Rep and UvrD Antagonize One Another at Stalled Replication Forks and This Is Exacerbated by SSB
| Autor: | Yi Shi, Xiaoyi Liu, Jiun Xiang Seet, Piero R. Bianco |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
0303 health sciences biology General Chemical Engineering ATPase 030302 biochemistry & molecular biology DNA replication Helicase General Chemistry Article Cell biology lcsh:Chemistry 03 medical and health sciences chemistry.chemical_compound Enzyme lcsh:QD1-999 chemistry RNA polymerase biology.protein Holliday junction DNA 030304 developmental biology |
| Zdroj: | ACS Omega ACS Omega, Vol 4, Iss 3, Pp 5180-5196 (2019) |
| ISSN: | 2470-1343 |
| Popis: | The Rep and UvrD DNA helicases are proposed to act at stalled DNA replication forks to facilitate replication restart when RNA polymerase stalls forks. To clarify the role of these DNA helicases in fork rescue, we used a coupled spectrophotometric ATPase assay to determine how they act on model fork substrates. For both enzymes, activity is low on regressed fork structures, suggesting that they act prior to the regression step that generates a Holliday junction. In fact, the preferred cofactors for both enzymes are forks with a gap in the nascent leading strand, consistent with the 3′–5′ direction of translocation. Surprisingly, for Rep, this specificity is altered in the presence of stoichiometric amounts of a single-strand DNA-binding protein (SSB) relative to a fork with a gap in the nascent lagging strand. Even though Rep and UvrD are similar in structure, elevated concentrations of SSB inhibit Rep, but they have little to no effect on UvrD. Furthermore, Rep and UvrD antagonize one another at a fork. This is surprising given that these helicases have been shown to form a heterodimer and are proposed to act together to rescue an RNA polymerase-stalled fork. Consequently, the results herein indicate that although Rep and UvrD can act on similar fork substrates, they cannot function on the same fork simultaneously. |
| Databáze: | OpenAIRE |
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