Coexisting bacterial aminoacyl-tRNA synthetase paralogs exhibit distinct phylogenetic backgrounds and functional compatibility with Escherichia coli.

Aminoacyl-tRNA synthetases (aaRSs) are universally essential enzymes that synthesize aminoacyl-tRNA substrates for protein synthesis. Although most organisms require a single aaRS gene for each proteinogenic amino acid to translate their genetic information, numerous species encode multiple gene copies of an aaRS. Growing evidence indicates that organisms acquire extra aaRS genes to sustain or adapt to their unique lifestyle.

Dual incorporation of non-canonical amino acids enables production of post-translationally modified selenoproteins.

Post-translational modifications (PTMs) can occur on almost all amino acids in eukaryotes as a key mechanism for regulating protein function. The ability to study the role of these modifications in various biological processes requires techniques to modify proteins site-specifically. One strategy for this is genetic code expansion (GCE) in bacteria.