Cryo-EM analysis of E. coli ribosome recovery mechanism in the absence of the 30S maturation factor RimM
| Autoři | |
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| Rok publikování | 2025 |
| Druh | Konferenční abstrakty |
| Fakulta / Pracoviště MU | |
| Citace | |
| Popis | Ribosome biogenesis is a complex, multistep process that involves the folding and modification of ribosomal RNA (rRNA), followed by the sequential assembly and integration of ribosomal proteins. This intricate process is tightly regulated by numerous biogenesis factors that ensure the proper formation of functional ribosomal subunits. Disruptions in these factors can lead to severe growth defects and the accumulation of immature ribosomal subunits, highlighting their critical role in ribosome maturation. RimM, a key ribosome maturation factor, facilitates the correct assembly of the 30S small ribosomal subunit. In E. coli, deletion of the rimM gene results in impaired growth, accumulation of immature 30S particles, and reduced translational efficiency. Interestingly, the gradual recovery of bacterial growth suggests the presence of compensatory mechanisms that restore translation capacity over time. One such mechanism may involve the ribosomal silencing factor RsfS, which regulates protein synthesis by binding to the 50S ribosomal subunit. This interaction prevents premature 70S ribosome formation, potentially shielding mature 50S subunits from associating with immature 30S particles. In this study, we employed single particle cryo-electron microscopy (cryo-EM) to investigate the interplay between RsfS and translation initiation factors in the absence of RimM. Our structural analysis reveals that translation initiation factors bind to immature 30S subunits, preventing their association with 50S subunits until ribosomal proteins are fully assembled on the 30S subunit. Concurrently, RsfS binds to the 50S subunit, effectively inhibiting the formation of 70S ribosomes. These findings provide valuable structural and mechanistic insights into the final stages of ribosome assembly and underscore the critical roles of ribosome-associated factors in maintaining translational fidelity and cellular adaptation. |
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