5y0s
Crystal structure of apo Thermotoga maritima TmcAL(Form II)
Structural highlights
FunctionTMCAL_THEMA Catalyzes the formation of N(4)-acetylcytidine (ac(4)C) at the wobble position of elongator tRNA(Met), using acetate and ATP as substrates. First activates an acetate ion to form acetyladenylate (Ac-AMP) and then transfers the acetyl group to tRNA to form ac(4)C34.[HAMAP-Rule:MF_01539] Publication Abstract from PubMedModification 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. Acetate-dependent tRNA acetylation required for decoding fidelity in protein synthesis.,Taniguchi T, Miyauchi K, Sakaguchi Y, Yamashita S, Soma A, Tomita K, Suzuki T Nat Chem Biol. 2018 Nov;14(11):1010-1020. doi: 10.1038/s41589-018-0119-z. Epub, 2018 Aug 27. PMID:30150682[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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