Molecular analysis of mirror-arabinan present in cell wall polysaccharides of Mycobacteria and its degrading enzymes

2023 Fiscal Year Final Research Report

• Project/Area Number: 19H00929
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 38:Agricultural chemistry and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Fushinobu Shinya 東京大学, 大学院農学生命科学研究科(農学部), 教授 (00302589)
• Co-Investigator(Kenkyū-buntansha): 藤田 清貴 鹿児島大学, 農水産獣医学域農学系, 准教授 (20381189) ; 石渡 明弘 国立研究開発法人理化学研究所, 開拓研究本部, 専任研究員 (70342748) ; 隅田 泰生 鹿児島大学, 理工学域工学系, 教授 (70179282) ; 新地 浩之 鹿児島大学, 理工学域工学系, 助教 (70770155)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 糖質関連酵素 / 結核菌 / アラビノース / 阻害剤 / 可視化ツール

Outline of Final Research Achievements

Enzymes degrading mirror-arabinan, which consists of D-arabinose, in the cell wall polysaccharide of Mycobacterium, were studied. Structural and functional analyses and the development of visualization tools were performed. Four new enzymes capable of complete degradation of mirror-arabinan were discovered, and the crystal structures of three of them were solved. Structural analysis by electron microscopy and small-angle X-ray scattering, and reaction mechanism analysis by NMR were also carried out. Large quantities of linear and branched arabinan oligosaccharides, which were required for the various analyses, were synthesized using a convergent oligosaccharide synthesis strategy. Structural analysis of an endo-type enzyme EndoMA1 revealed the presence of a novel carbohydrate-binding domain, and its binding to glycans was analyzed using glycan-immobilized gold nanoparticles and fiber-type glycan-binding chips.

Free Research Field

構造生物学、農芸化学

Academic Significance and Societal Importance of the Research Achievements

結核菌・らい菌などを含む抗酸菌の細胞壁に存在する鏡像体アラビナンを主成分とするリポアラビノマンナン(LAM)は、これらの病原菌のヒトの免疫に対する抵抗性に寄与している。複数の鏡像体アラビナン分解酵素を発見して基質特異性や基質認識機構、反応機構を詳細に明らかにしたことにより、これらの酵素をLAMの化学構造や免疫制御機構を研究するための重要なツールとして利用できるようになった。また、可視化ツールも開発しており、将来的に結核菌などの抗酸菌のLAMをターゲットとした応用研究に貢献できると期待される。