Signal peptide–chaperone interactions on the twin-arginine protein transport pathway

Kostas Hatzixanthis, Thomas A. Clarke, Arthur Oubrie, David J. Richardson, Raymond J. Turner, Frank Sargent, Linda L. Randall (Editor)

    Research output: Contribution to journalArticlepeer-review

    79 Citations (Scopus)


    The twin-arginine transport (Tat) system is a protein-targeting pathway of prokaryotes and chloroplasts. Most Escherichia coli Tat substrates are complex metalloenzymes that must be correctly folded and assembled before transport, and a preexport chaperone-mediated “proofreading” process is therefore in operation. The paradigm proofreading chaperone is TorD, which coordinates maturation and export of the key respiratory enzyme trimethylamine N-oxide reductase (TorA). It is demonstrated here that purified TorD binds tightly and with exquisite specificity to the TorA twin-arginine signal peptide in vitro. It is also reported that the TorD family constitutes a hitherto unexpected class of nucleotide-binding proteins. The affinity of TorD for GTP is enhanced by initial signal peptide binding, and it is proposed that GTP governs signal peptide binding-and-release cycles during Tat proofreading.
    Original languageEnglish
    Pages (from-to)8460-8465
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Issue number24
    Publication statusPublished - 2005


    • Protein transport
    • Twin arginine signal peptide
    • Tat pathway


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