Proteomic analysis of the rare Uracoan rattlesnake Crotalus vegrandis venom: Evidence of a broad arsenal of toxins.

The investigation of venoms has many clinical, pharmacological, ecological and evolutionary outcomes. The Crotalus spp. venom can cause hemorrhage, neurotoxicity, myotoxicity, coagulopathy and hypotension. Although neurotoxicity and hemorrhage usually does not occur for the same species, the rare Venezuelan species Crotalus vegrandis presents both characteristic. Different from the other species it has a restricted ecological niche and geographical distribution. Nevertheless, it has a raising medical importance as this rattlesnake population is increasing. Few works describe its neurotoxic and hemorrhagic features, but other toxins might play an important role in envenomation. We combined proteomic methods to identify for the first time the main components of it venom: 2D SDS-PAGE and gel-filtration chromatography for protein mixture decomplexation; LC-MS(2) of low molecular mass fractions and tryptic peptides; bioinformatic identification of toxin families and specific protein species based on unique peptide analysis and sequence database enriched with species-specific venom gland transcripts; and finally polyclonal anti-crotamine Western-blotting. Our results point to a broad arsenal of toxins in C. vegrandis venom: PIII and PII metalloproteases, crotoxin subunits, other phospholipases, isoforms of serine proteases and lectins, l-amino-acid oxidase, nerve growth factor, as well as other less abundant toxins.

Venomics of the Australian eastern brown snake (Pseudonaja textilis): Detection of new venom proteins and splicing variants.

The eastern brown snake is the predominant cause of snakebites in mainland Australia. Its venom induces defibrination coagulopathy, renal failure and microangiopathic hemolytic anemia. Cardiovascular collapse has been described as an early cause of death in patients, but, so far, the mechanisms involved have not been fully identified. In the present work, we analysed the venome of Pseudonaja textilis by combining high throughput proteomics and transcriptomics, aiming to further characterize the components of this venom. The combination of these techniques in the analysis and identification of toxins, venom proteins and putative toxins allowed the sequence description and the identification of the following: prothrombinase coagulation factors, neurotoxic textilotoxin phospholipase A2 (PLA2) subunits and "acidic PLA2", three-finger toxins (3FTx) and the Kunitz-type protease inhibitor textilinin, venom metalloproteinase, C-type lectins, cysteine rich secretory proteins, calreticulin, dipeptidase 2, as well as evidences of Heloderma lizard peptides. Deep data-mining analysis revealed the secretion of a new transcript variant of venom coagulation factor 5a and the existence of a splicing variant of PLA2 modifying the UTR and signal peptide from a same mature protein. The transcriptome revealed the diversity of transcripts and mutations, and also indicates that splicing variants can be an important source of toxin variation.