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-Structure paper
Title | Structure of Escherichia coli heat shock protein Hsp15 in complex with the ribosomal 50S subunit bearing peptidyl-tRNA. |
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Journal, issue, pages | Nucleic Acids Res, Vol. 50, Issue 21, Page 12515-12526, Year 2022 |
Publish date | Nov 28, 2022 |
Authors | Haaris A Safdari / Sergo Kasvandik / Christine Polte / Zoya Ignatova / Tanel Tenson / Daniel N Wilson / |
PubMed Abstract | In Escherichia coli, the heat shock protein 15 (Hsp15) is part of the cellular response to elevated temperature. Hsp15 interacts with peptidyl-tRNA-50S complexes that arise upon dissociation of ...In Escherichia coli, the heat shock protein 15 (Hsp15) is part of the cellular response to elevated temperature. Hsp15 interacts with peptidyl-tRNA-50S complexes that arise upon dissociation of translating 70S ribosomes, and is proposed to facilitate their rescue and recycling. A previous structure of E. coli Hsp15 in complex with peptidyl-tRNA-50S complex reported a binding site located at the central protuberance of the 50S subunit. By contrast, recent structures of RqcP, the Hsp15 homolog in Bacillus subtilis, in complex with peptidyl-tRNA-50S complexes have revealed a distinct site positioned between the anticodon-stem-loop (ASL) of the P-site tRNA and H69 of the 23S rRNA. Here we demonstrate that exposure of E. coli cells to heat shock leads to a decrease in 70S ribosomes and accumulation of 50S subunits, thus identifying a natural substrate for Hsp15 binding. Additionally, we have determined a cryo-EM reconstruction of the Hsp15-50S-peptidyl-tRNA complex isolated from heat shocked E. coli cells, revealing that Hsp15 binds to the 50S-peptidyl-tRNA complex analogously to its B. subtilis homolog RqcP. Collectively, our findings support a model where Hsp15 stabilizes the peptidyl-tRNA in the P-site and thereby promotes access to the A-site for putative rescue factors to release the aberrant nascent polypeptide chain. |
External links | Nucleic Acids Res / PubMed:36370110 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.0 Å |
Structure data | EMDB-15558, PDB-8ap4: |
Source |
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Keywords | TRANSLATION / S4 domain / heat shock / stress response / ribosome quality control |