Genetic Code Expansion for Multiprotein Complex Engineering

A method for producing multiprotein complexes engineered with site–specifically introduced noncanonical amino acids is described, enabling applications in biochemical and biophysical analysis, as well as in biotechnology. We present a baculovirus-based protein engineering method that enables site-specific introduction of unique functionalities in a eukaryotic protein complex recombinantly produced in insect cells. We demonstrate the versatility of this efficient and robust protein production platform, 'MultiBacTAG', (i) for the fluorescent labeling of target proteins and biologics using click chemistries, (ii) for glycoengineering of antibodies, and (iii) for structure–function studies of novel eukaryotic complexes using single-molecule Förster resonance energy transfer as well as site-specific crosslinking strategies.