3h4d
From Proteopedia
Ternary complex of human DNA polymerase iota with template U/T and incoming dGTP
Structural highlights
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.[1] [2] [3] [4] [5] [6] [7] 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 PubMedHuman 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[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: DNA-directed DNA polymerase | Human | Aggarwal, A K | Jain, R | Johnson, R E | Nair, D T | Prakash, L | Prakash, S | Dna damage | Dna polymerase iota | Dna repair | Dna replication | Dna synthesis | Dna-binding | Dna-directed dna polymerase | Magnesium | Metal-binding | Mutator protein | Nucleotidyltransferase | Nucleus | Replication | Replication-dna complex | Schiff base | Transferase
