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PDBsum entry 3pc8

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protein ligands metals Protein-protein interface(s) links
DNA binding protein/ligase PDB id
3pc8
Jmol
Contents
Protein chains
97 a.a.
77 a.a.
Ligands
TRS
Metals
_MG
Waters ×208
PDB id:
3pc8
Name: DNA binding protein/ligase
Title: X-ray crystal structure of the heterodimeric complex of xrcc ligase iii-alpha brct domains.
Structure: DNA repair protein xrcc1. Chain: a, b. Fragment: unp residues 534-631. Synonym: x-ray repair cross-complementing protein 1. Engineered: yes. DNA ligase 3. Chain: c, d. Fragment: unp residues 924-1008. Synonym: DNA ligase iii, polydeoxyribonucleotide synthase [
Source: Mus musculus. Mouse. Organism_taxid: 10090. Gene: xrcc-1, xrcc1. Expressed in: escherichia coli. Expression_system_taxid: 469008. Homo sapiens. Human. Organism_taxid: 9606.
Resolution:
2.31Å     R-factor:   0.200     R-free:   0.246
Authors: M.J.Cuneo,J.M.Krahn,R.E.London
Key ref: M.J.Cuneo et al. (2011). The structural basis for partitioning of the XRCC1/DNA ligase III-α BRCT-mediated dimer complexes. Nucleic Acids Res, 39, 7816-7827. PubMed id: 21652643 DOI: 10.1093/nar/gkr419
Date:
21-Oct-10     Release date:   15-Jun-11    
PROCHECK
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 Headers
 References

Protein chains
Pfam   ArchSchema ?
Q60596  (XRCC1_MOUSE) -  DNA repair protein XRCC1
Seq:
Struc:
 
Seq:
Struc:
631 a.a.
97 a.a.*
Protein chains
Pfam   ArchSchema ?
P49916  (DNLI3_HUMAN) -  DNA ligase 3
Seq:
Struc:
 
Seq:
Struc:
1009 a.a.
77 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 3 residue positions (black crosses)

 

 
DOI no: 10.1093/nar/gkr419 Nucleic Acids Res 39:7816-7827 (2011)
PubMed id: 21652643  
 
 
The structural basis for partitioning of the XRCC1/DNA ligase III-α BRCT-mediated dimer complexes.
M.J.Cuneo, S.A.Gabel, J.M.Krahn, M.A.Ricker, R.E.London.
 
  ABSTRACT  
 
The ultimate step common to almost all DNA repair pathways is the ligation of the nicked intermediate to form contiguous double-stranded DNA. In the mammalian nucleotide and base excision repair pathways, the ligation step is carried out by ligase III-α. For efficient ligation, ligase III-α is constitutively bound to the scaffolding protein XRCC1 through interactions between the C-terminal BRCT domains of each protein. Although structural data for the individual domains has been available, no structure of the complex has been determined and several alternative proposals for this interaction have been advanced. Interpretation of the models is complicated by the formation of homodimers that, depending on the model, may either contribute to, or compete with heterodimer formation. We report here the structures of both homodimer complexes as well as the heterodimer complex. Structural characterization of the heterodimer formed from a longer XRCC1 BRCT domain construct, including residues comprising the interdomain linker region, revealed an expanded heterodimer interface with the ligase III-α BRCT domain. This enhanced linker-mediated binding interface plays a significant role in the determination of heterodimer/homodimer selectivity. These data provide fundamental insights into the structural basis of BRCT-mediated dimerization, and resolve questions related to the organization of this important repair complex.