8H1G

The R406T mutant form of the Aquifex aeolicus MutL endonuclease domain

8H1G の概要

• エントリーDOI: 10.2210/pdb8h1g/pdb
• 分子名称: DNA mismatch repair protein MutL, DI(HYDROXYETHYL)ETHER, SODIUM ION, ... (5 entities in total)
• 機能のキーワード: endonuclease, dna binding protein
• 由来する生物種: Aquifex aeolicus VF5
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 12874.92

構造登録者

Fukui, K.,Yano, T. (登録日: 2022-10-03, 公開日: 2023-08-16)

主引用文献

Fukui, K.,Yamamoto, T.,Murakawa, T.,Baba, S.,Kumasaka, T.,Yano, T.
Catalytic mechanism of the zinc-dependent MutL endonuclease reaction.
Life Sci Alliance, 6:-, 2023

PubMed Abstract: DNA mismatch repair endonuclease MutL binds two zinc ions. However, the endonuclease activity of MutL is drastically enhanced by other divalent metals such as manganese, implying that MutL binds another catalytic metal at some site other than the zinc-binding sites. Here, we solved the crystal structure of the endonuclease domain of MutL in the manganese- or cadmium-bound form, revealing that these metals compete with zinc at the same sites. Mass spectrometry revealed that the MutL yielded 5'-phosphate and 3'-OH products, which is characteristic of the two-metal-ion mechanism. Crystallographic analyses also showed that the position and flexibility of a highly conserved Arg of MutL altered depending on the presence of zinc/manganese or the specific inhibitor cadmium. Site-directed mutagenesis revealed that the Arg was critical for the catalysis. We propose that zinc ion and its binding sites are physiologically of catalytic importance and that the two-metal-ion mechanism works in the reaction, where the Arg plays a catalytic role. Our results also provide a mechanistic insight into the inhibitory effect of a mutagen/carcinogen, cadmium, on MutL.

PubMed: 37487639
DOI: 10.26508/lsa.202302001

実験手法

X-RAY DIFFRACTION (1.43 Å)