A processed noncoding RNA regulates an altruistic bacterial antiviral system.
A processed noncoding RNA regulates an altruistic bacterial antiviral system.
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DOI：
10.1038/nsmb.1981
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发表时间：
2011-02
影响因子：
16.8
通讯作者：
Salmond GP
中科院分区：
文献类型：
--
作者：
Blower TR;Pei XY;Short FL;Fineran PC;Humphreys DP;Luisi BF;Salmond GP
地球上的≥1030噬菌体无情地推动适应性协同进化，迫使它们的细菌宿主产生保护机制。一种这样的细菌噬菌体抗性系统，毒素，由一种蛋白毒素(ToxN)组成，在体内被一种特定的RNA抗毒素(Toxi)抑制；然而，这种毒性和抑制的机制尚未确定。在这里，我们提出了毒素复合体的晶体结构，其分辨率为2.75。Toxi是一个36个核苷酸的非编码RNA假结，三个Toxi单体与三个ToxN单体结合形成三聚体ToxN-Toxi复合体。这种复合体的组装完全通过广泛的RNA-蛋白质相互作用来调节。此外，毒素3‘端的2’-3‘环磷酸和催化残基确定ToxN是一种内切核糖核酸酶，它从重复的前体中处理毒素，但受其自身催化产物的调节。
The ≥1030 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-Å 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.