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Essential cytoplasmic domains in the Escherichia coli TatC protein.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2002 Mar 22; Vol. 277 (12), pp. 10362-6. Date of Electronic Publication: 2002 Jan 07. - Publication Year :
- 2002
-
Abstract
- The twin-arginine translocation (Tat) system mediates the transport of proteins across the bacterial plasma membrane and chloroplast thylakoid membrane. Operating in parallel with Sec-type systems in these membranes, the Tat system is completely different in both structural and mechanistic terms, and is uniquely able to catalyze the translocation of fully folded proteins across coupled membranes. TatC is an essential, multispanning component that has been proposed to form part of the binding site for substrate precursor proteins. In this study we have tested the importance of conserved residues on the periplasmic and cytoplasmic face of the Escherichia coli protein. We find that many of the mutations on the cytoplasmic face have little or no effect. However, substitution at several positions in the extreme N-terminal cytoplasmic region or the predicted first cytoplasmic loop lead to a significant or complete loss of Tat-dependent export. The mutated strains are unable to grow anaerobically on trimethylamine N-oxide minimal media and are unable to export trimethylamine-N-oxide reductase (TorA). The same mutants are completely unable to export a chimeric protein, comprising the TorA signal peptide linked to green fluorescent protein, indicating that translocation is blocked rather than cofactor insertion into the TorA mature protein. The data point to two essential cytoplasmic domains on the TatC protein that are essential for export.
- Subjects :
- Amino Acid Sequence
Arabidopsis metabolism
Arginine chemistry
Binding Sites
Cell Membrane metabolism
Green Fluorescent Proteins
Luminescent Proteins metabolism
Membrane Proteins genetics
Membrane Proteins metabolism
Molecular Sequence Data
Mutagenesis, Site-Directed
Mutation
NADH, NADPH Oxidoreductases metabolism
Oxidoreductases Acting on CH-NH Group Donors
Oxidoreductases, N-Demethylating chemistry
Oxidoreductases, N-Demethylating metabolism
Plasmids metabolism
Protein Binding
Protein Structure, Tertiary
Protein Transport
Recombinant Fusion Proteins metabolism
Sequence Homology, Amino Acid
Subcellular Fractions
Cytoplasm chemistry
Escherichia coli metabolism
Membrane Proteins chemistry
Plant Proteins
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 277
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 11781311
- Full Text :
- https://doi.org/10.1074/jbc.M109135200