Leveraging Formylglycine-Generating Enzyme for Production of Site-Specifically Modified Bioconjugates.

Enzymatic modification of proteins can generate uniquely reactive chemical functionality, enabling site-specific reactions on the protein surface. Formylglycine-generating enzyme (FGE) is one enzyme that can be exploited in this fashion. FGE binds its consensus sequence (CXPXR, known as the "aldehyde-tag") and converts the cysteine to a formylglycine (fGly). fGly-containing proteins contain a bioorthogonal aldehyde on their surface that can be modified selectively in the presence of the 20 canonical amino acids. Here, we describe protocols for the generation of a site-specifically modified protein, an antibody-drug conjugate (ADC), using aldehyde-tagging protocols and aldehyde-reactive conjugation chemistry.