Biochemical and proteomic profiling reveals potent proteolytic activity in the venom of Erythrolamprus melanotus (Shaw's dark ground snake, Xenodontini)

Abstract

We describe here the Duvernoy's venom gland organization and biochemical and proteomic analyses of venom from the Colombian colubrid snake Erythrolamprus melanotus. Histological analysis indicated a serous venom gland distinct from the mucous supralabial gland. SDS-PAGE of the venom revealed >15 bands (∼15 kDa–∼200 kDa) and gelatin zymography revealed potent proteolytic activity; zymographic activity towards casein was considerably less. RP-HPLC yielded 16 peaks, several of which contained proteases, as assessed by gelatin zymography. Enzymatic assays using azocasein, azocoll and hide powder azure confirmed the proteolytic activity. The venom selectively degraded the Aα-chain of fibrinogen without affecting the Bβ and γ-chains (assessed by SDS-PAGE). All proteolytic activity was inhibited by EDTA (metalloproteinase inhibitor) but not by AEBSF (serine proteinase inhibitor). The venom had no l-amino acid oxidase, esterase, and PLA₂ activities. Proteomic analysis indicated the presence primarily of snake venom metalloproteinases (SVMP), snake venom matrix metalloproteinases (svMMP) and cysteine-rich secretory proteins (CRiSP). SVMP and svMMP were the major components, indicating that this venom is rich in proteases, in agreement with the findings for zymography and enzymatic assays. This study provides the first characterization of Colombian E. melanotus venom and highlights its rich content of metalloproteinases and potent proteolytic activity.