Doublet decoding of tRNA<sup>Ser3</sup> demonstrates plasticity of ribosomal decoding center.
basic_science · Level V
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- Record sourced from PubMed, PMID 40571681.
- Also identified by DOI 10.1038/s41467-025-61016-5 and PMC identifier 12202706.
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Abstract
Frameshifts can be caused by specific combinations of tRNA and mRNA. The wildtype AGC-decoding E. coli tRNA<sup>Ser3</sup><sub>GCU</sub> has been shown to induce -1 ribosomal frameshifting on GCA alanine codons, and proposed to read a two-base codon instead of a canonical triplet. However, it has remained unclear whether this type of non-cognate decoding can be accommodated by the ribosome. Here, we perform single-particle cryo-EM reconstructions on E. coli 70S ribosomes with the frameshift-inducing tRNA<sup>Ser3</sup> bound to the non-cognate GCA codon or the cognate AGC codon in the ribosomal A site. The structures demonstrate that doublet decoding is made possible when A1493, the conserved monitoring base in 16S rRNA, mimics a first codon base, forming a Hoogsteen base pair with U36 from the anticodon and stacking with the mRNA. This interaction pushes the first two bases of the A-site codon in position for base pairing with C35 and G34 of the anticodon.
Medical subject headings
- Escherichia coli
- Ribosomes
- Frameshifting, Ribosomal
- RNA, Transfer, Ser