Twin Arginine Translocation

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Twin Arginine Translocation
Transporter classification
TCDB 2.A.64
designation Tat family
Occurrence
Parent taxon Archaea, bacteria, plants

As a twin-arginine translocation (Engl. For twin-arginine transport ), short- fact , even Tat system is described in Biochemistry , a special transport system for proteins in plants , bacteria and archaea called. This protein transport path is used in the plant thylakoid membrane and in the plasma membrane of bacteria and archaea for protein secretion . It is one of the post-translational protein transport routes and, in contrast to Sec-dependent protein transport , enables the transport of proteins in the folded state.

Tat-dependent protein transport was first discovered in plants, where it was initially described as ΔpH-dependent protein transport, since the proton gradient ΔP across the thylakoid membrane serves as an energy source for transport through chemiosmotic coupling . However, this dependency is now controversial. The Tat path was also found in bacteria, the evolutionary precursors of the chloroplasts (see endosymbiotic theory ).

So far, three membrane proteins have been identified that are essential for transport. These are referred to as TatA, TatB and TatC. Originally, the proteins in the plant system were called Tha4 (TatA), Hcf106 (TatB) and cpTatC (TatC). Furthermore, z. For example, another protein TatE was found in the bacterium Escherichia coli , which obviously corresponds to the TatA protein in its function. Furthermore, bacteria are known which only require two of the proteins mentioned above (TatA and TatC in Bacillus subtilis ).

Proteins that are transported via the Tat pathway have a signal peptide at the N terminus . The name twin-arginine translocation is derived from this signal peptide, as it contains the characteristic sequence motif (S / T) -RRxFLK (in the one -letter code ), which, among other things, consists of two adjacent arginine residues ( twin-arginine motif ). After the protein has been transported across the membrane, the signal peptide is split off by a signal peptidase .

swell

  1. ↑ TCDB entry
  2. ↑ Taylor, PD et al. (2006): TATPred: a Bayesian method for the identification of twin arginine translocation pathway signal sequences . In: Bioinformation . Vol. 1, No. 5, pp. 184-187. PMID 17597885

literature

  • Pohlschröder, M. et al. (2005): Diversity and evolution of protein translocation. In: Annu. Rev. Microbiol. Vol. 59, pp. 91-111. PMID 16153164
  • Müller, M. & Klösgen, RB (2005): The Tat pathway in bacteria and chloroplasts. In: Mol. Membr. Biol. Vol. 22, pp. 113-121. PMID 16092529
  • Palmer, T. et al. (2005): Export of complex cofactor-containing proteins by the bacterial Tat pathway. In: Trends Microbiol. Vol. 13, pp. 175-180. PMID 15817387
  • Müller, M. (2005): Twin-arginine-specific protein export in Escherichia coli. In: Res. Microbiol. Vol. 156, pp. 131-136. PMID 15748976
  • Robinson, C. & Bolhuis, A. (2004): Tat-dependent protein targeting in prokaryotes and chloroplasts. In: Biochim. Biophys. Acta . Vol. 1694, pp. 135-147. PMID 15546663