Structural and functional characterisation of isolated puff adder (Bitis arietans) venom serine proteases

Posted by
  Structural and functional characterisation of isolated puff adder (Bitis arietans) venom serine proteases Abstract Serine proteases (SVSPs) are known to play a major role in the haemotoxic actions of viper venom, but compared with those from other medically important vipers, the serine proteases of puff adder venoms have not been extensively characterised. To address this, we isolated, identified and characterised the bioactivity of the serine proteases within the venom of the Nigerian puff adder, which we had previously shown to be especially rich in this class of toxin. Two distinct groups were identified, each with different protein substrate specificities. Both had similar molecular weights of 52-62 kDa, with 4-6 N-glycans, but one group consisted of trypsin-like acidic SVSPs and the other of non-trypsin-like basic SVSPs with a specificity for aliphatic amino acids at the P 1 position. Each acted differently on fibrinogen: the acidic SVSPs showed thrombin-like alpha/beta-fib...

Functional venom activity and antivenom neutralization in rattlesnakes across Baja California and Gulf of California islands

Posted by

 


Functional venom activity and antivenom neutralization in rattlesnakes across Baja California and Gulf of California islands

Abstract

Snake venoms are complex biochemical phenotypes whose composition can diverge dramatically among taxa, yet the functional and biomedical consequences of such variation remain understudied for many lineages. Here, we characterized the functional activities of venom from multiple rattlesnake species distributed across insular and mainland localities in the Baja California Peninsula and Gulf of California. We quantified phospholipase A2 (PLA2), proteolytic, and fibrinogenolytic activities as well as median lethal doses (LD50) for 55 individuals across Crotalus enyo, C. mitchellii, C. pyrrhus sensu lato, and C. ruber. We also evaluated the neutralization efficacy of the commercial polyvalent antivenom Antivipmyn®. Venom functional activities differed significantly among species. Crotalus mitchellii expressed a neurotoxic phenotype characterized by the highest PLA2 activity, the lowest LD50 values, and minimal proteolysis. Crotalus pyrrhus and C. ruber expressed proteolytic phenotypes with high enzymatic activity and ubiquitous dual-chain fibrinogenolysis. Crotalus enyo exhibited intermediate functional activities with moderate enzymatic output and the most efficient antivenom neutralization among species. Although Antivipmyn® neutralized the lethal activity of all venoms, efficacy differed significantly among species in both mass-normalized (mgAV/mgV) and potency-scaled (LD50-equivalents per vial) metrics. Notably, insular and mainland populations within species showed qualitative variation in both functional activities and antivenom responses. These results establish that the focal species possess functionally distinct venom phenotypes with species-specific consequences for antivenom neutralization, underscoring the relevance of venom functional characterization for clinical management of envenomation across the Baja California region.
Hirst, S. R., Neri-Castro, E., Vázquez-García, E., Zarzosa, V., Olvera, F., VanHorn, C. M., Alagón, A., Franz-Chávez, H., Castañeda-Gaytán, G., Parkinson, C. L., Strickland, J. L., Borja, M., & Margres, M. J. (2026). Functional venom activity and antivenom neutralization in rattlesnakes across Baja California and Gulf of California islands. Toxicon, 109266. https://doi.org/10.1016/j.toxicon.2026.109266