Triterpene cyclases: catalytic mechanism and substrate recognition by evaluating activities and subsrate analogs

2016 Fiscal Year Final Research Report

• Project/Area Number: 25450150
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Bioorganic chemistry
• Research Institution: Niigata University
• Principal Investigator: Hoshino Tsutomu 新潟大学, 自然科学系, フェロー (20102709)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: トリテルペン / βーアミリン / オキシドスクアレン / 部位特異的変異実験 / 基質アナログ / 酵素反応 / ホペン

Outline of Final Research Achievements

This study is to elucidate the catalytic mechanism and substrate recognition for beta-amyrin synthase. Studies on the triterpene cyclase has encountered a difficulty, becaseu of the unstability of the membrane-bound protein. We developted a new strategy to evaluate the enzyme activity in vivo by estimating the expression amount of the cyclase enzyme and the quantities of triterpene produced. By this procedure, we identified many active site residues, especailly, Trp257 residue works not only to stabilize the cationic intermediate via cation-pi interaction, but also to tightly hold the Methyl-30 of the substrate via CH-pi interaction. In the substrate analog experiments revealed the importance of methyl-30 for the normal folding conformation leading to beta-amyrin skeleton.

Free Research Field

生物有機化学