Two distinct conformational states define the interaction of human RAD51-ATP with single-stranded DNA.

Authors
Brouwer, Ineke 
Moschetti, Tommaso 
Candelli, Andrea 
Garcin, Edwige B 
Modesti, Mauro 

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Type
Article
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Abstract

An essential mechanism for repairing DNA double-strand breaks is homologous recombination (HR). One of its core catalysts is human RAD51 (hRAD51), which assembles as a helical nucleoprotein filament on single-stranded DNA, promoting DNA-strand exchange. Here, we study the interaction of hRAD51 with single-stranded DNA using a single-molecule approach. We show that ATP-bound hRAD51 filaments can exist in two different states with different contour lengths and with a free-energy difference of ~4 kBT per hRAD51 monomer. Upon ATP hydrolysis, the filaments convert into a disassembly-competent ADP-bound configuration. In agreement with the single-molecule analysis, we demonstrate the presence of two distinct protomer interfaces in the crystal structure of a hRAD51-ATP filament, providing a structural basis for the two conformational states of the filament. Together, our findings provide evidence that hRAD51-ATP filaments can exist in two interconvertible conformational states, which might be functionally relevant for DNA homology recognition and strand exchange.

Publication Date
2018-04-03
Online Publication Date
2018-03-05
Acceptance Date
2018-02-08
Keywords
DNA repair, RAD51, homologous recombination, single‐stranded DNA, Adenosine Triphosphate, Crystallography, X-Ray, DNA, DNA Breaks, Double-Stranded, DNA Repair, DNA Replication, DNA, Single-Stranded, DNA-Binding Proteins, Homologous Recombination, Models, Molecular, Molecular Conformation, Nucleoproteins, Rad51 Recombinase
Journal Title
EMBO J
Journal ISSN
0261-4189
1460-2075
Volume Title
37
Publisher
EMBO
Sponsorship
Wellcome Trust (104641/Z/14/Z)