Separate Analysis of Twin-arginine Translocation (Tat)-specific Membrane Binding and Translocation in Escherichia coli

• Published in: The Journal of biological chemistry Vol. 277; no. 23; pp. 20499 - 20503
• Main Authors: Alami, Meriem, Trescher, Dorothea, Wu, Long-Fei, Müller, Matthias
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 07.06.2002; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Base Sequence; DNA Primers; Escherichia coli - metabolism; Escherichia coli Proteins - metabolism; Membrane Transport Proteins - metabolism; Molecular Sequence Data; Protein Binding; Protein Transport
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M201711200

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.