Weldon David J, Shah F, Chittiboyina AG, Sheri A, Chada RR, Gut J, Rosenthal PJ, Shivakumar D, Sherman W, Desai P, Jung JC, Avery MA. Synthesis, biological evaluation, hydration site thermodynamics, and chemical reactivity analysis of α-keto substituted peptidomimetics for the inhibition of Plasmodium falciparum. Bioorg Med Chem Lett. 2014; 24(5),1274-9. ( 1/2014 )
A new series of peptidomimetic pseudo-prolyl-homophenylalanylketones were designed, synthesized and evaluated for inhibition of the Plasmodium falciparum cysteine proteases falcipain-2 (FP-2) and falcipain-3 (FP-3). In addition, the parasite killing activity of these compounds in human blood-cultured P. falciparum was examined. Of twenty-two (22) compounds synthesized, one peptidomimetic comprising a homophenylalanine-based α-hydroxyketone linked Cbz-protected hydroxyproline (39) showed the most potency (IC50 80 nM against FP-2 and 60 nM against FP-3). In silico analysis of these peptidomimetic analogs offered important protein-ligand structural insights including the role, by WaterMap, of water molecules in the active sites of these protease isoforms. The pseudo-dipeptide 39 and related compounds may serve as a promising direction forward in the design of competitive inhibitors of falcipains for the effective treatment of malaria.