Document Type

Article

Version Deposited

Published Version

Publication Date

9-4-2020

Publication Title

Nucleic Acids Research

DOI

10.1093/nar/gkaa551

Abstract

Type II toxin-antitoxins systems are widespread in prokaryotic genomes. Typically, they comprise two proteins, a toxin, and an antitoxin, encoded by adjacent genes and forming a complex in which the enzymatic activity of the toxin is inhibited. Under stress conditions, the antitoxin is degraded liberating the active toxin. Though thousands of various toxin-antitoxins pairs have been predicted bioinformatically, only a handful has been thoroughly characterized. Here, we describe the AtaT2 toxin from a toxin-antitoxin system from Escherichia coli O157:H7. We show that AtaT2 is the first GNAT (Gcn5-related N-acetyltransferase) toxin that specifically targets charged glycyl tRNA. In vivo, the AtaT2 activity induces ribosome stalling at all four glycyl codons but does not evoke a stringent response. In vitro, AtaT2 acetylates the aminoacyl moiety of isoaccepting glycyl tRNAs, thus precluding their participation in translation. Our study broadens the known target specificity of GNAT toxins beyond the earlier described isoleucine and formyl methionine tRNAs, and suggest that various GNAT toxins may have evolved to specifically target other if not all individual aminoacyl tRNAs.

Comments

Authors of Oxford Open articles are entitled to deposit their original version or the version of record in institutional and/or centrally organized repositories and can make this publicly available immediately upon publication…The journal strongly encourages Oxford Open authors to deposit the version of record instead of the original version.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Published Citation

https://academic.oup.com/nar/article/48/15/8617/5864706

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