The division Molecular Medicine aims to reengineer proteins for medical applications with a focus on anti-tumor enzymes and ß-barrel channel proteins as interactive bio-/hybrid materials and catalysts. For this purpose, we use diversity generation and cloning methods which have been developed in Molecular Biology division and meanwhile develop screening methods for specific case. In the division Molecular Medicine, we have two application platforms: arginine deiminase ADI as an anti-tumor drug - platform 1, the ß-barrel channel proteins FhuA and nitrobindin for controlling compound fluxes and as hosts for biohybrid catalysts - platform 2.
Platform 1: By protein engineering, we are improving arginine deiminase ADI as an anti-tumor enzyme for improved activity and stability at physiological conditions for anti-tumor treatment. ADI variant with >400 times lowered IC50 value against the melanoma SK-MEL-28 was obtained. Besides, methodological advancements are being pursued in flow cytometer based screening systems for directed PpADI evolution at physiological arginine concentrations.
Platform 2: By reengineering channel protein FhuA, we intend to make a ‘chiral filter’ for separation of amino acid enantiomers. Besides, triggerable release systems based on polymersomes for medical application are also under development. Furthermore, FhuA was successfully reengineered for biohybrid catalyst to equip the metal catalyst with tailored enatioselectivity.
A cross-cutting topic with potential to develop into a core research topic is the directed enzyme evolution to improve ionic liquids/salt/organic solvent resistance, for example lipase BSLA and Laccase. Based on screening of the SSM-BSLA library which covers the full natural diversity with one single amino acid exchange, important and general insights on directed evolution and enzyme reengineering were obtained. These findings have significant impact on the Molecular Biology division to develop improved diversity generation methods.