The twin arginine consensus motif of Tat signal peptides is involved in Sec-independent protein targeting in Escherichia coli

Stanley, N.R., Palmer, T. and Berks, B.C. (2000) The twin arginine consensus motif of Tat signal peptides is involved in Sec-independent protein targeting in Escherichia coli. Journal of Biological Chemistry, 275. pp. 11591-11596. ISSN 1083-351X

Full text not available from this repository.

Abstract

In Escherichia coli a subset of periplasmic proteins is exported through the Tat pathway to which substrates are directed by an NH2-terminal signal peptide containing a consensus SRRXFLK “twin arginine” motif. The importance of the individual amino acids of the consensus motif forin vivo Tat transport has been assessed by site-directed mutagenesis of the signal peptide of the Tat substrate pre-SufI. Although the invariant arginine residues are crucial for efficient export, we find that slow transport of SufI is still possible if a single arginine is conservatively substituted by a lysine residue. Thus, in at least one signal peptide context there is no absolute dependence of Tat transport on the arginine pair. The consensus phenylalanine residue was found to be a critical determinant for efficient export but could be functionally substituted by leucine, another amino acid with a highly hydrophobic side chain. Unexpectedly, the consensus lysine residue was found to retard Tat transport. These observations and others suggest that the sequence conservation of the Tat consensus motif is a reflection of the functional importance of the consensus residues. Tat signal peptides characteristically have positively charged carboxyl-terminal regions. However, changing the sign of this charge does not affect export of SufI.

Item Type: Article
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: LivePure Connector
Date Deposited: 09 Jan 2019 14:30
Last Modified: 24 Jul 2019 18:27
URI: https://ueaeprints.uea.ac.uk/id/eprint/69522
DOI: 10.1074/jbc.275.16.11591

Actions (login required)

View Item View Item