3qvg

XRCC1 bound to DNA ligase

spinqualitylabelsall models 3qvg, resolution 2.26Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3qvg is a 4 chain structure with sequence from Human and Lk3 transgenic mice. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 3pc7, 3pc6, 3pc8 Gene: LIG3 (HUMAN), Xrcc-1, Xrcc1 (LK3 transgenic mice) Activity: DNA ligase (ATP), with EC number 6.5.1.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [DNLI3_HUMAN] Interacts with DNA-repair protein XRCC1 and can correct defective DNA strand-break repair and sister chromatid exchange following treatment with ionizing radiation and alkylating agents. [XRCC1_MOUSE] Corrects defective DNA strand-break repair and sister chromatid exchange following treatment with ionizing radiation and alkylating agents. Publication Abstract from PubMed 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-alpha. For efficient ligation, ligase III-alpha 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-alpha 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. The structural basis for partitioning of the XRCC1/DNA ligase III-alpha BRCT-mediated dimer complexes.,Cuneo MJ, Gabel SA, Krahn JM, Ricker MA, London RE Nucleic Acids Res. 2011 Sep 1;39(17):7816-27. Epub 2011 Jun 7. PMID:21652643 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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