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The RNA acetyltransferase driven by ATP hydrolysis synthesizes N 4 ‐acetylcytidine of tRNA anticodon
Author(s) -
Ikeuchi Yoshiho,
Kitahara Kei,
Suzuki Tsutomu
Publication year - 2008
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2008.154
Subject(s) - transfer rna , biology , rna , biochemistry , acetyltransferase , gene , acetylation
The wobble base of Escherichia coli elongator tRNA Met is modified to N 4 ‐acetylcytidine (ac 4 C), which is thought to ensure the precise recognition of the AUG codon by preventing misreading of near‐cognate AUA codon. By employing genome‐wide screen of uncharacterized genes in Escherichia coli (‘ribonucleome analysis’), we found the ypfI gene, which we named tmcA (tRNA Met cytidine acetyltransferase), to be responsible for ac 4 C formation. TmcA is an enzyme that contains a Walker‐type ATPase domain in its N‐terminal region and an N ‐acetyltransferase domain in its C‐terminal region. Recombinant TmcA specifically acetylated the wobble base of E. coli elongator tRNA Met by utilizing acetyl‐coenzyme A (CoA) and ATP (or GTP). ATP/GTP hydrolysis by TmcA is stimulated in the presence of acetyl‐CoA and tRNA Met . A mutation study revealed that E. coli TmcA strictly discriminates elongator tRNA Met from the structurally similar tRNA Ile by mainly recognizing the C27–G43 pair in the anticodon stem. Our findings reveal an elaborate mechanism embedded in tRNA Met and tRNA Ile for the accurate decoding of AUA/AUG codons on the basis of the recognition of wobble bases by the respective RNA‐modifying enzymes.