An intermediate state of bacterial ribosome dissociation is fixed by yeast mitochondrial initiation factor 3
- Published
- Accepted
- Subject Areas
- Biochemistry, Molecular Biology
- Keywords
- ribosome, initiation factor 3, subunit dissociation, mitochondria, translation
- Copyright
- © 2018 Levitskii et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2018. An intermediate state of bacterial ribosome dissociation is fixed by yeast mitochondrial initiation factor 3. PeerJ Preprints 6:e26997v1 https://doi.org/10.7287/peerj.preprints.26997v1
Abstract
The processes of association and dissociation of ribosomal subunits are of great importance for the protein biosynthesis. The mechanistic details of these processes, however, are not well known. In bacteria, upon translation termination, ribosome dissociates into subunits which is necessary for its further involvement into new initiation step. The dissociated state of ribosome is maintained by initiation factor 3 (IF3) which binds to free small subunits and prevents their premature association with the large subunits. In this work, we have exchanged IF3 in E.coli cells by its ortholog from Saccharomyces cerevisiae mitochondria (Aim23p) and showed that yeast protein cannot functionally substitute the bacterial one and is even slightly toxic for bacterial cells. Our in vitro experiments have demonstrated that Aim23p does not split E.coli ribosomes into subunits. Instead, it fixes an intermediate state of ribosomes dissociation characterized by sedimentation coefficient about 60S. Using molecular modeling, we show that such fixation is due to mitochondria-specific terminal extensions of Aim23p that stabilize the position of the protein on the bacterial ribosome.
Author Comment
This is a submission to PeerJ for review.
We understand the PeerJ Preprints policy and wish to proceed with publishing our work as a preprint.
Supplemental Information
Raw data for Fig2D (initial scan of the Western-blotting results)
Initial modeling of Aim23p binding to 16S rRNA of E.coli
Aim23p is in green. Long unstructured extensions can be seen on the left side of the picture.
