1ik9

CRYSTAL STRUCTURE OF A XRCC4-DNA LIGASE IV COMPLEXCRYSTAL STRUCTURE OF A XRCC4-DNA LIGASE IV COMPLEX

Structural highlights 1ik9 is a 3 chain structure with sequence from Human. The July 2004 RCSB PDB Molecule of the Month feature on DNA Ligase by David S. Goodsell is 10.2210/rcsb_pdb/mom_2004_7. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: XRCC4 (HUMAN), LIG4 (HUMAN) Activity: DNA ligase (ATP), with EC number 6.5.1.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease [DNLI4_HUMAN] Defects in LIG4 are the cause of LIG4 syndrome (LIG4S) [MIM:606593]. This disease is characterized by immunodeficiency and developmental and growth delay. Patients display unusual facial features, microcephaly, growth and/or developmental delay, pancytopenia, and various skin abnormalities. Defects in LIG4 are a cause of severe combined immunodeficiency autosomal recessive T-cell-negative/B-cell-negative/NK-cell-positive with sensitivity to ionizing radiation (RSSCID) [MIM:602450]. SCID refers to a genetically and clinically heterogeneous group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. Patients with SCID present in infancy with recurrent, persistent infections by opportunistic organisms. The common characteristic of all types of SCID is absence of T-cell-mediated cellular immunity due to a defect in T-cell development. Individuals affected by RS-SCID show defects in the DNA repair machinery necessary for coding joint formation and the completion of V(D)J recombination. A subset of cells from such patients show increased radiosensitivity. Function [XRCC4_HUMAN] Involved in DNA non-homologous end joining (NHEJ) required for double-strand break repair and V(D)J recombination. Binds to DNA and to DNA ligase IV (LIG4). The LIG4-XRCC4 complex is responsible for the NHEJ ligation step, and XRCC4 enhances the joining activity of LIG4. Binding of the LIG4-XRCC4 complex to DNA ends is dependent on the assembly of the DNA-dependent protein kinase complex DNA-PK to these DNA ends. [DNLI4_HUMAN] Efficiently joins single-strand breaks in a double-stranded polydeoxynucleotide in an ATP-dependent reaction. Involved in DNA non-homologous end joining (NHEJ) required for double-strand break repair and V(D)J recombination. The LIG4-XRCC4 complex is responsible for the NHEJ ligation step, and XRCC4 enhances the joining activity of LIG4. Binding of the LIG4-XRCC4 complex to DNA ends is dependent on the assembly of the DNA-dependent protein kinase complex DNA-PK to these DNA ends. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed A complex of two proteins, Xrcc4 and DNA ligase IV, plays a fundamental role in DNA non-homologous end joining (NHEJ), a cellular function required for double-strand break repair and V(D)J recombination. Here we report the crystal structure of human Xrcc4 bound to a polypeptide that corresponds to the DNA ligase IV sequence linking its two BRCA1 C-terminal (BRCT) domains. In the complex, a single ligase chain binds asymmetrically to an Xrcc4 dimer. The helical tails of Xrcc4 undergo a substantial conformational change relative to the uncomplexed protein, forming a coiled coil that unwinds upon ligase binding, leading to a flat interaction surface. A buried network of charged hydrogen bonds surrounded by extensive hydrophobic contacts explains the observed tightness of the interaction. The strong conservation of residues at the interface between the two proteins provides evidence that the observed mode of interaction has been maintained in NHEJ throughout evolution. Crystal structure of an Xrcc4-DNA ligase IV complex.,Sibanda BL, Critchlow SE, Begun J, Pei XY, Jackson SP, Blundell TL, Pellegrini L Nat Struct Biol. 2001 Dec;8(12):1015-9. PMID:11702069 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also DNA ligase 3D structures

spinqualitylabelsall models 1ik9, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image