3i7o

Crystal Structure of DDB1 in Complex with the H-Box Motif of IQWD1

spinqualitylabelsall models 3i7o, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3i7o is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.8Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DDB1_HUMAN Required for DNA repair. Binds to DDB2 to form the UV-damaged DNA-binding protein complex (the UV-DDB complex). The UV-DDB complex may recognize UV-induced DNA damage and recruit proteins of the nucleotide excision repair pathway (the NER pathway) to initiate DNA repair. The UV-DDB complex preferentially binds to cyclobutane pyrimidine dimers (CPD), 6-4 photoproducts (6-4 PP), apurinic sites and short mismatches. Also appears to function as a component of numerous distinct DCX (DDB1-CUL4-X-box) E3 ubiquitin-protein ligase complexes which mediate the ubiquitination and subsequent proteasomal degradation of target proteins. The functional specificity of the DCX E3 ubiquitin-protein ligase complex is determined by the variable substrate recognition component recruited by DDB1. DCX(DDB2) (also known as DDB1-CUL4-ROC1, CUL4-DDB-ROC1 and CUL4-DDB-RBX1) may ubiquitinate histone H2A, histone H3 and histone H4 at sites of UV-induced DNA damage. The ubiquitination of histones may facilitate their removal from the nucleosome and promote subsequent DNA repair. DCX(DDB2) also ubiquitinates XPC, which may enhance DNA-binding by XPC and promote NER. DCX(DTL) plays a role in PCNA-dependent polyubiquitination of CDT1 and MDM2-dependent ubiquitination of TP53 in response to radiation-induced DNA damage and during DNA replication. DCX(ERCC8) (the CSA complex) plays a role in transcription-coupled repair (TCR). May also play a role in ubiquitination of CDKN1B/p27kip when associated with CUL4 and SKP2. 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 The cullin 4-DNA-damage-binding protein 1 (CUL4-DDB1) ubiquitin ligase machinery regulates diverse cellular functions and can be subverted by pathogenic viruses. Here we report the crystal structure of DDB1 in complex with a central fragment of hepatitis B virus X protein (HBx), whose DDB1-binding activity is important for viral infection. The structure reveals that HBx binds DDB1 through an alpha-helical motif, which is also found in the unrelated paramyxovirus SV5-V protein despite their sequence divergence. Our structure-based functional analysis suggests that, like SV5-V, HBx captures DDB1 to redirect the ubiquitin ligase activity of the CUL4-DDB1 E3 ligase. We also identify the alpha-helical motif shared by these viral proteins in the cellular substrate-recruiting subunits of the E3 complex, the DDB1-CUL4-associated factors (DCAFs) that are functionally mimicked by the viral hijackers. Together, our studies reveal a common yet promiscuous structural element that is important for the assembly of cellular and virally hijacked CUL4-DDB1 E3 complexes. A promiscuous alpha-helical motif anchors viral hijackers and substrate receptors to the CUL4-DDB1 ubiquitin ligase machinery.,Li T, Robert EI, van Breugel PC, Strubin M, Zheng N Nat Struct Mol Biol. 2010 Jan;17(1):105-11. Epub 2009 Dec 6. PMID:19966799 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also DNA damage-binding protein

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