Large-Scale Movements of IF3 and tRNA during Bacterial Translation Initiation.Hussain, T., Llacer, J.L., Wimberly, B.T., Kieft, J.S., Ramakrishnan, V.
(2016) Cell 167: 133-144.e13
- PubMed: 27662086
- DOI: https://doi.org/10.1016/j.cell.2016.08.074
- Primary Citation of Related Structures:
5LMN, 5LMO, 5LMP, 5LMQ, 5LMR, 5LMS, 5LMT, 5LMU, 5LMV
- PubMed Abstract:
In bacterial translational initiation, three initiation factors (IFs 1-3) enable the selection of initiator tRNA and the start codon in the P site of the 30S ribosomal subunit. Here, we report 11 single-particle cryo-electron microscopy (cryoEM) reconstructions of the complex of bacterial 30S subunit with initiator tRNA, mRNA, and IFs 1-3, representing different steps along the initiation pathway. IF1 provides key anchoring points for IF2 and IF3, thereby enhancing their activities. IF2 positions a domain in an extended conformation appropriate for capturing the formylmethionyl moiety charged on tRNA. IF3 and tRNA undergo large conformational changes to facilitate the accommodation of the formylmethionyl-tRNA (fMet-tRNA(fMet)) into the P site for start codon recognition.
MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA.