Comparative analysis of the high molecular mass subproteomes of eight Bothrops snake venoms

ABSTRACT

Snake venoms are extremely active biological secretions composed primarily of various classes of enzymes. The genusBothropscomprises various pit viper speciesthat represent the most medically significant taxa in Central and South America, accounting for more human envenomations and fatalities than any other snakes inthe region. Venom proteomes of manyBothropsspecies have been well-characterized but investigations have focused almost exclusively on proteins smaller than100 kDa despite expression of larger components being documented in severalBothropsvenoms. This study sought to achieve detailed identification of majorcomponents in the high molecular mass subproteome of venoms from eightBothropsspecies (B.brazili,B.cotiara,B.insularis,B.jararaca,B.jararacussu,B.leucurus,B.moojeniandB. neuwiedi). Enzymes such as metalloproteinases and L-amino acid oxidases were the most prominent components identified in the first size-exclusionchromatography fractions of these venoms. Minor components also identified in the first peaks included 5'-nucleotidase, aminopeptidase, phosphodiesterase, andphospholipases A2and B. Most of these components disappeared in electrophoretic profiles under reducing conditions, suggesting that they may be composed of morethan one polypeptide chain. A significant shift in the molecular masses of these protein bands was observed following enzymatic N-deglycosylation, indicating thatthey may contain N-glycans. Furthermore, none of the identified high molecular mass proteins were shared by all eight species, revealing a high level of interspecificvariability among these venom components.