3OSN

Structural Basis for Proficient Incorporation of dTTP Opposite O6-Methylguanine by Human DNA Polymerase Iota

3OSN の概要

• エントリーDOI: 10.2210/pdb3osn/pdb
• 関連するPDBエントリー: 2ALZ 2FLL 3EPG 3EPI 3NGD
• 分子名称: 5'-D(*TP*CP*TP*(6OG)P*GP*GP*GP*TP*CP*CP*TP*AP*GP*GP*AP*CP*CP*(DOC))-3', DNA polymerase iota, THYMIDINE-5'-TRIPHOSPHATE, ... (6 entities in total)
• 機能のキーワード: hoogsteen base pair, protein-dna complex, y-family dna polymerase, translesion synthesis, nucleoside triphosphate, o6-methylguanine, transferase-dna complex, transferase/dna
• 由来する生物種: Homo sapiens (human); 詳細
• 細胞内の位置: Nucleus: Q9UNA4
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 58594.27

構造登録者

Pence, M.G. (登録日: 2010-09-09, 公開日: 2010-10-20, 最終更新日: 2023-09-06)

主引用文献

Pence, M.G.,Choi, J.Y.,Egli, M.,Guengerich, F.P.
Structural Basis for Proficient Incorporation of dTTP Opposite O6-Methylguanine by Human DNA Polymerase {iota}.
J.Biol.Chem., 285:40666-40672, 2010

PubMed Abstract: O(6)-methylguanine (O(6)-methylG) is highly mutagenic and is commonly found in DNA exposed to methylating agents, even physiological ones (e.g. S-adenosylmethionine). The efficiency of a truncated, catalytic DNA polymerase ι core enzyme was determined for nucleoside triphosphate incorporation opposite O(6)-methylG, using steady-state kinetic analyses. The results presented here corroborate previous work from this laboratory using full-length pol ι, which showed that dTTP incorporation occurs with high efficiency opposite O(6)-methylG. Misincorporation of dTTP opposite O(6)-methylG occurred with ∼6-fold higher efficiency than incorporation of dCTP. Crystal structures of the truncated form of pol ι with O(6)-methylG as the template base and incoming dCTP or dTTP were solved and showed that O(6)-methylG is rotated into the syn conformation in the pol ι active site and that dTTP misincorporation by pol ι is the result of Hoogsteen base pairing with the adduct. Both dCTP and dTTP base paired with the Hoogsteen edge of O(6)-methylG. A single, short hydrogen bond formed between the N3 atom of dTTP and the N7 atom of O(6)-methylG. Protonation of the N3 atom of dCTP and bifurcation of the N3 hydrogen between the N7 and O(6) atoms of O(6)-methylG allow base pairing of the lesion with dCTP. We conclude that differences in the Hoogsteen hydrogen bonding between nucleotides is the main factor in the preferential selectivity of dTTP opposite O(6)-methylG by human pol ι, in contrast to the mispairing modes observed previously for O(6)-methylG in the structures of the model DNA polymerases Sulfolobus solfataricus Dpo4 and Bacillus stearothermophilus DNA polymerase I.

PubMed: 20961860
DOI: 10.1074/jbc.M110.183665

実験手法

X-RAY DIFFRACTION (1.9 Å)