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-Structure paper
タイトル | Structural basis for the tryptophan sensitivity of TnaC-mediated ribosome stalling. |
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ジャーナル・号・ページ | Nat Commun, Vol. 12, Issue 1, Page 5340, Year 2021 |
掲載日 | 2021年9月9日 |
著者 | Anne-Xander van der Stel / Emily R Gordon / Arnab Sengupta / Allyson K Martínez / Dorota Klepacki / Thomas N Perry / Alba Herrero Del Valle / Nora Vázquez-Laslop / Matthew S Sachs / Luis R Cruz-Vera / C Axel Innis / |
PubMed 要旨 | Free L-tryptophan (L-Trp) stalls ribosomes engaged in the synthesis of TnaC, a leader peptide controlling the expression of the Escherichia coli tryptophanase operon. Despite extensive ...Free L-tryptophan (L-Trp) stalls ribosomes engaged in the synthesis of TnaC, a leader peptide controlling the expression of the Escherichia coli tryptophanase operon. Despite extensive characterization, the molecular mechanism underlying the recognition and response to L-Trp by the TnaC-ribosome complex remains unknown. Here, we use a combined biochemical and structural approach to characterize a TnaC variant (R23F) with greatly enhanced sensitivity for L-Trp. We show that the TnaC-ribosome complex captures a single L-Trp molecule to undergo termination arrest and that nascent TnaC prevents the catalytic GGQ loop of release factor 2 from adopting an active conformation at the peptidyl transferase center. Importantly, the L-Trp binding site is not altered by the R23F mutation, suggesting that the relative rates of L-Trp binding and peptidyl-tRNA cleavage determine the tryptophan sensitivity of each variant. Thus, our study reveals a strategy whereby a nascent peptide assists the ribosome in detecting a small metabolite. |
リンク | Nat Commun / PubMed:34504068 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.4 - 2.9 Å |
構造データ | EMDB-12693, PDB-7o19: EMDB-12694, PDB-7o1a: EMDB-12695, PDB-7o1c: |
化合物 | ChemComp-MG: ChemComp-ZN: ChemComp-TRP: ChemComp-HOH: ChemComp-K: |
由来 |
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キーワード | TRANSLATION / ribosome / regulation / TnaC / arrest peptide / L-tryptophan / indole / stalling |