Characterization of a human coagulation factor Xa-binding site on Viperidae snake venom phospholipases A2 by affinity binding studies and molecular bioinformatics

Abstract

Background: The snake venom group IIA secreted phospholipases A 2 (SVPLA 2 ), present in the Viperidae snake family exhibit a wide range of toxic and pharmacological effects. They exert their different functions by catalyzing the hydrolysis of phospholipids (PL) at the membrane/water interface and by highly specific direct binding to: (i) presynaptic membrane-bound or intracellular receptors; (ii) natural PLA 2 -inhibitors from snake serum; and (iii) coagulation factors present in human blood.

Crotoxin from Crotalus durissus terrificus and Crotoxin-Related Proteins: Structure and Function Relationship

“…Surface Plasmon Resonance (SPR) analysis showed that binding affinity depends on the CB isoform. CBc interacts with hFXa with very high affinity (K D = 0.6AE0.3 nM) compared to CBa 2 (K D = 52AE4 nM), which is correlated with anticoagulant activity (stronger inhibition of prothrombinase complex formation) (Faure et al 2007).…”

“…Moreover, analysis of crystallographic structures showed that His1, Arg34, and Gly128 may be essential in the binding of hFXa by isoform CBc. Mutations of these residues in isoform CBa 2 (Ser1, Gln34, and Glu128) lead to conformational changes in adjacent residues and result in lower affinity for hFXa (Faure et al 2007;.…”

“…CA prevents the formation of oligomers between PLA 2 subunits and targets CB to reach the specific crotoxin receptor. CA also inhibits the PLA 2 and anticoagulant activities of CB (Faure et al 1991(Faure et al , 1993(Faure et al , 2007.…”

“…4) to explore possible modes of binding of CB to different protein targets. Lomonte et al (2015) CB Interaction with Human Coagulation Factor Xa It has been shown that CB can form complexes with human coagulation factor Xa (hFXa) (Faure et al 2007). This interaction influences the coagulation pathway by inhibiting the prothrombinase complex formation and retarding the formation of thrombin.…”

“…The anticoagulant binding site of CB was identified by mutagenesis, affinitybinding studies, functional assays, and molecular docking calculations (Faure et al 2007;. Two adjacent regions were identified.…”