A processed noncoding RNA regulates an altruistic bacterial antiviral system

作者：Blower Tim R; Pei Xue Y; Short Francesca L; Fineran Peter C; Humphreys David P; Luisi Ben F; Salmond George P C^*

来源：Nature Structural & Molecular Biology, 2011, 18(2): 185-U246.

DOI：10.1038/nsmb.1981

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-angstrom resolution. 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'-3' cyclic phosphate at the 3' 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.

• 出版日期2011-2