1PU7

Crystal structure of H.pylori 3-methyladenine DNA glycosylase (MagIII) bound to 3,9-dimethyladenine

1PU7 の概要

• エントリーDOI: 10.2210/pdb1pu7/pdb
• 関連するPDBエントリー: 1PU6 1PU8
• 分子名称: 3-METHYLADENINE DNA GLYCOSYLASE, 6-AMINO-3,9-DIMETHYL-9H-PURIN-3-IUM, BETA-MERCAPTOETHANOL, ... (4 entities in total)
• 機能のキーワード: helix-hairpin-helix, 3-methyladenine, base excision repair, glycosylase, hydrolase
• 由来する生物種: Helicobacter pylori
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 50920.77

構造登録者

Eichman, B.F.,O'Rourke, E.J.,Radicella, J.P.,Ellenberger, T. (登録日: 2003-06-24, 公開日: 2003-10-07, 最終更新日: 2023-11-15)

主引用文献

Eichman, B.F.,O'Rourke, E.J.,Radicella, J.P.,Ellenberger, T.
Crystal structures of 3-methyladenine DNA glycosylase MagIII and the recognition of alkylated bases
Embo J., 22:4898-4909, 2003

PubMed Abstract: DNA glycosylases catalyze the excision of chemically modified bases from DNA. Although most glycosylases are specific to a particular base, the 3-methyladenine (m3A) DNA glycosylases include both highly specific enzymes acting on a single modified base, and enzymes with broader specificity for alkylation-damaged DNA. Our structural understanding of these different enzymatic specificities is currently limited to crystal and NMR structures of the unliganded enzymes and complexes with abasic DNA inhibitors. Presented here are high-resolution crystal structures of the m3A DNA glycosylase from Helicobacter pylori (MagIII) in the unliganded form and bound to alkylated bases 3,9-dimethyladenine and 1,N6-ethenoadenine. These are the first structures of a nucleobase bound in the active site of a m3A glycosylase belonging to the helix-hairpin-helix superfamily. MagIII achieves its specificity for positively-charged m3A not by direct interactions with purine or methyl substituent atoms, but rather by stacking the base between two aromatic side chains in a pocket that excludes 7-methylguanine. We report base excision and DNA binding activities of MagIII active site mutants, together with a structural comparison of the HhH glycosylases.

PubMed: 14517230
DOI: 10.1093/emboj/cdg505

実験手法

X-RAY DIFFRACTION (1.93 Å)