title: Dmd of bacteriophage T4 functions as an antitoxin against Escherichia coli LsoA and RnlA toxins.
abstract: 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.
authors.affiliation: Department of Biological sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho,Toyonaka-shi, Osaka 560-0043, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Otsuka
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Yonesaki
mesh_terms: D001427:Bacterial Toxins / Q000037:antagonists & inhibitors* / Q000235:genetics; D017122:Bacteriophage T4 / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D048168:Escherichia coli K12 / Q000235:genetics; D019453:Escherichia coli O157 / Q000378:metabolism / Q000821:virology*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D010957:Plasmids; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D001427:Bacterial Toxins; C453723:Dmd protein, Enterobacteria phage T4; D029968:Escherichia coli Proteins; C572392:LsoA protein, E coli; C572393:LsoB protein, E coli; C525943:RnlA protein, E coli; D014764:Viral Proteins; C557568:rnlB protein, E coli