Two functions - one enzyme; generation of a dual-function nucleoside kinase

• Applicant: Dr. Helge Jochens
• Subject Area: Biological and Biomimetic Chemistry
• Term: from 2010 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 184208666

Nucleoside analogs are important weapons against cancer and viral diseases. These compounds represent prodrugs that have to be activated to their corresponding triphosphates by three consecutive nucleoside kinases to exhibit their function. However, the narrow substrate specificity of endogeneous human kinases limits the application of a multitude of imaginable agents. Recently, there has been great progress in the evolution of enzymes that catalyze efficiently the first phosphorylation of a nucleoside analog without interfering with the sensitive natural nucleoside metabolism. But even these advances only shifts the bottleneck one reaction ahead towards the second phosphorylation (the third step can be catalyzed by various endogeneous enzymes).The requested research project focuses on the generation of a nucleoside kinase capable to catalyze both the first and the second phosphorylation step. The reactions follow an identical reaction mechanism and although the natural enzymes have a very exclusive substrate preference the structural similarities are striking. State-of-the-art rational protein design and directed evolution methodologies will be applied in combination with a newly generated conditional auxotrophic E.coli for the selection for dual-function kinases. The outcome of this project will not only improve our understanding how nucleoside kinases function and how they have divergently evolved but would also enable exciting new therapeutical application.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Stefan Lutz