Extended Snake Venomics by Top-Down In-Source Decay: Investigating the Newly Discovered Anatolian Meadow Viper Subspecies, Vipera anatolica senliki

Herein, we report on the venom proteome
of Vipera
anatolica senliki, a recently discovered
and hitherto unexplored subspecies of the critically endangered Anatolian
meadow viper endemic to the Antalya Province of Turkey. Integrative
venomics, including venom gland transcriptomics as well as complementary
bottom-up and top-down proteomics analyses, were applied to fully
characterize the venom of V. a. senliki. Furthermore, the classical top-down venomics approach was extended
to elucidate the venom proteome by an alternative in-source decay
(ISD) proteomics workflow using the reducing matrix 1,5-diaminonaphthalene.
Top-down ISD proteomics allows for disulfide bond counting and effective
de novo sequencing-based identification of high-molecular-weight venom
constituents, both of which are difficult to achieve by commonly established
top-down approaches. Venom gland transcriptome analysis identified
96 toxin transcript annotations from 18 toxin families. Relative quantitative
snake venomics revealed snake venom metalloproteinases (42.9%) as
the most abundant protein family,
followed by several less dominant toxin families. Online mass profiling
and top-down venomics provide a detailed insight into the venom proteome
of V. a. senliki and facilitate a comparative
analysis of venom variability for the closely related subspecies, Vipera anatolica anatolica.