8T5H
Cryo-EM studies of the interplay between uS2 ribosomal protein and leaderless mRNA during bacterial translation initiation
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Summary for 8T5H
| Entry DOI | 10.2210/pdb8t5h/pdb |
| EMDB information | 41050 |
| Descriptor | 50S ribosomal protein L32, 50S ribosomal protein L4, 50S ribosomal protein L5, ... (51 entities in total) |
| Functional Keywords | leaderless mrna, cryo-em, 70s, hflx, ribosome, bs21, us2 |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 51 |
| Total formula weight | 2090185.67 |
| Authors | |
| Primary citation | Acosta-Reyes, F.J.,Bhattacharjee, S.,Gottesman, M.,Frank, J. How Dedicated Ribosomes Translate a Leaderless mRNA. J.Mol.Biol., 436:168423-168423, 2024 Cited by PubMed Abstract: In bacteriophage λ lysogens, the λcI repressor is encoded by the leaderless transcript (lmRNA) initiated at the λpRM promoter. Translation is enhanced in rpsB mutants deficient in ribosomal protein uS2. Although translation initiation of lmRNA is conserved in bacteria, archaea, and eukaryotes, structural insight of a lmRNA translation initiation complex is missing. Here, we use cryo-EM to solve the structures of the uS2-deficient 70S ribosome of host E. coli mutant rpsB11 and the wild-type 70S complex with λcI lmRNA and fMet-tRNA. Importantly, the uS2-deficient 70S ribosome also lacks protein bS21. The anti-Shine-Dalgarno (aSD) region is structurally supported by bS21, so that the absence of the latter causes the aSD to divert from the normal mRNA exit pathway, easing the exit of lmRNA. A π-stacking interaction between the monitor base A1493 and A(+4) of lmRNA potentially acts as a recognition signal. Coulomb charge flow, along with peristalsis-like dynamics within the mRNA entrance channel due to the increased 30S head rotation caused by the absence of uS2, are likely to facilitate the propagation of lmRNA through the ribosome. These findings lay the groundwork for future research on the mechanism of translation and the co-evolution of lmRNA and mRNA that includes the emergence of a defined ribosome-binding site of the transcript. PubMed: 38185325DOI: 10.1016/j.jmb.2023.168423 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.3 Å) |
Structure validation
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