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-Structure paper
Title | Recycling of aborted ribosomal 50S subunit-nascent chain-tRNA complexes by the heat shock protein Hsp15. |
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Journal, issue, pages | J Mol Biol, Vol. 386, Issue 5, Page 1357-1367, Year 2009 |
Publish date | Mar 13, 2009 |
Authors | Linhua Jiang / Christiane Schaffitzel / Rouven Bingel-Erlenmeyer / Nenad Ban / Philipp Korber / Roman I Koning / Daniël C de Geus / Jasper R Plaisier / Jan Pieter Abrahams / |
PubMed Abstract | When heat shock prematurely dissociates a translating bacterial ribosome, its 50S subunit is prevented from reinitiating protein synthesis by tRNA covalently linked to the unfinished protein chain ...When heat shock prematurely dissociates a translating bacterial ribosome, its 50S subunit is prevented from reinitiating protein synthesis by tRNA covalently linked to the unfinished protein chain that remains threaded through the exit tunnel. Hsp15, a highly upregulated bacterial heat shock protein, reactivates such dead-end complexes. Here, we show with cryo-electron microscopy reconstructions and functional assays that Hsp15 translocates the tRNA moiety from the A site to the P site of stalled 50S subunits. By stabilizing the tRNA in the P site, Hsp15 indirectly frees up the A site, allowing a release factor to land there and cleave off the tRNA. Such a release factor must be stop codon independent, suggesting a possible role for a poorly characterized class of putative release factors that are upregulated by cellular stress, lack a codon recognition domain and are conserved in eukaryotes. |
External links | J Mol Biol / PubMed:19013177 |
Methods | EM (single particle) |
Resolution | 10.0 - 14.0 Å |
Structure data | EMDB-1455: Recycling of Aborted Ribosomal 50S Subunit-Nascent Chain-tRNA Complexes by the Heat Shock Protein Hsp15. EMDB-1456: |
Chemicals | ChemComp-MG: ChemComp-HOH: |
Source |
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Keywords | RIBOSOME / Alpha-L RNA binding / heat shock / rescue stalled ribosome / PHE / tRNA / ribosomal complex / large subunit / 50S rescue stalled ribosome |