PDBsum entry 2v1c

Recombination

PDB id: 2v1c

Contents

Protein chains

199 a.a. *

229 a.a. *

Metals

_ZN ×3

* Residue conservation analysis

PDB id:

2v1c

Name:

Recombination

Title:

Crystal structure and mutational study of recor provide insight into its role in DNA repair

Structure:

Recombination protein recr. Chain: a, b. Synonym: recr. Engineered: yes. Hypothetical protein. Chain: c. Synonym: reco. Engineered: yes

Source:

Deinococcus radiodurans. Organism_taxid: 243230. Strain: r1. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

3.80Å R-factor: 0.458 R-free: 0.443

Authors:

J.Timmins,I.Leiros,S.Mcsweeney

Key ref:

J.Timmins et al. (2007). Crystal structure and mutational study of RecOR provide insight into its mode of DNA binding. EMBO J, 26, 3260-3271. PubMed id: 17581636 DOI: 10.1038/sj.emboj.7601760

Date:

23-May-07 Release date: 03-Jul-07

Protein chains

Q9ZNA2  (RECR_DEIRA) -  Recombination protein RecR from Deinococcus radiodurans (strain ATCC 13939 / DSM 20539 / JCM 16871 / CCUG 27074 / LMG 4051 / NBRC 15346 / NCIMB 9279 / VKM B-1422 / R1)

Seq: 220 a.a.

Struc: 199 a.a.

Protein chain

Q9RW50  (Q9RW50_DEIRA) -  DNA repair protein RecO from Deinococcus radiodurans (strain ATCC 13939 / DSM 20539 / JCM 16871 / CCUG 27074 / LMG 4051 / NBRC 15346 / NCIMB 9279 / VKM B-1422 / R1)

Seq: 244 a.a.

Struc: 229 a.a.

DOI no: 10.1038/sj.emboj.7601760

EMBO J 26:3260-3271 (2007)

PubMed id: 17581636

Crystal structure and mutational study of RecOR provide insight into its mode of DNA binding.

J.Timmins, I.Leiros, S.McSweeney.

ABSTRACT

The crystal structure of the complex formed between Deinococcus radiodurans RecR and RecO (drRecOR) has been determined. In accordance with previous biochemical characterisation, the drRecOR complex displays a RecR:RecO molecular ratio of 2:1. The biologically relevant drRecOR entity consists of a heterohexamer in the form of two drRecO molecules positioned on either side of the tetrameric ring of drRecR, with their OB (oligonucleotide/oligosaccharide-binding) domains pointing towards the interior of the ring. Mutagenesis studies validated the protein-protein interactions observed in the crystal structure and allowed mapping of the residues in the drRecOR complex required for DNA binding. Furthermore, the preferred DNA substrate of drRecOR was identified as being 3'-overhanging DNA, as encountered at ssDNA-dsDNA junctions. Together these results suggest a possible mechanism for drRecOR recognition of stalled replication forks.

Selected figure(s)

Figure 3.
Figure 3 Study of the ionic interactions between drRecO and drRecR. (A) Ribbon illustration of a monomer and a tetramer of drRecR with ball-and-sticks representation of the mutated residues. (B) Ribbon illustration of drRecO with ball-and-sticks representation of the mutated residues. Residues coloured in blue were mutated in order to disrupt protein–protein interactions, whereas residues in red were predicted to be involved in protein–DNA contacts. (C) Overlay of the chromatograms obtained when purifying wild-type drRecOR (C1) and mutant drRecOR (C2) on a Superdex 200 size-exclusion column. The three peaks are labelled from 1 to 3. (D) Western blot analysis of fractions corresponding to peaks 1, 2 and 3 from the gel filtration runs of each of the drRecOR complexes (C1–C7 and C10–C16). The Western blots were duplicated and were stained for either drRecO (upper bands) or drRecR (lower bands). (E) Illustration of the drRecR (gold)—drRecO (blue) interface with a ball-and-sticks representation of drRecO-His93 and drRecR-Glu146, displaying the 2mFo-DFc sigmaA-weighted electron density map contoured at 1.3 .

Figure 6.
Figure 6 Model for RecOR recognition of stalled replication forks. Whereas the role of RecF in this process is still unclear, it is known to associate with DNA in an ATP-dependent fashion. Upon binding of RecOR to ssDNA–dsDNA junctions (step 2), we propose that interactions with RecF, SSB and/or DNA may cause a structural rearrangement of RecOR (e.g. one RecO and two RecR molecules may dissociate from the RecOR complex). RecF-dependent ATP hydrolysis may provide the necessary energy for this reorganisation (step 3) resulting in the formation of a stable complex between RecOR and the stalled replication fork (step 4). As a consequence, the assembled RecOR complex may initiate the displacement of SSB and thus facilitate the loading of RecA onto ssDNA, allowing for homologous recombination to take place (step 5).

The above figures are reprinted by permission from Macmillan Publishers Ltd: EMBO J (2007, 26, 3260-3271) copyright 2007.

Figures were selected by an automated process.