Fig. 7. (a) Bioconjugation of peptides and proteins based on the selective alkylation of tryptophan residues using rhodium carbenoids reported by Antos and Francis. (b) Bioconjugation of proteins based on the alkylation of the N-terminus. (c) Bioconjugation using Fischer carbenes on gold or glass surfaces. (d) Proximity-driven bioconjugation using rhodium metallopeptides developed by Ball for the site-specific modification of peptides, proteins and antibodies. The figure shows the structure of subtilisin Carlsberg ((a) PDB ID: 1SBC, tryptophans in blue) and RNase A ((b) PDB ID: 3A1R, N-terminus in blue).
