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-Structure paper
タイトル | Structures of the ribosome bound to EF-Tu-isoleucine tRNA elucidate the mechanism of AUG avoidance. |
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ジャーナル・号・ページ | Nat Struct Mol Biol, Vol. 31, Issue 5, Page 810-816, Year 2024 |
掲載日 | 2024年3月27日 |
著者 | Mariia Yu Rybak / Matthieu G Gagnon / |
PubMed 要旨 | The frequency of errors upon decoding of messenger RNA by the bacterial ribosome is low, with one misreading event per 1 × 10 codons. In the universal genetic code, the AUN codon box specifies ...The frequency of errors upon decoding of messenger RNA by the bacterial ribosome is low, with one misreading event per 1 × 10 codons. In the universal genetic code, the AUN codon box specifies two amino acids, isoleucine and methionine. In bacteria and archaea, decoding specificity of the AUA and AUG codons relies on the wobble avoidance strategy that requires modification of C34 in the anticodon loop of isoleucine transfer RNA (tRNA). Bacterial tRNA with 2-lysylcytidine (lysidine) at the wobble position deciphers AUA while avoiding AUG. Here we report cryo-electron microscopy structures of the Escherichia coli 70S ribosome complexed with elongation factor thermo unstable (EF-Tu) and isoleucine-tRNA in the process of decoding AUA and AUG. Lysidine in tRNA excludes AUG by promoting the formation of an unusual Hoogsteen purine-pyrimidine nucleobase geometry at the third position of the codon, weakening the interactions with the mRNA and destabilizing the EF-Tu ternary complex. Our findings elucidate the molecular mechanism by which tRNA specifically decodes AUA over AUG. |
リンク | Nat Struct Mol Biol / PubMed:38538914 |
手法 | EM (単粒子) |
解像度 | 2.8 - 3.1 Å |
構造データ | EMDB-29819, PDB-8g7p: EMDB-29820, PDB-8g7q: EMDB-29821, PDB-8g7r: EMDB-29822, PDB-8g7s: |
化合物 | ChemComp-MG: ChemComp-K: ChemComp-ILE: ChemComp-GCP: ChemComp-ZN: ChemComp-HOH: ChemComp-PAR: |
由来 |
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キーワード | RIBOSOME / Elongation factor Tu / lysidine 34 / cryo-EM / tRNA / paromomycin |