SNAP output for PDB entry 7chd [SNAP web server]

PDB-id

7chd; SNAP-derived features in text and JSON formats; DNAproDB

Class

transferase

Method

X-ray (3.804 Å)

Summary

Atat complexed with acetyl-methionyl-trnafmet

Reference

Yashiro Y, Sakaguchi Y, Suzuki T, Tomita K (2020): "Mechanism of aminoacyl-tRNA acetylation by an aminoacyl-tRNA acetyltransferase AtaT from enterohemorrhagic E. coli." Nat Commun, 11, 5438. doi: 10.1038/s41467-020-19281-z.

Abstract

Toxin-antitoxin systems in bacteria contribute to stress adaptation, dormancy, and persistence. AtaT, a type-II toxin in enterohemorrhagic E. coli, reportedly acetylates the α-amino group of the aminoacyl-moiety of initiator Met-tRNAf_Met, thus inhibiting translation initiation. Here, we show that AtaT has a broader specificity for aminoacyl-tRNAs than initially claimed. AtaT efficiently acetylates Gly-tRNA_Gly, Trp-tRNA_Trp, Tyr-tRNA_Tyr and Phe-tRNA_Phe isoacceptors, in addition to Met-tRNAf_Met, and inhibits global translation. AtaT interacts with the acceptor stem of tRNAf_Met, and the consecutive G-C pairs in the bottom-half of the acceptor stem are required for acetylation. Consistently, tRNA_Gly, tRNA_Trp, tRNA_Tyr and tRNA_Phe also possess consecutive G-C base-pairs in the bottom halves of their acceptor stems. Furthermore, misaminoacylated valyl-tRNAf_Met and isoleucyl-tRNAf_Met are not acetylated by AtaT. Therefore, the substrate selection by AtaT is governed by the specific acceptor stem sequence and the properties of the aminoacyl-moiety of aminoacyl-tRNAs.