A genetic analysis of in vivo selenate reduction by Salmonella enterica serovar Typhimurium LT2 and Escherichia coli K12

David Guymer, Julien Maillard, Frank Sargent

    Research output: Contribution to journalArticle

    40 Citations (Scopus)

    Abstract

    The twin-arginine transport (Tat) system is dedicated to the translocation of folded proteins across the bacterial cytoplasmic membrane. Proteins are targeted to the Tat system by signal peptides containing a twin-arginine motif. In Salmonella enterica serovar Typhimurium and Escherichia coli many Tat substrates are known or predicted to bind a molybdenum cofactor in the cytoplasm prior to export. In the case of N- and S-oxide reductases, co-ordination of molybdenum cofactor insertion with protein export involves a 'Tat proofreading' process where chaperones of the TorD family bind the signal peptides, thus preventing premature export. Here, a genetic approach was taken to determine factors required for selenate reductase activity in Salmonella and E. coli. It is reported for both biological systems that an active Tat translocase and a TorD-like chaperone (DmsD) are required for complete in vivo reduction of selenate to elemental red selenium. Further mutagenesis and in vitro biophysical experiments implicate the Salmonella ynfE gene product, and the E. coli YnfE and YnfF proteins, as putative Tat-targeted selenate reductases.

    Original languageEnglish
    Pages (from-to)519-528
    Number of pages10
    JournalArchives of Microbiology
    Volume191
    Issue number6
    DOIs
    Publication statusPublished - Jun 2009

    Keywords

    • Enteric bacteria
    • Bacterial respiration
    • Twin-arginine translocation pathway
    • Molybdo-enzymes
    • Selenate reductase
    • Molecular chaperone
    • Mutagenesis
    • Isothermal titration calorimetry
    • ENTEROBACTER-CLOACAE SLD1A-1
    • DIMETHYL-SULFOXIDE REDUCTASE
    • SIGNAL PEPTIDE
    • NITRATE REDUCTASE
    • PROOFREADING CHAPERONE
    • TRANSLOCATION PATHWAY
    • DMSO REDUCTASE
    • EXPORT PATHWAY
    • UBIE GENE
    • COLI

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