Genetic Code Expansion in the Service of Bioelectrochemistry

Abstract

Genetic code expansion is a method that enables the inclusion of unnatural amino acids (UAAs) into proteins by expanding the genetic code beyond the 20 canonical amino acids. This can be accomplished by introducing new codons (triplet sequences that encode specific amino acids) into the genetic code via orthogonal tRNA/synthetase pairs.Orthogonal tRNA/synthetase pairs are comprised of aminoacyl-tRNA synthetases (aaRSs) and tRNAs that are not present in nature. These pairs can recognize and charge UAAs with tRNAs that possess non-natural codons, allowing for the integration of these amino acids into proteins in response to non-sense codons.In our laboratory, we utilize this approach to incorporate various UAAs, some of which serve as orthogonal chemical handles for "clicking" them with redox-active molecules or biomolecules (via click chemistry) or for attaching them to electrodes to enable site-specific orientation of enzymes. Some UAAs are redox-active on their own, which imparts new properties to the proteins and enzymes into which they are incorporated for biosensing and catalysis. In my presentation, I will outline a simple straightforward technique developed in our lab for selecting new UAAs-compatible aaRSs and provide examples and electrochemical characterizations from our recent investigations. Genetic code expansion is a method that enables the inclusion of unnatural amino acids (UAAs) into proteins by expanding the genetic code beyond the 20 canonical amino acids. This can be accomplished by introducing new codons (triplet sequences that encode specific amino acids) into the genetic code via orthogonal tRNA/synthetase pairs.Orthogonal tRNA/synthetase pairs are comprised of aminoacyl-tRNA synthetases (aaRSs) and tRNAs that are not present in nature. These pairs can recognize and charge UAAs with tRNAs that possess non-natural codons, allowing for the integration of these amino acids into proteins in response to non-sense codons.In our laboratory, we utilize this approach to incorporate various UAAs, some of which serve as orthogonal chemical handles for "clicking" them with redox-active molecules or biomolecules (via click chemistry) or for attaching them to electrodes to enable site-specific orientation of enzymes. Some UAAs are redox-active on their own, which imparts new properties to the proteins and enzymes into which they are incorporated for biosensing and catalysis. In my presentation, I will outline a simple straightforward technique developed in our lab for selecting new UAAs-compatible aaRSs and provide examples and electrochemical characterizations from our recent investigations.