Comprehensive Study of the Proteome and Transcriptome of the Venom of the Most Venomous European Viper: Discovery of a New Subclass of Ancestral Snake Venom Metalloproteinase Precursor-Derived Proteins

Abstract

The nose-horned viper, its nominotypical subspecies Vipera ammodytes ammodytes ( Vaa ), in particular, is, medically, one of the most relevant snakes in Europe. The local and systemic clinical manifestations of poisoning by the venom of this snake are the result of the pathophysiological effects inflicted by enzymatic and nonenzymatic venom components acting, most prominently, on the blood, cardiovascular, and nerve systems. This venom is a very complex mixture of pharmacologically active proteins and peptides. To help improve the current antivenom therapy toward higher specificity and efficiency and to assist drug discovery, we have constructed, by combining transcriptomic and proteomic analyses, the most comprehensive library yet of the Vaa venom proteins and peptides. Sequence analysis of the venom gland cDNA library has revealed the presence of messages encoding 12 types of polypeptide precursors. The most abundant are those for metalloproteinase inhibitors (MPis), bradykinin-potentiating peptides (BPPs), and natriuretic peptides (NPs) (all three on a single precursor), snake C-type lectin-like proteins (snaclecs), serine proteases (SVSPs), P-II and P-III metalloproteinases (SVMPs), secreted phospholipases A 2 (sPLA 2 s), and disintegrins (Dis). These constitute >88% of the venom transcriptome. At the protein level, 57 venom proteins belonging to 16 different protein families have been identified and, with SVSPs, sPLA 2 s, snaclecs, and SVMPs, comprise ∼80% of all venom proteins. Peptides detected in the venom include NPs, BPPs, and inhibitors of SVSPs and SVMPs. Of particular interest, a transcript coding for a protein similar to P-III SVMPs but lacking the MP domain was also found at the protein level in the venom. The existence of such proteins, also supported by finding similar venom gland transcripts in related snake species, has been demonstrated for the first time, justifying the proposal of a new P-IIIe subclass of ancestral SVMP precursor-derived proteins.

Biological Activities and Proteomic Profile of the Venom of Vipera ursinii ssp., a very Rare Karst Viper from Croatia

“…Gel-based proteomic analysis of the venom of the wild V. ursinii ssp. species revealed a proteome much simpler than that of the recently published V. a. ammodytes venom proteome [15]. Almost two times fewer proteins were identified in the V. ursinii ssp.…”

“…In vitro, VaH3 also markedly prolonged blood coagulation, due to its fibrinogenolytic activity, but only weakly affected platelet aggregation. Vaa-MPIII-1 and Vaa-MPIII-4 are present in trace amounts in the V. a. ammodytes venom [15]. In contrast, in the V. ursinii ssp.…”

“…Vaa-MPIII-3 is a member of the recently introduced P-IIIe SVMP subclass. That subclass evolved from the classical P-III SVMPs by loss of the MP domain [15], thus consisting of only a complete or a partial disintegrin-like domain and a Cys-rich domain. Interestingly, the V. ursinii ssp.…”

“…The V. ursinii ssp. proteome was compared with the recently published proteome of the V. a. ammodytes venom [15]. In general, there are far fewer basic proteins in the V. ursinii ssp.…”

Snake Venom Metalloproteinases (SVMPs): A structure-function update

“…The four subclasses (P-IIIa, b, c, and d) are well-known and documented in the literature. However, studies suggested the existence of a P-IIIe subclass comprising proteins that lack the catalytic metalloproteinase domain ( Balija et al, 2020 ; Leonardi et al, 2019 ). Although Casewell et al (2011) had previously correlated the evolutionary history of serpents to a repeated domain loss ( Casewell et al, 2011 ), recent data from proteomic and transcriptomic analysis of Vipera ammodytes ammodytes venom identified Vaa-MPIII-3 as a member of the new P-IIIe subclass ( Leonardi et al, 2019 ).…”