3rb3

Dpo4 extension ternary complex with 3'-terminal primer A base opposite the 1-methylguanine (m1g) lesion

spinqualitylabelsall models 3rb3, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3rb3 is a 3 chain structure with sequence from Sulso. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA, DGT, EPE NonStd Res: 2DA, MG1 Related: 3raq, 3rb0 Gene: dbh, dpo4, SSO2448 (SULSO) Activity: DNA-directed DNA polymerase, with EC number 2.7.7.7 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [DPO4_SULSO] Poorly processive, error-prone DNA polymerase involved in untargeted mutagenesis. Copies undamaged DNA at stalled replication forks, which arise in vivo from mismatched or misaligned primer ends. These misaligned primers can be extended by PolIV. Exhibits no 3'-5' exonuclease (proofreading) activity. It is involved in translesional synthesis.[HAMAP-Rule:MF_01113] Publication Abstract from PubMed DNA is susceptible to alkylation damage by a number of environmental agents that modify the Watson-Crick edge of the bases. Such lesions, if not repaired, may be bypassed by Y-family DNA polymerases. The bypass polymerase Dpo4 is strongly inhibited by 1-methylguanine (m1G) and 3-methylcytosine (m3C), with nucleotide incorporation opposite these lesions being predominantly mutagenic. Further, extension after insertion of both correct and incorrect bases, introduces additional base substitution and deletion errors. Crystal structures of the Dpo4 ternary extension complexes with correct and mismatched 3'-terminal primer bases opposite the lesions reveal that both m1G and m3C remain positioned within the DNA template/primer helix. However, both correct and incorrect pairing partners exhibit pronounced primer terminal nucleotide distortion, being primarily evicted from the DNA helix when opposite m1G or misaligned when pairing with m3C. Our studies provide insights into mechanisms related to hindered and mutagenic bypass of methylated lesions and models associated with damage recognition by repair demethylases. Implications for damage recognition during Dpo4-mediated mutagenic bypass of m1G and m3C lesions.,Rechkoblit O, Delaney JC, Essigmann JM, Patel DJ Structure. 2011 Jun 8;19(6):821-32. doi: 10.1016/j.str.2011.03.020. PMID:21645853 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also DNA polymerase

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