3h4b

Ternary complex of human DNA polymerase iota with template U/T and incoming dATP

spinqualitylabelsall models 3h4b, resolution 2.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3h4b is a 3 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 2.85Å Ligands: BRU, DOC, DTP, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function POLI_HUMAN Error-prone DNA polymerase specifically involved in DNA repair. Plays an important role in translesion synthesis, where the normal high-fidelity DNA polymerases cannot proceed and DNA synthesis stalls. Favors Hoogsteen base-pairing in the active site. Inserts the correct base with high-fidelity opposite an adenosine template. Exhibits low fidelity and efficiency opposite a thymidine template, where it will preferentially insert guanosine. May play a role in hypermutation of immunogobulin genes. Forms a Schiff base with 5'-deoxyribose phosphate at abasic sites, but may not have lyase activity. 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 Human DNA polymerase-iota (Poliota) incorporates correct nucleotides opposite template purines with a much higher efficiency and fidelity than opposite template pyrimidines. In fact, the fidelity opposite template T is so poor that Poliota inserts an incorrect dGTP approximately 10 times better than it inserts the correct dATP. We determine here how a template T/U is accommodated in the Poliota active site and why a G is incorporated more efficiently than an A. We show that in the absence of incoming dATP or dGTP (binary complex), template T/U exists in both syn and anti conformations, but in the presence of dATP or dGTP (ternary complexes), template T/U is predominantly in the anti conformation. We also show that dATP and dGTP insert differently opposite template T/U, and that the basis of selection of dGTP over dATP is a hydrogen bond between the N2 amino group of dGTP and Gln59 of Poliota. Replication across template T/U by human DNA polymerase-iota.,Jain R, Nair DT, Johnson RE, Prakash L, Prakash S, Aggarwal AK Structure. 2009 Jul 15;17(7):974-80. PMID:19604477 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also DNA polymerase 3D structures

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