3UFJ

Human Thymine DNA Glycosylase Bound to Substrate Analog 2'-fluoro-2'-deoxyuridine

3UFJ の概要

• エントリーDOI: 10.2210/pdb3ufj/pdb
• 関連するPDBエントリー: 2RBA
• 分子名称: G/T mismatch-specific thymine DNA glycosylase, 5'-D(*CP*AP*GP*CP*TP*CP*TP*GP*TP*AP*CP*GP*TP*GP*AP*GP*CP*AP*GP*TP*GP*GP*A)-3', 5'-D(*CP*CP*AP*CP*TP*GP*CP*TP*CP*AP*(UF2)P*GP*TP*AP*CP*AP*GP*AP*GP*CP*TP*GP*T)-3', ... (4 entities in total)
• 機能のキーワード: dna damage, dna repair, dna binding, glycosidase, nucleus, hydrolase-dna complex, hydrolase/dna
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Nucleus: Q13569
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 74425.53

構造登録者

Pozharski, E.,Maiti, A.,Drohat, A.C. (登録日: 2011-11-01, 公開日: 2012-04-25, 最終更新日: 2023-09-13)

主引用文献

Maiti, A.,Noon, M.S.,Mackerell, A.D.,Pozharski, E.,Drohat, A.C.
Lesion processing by a repair enzyme is severely curtailed by residues needed to prevent aberrant activity on undamaged DNA.
Proc.Natl.Acad.Sci.USA, 109:8091-8096, 2012

PubMed Abstract: DNA base excision repair is essential for maintaining genomic integrity and for active DNA demethylation, a central element of epigenetic regulation. A key player is thymine DNA glycosylase (TDG), which excises thymine from mutagenic G·T mispairs that arise by deamination of 5-methylcytosine (mC). TDG also removes 5-formylcytosine and 5-carboxylcytosine, oxidized forms of mC produced by Tet enzymes. Recent studies show that the glycosylase activity of TDG is essential for active DNA demethylation and for embryonic development. Our understanding of how repair enzymes excise modified bases without acting on undamaged DNA remains incomplete, particularly for mismatch glycosylases such as TDG. We solved a crystal structure of TDG (catalytic domain) bound to a substrate analog and characterized active-site residues by mutagenesis, kinetics, and molecular dynamics simulations. The studies reveal how TDG binds and positions the nucleophile (water) and uncover a previously unrecognized catalytic residue (Thr197). Remarkably, mutation of two active-site residues (Ala145 and His151) causes a dramatic enhancement in G·T glycosylase activity but confers even greater increases in the aberrant removal of thymine from normal A·T base pairs. The strict conservation of these residues may reflect a mechanism used to strike a tolerable balance between the requirement for efficient repair of G·T lesions and the need to minimize aberrant action on undamaged DNA, which can be mutagenic and cytotoxic. Such a compromise in G·T activity can account in part for the relatively weak G·T activity of TDG, a trait that could potentially contribute to the hypermutability of CpG sites in cancer and genetic disease.

PubMed: 22573813
DOI: 10.1073/pnas.1201010109

実験手法

X-RAY DIFFRACTION (2.967 Å)