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.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 2005|
- Protein transport
- Twin arginine signal peptide
- Tat pathway
Hatzixanthis, K., Clarke, T. A., Oubrie, A., Richardson, D. J., Turner, R. J., Sargent, F., & Randall, L. L. (Ed.) (2005). Signal peptide–chaperone interactions on the twin-arginine protein transport pathway. Proceedings of the National Academy of Sciences of the United States of America, 102(24), 8460-8465. https://doi.org/10.1073/pnas.0500737102