Study provides a new understanding of snake venom

Each year, about half a million people in sub-Saharan Africa suffer from snake bites, which lead to an estimated 7,000 to 20,000 deaths. Many snake species native to this region, such as the highly feared black mamba, are currently classified as species of the highest medical importance by the World Health Organization. Thus, using systematic approaches to better understand the composition and function of these creatures’ venom is a medical priority.

Now, a research team led by the Center for Antibody Technologies from the Technical University of Denmark has systematically analyzed and compared the protein compositions and functions of the venoms of the 26 medically most important snake species in sub-Saharan Africa. The snakes belong to two main categories – elapids, including the black and green mambas and the ring-necked spitting cobra, and vipers, such as the Puff adder and the Gabon viper.

The analysis revealed that the composition and function of snake venoms is highly complex and varies significantly from species to species. Elapid venoms, for instance, contain large amounts of a type of proteins called “three finger toxins” that act by blocking neuronal transmission or by killing cells, as well as phospholipases A₂ (PLA₂s), a class of enzymes which is found in many animal venoms. 

On the other hand, the viper venoms seem to be dominated by a different mixture of protein, including PLA₂s, but also substantial quantities of other enzymes like the Snake Venom Metalloproteinases and the Snake Venom Serine Proteinases.

While the venoms of most of these snake species have been described before, those of two species – the Anchieta’s cobra (Naja anchietae) and of the white-bellied carpet viper (Echis leucogaster) – have now been characterized for the first time. 

Furthermore, while previous studies have typically focused on just a handfuls of species each – and often with little or even no data on functional aspects – the present study is an integrated approach that provides a solid foundation for further investigations of snake biology, and could be of crucial importance in the development of efficient antivenoms.

“Overall, this study provides a foundation for further studies on snake biology and evolution, for which we recommend an integrated approach combining genomics, transcriptomics, and proteomics to provide information on gene expression and other molecular mechanisms linked to phenotypic diversity,” said the researchers.

“Moreover, the toxicovenomic profiles elucidated in this study may aid in the development of effective antivenoms through better understanding of the behavior of snake venoms and their roles as drug targets.”

The research results are published in the journal GigaScience.

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By Andrei Ionescu, Earth.com Staff Writer

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