8t5h

Cryo-EM studies of the interplay between uS2 ribosomal protein and leaderless mRNA during bacterial translation initiation

spinqualitylabelsall models 8t5h, resolution 3.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8t5h is a 10 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.3Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A828UBL8_ECOLX Publication Abstract from PubMed In bacteriophage lambda lysogens, the lambdacI repressor is encoded by the leaderless transcript (lmRNA) initiated at the lambdapRM 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 lambdacI lmRNA and fMet-tRNA(fMet). 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 pi-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. How Dedicated Ribosomes Translate a Leaderless mRNA.,Acosta-Reyes FJ, Bhattacharjee S, Gottesman M, Frank J J Mol Biol. 2024 Feb 15;436(4):168423. doi: 10.1016/j.jmb.2023.168423. Epub 2024 , Jan 5. PMID:38185325 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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