Molecular models of the Mojave rattlesnake (Crotalus scutulatus scutulatus) venom metalloproteinases reveal a structural basis for differences in hemorrhagic activities

Abstract

Rattlesnake venom can differ in composition and in metalloproteinase-associated activities. The molecular basis for this intra-species variation in Crotalus scutulatus scutulatus (Mojave rattlesnake) remains an enigma. To understand the molecular basis for intra-species variation of metalloproteinase-associated activities, we modeled the threedimensional structures of four metalloproteinases based on the amino acid sequence of four variations of the proteinase domain of the C. s. scutulatus metalloproteinase gene (GP1, GP2, GP3, and GP4). For comparative purposes, we modeled the atrolysin metalloproteinases of C. atrox as well. All molecular models shared the same topology. While the atrolysin metalloproteinase molecular models contained highly conserved substrate binding sites, the Mojave rattlesnake metalloproteinases showed higher structural divergence when superimposed onto each other. The highest structural divergence among the four C. s. scutulatus molecular models was located at the northern cleft wall and the S' 1 -pocket of the substrate binding site, molecular regions that modulate substrate selectivity. Molecular dynamics and field potential maps for each C. s. scutulatus metalloproteinase model demonstrated that the non-hemorrhagic metalloproteinases (GP2 and GP3) contain highly basic molecular and field potential surfaces while the hemorrhagic metalloproteinases GP1 and atrolysin C showed extensive acidic field potential maps and shallow but less dynamic active site pockets. Hence, differences in the spatial arrangement of the northern cleft wall, the S' 1 -pocket, and the physico-chemical environment surrounding the catalytic site contribute to differences in metalloproteinase activities in the Mojave rattlesnake. Our results provide a structural basis for variation of metalloproteinase-associated activities in the rattlesnake venom of the Mojave rattlesnake.

Phenotypic Variation in Mojave Rattlesnake (Crotalus scutulatus) Venom Is Driven by Four Toxin Families

“…The presence/absence expression difference between MTX and SVMPs is the characteristic difference between the Type A (neurotoxic) and Type B (hemorrhagic) venom dichotomy seen within rattlesnakes. As expected, both subunits of the neurotoxic PLA (Mojave toxin) were exclusively found in Type A individuals, and Type B individuals had a high diversity of SVMPs [ 43 , 44 ]. All but two SVMPs (SVMPIII-2 and SVMPIII-4) were absent from all Type A individuals which is similar to what was found in the Type A C. horridus [ 28 ].…”

Insights into the Mechanisms Involved in Strong Hemorrhage and Dermonecrosis Induced by Atroxlysin-Ia, a PI-Class Snake Venom Metalloproteinase

“…The region which comprises residues 153–176, could influence the interaction with substrates of the ECM [ 44 , 45 ]. In addition, hemorrhagic PI-class SVMPs exhibit extensive acidic aminoacid spots, which would facilitate the attraction of positive charges of the substrates [ 46 ]. In a recently published article [ 47 ], the authors compare two dynamical models of Atroxlysin-I with Leucurolysin-A, considered in this study as examples of hemorrhagic and non-hemorrhagic PI-class SVMP respectively.…”

The possible role of nonbilayer structures in regulating ATP synthase activity in mitochondrial membranes

“…31 P-NMR spectra of mitochondria and MLLs were recorded as described previously [5]. The spatial structure coordinates of CTII were retrieved from PDB (ID 1CB9); energy minimization of the CTII structure was performed as described previously [11]. Cardiolipin coordinates were obtained from a crystal structure of a bovine heart oxidoreductase–cardiolipin complex (PDB ID 1V54).…”