8WHN

Crystal Structure of the cytoplasmic domain of OST1 (Ribophorin I) from Candidatus Prometheoarchaeum syntrophicum strain MK-D1

Summary for 8WHN

• Entry DOI: 10.2210/pdb8whn/pdb
• Descriptor: Ribophorin 1 superfamily protein (2 entities in total)
• Functional Keywords: asgard archaea ost complex, translocase
• Biological source: Candidatus Prometheoarchaeum syntrophicum
• Total number of polymer chains: 1
• Total formula weight: 19016.02

Authors

Robinson, R.C.,Carilo, I. (deposition date: 2023-09-23, release date: 2024-09-25, Last modification date: 2024-10-02)

Primary citation

Carilo, I.,Senju, Y.,Yokoyama, T.,Robinson, R.C.
Intercompatibility of eukaryotic and Asgard archaea ribosome-translocon machineries.
J.Biol.Chem., 300:107673-107673, 2024

PubMed Abstract: In all domains of life, the ribosome-translocon complex inserts nascent transmembrane proteins into, and processes and transports signal peptide-containing proteins across, membranes. Eukaryotic translocons are anchored in the endoplasmic reticulum, while the prokaryotic complexes reside in cell membranes. Phylogenetic analyses indicate the inheritance of eukaryotic Sec61/oligosaccharyltransferase/translocon-associated protein translocon subunits from an Asgard archaea ancestor. However, the mechanism for translocon migration from a peripheral membrane to an internal cellular compartment (the proto-endoplasmic reticulum) during eukaryogenesis is unknown. Here we show compatibility between the eukaryotic ribosome-translocon complex and Asgard signal peptides and transmembrane proteins. We find that Asgard translocon proteins from Candidatus Prometheoarchaeum syntrophicum strain Candidatus Prometheoarchaeum syntrophicum strain MK-D1, a Lokiarchaeon confirmed to contain no internal cellular membranes, are targeted to the eukaryotic endoplasmic reticulum on ectopic expression. Furthermore, we show that the cytoplasmic domain of Candidatus Prometheoarchaeum syntrophicum strain MK-D1 oligosaccharyltransferase 1 (ribophorin I) can interact with eukaryotic ribosomes. Our data indicate that the location of existing ribosome-translocon complexes, at the protein level, determines the future placement of yet-to-be-translated translocon subunits. This principle predicts that during eukaryogenesis, under positive selection pressure, the relocation of a few translocon complexes to the proto-endoplasmic reticulum will have contributed to propagating the new translocon location, leading to their loss from the cell membrane.

PubMed: 39128722
DOI: 10.1016/j.jbc.2024.107673

Experimental method

X-RAY DIFFRACTION (1.95 Å)