4a09
From Proteopedia
Structure of hsDDB1-drDDB2 bound to a 15 bp CPD-duplex (purine at D-1 position) at 3.1 A resolution (CPD 2)
Structural highlights
FunctionDDB2_DANRE Required for DNA repair. Binds to ddb1 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. Also appears to function as the substrate recognition module for a DCX (DDB1-CUL4-X-box) E3 ubiquitin-protein ligase complex which 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 (By similarity). Publication Abstract from PubMedThe DDB1-CUL4-RBX1 (CRL4) ubiquitin ligase family regulates a diverse set of cellular pathways through dedicated substrate receptors (DCAFs). The DCAF DDB2 detects UV-induced pyrimidine dimers in the genome and facilitates nucleotide excision repair. We provide the molecular basis for DDB2 receptor-mediated cyclobutane pyrimidine dimer recognition in chromatin. The structures of the fully assembled DDB1-DDB2-CUL4A/B-RBX1 (CRL4(DDB2)) ligases reveal that the mobility of the ligase arm creates a defined ubiquitination zone around the damage, which precludes direct ligase activation by DNA lesions. Instead, the COP9 signalosome (CSN) mediates the CRL4(DDB2) inhibition in a CSN5 independent, nonenzymatic, fashion. In turn, CSN inhibition is relieved upon DNA damage binding to the DDB2 module within CSN-CRL4(DDB2). The Cockayne syndrome A DCAF complex crystal structure shows that CRL4(DCAF(WD40)) ligases share common architectural features. Our data support a general mechanism of ligase activation, which is induced by CSN displacement from CRL4(DCAF) on substrate binding to the DCAF. The Molecular Basis of CRL4(DDB2/CSA) Ubiquitin Ligase Architecture, Targeting, and Activation.,Fischer ES, Scrima A, Bohm K, Matsumoto S, Lingaraju GM, Faty M, Yasuda T, Cavadini S, Wakasugi M, Hanaoka F, Iwai S, Gut H, Sugasawa K, Thoma NH Cell. 2011 Nov 23;147(5):1024-39. PMID:22118460[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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