The overall aim of the project is the synthesis of novel chemo- and biocatalytic combinatorial libraries which will be screened for biological activities (e.g. as antibacterial or anticancer agents). This includes development of novel methodologies for reactions on support, either on soluble high molecular weight polymers or on solid supports together with a new class of enzymatically cleavable linkers. Enzyme cleavable linkers allow release of compounds directly into assay mixtures, because release is in aqueous medium. The application of enzymes and whole cells for a biocatalytic combinatorial approach offers the opportunity to combine functionalities in macrocyclic target structures, which are difficult to obtain by traditional chemical methods.
During the first project period the following results hae been achieved:
- Recombinant penicillin G acylase (PGA) Recombinant PGA originating from two different origins can be produced using efficent expression systems. These two enzymes differ from the commercially available PGA with respect to stability, activity and substrate specificity. Furthermore the clones now offer the possibility for directed evolution of the enzyme to improve its cleavage of the linker;
- Insoluble carriers with improved properties Insoluble supports based either on polystyrene or polyethylenglycol have been modified in order to improve its swelling behavior in various solvents and therefore give better access to the linker for the enzymes;
- Penicillin G acylase cleavable linkers Based on modelling of the linker geometry in the active site of the enzymes derivatives of the linker have been developed which are cleaved by the enzyme with better results. For a novel type of linker also other hydrolytic enzymes can be used for cleavage;
- Membrane process for filtration of soluble polymers To recover soluble polymers - which in special cases have advantages over insoluble carriers e.g. when using immobilized enzymes - membrane filtration has been adapted for its application in organic solvents such as dichloromethane;
- Combinatorial synthesis of macrocyle libraries and macrocycles on solid support To develop short and combinatorial synthetic strategies for functionalized macrocycles at the beginning the focus was on solution phase synthesis. A first set of compounds was synthesized, characterized and introduced into the activity screening. Coupling of macrocycles to solid supports has been successful as well as their derivatisation by hydrolytic enzymes.
Funding SchemeCSC - Cost-sharing contracts
412 96 Goeteborg
06120 Halle (Saale)
EH9 3JJ Edinburgh