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8bf7

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Elongating E. coli 70S ribosome containing deacylated tRNA(iMet) in the P-site and AAA mRNA codon with cognate dipeptidyl-tRNA(Lys) in the A-site

Structural highlights

8bf7 is a 10 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 2.33Å
Ligands:	, , , , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

RL17_ECOLI Requires L15 for assembly into the 50S subunit.[HAMAP-Rule:MF_01368]

Publication Abstract from PubMed

N(6)-methyladenosine (m(6)A) is an abundant, dynamic mRNA modification that regulates key steps of cellular mRNA metabolism. m(6)A in the mRNA coding regions inhibits translation elongation. Here, we show how m(6)A modulates decoding in the bacterial translation system using a combination of rapid kinetics, smFRET and single-particle cryo-EM. We show that, while the modification does not impair the initial binding of aminoacyl-tRNA to the ribosome, in the presence of m(6)A fewer ribosomes complete the decoding process due to the lower stability of the complexes and enhanced tRNA drop-off. The mRNA codon adopts a pi-stacked codon conformation that is remodeled upon aminoacyl-tRNA binding. m(6)A does not exclude canonical codon-anticodon geometry, but favors alternative more dynamic conformations that are rejected by the ribosome. These results highlight how modifications outside the Watson-Crick edge can still interfere with codon-anticodon base pairing and complex recognition by the ribosome, thereby modulating the translational efficiency of modified mRNAs.

Modulation of translational decoding by m(6)A modification of mRNA.,Jain S, Koziej L, Poulis P, Kaczmarczyk I, Gaik M, Rawski M, Ranjan N, Glatt S, Rodnina MV Nat Commun. 2023 Aug 8;14(1):4784. doi: 10.1038/s41467-023-40422-7. PMID:37553384^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Jain S, Koziej L, Poulis P, Kaczmarczyk I, Gaik M, Rawski M, Ranjan N, Glatt S, Rodnina MV. Modulation of translational decoding by m(6)A modification of mRNA. Nat Commun. 2023 Aug 8;14(1):4784. PMID:37553384 doi:10.1038/s41467-023-40422-7