Twin-arginine-dependent translocation of SufI in the absence of cytosolic helper proteins

Eva Holzapfel, Michael Moser, Emile Schiltz, Takuya Ueda, Jean Michel Betton, Matthias Muller*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


The twin-arginine translocation (Tat) machinery present in bacterial and thylakoidal membranes is able to transport fully folded proteins. Folding of some Tat precursor proteins requires dedicated chaperones that also sequester the signal sequence during the maturation process.Whether or not signal sequence-binding chaperones are a general prerequisite for all Tat substrate proteins is not known. Here, we have studied the propensity of Tat signal sequences of Escherichia coli to interact with general chaperones and peptidyl-prolyl-cis, trans-isomerases. Site-specific photocross-linking revealed a clear specificity for FK506-binding proteins. Nevertheless transport of the Tat substrate SufI into inverted inner membrane vesicles of E. coli was found to occur in the bona fide absence of any cytosolic chaperone. Our results suggest that in E. coli, cytosolic chaperones are not essential for the twin-arginine-dependent export of cofactor-less substrates.

Original languageEnglish
Pages (from-to)5096-5105
Number of pages10
Issue number23
Publication statusPublished - 2009 Jun 16
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry


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