9TI8

Staphylococcus aureus 50S ribosome in complex with RRF, EF-G and fusidic acid (50S-RRF-EF-G-FA)

Summary for 9TI8

• Entry DOI: 10.2210/pdb9ti8/pdb
• EMDB information: 55947
• Descriptor: 50S ribosomal protein L28, 23S rRNA, 5S rRNA, ... (36 entities in total)
• Functional Keywords: rrf, ef-g, ribosome, recycling
• Biological source: Staphylococcus aureus subsp. aureus NCTC 8325; More
• Total number of polymer chains: 32
• Total formula weight: 1458854.33

Authors

Gonzalez-Lopez, A.,Selmer, M. (deposition date: 2025-12-05, release date: 2026-07-22, Last modification date: 2026-08-19)

Primary citation

Gonzalez-Lopez, A.,Selmer, M.
Structural characterization of ribosome recycling and fusidic acid inhibition in Staphylococcus aureus.
Nucleic Acids Res., 54:-, 2026

PubMed Abstract: During bacterial ribosome recycling, 70S ribosomes are split into subunits by ribosome recycling factor (RRF) and elongation factor G (EF-G). The antibiotic fusidic acid (FA) inhibits elongation and ribosome recycling by locking EF-G to the ribosome. Yet, no functional ribosome recycling FA complex has been successfully captured. Here, we used single-particle cryo-electron microscopy to resolve multiple FA-stalled intermediates of Staphylococcus aureus ribosomes, including a 70S intermediate with RRF and EF-G in a previously unobserved conformation. Our structures reveal how RRF and EF-G jointly disrupt inter-subunit bridges, promote back-rotation of the small subunit, and move the transfer RNA toward the E site to facilitate ribosome splitting. We further show that FA predominantly inhibits recycling by trapping EF-G on the post-termination complex in the absence of RRF, preventing formation of the active RRF•EF-G complex. These insights advance understanding of the molecular mechanism of bacterial ribosome recycling and the mode of action of FA as an antibiotic.

PubMed: 42573073
DOI: 10.1093/nar/gkag778

Experimental method

ELECTRON MICROSCOPY (2.18 Å)