Transfer RNA Misidentification Scrambles Sense Codon Recoding |
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Authors: | Dr. Radha Krishnakumar Dr. Laure Prat Dr. Hans‐Rudolf Aerni Dr. Jiqiang Ling Prof. Dr. Chuck Merryman Prof. John I. Glass Prof. Jesse Rinehart Prof. Dieter Söll |
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Affiliation: | 1. Synthetic Biology and Bioenergy, J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850 (USA);2. Department of Molecular Biophysics and Biochemistry and Chemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06511 (USA);3. Department of Cellular and Molecular Physiology, Yale University, 333 Cedar Street, New Haven, CT 06520 (USA);4. Systems Biology Institute, Yale University, 100 West Campus Drive,Orange, CT 06477 (USA);5. Synthetic Biology and Bioenergy, J. Craig Venter Institute, 10355 Science Center Drive, San Diego, CA 92121 (USA) |
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Abstract: | Sense codon recoding is the basis for genetic code expansion with more than two different noncanonical amino acids. It requires an unused (or rarely used) codon, and an orthogonal tRNA synthetase:tRNA pair with the complementary anticodon. The Mycoplasma capricolum genome contains just six CGG arginine codons, without a dedicated tRNAArg. We wanted to reassign this codon to pyrrolysine by providing M. capricolum with pyrrolysyl‐tRNA synthetase, a synthetic tRNA with a CCG anticodon (${{rm tRNA}{{{rm Pyl}hfill atop {rm CCG}hfill}}}$ ), and the genes for pyrrolysine biosynthesis. Here we show that ${{rm tRNA}{{{rm Pyl}hfill atop {rm CCG}hfill}}}$ is efficiently recognized by the endogenous arginyl‐tRNA synthetase, presumably at the anticodon. Mass spectrometry revealed that in the presence of ${{rm tRNA}{{{rm Pyl}hfill atop {rm CCG}hfill}}}$ , CGG codons are translated as arginine. This result is not unexpected as most tRNA synthetases use the anticodon as a recognition element. The data suggest that tRNA misidentification by endogenous aminoacyl‐tRNA synthetases needs to be overcome for sense codon recoding. |
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Keywords: | aminoacyl‐tRNA synthetase recognition anticodons gene technology sense codon recoding tRNA |
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