Structure of the 40S-ABCE1 post-splitting complex in ribosome recycling and translation initiation.Heuer, A., Gerovac, M., Schmidt, C., Trowitzsch, S., Preis, A., Kotter, P., Berninghausen, O., Becker, T., Beckmann, R., Tampe, R.
(2017) Nat Struct Mol Biol 24: 453-460
- PubMed: 28368393
- DOI: https://doi.org/10.1038/nsmb.3396
- Primary Citation of Related Structures:
- PubMed Abstract:
The essential ATP-binding cassette protein ABCE1 splits 80S ribosomes into 60S and 40S subunits after canonical termination or quality-control-based mRNA surveillance processes. However, the underlying splitting mechanism remains enigmatic. Here, we present a cryo-EM structure of the yeast 40S-ABCE1 post-splitting complex at 3.9-Å resolution. Compared to the pre-splitting state, we observe repositioning of ABCE1's iron-sulfur cluster domain, which rotates 150° into a binding pocket on the 40S subunit. This repositioning explains a newly observed anti-association activity of ABCE1. Notably, the movement implies a collision with A-site factors, thus explaining the splitting mechanism. Disruption of key interactions in the post-splitting complex impairs cellular homeostasis. Additionally, the structure of a native post-splitting complex reveals ABCE1 to be part of the 43S initiation complex, suggesting a coordination of termination, recycling, and initiation.
Gene Center and Center of Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany.