Peptide nanoparticle catalysis

Improved catalysis for more efficient chemical processing, biomass conversions and water oxidation-hydrogen production will be important for achieving new clean technologies. Our research work involves a novel approach to produce catalytic mechanistic properties in synthetic peptide nanoparticle structures that mimic the active sites of enzymes. A series of six peptides have now been designed and synthesized which contain a cysteine sulfhydryal group (nucleophile) and histidine imidazole group (general base) in close proximity. Upon acylation of the cysteine sulfhydryal group, some of the peptides with closely proximated imidazole groups, exhibit accelerated deacylation in the presence of a trapping reagent. Peptides with phenylalanine groups between the cysteine and histidine have deacylation rates more than 10 times higher than in the peptides without a histidine. This accelerated deacylation indicates that the histidine imidazole group is functioning much like it does in the catalytic sites of the natural cysteine and serine proteases. These peptides will ultimately be attached to derivatized nanoparticles which are designed to bind appropriate substrates (esters and amides) through hydrophobic and/or electrostatic interactions. The final goal being to use the peptide nanoparticle structures to accelerate both the acylation and deacylation rates and produce true substrate turnover.