Ribosomal protein S1 induces a conformational change of tmRNA; more than one protein S1 per molecule of tmRNA.Report as inadecuate




Ribosomal protein S1 induces a conformational change of tmRNA; more than one protein S1 per molecule of tmRNA. - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 Fonction, structure et inactivation d-ARN bactériens

Abstract : tmRNA 10Sa RNA, ssrA acts to rescue stalled bacterial ribosomes while encoding a peptide tag added trans-translationally to the nascent peptide, targeting it for proteolysis. Ribosomal protein S1 is required for tmRNA binding to isolated and poly U-programmed ribosomes. Mobility assays on native gels indicate that the binding curves of both recombinant and purified proteins S1 from E. coli is biphasic with apparent binding constants of approximately 90 and approximately 300 nM, respectively, suggesting that more than one protein interacts with tmRNA. Structural probing of native tmRNA in the presence and absence of the purified protein suggest that when S1 binds, tmRNA undergoes a significant conformational change. In the presence of the protein, nucleotides from tmRNA with enhanced H2, H3, PK1, PK2, PK4, in and around the first triplet to be translated, or decreased H5 and PK2, reactivity towards a probe specific for RNA single-strands are scattered throughout the molecule, with the exception of the tRNA-like domain that may be dispensable for the interaction. Converging experimental evidence suggests that ribosomal protein S1 binds to pseudoknot PK2. Previous structural studies of tmRNA in solution have revealed several discrepancies between the probing data and the phylogeny, and most of these are reconciled when analyzing tmRNA structure in complex with the proteins. Ribosomal proteins S1 is proposed to set tmRNA in the mRNA mode, relieving strains that may develop when translating a looped mRNA.

Keywords : Bacterial ribosome Trans-translation Transfer-messenger RNA Ribosomal protein S1 Structural probing





Author: Valérie Bordeau - Brice Felden -

Source: https://hal.archives-ouvertes.fr/



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