PMID: 30150682

Authors:

Taniguchi T, Miyauchi K, Sakaguchi Y, Yamashita S, Soma A, Tomita K, Suzuki T

Title:

Acetate-dependent tRNA acetylation required for decoding fidelity in protein synthesis.

Journal:

Nat Chem Biol. 2018 Nov;14(11):1010-1020. doi: 10.1038/s41589-018-0119-z. Epub, 2018 Aug 27.

Abstract:

Modification of tRNA anticodons plays a critical role in ensuring accurate translation. N(4)-acetylcytidine (ac(4)C) is present at the anticodon first position (position 34) of bacterial elongator tRNA(Met). Herein, we identified Bacillus subtilis ylbM (renamed tmcAL) as a novel gene responsible for ac(4)C34 formation. Unlike general acetyltransferases that use acetyl-CoA, TmcAL activates an acetate ion to form acetyladenylate and then catalyzes ac(4)C34 formation through a mechanism similar to tRNA aminoacylation. The crystal structure of TmcAL with an ATP analog reveals the molecular basis of ac(4)C34 formation. The DeltatmcAL strain displayed a cold-sensitive phenotype and a strong genetic interaction with tilS that encodes the enzyme responsible for synthesizing lysidine (L) at position 34 of tRNA(Ile) to facilitate AUA decoding. Mistranslation of the AUA codon as Met in the DeltatmcAL strain upon tilS repression suggests that ac(4)C34 modification of tRNA(Met) and L34 modification of tRNA(Ile) act cooperatively to prevent misdecoding of the AUA codon.