Site-specific incorporation of bioorthogonal unnatural amino acids into proteins provides a useful tool for the installation of specific functionalities that will allow for the labeling of proteins with virtually any probe. We demonstrate the genetic encoding of a set of alkene lysines using the orthogonal PylRS/PylTCUA pair in Escherichia coli. The installed double bond functionality was then applied in a photoinitiated thiol-ene reaction of the protein with a fluorescent thiol-bearing probe, as well as a cysteine residue of a second protein, showing the applicability of this approach in the formation of heterogeneous non-linear fused proteins.
Torres-Kolbus, J., Chou, C., Liu, J., & Deiters, A. (2014). Synthesis of non-linear protein dimers through a genetically encoded thiol-ene reaction. PLoS ONE, 9(9). https://doi.org/10.1371/journal.pone.0105467