Related Experiment Video
Updated: Mar 10, 2026

Removal of an Internal Translational Start Site from mRNA While Retaining Expression of the Full-Length Protein
Published on: March 16, 2022
Modification of orthogonal tRNAs: unexpected consequences for sense codon reassignment
Wil Biddle1, Margaret A Schmitt2, John D Fisk3,2,4
1Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
Genetic code engineering can incorporate non-canonical amino acids. We found a tRNA modification that unexpectedly altered codon recognition, impacting protein synthesis and offering new strategies for genetic code expansion.
Area of Science:
- Synthetic Biology
- Molecular Biology
- Biochemistry
Background:
- Sense codon reassignment enables incorporating non-canonical amino acids into proteins.
- Orthogonal tRNAs are crucial tools for genetic code engineering.
Purpose of the Study:
- Investigate an unexpected modification of an engineered orthogonal tRNA.
- Determine the impact of this modification on codon decoding and translation.
- Identify strategies to control tRNA activity for improved genetic code expansion.
Main Methods:
- Engineered an orthogonal tRNA (tRNAOpt) with an AUG anticodon.
- Analyzed tRNA decoding activity for histidine codons (CAU, CAC).
- Identified tRNA modifications using biochemical and genetic approaches.
- Generated and tested tRNA anticodon loop variants.
Main Results:
- The engineered tRNAOpt unexpectedly decoded both CAU and CAC histidine codons equally.
- Adenosine 34 in the tRNAOpt anticodon was modified to inosine by a host enzyme.
- Specific tRNAOpt anticodon loop variants altered codon reassignment, favoring CAU over CAC.
- Variants improved cellular growth and protein synthesis.
Conclusions:
- Adventitious tRNA modification by host enzymes can impact genetic code engineering.
- Understanding and manipulating tRNA modifications is key for directed genetic code alteration.
- This work provides insights into controlling tRNA activity for enhanced protein synthesis and genetic code expansion.
More Related Videos
10:31Residue-Specific Exchange of Proline by Proline Analogs in Fluorescent Proteins: How "Molecular Surgery" of the Backbone Affects Folding and Stability
Published on: February 3, 2022
10:44Single Cell Multiplex Reverse Transcription Polymerase Chain Reaction After Patch-clamp
Published on: June 20, 2018
Related Concept Videos
Mutations
Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Transfer RNA Synthesis
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Exon Recombination
Exon shuffling follows “splice frame rules.” Each exon...
From DNA to Protein
Overview of Transposition and Recombination