title: Structure of the 40S-ABCE1 post-splitting complex in ribosome recycling and translation initiation.
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.
authors.affiliation: Gene Center and Center of Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Heuer
authors.affiliation: Institute of Biochemistry, Biocenter, Goethe University, Frankfurt/Main, Germany.
authors.forename: Milan
authors.initials: M
authors.lastname: Gerovac
authors.affiliation: Gene Center and Center of Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Schmidt
authors.affiliation: Institute of Biochemistry, Biocenter, Goethe University, Frankfurt/Main, Germany.
authors.forename: Simon
authors.identifier: http://orcid.org/0000-0001-9143-766X
authors.initials: S
authors.lastname: Trowitzsch
authors.affiliation: Gene Center and Center of Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Preis
authors.affiliation: Institute for Molecular Genetics and Cellular Microbiology, Biocenter, Goethe University, Frankfurt/Main, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kötter
authors.affiliation: Gene Center and Center of Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany.
authors.forename: Otto
authors.initials: O
authors.lastname: Berninghausen
authors.affiliation: Gene Center and Center of Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Becker
authors.affiliation: Gene Center and Center of Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Beckmann
authors.affiliation: Institute of Biochemistry, Biocenter, Goethe University, Frankfurt/Main, Germany.
authors.forename: Robert
authors.identifier: http://orcid.org/0000-0002-0403-2160
authors.initials: R
authors.lastname: Tampé
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D008954:Models, Biological; D008958:Models, Molecular; D010442:Peptide Chain Initiation, Translational; D010443:Peptide Chain Termination, Translational; D011485:Protein Binding; D054682:Ribosome Subunits, Small, Eukaryotic / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D018528:ATP-Binding Cassette Transporters; D029701:Saccharomyces cerevisiae Proteins