Protein complexes in snake venom

Abstract

Snake venom contains mixture of bioactive proteins and polypeptides. Most of these proteins and polypeptides exist as monomers, but some of them form complexes in the venom. These complexes exhibit much higher levels of pharmacological activity compared to individual components and play an important role in pathophysiological effects during envenomation. They are formed through covalent and/or non-covalent interactions. The subunits of the complexes are either identical (homodimers) or dissimilar (heterodimers; in some cases subunits belong to different families of proteins). The formation of complexes, at times, eliminates the non-specific binding and enhances the binding to the target molecule. On several occasions, it also leads to recognition of new targets as protein-protein interaction in complexes exposes the critical amino acid residues buried in the monomers. Here, we describe the structure and function of various protein complexes of snake venoms and their role in snake venom toxicity.

Medically important differences in snake venom composition are dictated by distinct postgenomic mechanisms

“…Venom complexity is further influenced by the effect of posttranslational protein modifications (34,35). Across the sampled species, we detected multiple instances of the same toxin being identified in distinct proteomic fractions (SI Appendix, Tables S1-S6), signifying the presence of multiple protein products as the result of proteolysis (SI Appendix, Fig.…”

“…These observations likely reflect (i) the proteolytic cleavage of single gene proteins forming multiple products (e.g., SVMPs; ref. 34) and (ii) the cleavage of multimeric structures, which can be encoded by the same gene or different genes from either the same or distinct toxin families (35). Considerable interspecific variation in the number of proteolysed toxins was observed, ranging from three genes in E. p. leakeyi producing six venom protein products, to 13 forming 36 in B. arietans venom (SI Appendix, Fig.…”

Deep venomics of the Pseudonaja genus reveals inter- and intra-specific variation

“…Moreover, the formation of polymeric (mostly covalently linked) toxin complexes often enhances the binding efficiency toward specific molecular targets compared to their monomeric forms and leads to new pharmacologies [4]. Not only is this variation a result of toxin gene duplication followed by neofunctionalization, but can also be a function of phylogeny, ecology and/or geography [5].…”

Reversible Posterior Leukoencephalopathy in a Venomous Snake (Bothrops asper) Bite Victim

“…3 Relevant snake venom toxins include metalloproteinases (factor X activators), serine proteases (prothrombin activators), snake venom C-type lectins, and three-finger toxins (anticoagulant or procoagulant activity). 4 Neurological manifestations are the most feared complications of venomous snake bites, because they add significant morbidity and mortality to the victims. 5 These are not caused by direct toxic effects of the venom within the central nervous system, because venom proteins do not cross the blood-brain barrier.…”