Comparative venom toxin analyses of Nigerian viperidae and elapidae snakes

•Comparative proteomic analysis showing protein expression levels in some medically important Nigerian snakes is presented.•Venom toxins varied across species and between the viper and elapid families.•Viper venoms contained cytotoxins SVMPs and SVSPs, while elapid venoms were composed of neurotoxins PLA2 and 3-FTx. Envenoming by snakebite is a serious health problem that maims and kills a large number of people, primarily in rural areas of developing African countries. The first comparative venom proteomic analyses of four snakes from the viperidae (E. ocellatus and B. arietans) and elapidae (N. haje and N. katiensis) families are presented in this study. Two-dimensional electrophoresis was combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry to analyze the venoms. Proteins were identified by comparing mass spectrometry spectra to those in the reviewed Uniprot-Serpentes database. A protein spot was considered differentially present between samples at a p-value of < 0.05 and a fold change of >2. Viper venoms contained cytotoxic-inducing proteins such as SVMPs, SVSPs, and cytotoxins, whereas elapid snake venoms contained neurotoxic proteins such as PLA2, 3-FTx, and neurotoxins. The PDQuest annotated protein spots on the 2-DE gels showed that the proteins in these snakes' venoms were differentially expressed between snake families and species. The elapid venoms were predominantly acidic (low pI) with low molecular masses, whereas the viperid venoms had high molecular masses and a pI in the region of 7. Venom phosphodiesterase, L-amino acid oxidase and cysteine-rich venom protein were common in the venoms of these snakes, while an uncommon protein actiflagelin was detected in the Naja venoms. Our findings show that there is significant variation in the toxin profiles of these snakes, both at the species and family levels. This has an impact on the clinical manifestations of envenomation. A thorough understanding of the various toxins found in venomous snakes may aid in the development of new and improved therapeutic strategies.