Identification of metabolon fot plant cell wall polysaccharide synthesis

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21403
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 43:Biology at molecular to cellular levels, and related fields
• Research Institution: Ritsumeikan University
• Principal Investigator: Ishimizu Takeshi 立命館大学, 生命科学部, 教授 (30314355)
• Co-Investigator(Kenkyū-buntansha): 大橋 貴生 摂南大学, 理工学部, 准教授 (10597876)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 糖転移酵素 / 植物細胞壁 / 多糖 / タンパク質複合体

Outline of Final Research Achievements

It is thought that carbohydrate compounds in plants are efficiently biosynthesized by a protein complex including glycosyltransferases. In this study, we aimed to detect such an enzyme complex.
We found that pectin rhamnogalacturonan I biosynthetic galactosyltransferase is superactivated by polyelectrolytes, suggesting that a protein complex was formed with this enzyme at the core. We also found a protein complex with molecular mass of 610 kDa that contains xylan biosynthetic glycosyltransferases IRX9, IRX10, and IRX14-L. Furthermore, a complex with molecular mass of 450 kDa containing the flavonoid glycoside apiin biosynthetic enzymes was found. These complexes were detected in very low amounts, suggesting that they were formed temporarily.

Free Research Field

植物生化学

Academic Significance and Societal Importance of the Research Achievements

生命科学における主流研究技術（次世代シーケンサーを用いた遺伝子発現解析や各種オミクス解析、変異体の解析など）では、酵素複合体は解析できない。このような技術的な理由から、本研究が目指す糖転移酵素を含む複合体の検出・解析は遅れている。本研究では、植物糖質化合物の生合成に関する酵素複合体を複数見出した。いずれも量が少ないことも見出しており、一過的に形成されることが多い相分離集合体である可能性もある。このように本研究成果は、未解明なことが多い細胞内でのタンパク質集合体の形成と機能について、一定の回答を示すものであり、学術的意義が大きい。