Related Experiment Video
Updated: May 29, 2026

Förster Resonance Energy Transfer Mapping: A New Methodology to Elucidate Global Structural Features
Published on: March 16, 2022
An energy transduction mechanism used in bacterial flagellar type III protein export
Tohru Minamino1, Yusuke V Morimoto, Noritaka Hara
1Graduate School of Frontier Bioscience, Osaka University, Suita, Japan.
Abstract:
Flagellar proteins of bacteria are exported by a specific export apparatus. FliI ATPase forms a complex with FliH and FliJ and escorts export substrates from the cytoplasm to the export gate complex, which is made up of six membrane proteins. The export gate complex utilizes proton motive force across the cytoplasmic membrane for protein translocation, but the mechanism remains unknown. Here we show that the export gate complex by itself is a proton-protein antiporter that uses the two components of proton motive force, Δψ and ΔpH, for different steps of the protein export process. However, in the presence of FliH, FliI and FliJ, a specific binding of FliJ with an export gate membrane protein, FlhA, is brought about by the FliH-FliI complex, which turns the export gate into a highly efficient, Δψ-driven protein export apparatus.
Related Concept Videos
Bacterial Translocation and Protein Secretion
Insertion of Single-pass Transmembrane Proteins in the RER
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Nuclear Export
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
Electron Transport Chain Components
Gram-negative Bacterial Protein Secretion Systems
Cotranslational Protein Translocation
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...

