3Q8D

E. coli RecO complex with SSB C-terminus

Summary for 3Q8D

• Entry DOI: 10.2210/pdb3q8d/pdb
• Descriptor: DNA repair protein recO, Single-stranded DNA-binding protein, D-MALATE, ... (6 entities in total)
• Functional Keywords: dna-binding protein, ob-fold, recombination initation, recombination initiation, ssb, dna, recr, dna binding protein
• Biological source: Escherichia coli; More
• Total number of polymer chains: 4
• Total formula weight: 58259.09

Authors

Koroleva, O.,Ryzhikov, M.,Korolev, S. (deposition date: 2011-01-06, release date: 2011-05-04, Last modification date: 2024-02-21)

Primary citation

Ryzhikov, M.,Koroleva, O.,Postnov, D.,Tran, A.,Korolev, S.
Mechanism of RecO recruitment to DNA by single-stranded DNA binding protein.
Nucleic Acids Res., 39:6305-6314, 2011

PubMed Abstract: RecO is a recombination mediator protein (RMP) important for homologous recombination, replication repair and DNA annealing in bacteria. In all pathways, the single-stranded (ss) DNA binding protein, SSB, plays an inhibitory role by protecting ssDNA from annealing and recombinase binding. Conversely, SSB may stimulate each reaction through direct interaction with RecO. We present a crystal structure of Escherichia coli RecO bound to the conserved SSB C-terminus (SSB-Ct). SSB-Ct binds the hydrophobic pocket of RecO in a conformation similar to that observed in the ExoI/SSB-Ct complex. Hydrophobic interactions facilitate binding of SSB-Ct to RecO and RecO/RecR complex in both low and moderate ionic strength solutions. In contrast, RecO interaction with DNA is inhibited by an elevated salt concentration. The SSB mutant lacking SSB-Ct also inhibits RecO-mediated DNA annealing activity in a salt-dependent manner. Neither RecO nor RecOR dissociates SSB from ssDNA. Therefore, in E. coli, SSB recruits RMPs to ssDNA through SSB-Ct, and RMPs are likely to alter the conformation of SSB-bound ssDNA without SSB dissociation to initiate annealing or recombination. Intriguingly, Deinococcus radiodurans RecO does not bind SSB-Ct and weakly interacts with the peptide in the presence of RecR, suggesting the diverse mechanisms of DNA repair pathways mediated by RecO in different organisms.

PubMed: 21504984
DOI: 10.1093/nar/gkr199

Experimental method

X-RAY DIFFRACTION (2.3 Å)