Topology of the Bacillus subtilis SpoIISA protein and its role in toxin–antitoxin function

Authors

  • Jana Makroczyová,

    1. Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
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  • Stanislava Rešetárová,

    1. Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
    Current affiliation:
    1. Institute of Microbiology, AS ČR, Praha 4-Krč, Czech Republic
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  • Patrik Florek,

    1. Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
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  • Imrich Barák

    Corresponding author
    1. Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
    • Correspondence: Imrich Barák, Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia. Tel.: +421 2 5930 7418; fax: +421 2 5930 7416;

      e-mail: imrich.barak@savba.sk

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Abstract

SpoIISAB is a toxin–antitoxin module encoded on the chromosomes of Bacillus subtilis and related Bacilli species. The SpoIISA toxin was previously shown to target the cytoplasmic membrane and to induce lysis in both B. subtilis and Escherichia coli; however, the precise manner of SpoIISA toxicity remains unknown. In this work, we focused on the N-terminal, transmembrane domain of SpoIISA and verified the prediction of its topology. Using truncated SpoIISA constructs, we show that the entire transmembrane domain is required for its toxicity. Moreover, we propose that the oligomerization of this transmembrane domain is crucial for activity of SpoIISA, possibly by forming a pore-like structure.

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