Mechanism for accurate, protein-assisted DNA annealing by Deinococcus radiodurans DdrB.

ABSTRACT: Accurate pairing of DNA strands is essential for repair of DNA double-strand breaks (DSBs). How cells achieve accurate annealing when large regions of single-strand DNA are unpaired has remained unclear despite many efforts focused on understanding proteins, which mediate this process. Here we report the crystal structure of a single-strand annealing protein [DdrB (DNA damage response B)] in complex with a partially annealed DNA intermediate to 2.2 Å. This structure and supporting biochemical data reveal a mechanism for accurate annealing involving DdrB-mediated proofreading of strand complementarity. DdrB promotes high-fidelity annealing by constraining specific bases from unauthorized association and only releases annealed duplex when bound strands are fully complementary. To our knowled

SUBMITTER: Sugiman-Marangos SN 

PROVIDER: S-EPMC4843489 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature