Abstract
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 language | English |
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Pages (from-to) | 185-191 |
Number of pages | 7 |
Journal | Nature Structural and Molecular Biology |
Volume | 18 |
Issue number | 2 |
Early online date | 16 Jan 2011 |
DOIs | |
Publication status | Published - Feb 2011 |
Externally published | Yes |