Structure and dynamics of the type III secretion system

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H02386
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Structural biochemistry
• Research Institution: Osaka University
• Principal Investigator: Imada Katsumi 大阪大学, 理学研究科, 教授 (40346143)
• Co-Investigator(Kenkyū-buntansha): 川岸 郁朗 法政大学, 生命科学部, 教授 (80234037)
• Co-Investigator(Renkei-kenkyūsha): MINAMINO Tohru 大阪大学, 大学院生命機能研究科, 准教授 (20402993) ; KAWAMOTO Akihiro 大阪大学, 大学院生命機能研究科, 研究員 (90631523) ; KAWAGUCHI Tatsuya 大阪大学, 大学院理学研究科, 助教 (10314353)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 構造生物学 / 生物物理 / 細菌 / 結晶構造解析 / 電子顕微鏡 / 蛋白質輸送

Outline of Final Research Achievements

Type III secretion system (T3SS) is one of the bacterial protein transporters used to deliver virulence proteins directly into their eukaryotic host cells for infection. To elucidate the molecular mechanism of the type III secretion, we investigated the flagellar T3SS, which is used for construction of the bacterial flagellum and is the most well-studied T3SS, by X-ray crystallography, electron microscopy, atomic force microscopy and inverted membrane vesicle assay techniques. We solved the structure of the export ATPase complex and found its novel roles on T3SS export. The structure of an export chaperone was also determined and the regulation mechanism of the secretion order was revealed. In addition, we proposed novel mechanistic models on the flagellar protein export, such as the mechanism of the export substrate switching, the assembly mechanism of the export gate complex and regulation of protein export by the interaction between the export substrates.

Free Research Field

生物物理学