Download MendeleyA new family of bacterial ribosome hibernation factors.
Helena-Bueno, K., Rybak, M.Y., Ekemezie, C.L., Sullivan, R., Brown, C.R., Dingwall, C., Basle, A., Schneider, C., Connolly, J.P.R., Blaza, J.N., Csorgo, B., Moynihan, P.J., Gagnon, M.G., Hill, C.H., Melnikov, S.V.(2024) Nature 626: 1125-1132
- PubMed: 38355796
- DOI: https://doi.org/10.1038/s41586-024-07041-8
- Primary Citation of Related Structures:
8RD8, 8RDV, 8RDW, 8V9J, 8V9K, 8V9L - PubMed Abstract:
To conserve energy during starvation and stress, many organisms use hibernation factor proteins to inhibit protein synthesis and protect their ribosomes from damage 1,2 . In bacteria, two families of hibernation factors have been described, but the low conservation of these proteins and the huge diversity of species, habitats and environmental stressors have confounded their discovery 3-6 . Here, by combining cryogenic electron microscopy, genetics and biochemistry, we identify Balon, a new hibernation factor in the cold-adapted bacterium Psychrobacter urativorans. We show that Balon is a distant homologue of the archaeo-eukaryotic translation factor aeRF1 and is found in 20% of representative bacteria. During cold shock or stationary phase, Balon occupies the ribosomal A site in both vacant and actively translating ribosomes in complex with EF-Tu, highlighting an unexpected role for EF-Tu in the cellular stress response. Unlike typical A-site substrates, Balon binds to ribosomes in an mRNA-independent manner, initiating a new mode of ribosome hibernation that can commence while ribosomes are still engaged in protein synthesis. Our work suggests that Balon-EF-Tu-regulated ribosome hibernation is a ubiquitous bacterial stress-response mechanism, and we demonstrate that putative Balon homologues in Mycobacteria bind to ribosomes in a similar fashion. This finding calls for a revision of the current model of ribosome hibernation inferred from common model organisms and holds numerous implications for how we understand and study ribosome hibernation.
Organizational Affiliation:
Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK.
