Damage-recognition mechanism of MutM in a base excision repair

2016 Fiscal Year Final Research Report

• Project/Area Number: 26440030
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Structural biochemistry
• Research Institution: Osaka University
• Principal Investigator: Nakagawa Noriko 大阪大学, 理学研究科, 招へい研究員 (50379278)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: DNA 修復 / 塩基除去修復 / X線結晶構造解析 / 酵素 / 基質認識 / 高度好熱菌

Outline of Final Research Achievements

MutM protein is a trifunctional DNA base excision repair enzyme, which removes oxidatively damaged bases and cleaves both the 3’- and 5’-phoshodiester bonds of the resulting apurinic/apyrimidinic site. The structures of the various complexes between a DNA glycosylase and same kinds of damaged DNA were reported. However, it remains to reveal the initial recognition mechanism of DNA glycosylases. To elucidate the initial recognition mechanism based on 3D structures, the complexes between of MutM and normal DNA or damaged DNA were crystallized and the structures of these complexes were determined. In the complex with damaged DNA, the DNA helix was sharply bent at the potion of the lesion and the 8-oxoguanine was flipped out of the DNA helix. In contrast, DNA bending and nucleotide flipping were not observed in the complex with the normal DNA. These results suggest that MutM searches lesions in an intact DNA helix at an initial recognition.

Free Research Field

構造生物化学