First Insights into the Venom Composition of Two Ecuadorian Coral Snakes

Abstract

Micrurus is a medically relevant genus of venomous snakes composed of 85 species. Bites caused by coral snakes are rare, but they are usually associated with very severe and life-threatening clinical manifestations. Ecuador is a highly biodiverse country with a complex natural environment, which is home to approximately 20% of identified Micrurus species. Additionally, it is on the list of Latin American countries with the highest number of snakebites. However, there is no local antivenom available against the Ecuadorian snake venoms, and the biochemistry of these venoms has been poorly explored. Only a limited number of samples collected in the country from the Viperidae family were recently characterised. Therefore, this study addressed the compositional patterns of two coral snake venoms from Ecuador, M. helleri and M. mipartitus, using venomics strategies, integrating sample fractionation, gel electrophoresis, and mass spectrometry. Chromatographic and electrophoretic profiles of these snake venoms revealed interspecific variability, which was ascertained by mass spectrometry. The two venoms followed the recently recognised dichotomic toxin expression trends displayed by Micrurus species: M. helleri venom contains a high proportion (72%) of phospholipase A2, whereas M. mipartitus venom is dominated by three-finger toxins (63%). A few additional protein families were also detected in these venoms. Overall, these results provide the first comprehensive views on the composition of two Ecuadorian coral snake venoms and expand the knowledge of Micrurus venom phenotypes. These findings open novel perspectives to further research the functional aspects of these biological cocktails of PLA2s and 3FTxs and stress the need for the preclinical evaluation of the currently used antivenoms for therapeutic purposes in Ecuador.

Unveiling the Venom Composition of the Colombian Coral Snakes Micrurus helleri, M. medemi, and M. sangilensis

“…The venom of a subpopulation of M. helleri, which is a taxonomically controversial species, was also characterized. Our samples of M. helleri, M. medemi, and M. sangilensis comprised several members of the PLA 2 and 3FTx families, which is consistent with the results of studies of other South American coral snake venoms [16,17,28,[35][36][37][40][41][42], according to electrophoretic, chromatographic, and proteomic analysis. The properties of Micrurus venoms vary greatly among species, which is attributed to their diverse habitats and prey preferences as well as phylogenetic inertia [12,[43][44][45][46].…”

“…However, the venoms of the short-tailed triadal species M. helleri, as well as the two monadal short-tailed species M. medemi and M. sangilensis, are dominated by phospholipase components with PLA 2 comprising 40.6%, 43.1%, and 30.4% of the total venom proteins and 3FTx comprising 14.1%, 17.7%, and 17.7% of the total venom proteins, respectively. Similar results have been obtained for M. helleri from the Amazonian region of Colombia and Ecuador; in Colombia, PLA 2 and 3FTx comprise 62.5% and 21.1% of the total venom proteins, respectively, whereas in Ecuador, PLA 2 and 3FTx comprise 72.1% and 17.8% of the total venom proteins, respectively [36,37]. The proteomic composition of various coral snake species reported over the last four years, including this work, does not support the hypothesis of the divergent latitudinal pattern nor a triadal vs. monadal (or long-tailed vs. short-tailed) divergence for explaining the phospholipase/3FTx-dominant phenotypes (see Supplementary Table S1).…”

“…Some elapid species such as Naja naja (common cobra) and Naja melanoleuca (black and white cobra) have significant amounts of metalloproteinases in their proteomes [54]. Nevertheless, the metalloproteinases in Micrurus venoms are minor components of the proteome, comprising less than 5% of the total venom, and serine proteases, if detectable, comprise less than 2% of the venom components; thus, their enzymatic activity tends to be minimal [16,37,53,55]. Low-activity protease-like enzymes have been identified in M. dumerilii and M. alleni venoms, and the percentages of these enzymes in the proteome are low [11,61].…”

“…Snake venom proteinases comprise a minor proportion (less than 5%) of the total toxins in most Micrurus venoms reported to date (Supplementary Table S1). However, this toxin family comprises nearly 6%, 7.6%, and 12% of the venoms of M. mipartitus [37], M. yatesi [38], and M. pyrrhocryptus [39], respectively. Our results indicate that these proteinases are more abundant in the venoms of M. medemi, M. sangilensis, and M. helleri (9.6, 11.8, and 13.8%, respectively).…”

Unveiling Novel Kunitz- and Waprin-Type Toxins in the Micrurus mipartitus Coral Snake Venom Gland: An In Silico Transcriptome Analysis

“…Proteomic analyses of Colombian M. mipartitus venom revealed that its composition comprises three finger toxins (3FTx) (~60%) and phospholipase A 2 (PLA 2 ) (~30%), constituting the major components, followed by L-amino acid oxidase (4.0%), P-III metalloproteinase (1.6%), Kunitz-type protease inhibitor (1.9%), serine proteinase (1.3%), and C-type lectinlike families (1.1%) [31]. Costa Rican M. mipartitus also contains 1.9% KSPIs [31], while these proteins were not detected in M. mipartitus from Ecuador [43].…”