Toolbox for Bioconjugations
Covalent linkage of certain peptidic units, being an alternative or a complementary strategy to recombinant production, often becomes a method of choice for the synthesis of sophisticated macromolecular constructs with tailored properties. To date a vast number of bioconjugates and the respective techniques have been reported, ranging from relatively simple fluorescently or small-molecule-labelled peptides to complex, multifunctional architectures like antibody-drug conjugates. Obviously, chemical transformations suitable for bioconjugations must satisfy at least two obligatory requirements – chemoselectivity and efficiency. Making allowance for the variety of inherent functional groups present in peptidic molecules, we develop a toolbox for viable bioconjugations incorporating a uniquely addressable group or recognition unit at the desired position in the molecule of interest followed by its peculiar reaction with the desired counterpart. Such a uniquely addressable moiety could be incorporated into biomolecules through a vast number of post-synthetic modifications, e.g. periodate oxidation of β-aminoalcohols, or via the non-natural building blocks either upon recombinant production or in the course of chemical synthesis. Bioorthogonal reactions to target these non-natural functional groups often make use of rich ketone and aldehyde chemistry as well as numerous click-type reactions.
Moreover, we use Sortase A-mediated ligation to join or immobilize biomolecules via the native amide bond (Fig. 1). Additionally, we also use other enzyme-mediated conjugation techniques for functionalization of proteins with therapeutic relevance like antibodies and antibody fragments. These functionalities include different reporter molecules and toxins or moieties mediating specific binding of target proteins with the aim of generating antibody-drug conjugates (ADCs).
- 1. C. Uth, S. Zielonka, S. Hörner, N. Rasche, A. Plog, H. Orelma, O. Avrutina, K. Zhang, H. Kolmar. A chemoenzymatic approach to protein immobilization onto crystalline cellulose nanoscaffolds. Angew. Chem. Int. Ed. 2014, 53, 12618-12623
- 2. S. Fabritz, S. Hörner, O. Avrutina, H. Kolmar. Bioconjugation on cube-octameric silsesquioxanes, Org. Biomol. Chem., 2013, 11, 2224-2236.
- 3. S. Fabritz, S. Hörner, D. Könning, M. Empting, M. Reinwarth, C. Dietz, B. Glotzbach, H. Frauendorf, H. Kolmar, O. Avrutina. From pico to nano: biofunctionalization of cube-octameric silsesquioxanes by peptides and miniproteins, Org. Biomol. Chem, 2012, 10, 6287-6293.
- 4. S. Fabritz, D. Heyl, V. Bagutski, M. Empting, E. Rickowski, H. Frauendorf, I. Balog, W.-D. Fessner, J. J. Schneider, O. Avrutina, H. Kolmar. Towards click bioconjugations on cube-octameric silsesquioxane scaffolds, Org. Biomol. Chem, 2010, 8, 2212-2218.