FusB energizes import across the outer membrane through direct interaction with its ferredoxin substrate

Wojnowska, M. and Walker, D. (2020) FusB energizes import across the outer membrane through direct interaction with its ferredoxin substrate. mBio, 11(5), e02081-20. (doi: 10.1128/mBio.02081-20) (PMID:33109756) (PMCID:PMC7593965)

Abstract

Phytopathogenic Pectobacterium spp. import ferredoxin into the periplasm for proteolytic processing and iron release via the ferredoxin uptake system. Although the ferredoxin receptor FusA and the processing protease FusC have been identified, the mechanistic basis of ferredoxin import is poorly understood. In this work, we demonstrate that protein translocation across the outer membrane is dependent on the TonB-like protein FusB. In contrast to the loss of FusC, loss of FusB or FusA abolishes ferredoxin transport to the periplasm, demonstrating that FusA and FusB work in concert to transport ferredoxin across the outer membrane. In addition to an interaction with the “TonB box” region of FusA, FusB also forms a complex with the ferredoxin substrate, with complex formation required for substrate transport. These data suggest that ferredoxin transport requires energy transduction from the cytoplasmic membrane via FusB both for removal of the FusA plug domain and for substrate translocation through the FusA barrel.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Walker, Professor Daniel and Wojnowska, Marta
• Authors: Wojnowska, M., and Walker, D.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: mBio
• Publisher: American Society for Microbiology
• ISSN: 2150-7511
• ISSN (Online): 2150-7511
• Published Online: 27 October 2020
• Copyright Holders: Copyright © 2020 Wojnowska and Walker
• First Published: First published in mBio 11(5): e02081-20
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
190773		A novel mechanism of protein uptake in Gram-negative bacteria	Daniel Walker	Biotechnology and Biological Sciences Research Council (BBSRC)	BB/L02022X/1	III - Bacteriology