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A Conserved Ribosomal Protein Has Entirely Dissimilar Structures in Different Organisms

Lookup NU author(s): Charlotte Brown, Karla Helena Bueno, Professor Robert HirtORCiD, Dr Sergey MelnikovORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© The Author(s) 2023. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution. Ribosomes from different species can markedly differ in their composition by including dozens of ribosomal proteins that are unique to specific lineages but absent in others. However, it remains unknown how ribosomes acquire new proteins throughout evolution. Here, to help answer this question, we describe the evolution of the ribosomal protein msL1/msL2 that was recently found in ribosomes from the parasitic microorganism clade, microsporidia. We show that this protein has a conserved location in the ribosome but entirely dissimilar structures in different organisms: in each of the analyzed species, msL1/msL2 exhibits an altered secondary structure, an inverted orientation of the N-termini and C-termini on the ribosomal binding surface, and a completely transformed 3D fold. We then show that this fold switching is likely caused by changes in the ribosomal msL1/msL2-binding site, specifically, by variations in rRNA. These observations allow us to infer an evolutionary scenario in which a small, positively charged, de novo-born unfolded protein was first captured by rRNA to become part of the ribosome and subsequently underwent complete fold switching to optimize its binding to its evolving ribosomal binding site. Overall, our work provides a striking example of how a protein can switch its fold in the context of a complex biological assembly, while retaining its specificity for its molecular partner. This finding will help us better understand the origin and evolution of new protein components of complex molecular assemblies-thereby enhancing our ability to engineer biological molecules, identify protein homologs, and peer into the history of life on Earth.

Publication metadata

Author(s): Schierholz L, Brown CR, Helena-Bueno K, Uversky VN, Hirt RP, Barandun J, Melnikov SV

Publication type: Article

Publication status: Published

Journal: Molecular Biology and Evolution

Year: 2024

Volume: 41

Issue: 1

Print publication date: 01/01/2024

Online publication date: 21/11/2023

Acceptance date: 16/11/2023

Date deposited: 23/01/2024

ISSN (electronic): 1537-1719

Publisher: Oxford University Press


DOI: 10.1093/molbev/msad254

PubMed id: 37987564


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Funder referenceFunder name
ERC Starting Grant PolTube 948655
H2020 European Research Council
Horizon 2020 Framework programme
Laboratory for Molecular Infection Medicine Sweden
Newcastle University Oversears Research Scholarship 2021 award
Science for Life Laboratory National Fellows program
Swedish Research Council (2019-02011)