Rep and UvrD Antagonize One Another at Stalled Replication Forks and This Is Exacerbated by SSB.

ABSTRACT: 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 na

SUBMITTER: Liu X 

PROVIDER: S-EPMC6441946 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature