Session: General Catalysis:

The catalytic site of natural enzymes is usually surrounded by a delicate three-dimensional scaffold, which provides a suitable microenvironment for substrate binding and catalysis. Recently, the peptide-based enzyme mimics built from short peptide assembly have attracted growing attentions. To get insight into the effect of the microenvironment of peptide-based material on the enzyme-like catalytic behavior, in this study, histidine-containing pentapeptides (Fmoc-FFXAH) with different amino acids mutated at X position were designed to produce a series of esterase mimics which possess different microenviroments. The results indicated that the all the peptides formed amyloid-like architectures and displayed esterase-like catalytic ability in the hydrolysis of p-NPA. The introduction of hydrophobic residues at X position increase the hydrophobic microenvironment of assemblies, which had a beneficial effect on the substrate binding and enrichment. The positively charged and negatively charged residues inhibit the catalytic activity due to the electrostatic repulsion which reduce the intermediate state stability of substrates. The mutation of Gln is benefit for the stabilization of the intermediate transition state by forming hydrogen bond. Moreover, the chiral microenviroment of peptide assemblies can be changed by adjusting the amino acid at X position, which displayed chiral selectivity toward enantiomeric substrate.

Rongxin Su

Appearances