
==== Front
bioRxiv
BIORXIV
bioRxiv
2692-8205
Cold Spring Harbor Laboratory

10.1101/2024.08.21.609012
preprint
1
Article
Context-specific inhibition of mitochondrial ribosomes by phenicol and oxazolidinone antibiotics
Bibel Brianna http://orcid.org/0000-0001-8543-151X

Raskar Tushar http://orcid.org/0000-0001-7188-7428

Couvillion Mary http://orcid.org/0000-0002-6259-6431

Lee Muhoon
Kleinman Jordan I. http://orcid.org/0000-0001-7146-824X

Takeuchi-Tomita Nono http://orcid.org/0000-0003-4304-2633

Churchman L. Stirling http://orcid.org/0000-0003-3888-2574

Fraser James S. http://orcid.org/0000-0002-5080-2859

Fujimori Danica Galonić http://orcid.org/0000-0002-4066-9417

21 8 2024
2024.08.21.609012https://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator.
http://biorxiv.org/lookup/doi/10.1101/2024.08.21.609012
nihpp-2024.08.21.609012.pdf
ABSTRACT

The antibiotics chloramphenicol (CHL) and oxazolidinones including linezolid (LZD) are known to inhibit mitochondrial translation. This can result in serious, potentially deadly, side effects when used therapeutically. Although the mechanism by which CHL and LZD inhibit bacterial ribosomes has been elucidated in detail, their mechanism of action against mitochondrial ribosomes has yet to be explored. CHL and oxazolidinones bind to the ribosomal peptidyl transfer center (PTC) of the bacterial ribosome and prevent incorporation of incoming amino acids under specific sequence contexts, causing ribosomes to stall only at certain sequences. Through mitoribosome profiling, we show that inhibition of mitochondrial ribosomes is similarly context-specific – CHL and LZD lead to mitoribosome stalling primarily when there is an alanine, serine, or threonine in the penultimate position of the nascent peptide chain. We further validate context-specific stalling through in vitro translation assays. A high resolution cryo-EM structure of LZD bound to the PTC of the human mitoribosome shows extensive similarity to the mode of bacterial inhibition and also suggests potential avenues for altering selectivity. Our findings could help inform the rational development of future, less mitotoxic, antibiotics, which are critically needed in the current era of increasing antimicrobial resistance.
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pmc
