Separate analysis of twin-arginine translocation (Tat)-specific membrane binding and translocation in Escherichia coli.
The twin-arginine translocation (Tat) pathway exports those precursor proteins to the periplasmic space of bacteria that harbor a twin-arginine (RR) consensus motif in their signal sequences. We have reproduced translocation of several Tat substrates into inside-out plasma membrane vesicles from Escherichia coli. Translocation proceeding at an efficiency of up to 20% occurs specifically via the Tat pathway as indicated by (i) its requirement for elevated levels of the TatABC proteins in the membrane vesicles, (ii) competition by an intact twin-arginine signal peptide, and (iii) susceptibility toward dissipation of the transmembrane H(+) gradient. The latter treatment, while blocking translocation, still allows for functional membrane association of Tat precursors. This is shown by the finding that translocation of isolated membrane-bound Tat precursor is restored upon re-energization of the vesicles.
Alami
Meriem
M
Institut für Biochemie und Molekularbiologie, Universität Freiburg, Hermann-Herderstrasse 7, D-79104 Freiburg, Germany.
Trescher
Dorothea
D
Wu
Long-Fei
LF
Müller
Matthias
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D021381:Protein Transport
D017931:DNA Primers; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C408585:twin-arginine translocase complex, E coli