Abstract
AbstractIn bacteria, trans-translation is the main rescue system, freeing ribosomes stalled on defective messenger RNAs. This mechanism is driven by small protein B (SmpB) and transfer-messenger RNA (tmRNA), a hybrid RNA known to have both a tRNA-like and an mRNA-like domain. Here we present four cryo-EM structures of the ribosome during trans-translation at resolutions from 3.0 to 3.4 Å. These include the high-resolution structure of the whole pre-accommodated state, as well as structures of the accommodated state, the translocated state, and a translocation intermediate. Together, they shed light on the movements of the tmRNA-SmpB complex in the ribosome, from its delivery by the elongation factor EF-Tu to its passage through the ribosomal A and P sites after the opening of the B1 bridges. Additionally, we describe the interactions between the tmRNA-SmpB complex and the ribosome. These explain why the process does not interfere with canonical translation.
Publisher
Springer Science and Business Media LLC
Subject
General Physics and Astronomy,General Biochemistry, Genetics and Molecular Biology,General Chemistry
Reference89 articles.
1. Giudice, E. & Gillet, R. The task force that rescues stalled ribosomes in bacteria. Trends Biochem Sci. 38, 403–411 (2013).
2. Keiler, K. C. & Feaga, H. A. Resolving nonstop translation complexes is a matter of life or death. J. Bacteriol. 196, 2123–2130 (2014).
3. Buskirk, A. R. & Green, R. Ribosome pausing, arrest and rescue in bacteria and eukaryotes. Philos Trans R Soc Lond B Biol Sci. 372, 20160183 (2017).
4. Bessho, Y. et al. Structural basis for functional mimicry of long-variable-arm tRNA by transfer-messenger RNA. Proc. Natl Acad. Sci. U.S.A. 104, 8293–8298 (2007).
5. Komine, Y., Kitabatake, M., Yokogawa, T., Nishikawa, K. & Inokuchi, H. A tRNA-like structure is present in 10Sa RNA, a small stable RNA from Escherichia coli. Proc. Natl Acad. Sci. U.S.A. 91, 9223–9227 (1994).
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