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Moving folded proteins across the bacterial cell membrane
Tracy Palmer1,2, Ben C Berks3
1Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK.
Microbiology (Reading, England)
|March 14, 2003
Summary
The Tat protein export system moves folded proteins across bacterial membranes, unlike the Sec pathway. This essential system uses a proton gradient and TatA/TatBC proteins for functions in energy metabolism and pathogenesis.
Area of Science:
- Bacterial protein export
- Membrane transport systems
- Molecular mechanisms of protein translocation
Background:
- The Tat (Twin-arginine translocation) system is a bacterial protein export pathway distinct from the Sec pathway.
- Tat system translocates folded proteins, often those requiring cofactors for function, across the cytoplasmic membrane.
- Substrates are recognized by N-terminal signal peptides with conserved twin-arginine motifs.
Discussion:
- The Tat translocase must move structured proteins without compromising membrane integrity.
- Tat pathway substrates are crucial for bacterial energy metabolism (respiratory and photosynthetic) and pathogenesis.
- Protein movement is powered by the transmembrane proton electrochemical gradient.
Key Insights:
- TatA likely forms the transport channel, while TatBC acts as the substrate receptor complex.
- The system handles the challenge of exporting folded proteins across the membrane.
- Tat pathway plays roles in outer membrane biosynthesis and bacterial virulence.
Outlook:
- Further elucidation of TatA channel dynamics and TatBC receptor interactions.
- Investigating the precise mechanisms of cofactor-dependent protein folding and export.
- Exploring the Tat pathway's potential as a target in antimicrobial strategies.