1N3C

Structural and biochemical exploration of a critical amino acid in human 8-oxoguanine glycosylase

1N3C の概要

• エントリーDOI: 10.2210/pdb1n3c/pdb
• 関連するPDBエントリー: 1EBM 1FN7 1KO9 1N39 1N3A
• 分子名称: DNA complement strand, 8-oxoG-containing DNA, N-glycosylase/DNA lyase, ... (5 entities in total)
• 機能のキーワード: hhh-gpd dna glycosylase dna repair oxoguanine, hydrolase, lyase-dna complex, lyase/dna
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Nucleus, nucleoplasm. Isoform 1A: Nucleus. Isoform 2A: Mitochondrion: O15527
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 44884.36

構造登録者

Norman, D.P.,Chung, S.J.,Verdine, G.L. (登録日: 2002-10-25, 公開日: 2003-03-04, 最終更新日: 2024-02-14)

主引用文献

Norman, D.P.,Chung, S.J.,Verdine, G.L.
Structural and biochemical exploration of a critical amino acid in human 8-oxoguanine glycosylase
Biochemistry, 42:1564-1572, 2003

PubMed Abstract: Members of the HhH-GPD superfamily of DNA glycosylases are responsible for the recognition and removal of damaged nucleobases from DNA. The hallmark of these proteins is a motif comprising a helix-hairpin-helix followed by a Gly/Pro-rich loop and terminating in an invariant, catalytically essential aspartic acid residue. In this study, we have probed the role of this Asp in human 8-oxoguanine DNA glycosylase (hOgg1) by mutating it to Asn (D268N), Glu (D268E), and Gln (D268Q). We show that this aspartate plays a dual role, acting both as an N-terminal alpha-helix cap and as a critical residue for catalysis of both base excision and DNA strand cleavage by hOgg1. Mutation of this residue to asparagine, another helix-capping residue, preserves stability of the protein while drastically reducing enzymatic activity. A crystal structure of this mutant is the first to reveal the active site nucleophile Lys249 in the presence of lesion-containing DNA; this structure offers a tantalizing suggestion that base excision may occur by cleavage of the glycosidic bond and then attachment of Lys249. Mutation of the aspartic acid to glutamine and glutamic acid destabilizes the protein fold to a significant extent but, surprisingly, preserves catalytic activity. Crystal structures of these mutants complexed with an unreactive abasic site in DNA reveal these residues to adopt a sterically disfavored helix-capping conformation.

PubMed: 12578369
DOI: 10.1021/bi026823d

実験手法

X-RAY DIFFRACTION (2.7 Å)