4HSB

S. pombe 3-methyladenine DNA glycosylase-like protein Mag2 bound to damaged DNA

4HSB の概要

• エントリーDOI: 10.2210/pdb4hsb/pdb
• 関連するPDBエントリー: 3S6I
• 分子名称: Probable DNA-3-methyladenine glycosylase 2, DNA (5'-D(P*GP*GP*AP*CP*TP*(3DR)P*AP*CP*GP*GP*G)-3'), DNA (5'-D(P*CP*CP*CP*GP*TP*TP*AP*GP*TP*CP*C)-3'), ... (5 entities in total)
• 機能のキーワード: helix-hairpin-helix, non-specific dna-binding motif, hydrolase-dna complex, hydrolase/dna
• 由来する生物種: Schizosaccharomyces pombe 972h- (Fission yeast)
• 細胞内の位置: Nucleus: O94468
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 31414.71

構造登録者

Adhikary, S.,Eichman, B.F. (登録日: 2012-10-29, 公開日: 2013-01-23, 最終更新日: 2024-02-28)

主引用文献

Adhikary, S.,Cato, M.C.,McGary, K.L.,Rokas, A.,Eichman, B.F.
Non-productive DNA damage binding by DNA glycosylase-like protein Mag2 from Schizosaccharomyces pombe.
Dna Repair, 12:196-204, 2013

PubMed Abstract: Schizosaccharomyces pombe contains two paralogous proteins, Mag1 and Mag2, related to the helix-hairpin-helix (HhH) superfamily of alkylpurine DNA glycosylases from yeast and bacteria. Phylogenetic analysis of related proteins from four Schizosaccharomyces and other fungal species shows that the Mag1/Mag2 duplication is unique to the genus Schizosaccharomyces and most likely occurred in its ancestor. Mag1 excises N3- and N7-alkylguanines and 1,N(6)-ethenoadenine from DNA, whereas Mag2 has been reported to have no detectible alkylpurine base excision activity despite high sequence and active site similarity to Mag1. To understand this discrepancy we determined the crystal structure of Mag2 bound to abasic DNA and compared it to our previously determined Mag1-DNA structure. In contrast to Mag1, Mag2 does not flip the abasic moiety into the active site or stabilize the DNA strand 5' to the lesion, suggesting that it is incapable of forming a catalytically competent protein-DNA complex. Subtle differences in Mag1 and Mag2 interactions with the DNA duplex illustrate how Mag2 can stall at damage sites without fully engaging the lesion. We tested our structural predictions by mutational analysis of base excision and found a single amino acid responsible at least in part for Mag2's lack of activity. Substitution of Mag2 Asp56, which caps the helix at the base of the DNA intercalation loop, with the corresponding serine residue in Mag1 endows Mag2 with ɛA excision activity comparable to Mag1. This work provides novel insight into the chemical and physical determinants by which the HhH glycosylases engage DNA in a catalytically productive manner.

PubMed: 23273506
DOI: 10.1016/j.dnarep.2012.12.001

実験手法

X-RAY DIFFRACTION (1.9 Å)