A current perspective on snake venom composition and constituent protein families

Abstract

Snake venoms are heterogeneous mixtures of proteins and peptides used for prey subjugation. With modern proteomics there has been a rapid expansion in our knowledge of snake venom composition, resulting in the venom proteomes of 30% of vipers and 17% of elapids being characterised. From the reasonably complete proteomic coverage of front-fanged snake venom composition (179 species-68 species of elapids and 111 species of vipers), the venoms of vipers and elapids contained 42 different protein families, although 18 were only reported in < 5% of snake species. Based on the mean abundance and occurrence of the 42 protein families, they can be classified into 4 dominant, 6 secondary, 14 minor, and 18 rare protein families. The dominant, secondary and minor categories account for 96% on average of a snake's venom composition. The four dominant protein families are: phospholipase A 2 (PLA 2 ), snake venom metalloprotease (SVMP), three-finger toxins (3FTx), and snake venom serine protease (SVSP). The six secondary protein families are: L-amino acid oxidase (LAAO), cysteine-rich secretory protein (CRiSP), C-type lectins (CTL), disintegrins (DIS), kunitz peptides (KUN), and natriuretic peptides (NP). Venom variation occurs at all taxonomic levels, including within populations. The reasons for venom variation are complex, as variation is not always associated with geographical variation in diet. The four dominant protein families appear to be the most important toxin families in human envenomation, being responsible for coagulopathy, neurotoxicity, myotoxicity and cytotoxicity. Proteomic techniques can be used to investigate the toxicological profile of a snake venom and hence identify key protein families for antivenom immunorecognition.

Venom diversity inNaja mossambica: Insights from proteomic and immunochemical analyses reveal intraspecific differences

“…A notable amount of glutathione peroxidase protein (GPx) was identified in all groups, comprising a significant percentage (2.5 -4.5%) of the total proteins in the tested venoms. It is an unexpected result as GPx has been classified as a rare protein family and is usually identified in a minor amount [24]. Within the KwaZulu-Natal group, a considerable proportion of proteins from the Immunoglobulin-like (Ig-like) group were detected (~3.5%), consistent with our previous reports for different venoms from Naja genus, where this group of proteins was also identified [15,[25][26].…”

“…This cluster is formed by the proteins markedly increased in KwaZulu-Natal venom samples, and it includes 21 proteins belonging to the 'Immunoglobulin-like domain superfamily' (IPR 036179). While these proteins are not officially recognized as known venom components [24],…”

Venom diversity in Naja mossambica: Insights from proteomic and immunochemical analyses reveal intraspecific differences

“…A notable amount of glutathione peroxidase protein (GPx) was identified in all groups, comprising a significant percentage (2.5–4.5%) of the total proteins in the tested venoms. It is an unexpected result as GPx has been classified as a rare protein family and is usually identified in a minor amount [ 24 ]. Within the KwaZulu-Natal group, a considerable proportion of proteins from the immunoglobulin-like domain containing (Ig-like) group were detected (~3.5%), consistent with our previous reports for different venoms from Naja genus, where this group of proteins was also identified [ 15 , 25 – 26 ].…”

“…This cluster is formed by the proteins markedly increased in KwaZulu-Natal venom samples, and it includes 21 proteins belonging to the ‘Immunoglobulin-like domain superfamily’ (IPR 036179). While these proteins are not officially recognized as known venom components [ 24 ], our previous reports have detected them [ 15 , 25 – 26 ]. This analysis indicates they constitute nearly 4% of all venom proteins in the KwaZulu-Natal venom and around 0.6–0.7% in two others.…”

Natural Peptide Toxins as an Option for Renewed Treatment of Type 2 Vasopressin Receptor-Related Diseases

“…Due to a specific evolutionary process that occurs independently in many animal lineages, the great pharmacological qualities of toxins explain their major impact on the hemostatic, cardiovascular or peripheral nervous systems of prey. Toxins are largely known for their activities in ionic channels and the cardiovascular system, which have been reviewed for conus [ 55 ], snake [ 56 ], scorpion [ 57 ], spider [ 58 ], centipede [ 59 ] and sea anemone [ 60 ]. An increasing number of animal toxins have also been described to be active in GPCRs, with an interesting classification: agonist-mimicking toxins and non-related agonist toxins, as recently reviewed in [ 61 ].…”