Abstract
tmRNA (transfer messenger RNA) is a unique molecule used by all bacteria to rescue stalled ribosomes and to mark unfinished peptides with a specific degradation signal. tmRNA is recruited by arrested ribosomes in which it facilitates the translational switch from cellular mRNA to the mRNA part of tmRNA. Small protein B (SmpB) is a key partner for the trans-translation activity of tmRNA both in vivo and in vitro. It was shown that SmpB acts at the initiation step of the trans-translation process by facilitating tmRNA aminoacylation and binding to the ribosome. Little is known about the subsequent steps of trans-translation. Here we demonstrated the first example of an investigation of tmRNA.ribosome complexes at different stages of trans-translation. Our results show that the structural element at the position of tmRNA pseudoknot 3 remains intact during the translation of the mRNA module of tmRNA and that it is localized on the surface of the ribosome. At least one SmpB molecule remains bound to a ribosome.tmRNA complex isolated from the cell when translation is blocked at different positions within the mRNA part of tmRNA.
Highlights
TmRNA1 (SsrA RNA or 10 S RNA [1]) is a small stable RNA that is found in all eubacteria as well as in some chloroplasts and mitochondria [2, 3]
Our results show that the structural element at the position of tmRNA pseudoknot 3 remains intact during the translation of the mRNA module of tmRNA and that it is localized on the surface of the ribosome
The process of trans-translation has been studied for almost 10 years, the mechanism of the transition of tmRNA through the ribosome remains mainly unknown because previous studies with in vitro systems revealed only details of the initiation stage
Summary
Small protein B (SmpB) is a key partner for the trans-translation activity of tmRNA both in vivo and in vitro. It was shown that SmpB acts at the initiation step of the trans-translation process by facilitating tmRNA aminoacylation and binding to the ribosome. Our results show that the structural element at the position of tmRNA pseudoknot 3 remains intact during the translation of the mRNA module of tmRNA and that it is localized on the surface of the ribosome. At least one SmpB molecule remains bound to a ribosome1⁄7tmRNA complex isolated from the cell when translation is blocked at different positions within the mRNA part of tmRNA. Both in vivo and in vitro studies have shown that trans-translation does not take place in the absence of SmpB [13, 14] This protein facilitates tmRNA aminoacylation [15]. We have presented the first example of transtranslation study at different stages of the passage of tmRNA through ribosome based on the isolation and investigation of tmRNA1⁄7ribosome complexes in which ribosomes stopped at the 4th or 11th codon of the coding part of tmRNA
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
