Biochemistry

Biography

Biography: Akansha Pant

Abstract

 Falcipains  are among the critical enzymes req uired for parasite machinery  in Malaria. Our previous study suggested that t hey have unique pro and mature domains that interact via salt bridge and hydrophobic interactions, which are essential for their activation. Designing small  molecules that interfere at the hotspot residues of domains, would inhibit falcipains activation. Although multiple active site inhibitors exist for falcipains, specific inhibitors that halt processing without binding to active site remains unknown. Our study suggests that       azapeptide       compounds based on conformationally constrained disubstituted β- and γ-     ami         no acids    , inhibit the activation of falcipains. Among these, C-02 and C-07 hinders  the falcipains activity by binding to intact pro-FP2 rather than mature a ctive FP2 during hemoglobin hydrolysis and     fluorogenic     substrate assay. While these    compounds    did not affect the secondary structure of protein dur ing circular dichroism    spectroscopy   , Surface Plasmon Resonance result demonstrated over the range of inhibitor concentration indicated specific interaction with FP3 and equilibrium constant~80nM. Mo reover confirmation was done by MD   simulations   for ~5x130 ns confirms that compou nd-inhibitor complex provides rigidity to the pro domain to remain intact even at low pH preventing activation of the enzyme. For further authentication inhibitory concentration (IC50), of compound were examined on 3D7 strain of   Plasmodium falciparum  , parasite shows distorted  trophozoite  morphology with IC50~250nM. Further, we report a conserved histidine residue (His205) in pro domain of FP3, essential for pH sensing during auto-processing. Collectively, we provide a framework for targeting hotspot residues that can regula  te falcipains in  zymog en condition and halts i ts activation.