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Dmd of bacteriophage T4 functions as an antitoxin against Escherichia coli LsoA and RnlA toxins
Author(s) -
Otsuka Yuichi,
Yonesaki Tetsuro
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2012.07975.x
Subject(s) - antitoxin , biology , orfs , escherichia coli , bacteriophage , plasmid , open reading frame , microbiology and biotechnology , homology (biology) , genetics , toxin , gene , peptide sequence
Summary Enterohaemorrhagic Escherichia coli O157:H7 harbours a cryptic plasmid, pOSAK1, that carries only three ORFs: mobA (involved in plasmid mobilization), ORF1 and ORF2. Predicted proteins encoded by these two ORFs were found to share a weak homology with RnlA and RnlB, respectively, a toxin–antitoxin system encoded on the E. coli K‐12 chromosome. Here, we report that lsoA (ORF1) encodes a toxin and lsoB (ORF2) an antitoxin. In spite of the homologies, RnlB and LsoB functioned as antitoxins against only their cognate toxins and not interchangeably with each other. Interestingly, T4 phage Dmd suppressed the toxicities of both RnlA and LsoA by direct interaction, the first example of a phage with an antitoxin against multiple toxins.