| dc.description.abstract | We report the proteomic characterization of the Central American pitvipers Atropoides nummifer and
Atropoides picadoi. The crude venoms were fractionated by reverse-phase high-performance liquid
chromatography (HPLC), followed by analysis of each chromatographic fraction by sodium dodecyl
sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), N-terminal sequencing, matrix-assisted laser
desorption ionization-time of flight (MALDI-TOF) mass fingerprinting, and collision-induced
dissociation-tandem mass spectrometry (CID-MS/MS) of tryptic peptides. Each venom contained a
number of bradykinin-potentiating peptides and around 25–27 proteins of molecular masses in the
range of 7–112 kDa, belonging to only nine different toxin families (disintegrin, DC fragment, snake
venom vascular endothelial growth factor, phospholipases A2, serine protease, cysteine-rich secretory
proteins, C-type lectins, L-amino acid oxidase, and Zn2+-dependent metalloproteases), albeit distinctly
distributed among the two Atropoides species. In addition, A. nummifer expresses low amounts of a
three-finger toxin not detected in the venom of A. picadoi. The major toxins of A. nummifer belong to
the PLA2 (relative abundance, 36.5%) and the serine proteinase (22%) families, whereas the most
abundant A. picadoi toxins are Zn2+-dependent metalloproteinases (66.4%). We estimate that the
similarity of venom proteins between the two Atropoides taxa may be around 14–16%. The high degree
of differentiation in the venom proteome among congeneric taxa emphasizes unique aspects of venom
composition of related species of Atropoides snakes and points to a strong role for adaptive
diversification via natural selection as a cause of this distinctiveness. On the other hand, their distinct
venom toxin compositions provide clues for rationalizing the low hemorrhagic, coagulant, and
defibrinating activities and the high myotoxic and proteolytic effects evoked by A. nummifer snakebite
in comparison to other crotaline snake venoms and the high hemorrhagic activity of A. picadoi. | |
