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- Title
A conformational switch in initiation factor 2 controls the fidelity of translation initiation in bacteria.
- Authors
Caban, Kelvin; Pavlov, Michael; Ehrenberg, Måns; Gonzalez Jr., Ruben L.
- Abstract
Initiation factor (IF) 2 controls the fidelity of translation initiation by selectively increasing the rate of 50S ribosomal subunit joining to 30S initiation complexes (ICs) that carry an Nformyl-methionyl-tRNA (fMet-tRNAfMet). Previous studies suggest that rapid 50S subunit joining involves a GTP- and fMet-tRNAfMet-dependent “activation” of IF2, but a lack of data on the structure and conformational dynamics of 30S IC-bound IF2 has precluded a mechanistic understanding of this process. Here, using an IF2-tRNA single-molecule fluorescence resonance energy transfer signal, we directly observe the conformational switch that is associated with IF2 activation within 30S ICs that lack IF3. Based on these results, we propose a model of IF2 activation that reveals how GTP, fMet-tRNAfMet, and specific structural elements of IF2 drive and regulate this conformational switch. Notably, we find that domain III of IF2 plays a pivotal, allosteric, role in IF2 activation, suggesting that this domain can be targeted for the development of novel antibiotics.
- Subjects
FLUORESCENCE resonance energy transfer; PROTHROMBIN; LOYALTY; TRANSLATIONS
- Publication
Nature Communications, 2017, Vol 8, Issue 1, p1
- ISSN
2041-1723
- Publication type
Article
- DOI
10.1038/s41467-017-01492-6