The Bacterial Toxin RelE Displays Codon-Specific Cleavage of mRNAs in the Ribosomal A Site
نویسندگان
چکیده
The Escherichia coli relBE operon encodes a toxin-antitoxin pair, RelE-RelB. RelB can reverse inhibition of protein synthesis by RelE in vivo. We have found that although RelE does not degrade free RNA, it cleaves mRNA in the ribosomal A site with high codon specificity. Among stop codons UAG is cleaved with fast, UAA intermediate and UGA slow rate, while UCG and CAG are cleaved most rapidly among sense codons. We suggest that inhibition of protein synthesis by RelE is reversed with the help of tmRNA, and that RelE plays a regulatory role in bacteria during adaptation to poor growth conditions.
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Prokaryotic toxin-antitoxin loci encode mRNA cleaving enzymes that inhibit translation. Two types are known: those that cleave mRNA codons at the ribosomal A site and those that cleave any RNA site specifically. RelE of Escherichia coli cleaves mRNA at the ribosomal A site in vivo and in vitro but does not cleave pure RNA in vitro. RelE exhibits an incomplete RNase fold that may explain why Rel...
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ورودعنوان ژورنال:
- Cell
دوره 112 شماره
صفحات -
تاریخ انتشار 2003