AbstractVenom proteome profiling is important to understand the toxicology and treatment of persons poisoned by animal venoms. An in depth understanding of the pharmacological mechanisms induced by venom toxins could help in the discovery of novel drug molecules. In the current study, we aimed to delineate the venom toxins of Indian cobra (Naja naja) from the Western Ghats of India through SDS-PAGE and reversed-phase HPLC followed by Q-TOF LC-MS/MS analysis, incorporating PEAKS and Novor assisted de novo sequencing methodologies. A total of 143 proteins distributed across 17 different enzymatic and non-enzymatic venom protein families were identified. The de novo analysis exclusively yielded 59 peptides representing 28 venom protein families. Among these, glutathione peroxidase and endonuclease were reported for the first time in Indian cobra venom. Immunological cross-reactivity of cobra venom assessed using Indian polyvalent antivenoms suggested that VINS showed better EC50 (2.48 µg/mL) values than that of PSAV (6.04 µg/mL) and Virchow (6.03 µg/mL) antivenoms. Also, immunoaffinity chromatography performed using VINS antivenom indicated that it failed to detect few low molecular mass proteins (<10 kDa) that include three-finger toxins, phospholipase A2s and kunitz-type serine protease inhibitors. Taken together, the present study enabled a large-scale characterization of the venom proteome of Naja naja that offers valuable insights on the possible pharmacological mechanisms and future therapeutic potential of hitherto unexplored snake venom constituents.SignificanceThe present work describes the venom proteome characterization of Naja naja collected from the Western Ghats region in India, incorporating conventional proteomics approaches as well as de novo sequencing methods. Interestingly, we were able to determine proteins belong to glutathione peroxidase and endonuclease family, which was not reported in any of the previous studies on Naja naja venom. Notably, our study has reported the highest number of proteins from cobra venom so far. Also, the current study highlights the importance of developing region-specific antivenoms for improving the specificity and cross-neutralization potential of antivenoms.HighlightsProteomics of cobra venom resulted in the identification of 143 proteins.De novo approaches exclusively yielded 59 peptides representing 28 proteins.Glutathione peroxidase and endonuclease were identified for the first time in Indian cobra venom.Indian polyvalent antivenoms showed varying cross-reactivity towards cobra venom.VINS antivenom failed to detect few low molecular mass proteins (< 10 kDa).
Cardiotoxin II from Taiwan cobra venom, Naja naja atra. Structure in solution and comparison among homologous cardiotoxins.
