Bordusa

Covalent modified proteins play a crucial role in basic research for studying cellular interactions, localization and dynamic of divergent proteins. Furthermore, it exists a wide economic interest on selectively modified proteins for therapeutic and diagnostic purposes. In particular antibody conjugates are currently the fastest growing class of therapeutic molecules. Beside the attachment of polymers like polyethylene glycol or fluorescent dyes, especially antibody drug conjugates (ADCs) have revolutionized cancer therapy.

In contrast to the increasing interest of those artificial proteins, there is currently no gentle modification procedure allowing free choice of functionality to be introduced and in addition, being independent from the nature of the target protein. The goal of this project is to provide an efficient and universal biocatalysis platform for site-specific modification of mainly therapeutic proteins especially for C-terminal derivatization of pharmaceutically relevant antibody fragments.

In preliminary studies we successfully designed a trypsin variant enabling such terminal modifications via a transamidation reaction at a highly unique recognition sequence. Due to regeneration of the enzyme-specific recognition sequence in the synthesis product and the competitive secondary hydrolysis thereof, the maximum product yield is however currently limited to 30-40%. The project requested focuses on the optimization of the biocatalyst via directed evolution using random genetic mutation and phage-display technology to minimize the biocatalyst’s hydrolysis activity and thus, to increase the yield and stability of the product.

C. Meyer, S. Liebscher, F. Bordusa

Bioconjugate Chem2016, 27(1), 47-53
Selective Coupling of Click Anchors to Proteins via Trypsiligase
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S. Liebscher, P. Kornberger, G. Fink, E.-M. Trost-Gross, E. Höss, A. Skerra, F. Bordusa
ChemBioChem2014, 15, 1096-1100
Derivatization of Antibody Fab Fragments: A Designer Enzyme for Native Protein Modification
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S. Liebscher, M. Schöpfel, T. Aumüller, A. Sharkhuukhen, A. Pech, E. Höss, C. Parthier, G. Jahreis, M.T. Stubbs, F. Bordusa
Angew. Chem. Int. Ed.2014, 53, 3024-3028
N-Terminal Protein Modification by Substrate-Activated Reverse Proteolysis
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