Structural highlights
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.[1] [2] [3] [4]
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
XRCC4 is essential for carrying out non-homologous DNA end joining (NHEJ) in all eukaryotes and, in particular, V(D)J recombination in vertebrates. Xrcc4 protein forms a complex with DNA ligase IV that rejoins two DNA ends in the last step of V(D)J recombination and NHEJ to repair double strand breaks. XRCC4-defective cells are extremely sensitive to ionizing radiation, and disruption of the XRCC4 gene results in embryonic lethality in mice. Here we report the crystal structure of a functional fragment of Xrcc4 at 2.7 A resolution. Xrcc4 protein forms a strikingly elongated dumb-bell-like tetramer. Each of the N-terminal globular head domains consists of a beta-sandwich and a potentially DNA-binding helix- turn-helix motif. The C-terminal stalk comprising a single alpha-helix >120 A in length is partly incorporated into a four-helix bundle in the Xrcc4 tetramer and partly involved in interacting with ligase IV. The Xrcc4 structure suggests a possible mode of coupling ligase IV association with DNA binding for effective ligation of DNA ends.
Crystal structure of the Xrcc4 DNA repair protein and implications for end joining.,Junop MS, Modesti M, Guarne A, Ghirlando R, Gellert M, Yang W EMBO J. 2000 Nov 15;19(22):5962-70. PMID:11080143[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Li Z, Otevrel T, Gao Y, Cheng HL, Seed B, Stamato TD, Taccioli GE, Alt FW. The XRCC4 gene encodes a novel protein involved in DNA double-strand break repair and V(D)J recombination. Cell. 1995 Dec 29;83(7):1079-89. PMID:8548796
- ↑ Chen L, Trujillo K, Sung P, Tomkinson AE. Interactions of the DNA ligase IV-XRCC4 complex with DNA ends and the DNA-dependent protein kinase. J Biol Chem. 2000 Aug 25;275(34):26196-205. PMID:10854421 doi:10.1074/jbc.M000491200
- ↑ Nick McElhinny SA, Snowden CM, McCarville J, Ramsden DA. Ku recruits the XRCC4-ligase IV complex to DNA ends. Mol Cell Biol. 2000 May;20(9):2996-3003. PMID:10757784
- ↑ Foster RE, Nnakwe C, Woo L, Frank KM. Monoubiquitination of the nonhomologous end joining protein XRCC4. Biochem Biophys Res Commun. 2006 Mar 3;341(1):175-83. Epub 2006 Jan 6. PMID:16412978 doi:S0006-291X(05)02903-7
- ↑ Junop MS, Modesti M, Guarne A, Ghirlando R, Gellert M, Yang W. Crystal structure of the Xrcc4 DNA repair protein and implications for end joining. EMBO J. 2000 Nov 15;19(22):5962-70. PMID:11080143 doi:10.1093/emboj/19.22.5962
