and ionizing radiation, or due to replication of damaged DNA or collapse of a replication fork. Cell death, chromosome aberrations and tumorigenesis may occur if these breaks are left unrepaired. Homologous recombination is an important mechanism for the elimination of DSBs. Several models of this process have been proposed but the molecular details still remain poorly understood. One of the proteins taking part in this pathway in yeast Saccharomyces cerevisiae is the helicase Srs2, which on one hand prevents undesirable homologous recombination, and on the other is necessary for an efficient DSB repair by homologous recombination. In order to understand the mechanism of the biological activity of Srs2, we analyzed its binding affinity and helicase activity on different DNA substrates, which represent in a simpler way different structures that occur during DNA repair. We next studied how other DNA repair proteins could modulate the activity of Srs2. Results show that even though Srs2 has a preference for single-strand DNA, differences in helicase activities are not striking. However, this activity seems to be affected by the presence of other proteins as RPA, a single-strand DNA binding protein. |
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