Shirin Akbar

Abstract Frameshifts can be caused by specific combinations of tRNA and mRNA. The wildtype AGC-decoding E. coli tRNASer3GCU 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.

Highlights • High-resolution structures of ribosome in complex with protein biogenesis factors • The structures reveal a tertiary binding site for MetAP near the peptide tunnel exit • Simultaneous binding of PDF, MetAP, and TF would not be favorable for their function • Binding of multiple MetAPs at specific sites destabilizes ribosomal architecture Summary Bacterial co-translational N-terminal methionine excision, an early event of nascent polypeptide chain processing, is mediated by two...