A novel outer membrane transport system for aromatic compounds mediated by various TonB-dependent receptors

2018 Fiscal Year Final Research Report

• Project/Area Number: 15H04473
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied microbiology
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Masai Eiji 長岡技術科学大学, 工学研究科, 教授 (20272867)
• Co-Investigator(Kenkyū-buntansha): 城所 俊一 長岡技術科学大学, 工学研究科, 教授 (80195320) ; 笠井 大輔 長岡技術科学大学, 工学研究科, 准教授 (80452085)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: リグニン / 芳香族化合物 / 外膜輸送 / バクテリア / Sphingobium

Outline of Final Research Achievements

So far, only passive transporters such as porins and substrate-specific channels had been reported for the outer membrane transport of aromatic compounds in gram-negative bacteria. In this study, we revealed that the TonB system, which is generally involved in the active transport of siderophore, vitamin B12, and saccharides, is responsible for the outer membrane transport of a biphenyl-type lignin-derived compound (5,5’-dehydrodivanillate) in Sphingobium sp. SYK-6. In this system, the outer membrane transport is mediated by an outer membrane-localized TonB-dependent receptor (TBDR) encoded by ddvT. It is known that the TonB complex localized in the inner membrane plays a role in transmitting the energy derived from the proton motive force to TBDR. This study suggests that among the multiple SYK-6 genes encoding the components of the TonB complex, tonB1, exbB1, and exbD1 are involved in the uptake of 5,5’-dehydrodivanillate.

Free Research Field

応用微生物学

Academic Significance and Societal Importance of the Research Achievements

本研究により初めてTonB-dependent receptorが芳香族化合物の外膜輸送に関与することが明らかにされた。本研究で得られた成果は、グラム陰性菌における芳香族化合物の外膜輸送の解明に大きく貢献するとともに、微生物に新たな芳香族化合物の取り込み能を付与することや基質の取り込み量の適切な制御を可能にすることが期待される。将来的には、細菌による有用物質生産やバイオレメディエーションの高効率化のための新たな技術開発につながると考えられる。