Engineered Protein Variants for Bioconjugation

Abstract The possibility to covalently modify biological entities, namely proteins, nucleic acids, sugars, is possible through bioconjugation, creating a boundary between biology and chemistry. The field of protein bioconjugation, in particular, has been extremely active and rendered several methods to attain protein conjugates with drugs, enzymes, inorganic or organic materials, dyes and fluorescent reporter molecules, and polymers. The initial bioconjugation methods took advantage of the reactive side chains of naturally occurring amino acids and lately evolved toward the introduction of reactive amino acids at precise locations through DNA recombinant technologies. In addition, unnatural amino acids also provide a source of site-specific and selective bioconjugation tools. Bioconjugation derives from a profound cross talk between disciplines because modern organic chemistry has progressed enormously toward chemoselective reactions performed under physiological conditions.