Life without tRNA[superscript Ile]-lysidine synthetase: translation of the isoleucine codon AUA in Bacillus subtilis lacking the canonical tRNA[Ile over 2]
Name
Kohrer-2013-Life without tRNAIle.pdf
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3.93 MB
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Checksum (MD5)
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Author(s)
Koehrer, Caroline
Mandal, Debabrata
Gaston, Kirk W.
Grosjean, Henri
Limbach, Patrick A.
Rajbhandary, Uttam L
Date Issued
November 2013
Journal
Nucleic Acids Research
Publisher
Oxford University Press
Citation
Kohrer, C., D. Mandal, K. W. Gaston, H. Grosjean, P. A. Limbach, and U. L. RajBhandary. “Life without tRNAIle-lysidine synthetase: translation of the isoleucine codon AUA in Bacillus subtilis lacking the canonical tRNA2Ile.” Nucleic Acids Research (November 4, 2013).
Version
Final published version
Abstract
Translation of the isoleucine codon AUA in most prokaryotes requires a modified C (lysidine or agmatidine) at the wobble position of tRNA[Ile over 2] to base pair specifically with the A of the AUA codon but not with the G of AUG. Recently, a Bacillus subtilis strain was isolated in which the essential gene encoding tRNA[superscript Ile]-lysidine synthetase was deleted for the first time. In such a strain, C34 at the wobble position of tRNA[Ile over 2] is expected to remain unmodified and cells depend on a mutant suppressor tRNA derived from tRNA[Ile over 1], in which G34 has been changed to U34. An important question, therefore, is how U34 base pairs with A without also base pairing with G. Here, we show (i) that unlike U34 at the wobble position of all B. subtilis tRNAs of known sequence, U34 in the mutant tRNA is not modified, and (ii) that the mutant tRNA binds strongly to the AUA codon on B. subtilis ribosomes but only weakly to AUG. These in vitro data explain why the suppressor strain displays only a low level of misreading AUG codons in vivo and, as shown here, grows at a rate comparable to that of the wild-type strain.
MIT Department
Massachusetts Institute of Technology. Department of Biology
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DOI of Published Version
https://doi.org/10.1093/nar/gkt1009
