"Not-so-popular" orthogonal pairs in genetic code expansion

Area of Science:

• Biochemistry
• Molecular Biology
• Synthetic Biology

Background:

• Genetic code expansion is a key technology for protein research and engineering.
• Orthogonal pairs of synthetase and tRNA enable site-specific incorporation of noncanonical amino acids (ncAAs) into proteins across various hosts.
• Popular pairs include tyrosyl-tRNA synthetase/tRNA^Tyr from *Methanococcus jannaschii* and pyrrolysyl-tRNA synthetase/tRNA^Pyl from *Methanosarcina* species.

Purpose of the Study:

• To summarize the development and applications of underutilized orthogonal pairs for genetic code expansion.
• To highlight the advantages of these less common pairs in providing diverse ncAA choices.
• To underscore their necessity for simultaneous incorporation of multiple ncAAs into a single protein.

Main Methods:

• Review of literature on orthogonal pairs for genetic code expansion.
• Analysis of the development and application of less common synthetase/tRNA pairs.
• Discussion of host systems (bacteria, yeast, mammalian cells, animals, plants) used in these studies.

Main Results:

• Identification and characterization of several "not-so-popular" orthogonal pairs beyond the widely used ones.
• Demonstration of expanded ncAA repertoires achievable with these alternative pairs.
• Evidence for the utility of these pairs in facilitating multiple ncAA incorporation into single proteins.

Conclusions:

• Less common orthogonal pairs are crucial for advancing protein engineering and research.
• These pairs offer greater flexibility and expanded capabilities for incorporating diverse ncAAs.
• Further exploration and application of these pairs will drive innovation in protein science.