2fcc

Crystal Structure of T4 Pyrimidine Dimer Glycosylase (T4-Pdg) Covalently Complexed with a DNA Substrate Containing Abasic Site

spinqualitylabelsall models 2fcc, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2fcc is a 6 chain structure with sequence from Escherichia virus T4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.3Å Ligands: BRU, GOL, PED, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function END5_BPT4 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 base excision repair (BER) pathway for ultraviolet light (UV)-induced cyclobutane pyrimidine dimers is initiated by DNA glycosylases that also possess abasic (AP) site lyase activity. The prototypical enzyme known to catalyze these reactions is the T4 pyrimidine dimer glycosylase (T4-Pdg). The fundamental chemical reactions and the critical amino acids that lead to both glycosyl and phosphodiester bond scission are known. Catalysis proceeds via a protonated imine covalent intermediate between the alpha-amino group of the N-terminal threonine residue and the C1' of the deoxyribose sugar of the 5' pyrimidine at the dimer site. This covalent complex can be trapped as an irreversible, reduced cross-linked DNA-protein complex by incubation with a strong reducing agent. This active site trapping reaction is equally efficient on DNA substrates containing pyrimidine dimers or AP sites. Herein, we report the co-crystal structure of T4-Pdg as a reduced covalent complex with an AP site-containing duplex oligodeoxynucleotide. This high-resolution structure reveals essential precatalytic and catalytic features, including flipping of the nucleotide opposite the AP site, a sharp kink (approximately 66 degrees ) in the DNA at the dimer site and the covalent bond linking the enzyme to the DNA. Superposition of this structure with a previously published co-crystal structure of a catalytically incompetent mutant of T4-Pdg with cyclobutane dimer-containing DNA reveals new insights into the structural requirements and the mechanisms involved in DNA bending, nucleotide flipping and catalytic reaction. Structure of T4 pyrimidine dimer glycosylase in a reduced imine covalent complex with abasic site-containing DNA.,Golan G, Zharkov DO, Grollman AP, Dodson ML, McCullough AK, Lloyd RS, Shoham G J Mol Biol. 2006 Sep 15;362(2):241-58. Epub 2006 Jul 7. PMID:16916523 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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