Genome Expansion by tRNA +1 Frameshifting at Quadruplet Codons

J Mol Biol. 2022 Apr 30;434(8):167440. doi: 10.1016/j.jmb.2021.167440. Epub 2022 Jan 4.

Abstract

Inducing tRNA +1 frameshifting to read a quadruplet codon has the potential to incorporate a non-canonical amino acid (ncAA) into the polypeptide chain. While this strategy is attractive for genome expansion in biotechnology and bioengineering endeavors, improving the yield is hampered by a lack of understanding of where the shift can occur in an elongation cycle of protein synthesis. Lacking a clear answer to this question, current efforts have focused on designing +1-frameshifting tRNAs with an extra nucleotide inserted to the anticodon loop for pairing with a quadruplet codon in the aminoacyl-tRNA binding (A) site of the ribosome. However, the designed and evolved +1-frameshifting tRNAs vary broadly in achieving successful genome expansion. Here we summarize recent work on +1-frameshifting tRNAs. We suggest that, rather than engineering the quadruplet anticodon-codon pairing scheme at the ribosome A site, efforts should be made to engineer the pairing scheme at steps after the A site, including the step of the subsequent translocation and the step that stabilizes the pairing scheme in the +1-frame in the peptidyl-tRNA binding (P) site.

Keywords: ProL tRNA; ProM tRNA; SufB2 tRNA; m(1)G37-tRNA; mcmo(5)U34-tRNA.

Publication types

  • Review

MeSH terms

  • Anticodon / genetics
  • Anticodon / metabolism
  • Base Pairing
  • Codon* / genetics
  • Escherichia coli / metabolism
  • Frameshifting, Ribosomal* / genetics
  • Genetic Code*
  • Protein Engineering* / methods
  • RNA, Transfer* / genetics
  • RNA, Transfer* / metabolism
  • Ribosomes / metabolism

Substances

  • Anticodon
  • Codon
  • RNA, Transfer