Exploration and design of complexes between polyoxometalates and natural and de novo proteins

Proteomic research often relies on hydrolysis of proteins into smaller fragments. This requires the usage of a catalyst as the peptide bond has hydrolysis half-life of ±600 years. While proteases are efficient in hydrolyzing the peptide backbone, they often undergo self-hydrolysis and generate too small fragments to match to the parent protein. Chemical agents however require harsh reaction conditions, exhibit partial selectivity and give low yields. One class of catalysts, metal-substituted polyoxometalates (POMs), has proven to be able to hydrolyze proteins in a regioselective fashion under physiological conditions. Recently we have identified a range of POMs as ideal candidates for artificial proteases. X-ray diffraction of POM-protein crystals has given new insights into the interactions showing binding in the proximity of the reported cleavage sites. However, many questions regarding the mechanism of hydrolysis still remain unanswered.

Due to their high symmetry these POMs can also be used as artificial co-factor for computationally designed symmetrical proteins, which can surpass the capacity of naturally occurring enzymes. For

this part of the project we will computationally design cup-like symmetrical protein building blocks that will serve as a scaffold to accommodate a POM as an artificial cofactor.

Our aim is to expand on recent x-ray studies, link the acquired data to insights gained from complementary solution studies and improve these novel synthetic enzymes.