Recycling of Aborted Ribosomal 50S Subunit-Nascent Chain-tRNA Complexes by the Heat Shock Protein Hsp15

Jiang, Linhua and Schaffitzel, Christiane and Bingel-Erlenmeyer, Rouven and Ban, Nenad and Korber, Philipp and Koning, Roman I. and de Geus, Daniël C. and Plaisier, Jasper R. and Abrahams, Jan Pieter. (2009) Recycling of Aborted Ribosomal 50S Subunit-Nascent Chain-tRNA Complexes by the Heat Shock Protein Hsp15. Journal of Molecular Biology, 386 (5). pp. 1357-1367.

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Official URL: https://edoc.unibas.ch/75938/

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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.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Structural Biology & Biophysics > Nano-diffraction of Biological Specimen (Abrahams)
UniBasel Contributors:Abrahams, Jan Pieter
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:06 Nov 2020 07:45
Deposited On:06 Nov 2020 07:45

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