A processed noncoding RNA regulates an altruistic bacterial antiviral system

Tim R. Blower, Xue Y. Pei, Francesca L. Short, Peter C. Fineran, David P. Humphreys, Ben F. Luisi, George P.C. Salmond

Research output: Contribution to journalArticleResearchpeer-review

86 Citations (Scopus)


The ≥10 30 bacteriophages on Earth relentlessly drive adaptive coevolution, forcing the generation of protective mechanisms in their bacterial hosts. One such bacterial phage-resistance system, ToxIN, consists of a protein toxin (ToxN) that is inhibited in vivo by a specific RNA antitoxin (ToxI); however, the mechanisms for this toxicity and inhibition have not been defined. Here we present the crystal structure of the ToxN-ToxI complex from Pectobacterium atrosepticum, determined to 2.75-Åresolution. ToxI is a 36-nucleotide noncoding RNA pseudoknot, and three ToxI monomers bind to three ToxN monomers to generate a trimeric ToxN-ToxI complex. Assembly of this complex is mediated entirely through extensive RNA-protein interactions. Furthermore, a 2-2-3-2 cyclic phosphate at the 3-2 end of ToxI, and catalytic residues, identify ToxN as an endoRNase that processes ToxI from a repetitive precursor but is regulated by its own catalytic product.

Original languageEnglish
Pages (from-to)185-191
Number of pages7
JournalNature Structural & Molecular Biology
Issue number2
Publication statusPublished - Feb 2011
Externally publishedYes

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