Reconstitution of an in-vitro biological system driven and regulated by a small number of molecules

2015 Fiscal Year Final Research Report

• Project Area: Spying minority in biological phenomena -Toward bridging dynamics between individual and ensemble processes-
• Project/Area Number: 23115008
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: Osaka University
• Principal Investigator: Imada Katsumi 大阪大学, 理学(系)研究科(研究院), 教授 (40346143)
• Co-Investigator(Kenkyū-buntansha): Uchihashi Takayuki 金沢大学, 数物科学系研究科, 准教授 (30326300)
• Co-Investigator(Renkei-kenkyūsha): Minamino Tohru 大阪大学, 大学院生命機能研究科, 准教授 (20402993) ; TAKEUCHI Shoji 東京大学, 生産技術研究所, 教授 (90343110)
• Project Period (FY): 2011-04-01 – 2016-03-31
• Keywords: 生物物理 / 蛋白質輸送 / 再構成系 / III型輸送装置 / 高速AFM / 少数性 / 分子機械

Outline of Final Research Achievements

To understand the molecular mechanism of flagellar construction, we investigated the flagellar protein export system that is driven and regulated by the turnover of multifunctional component proteins, each of which functions in limited numbers. We established an in-vitro assay system using inverted membrane vesicle that enables precise control of the external condition. The system retains the secretion activity as in the cell. Using this system together with in vivo single molecule experiment and biochemical and genetic techniques, we revealed a novel role of the export ATPase proteins, the energy source for secretion and the mechanism of ordered secretion. We also found that export chaperone proteins change their structure to control the binding affinity for their interaction partners and thereby regulate the secretion order. In addition, we developed the high speed AFM and visualized the structural change and assembly dynamics of protein complexes.

Free Research Field

生物物理学