Selection of Effective HTRA3 Activators Using Combinatorial Chemistry

Herein, we report selection, synthesis, and enzymatic evaluation of a peptidomimetic library able to increase proteolytic activity of HtrA3 (high temperature requirement A) protease. Iterative deconvolution in solution of synthesized modified pentapeptides yielded two potent HtrA3 activators acting in the micromolar range (HCOO-CH2O-C6H4-OCH2-CO-Tyr-Asn-Phe-His-Asn-OH and HCOO-CH2O-C6H4-OCH2-CO-Tyr-Asn-Phe-His-Glu-OH). Both compounds increased proteolysis of an artificial HtrA3 substrate over 40-fold in a selective manner. On the basis of molecular modeling, the selected compounds bind strongly to the PDZ domain.