Genetic evidence for a TatC dimer at the core of the escherichia coli twin arginine (Tat) protein translocase

Barbara Maldonado , Grant Buchanan, Matthias Müller, Ben C. Berks, Tracy Palmer

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    20 Citations (Scopus)

    Abstract

    The twin arginine protein transport (Tat) system transports folded proteins across the cytoplasmic membranes of prokaryotes and the thylakoid membranes of plant chloroplasts. In Escherichia coli, the TatB and TatC components form a multivalent receptor complex that binds Tat substrates. Here, we have used a genetic fusion approach to construct covalent TatC oligomers in order to probe the organisation of TatC. A fused dimer of TatC supported Tat transport activity and was fully stable in vivo. Inactivating point mutations in one or other of the TatC units in the fused TatC dimer did not inactivate TatC function, indicating that only one TatC protomer in the TatC fused dimer needs to be active. Larger covalent fusions of TatC also supported Tat transport activity but were degraded in vivo to release smaller TatC forms. Taken together, these results strongly suggest that TatC forms a functional dimer, and support the idea that there is an even number of TatC protomers in the TatBC complex. Copyright (C) 2011 S. Karger AG, Basel

    Original languageEnglish
    Pages (from-to)168-175
    Number of pages8
    JournalJournal of Molecular Microbiology and Biotechnology
    Volume20
    Issue number3
    DOIs
    Publication statusPublished - 2011

    Keywords

    • Protein transport
    • Twin arginine signal peptide
    • Tat pathway
    • TatBC complex
    • Dimer
    • Genetic fusion
    • SEC-INDEPENDENT PROTEIN
    • CYSTEINE-SCANNING MUTAGENESIS
    • TRANSPORT SYSTEM
    • SIGNAL PEPTIDE
    • PRECURSOR PROTEINS
    • EXPORT PATHWAY
    • BINDING-SITE
    • COMPONENT
    • COMPLEXES
    • MEMBRANE

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