Gating mechanism of the bacterial flagellar protein export apparatus

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K15749
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 43030:Functional biochemistry-related
• Research Institution: Osaka University
• Principal Investigator: Kinoshita Miki 大阪大学, 生命機能研究科, 特任助教(常勤) (30790985)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: 細菌 / 蛋白質 / 電子顕微鏡 / 感染症

Outline of Final Research Achievements

The bacterial flagellar protein export apparatus is located at the base of the flagellum and is composed of a transmembrane export gate complex powered by proton motive force (PMF) across the cytoplasmic membrane and a cytoplasmic ATPase ring complex, which acts as an activator of the export gate complex. The export gate complex couples inward-directed proton flow through a transmembrane proton channel with protein translocation into a protein export channel. To clarify the gating mechanism of the flagellar export apparatus, I have provided experimental evidence that dynamic interactions of FlhA and FlhB with the ATPase ring complex allow the export gate complex to open both the proton and protein export channels in a PMF-dependent manner, thereby facilitating proton-coupled protein.

Free Research Field

生物物理学

Academic Significance and Societal Importance of the Research Achievements

サルモネラなどの病原細菌による感染症は社会問題の一つで、それらの感染機構の解明ならびに克服のための方法の探索が続けられている。べん毛タンパク質輸送装置と高い相同性を示すIII型分泌装置が急性胃腸炎の発症に深く関わっている。本研究成果に基づいて病原細菌のIII型分泌装置のゲート開閉機構を特異的に不活性化できれば、病原細菌の病原性のみを破壊できる。したがって、従来の抗菌剤のように細菌を死滅させることがないため耐性菌が発生しづらく、これまでにない新しい治療法の開発につながる。