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

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 repor...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2016-04, Vol.113 (16), p.4308-4313
Main Authors: Sugiman-Marangos, Seiji N., Weiss, Yoni M., Junop, Murray S.
Format: Article
Language:English
Subjects:
Accuracy
Annealing
Bacteria
Bacterial Proteins - metabolism
Biological Sciences
Cells
Deinococcus - genetics
Deinococcus - metabolism
Deinococcus radiodurans
Deoxyribonucleic acid
DNA
DNA Breaks, Double-Stranded
DNA Repair - physiology
DNA, Bacterial - genetics
DNA, Bacterial - metabolism
DNA-Binding Proteins - genetics
DNA-Binding Proteins - metabolism
Proteins
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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 knowledge, this mechanism provides the first understanding for how cells achieve accurate, protein-assisted strand annealing under biological conditions that would otherwise favor misannealing.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1520847113