Comparative venomic studies of the western cottonmouth (Agkistrodon Piscivorus Leucostoma) and the western diamondback rattlesnake (Crotalus Atrox)

The ability to identify and classify individual venomic variation is essential to understanding intraspecific and intergenus variation of snake venom proteomes (venomes) and useful for developing more toxin specific antivenom. The study of individual snake venomes using new methodologies is needed to improve our understanding of the ontogenic, ecological, and evolutionary forces that shape venom as well as provide a potential source for new therapeutic agents. The methodological groundwork for the intergenus and intraspecific comparison of the venom proteomes of the western cottonmouth (Agkistrodon piscivorus leucostoma) and the western diamondback rattlesnake (Crotalus atrox) is presented in this study. The use of multiple orthogonal techniques including nano-flow ultraperformance liquid chromatography elevated energy level mass spectroscopy (nanoUPLC-MSE) enabled the identification of 74 unique proteins with an average protein sequence coverage of 39.3%. Size exclusion chromatography, reverse phase high performance liquid chromatography (RPHPLC), matrix-assisted laser desorption/ionization tandem time of flight mass spectrometry (MALDI-TOF/TOF-MS) and de novo sequencing revealed 7 novel peptides. Quantitation of mass spectra data also showed that relative protein abundance differed considerably between A. p. leucostoma and C. atrox. In summary, the proteomics data generated have served to expand the current understanding of both the A. p. leucostoma venome and C. atrox venome and helped to build a framework for future venomic study.