Mechanism of homologous recombination from the RecA-ssDNA/dsDNA structures

Journal Article · Tue Jul 08 04:00:00 EDT 2008 · Nature

DOI:https://doi.org/10.1038/nature06971· OSTI ID:1006649

Chen, Zhucheng; Yang, Haijuan; Pavletich, Nikola P ^[1]

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1. HHMI

The RecA family of ATPases mediates homologous recombination, a reaction essential for maintaining genomic integrity and for generating genetic diversity. RecA, ATP and single-stranded DNA (ssDNA) form a helical filament that binds to double-stranded DNA (dsDNA), searches for homology, and then catalyses the exchange of the complementary strand, producing a new heteroduplex. Here we have solved the crystal structures of the Escherichia coli RecA-ssDNA and RecA-heteroduplex filaments. They show that ssDNA and ATP bind to RecA-RecA interfaces cooperatively, explaining the ATP dependency of DNA binding. The ATP {gamma}-phosphate is sensed across the RecA-RecA interface by two lysine residues that also stimulate ATP hydrolysis, providing a mechanism for DNA release. The DNA is underwound and stretched globally, but locally it adopts a B-DNA-like conformation that restricts the homology search to Watson-Crick-type base pairing. The complementary strand interacts primarily through base pairing, making heteroduplex formation strictly dependent on complementarity. The underwound, stretched filament conformation probably evolved to destabilize the donor duplex, freeing the complementary strand for homology sampling.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1006649
• Journal Information: Nature, Journal Name: Nature Journal Issue: 05, 2008 Vol. 453
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

60 APPLIED LIFE SCIENCES
ATP
ATP-ASE
CRYSTAL STRUCTURE
DNA
ESCHERICHIA COLI
FILAMENTS
GENETICS
HYDROLYSIS
INTERFACES
LYSINE
RECOMBINATION
RESIDUES
SAMPLING