| dc.description.abstract | The Lansberg’s hognose pitviper, Porthidium lansbergii lansbergii, inhabits northern Colombia. A recent
proteomic characterization of its venom (J. Proteomics [2015] 114, 287e299) revealed the presence of
phospholipases A2 (PLA2) accounting for 16.2% of its proteins. The two most abundant PLA2s were biochemically
and functionally characterized. Pllans-I is a basic, dimeric enzyme with a monomer mass of
14,136 Da, while Pllans-II is an acidic, monomeric enzyme of 13,901 Da. Both have Asp49 in their partial
amino acid sequences and, accordingly, are catalytically active upon natural or synthetic substrates.
Nevertheless, these two enzymes differ markedly in their bioactivities. Pllans-I induces myonecrosis,
edema, and is lethal by intracerebroeventricular injection in mice, as well as cytolytic and anticoagulant
in vitro. In contrast, Pllans-II is devoid of these effects, except for the induction of a moderate edema. In
spite of lacking myotoxicity, Pllans-II enhances the muscle damaging action of Pllans-I in vivo. Altogether,
results further illustrate the divergent functional profiles of basic and acidic PLA2s in viperid venoms, and
suggest that Pllans-I plays a myotoxic role in envenomings by P. l. lansbergii, whereas Pllans-II, apparently
devoid of toxicity, enhances muscle damage caused by Pllans-I. | |
