2006

A theoretical molecular model of this domain was built through folding recognition (threading) techniques and refined by molecular dynamics simulation. Then, the final BjussuMP-I catalytic
domain model was compared to other SVMPs and Reprolysin family proteins in order to identify eventual structural differences, which could help to understand the biochemical activities of these enzymes. The presence of large hydrophobic areas and some conserved surface charge-positive
residues were identified as important features of the SVMPs and other metalloproteases.

Tonismagi K, Samel M, Trummal K, Ronnholm G, Siigur J, Kalkkinen N, Siigur E.

The l-amino acid oxidase from Vipera lebetina venom was purified to homogeneity using combination of size exclusion, ion exchange and hydrophobic chromatography. The monomeric molecular mass of the homodimeric enzyme is 60.9kDa. The N-terminal and the tryptic peptides share high homology with other snake venom l-amino acid oxidases. The enzyme displays high specificity towards hydrophobic l-amino acids, the best substrates are l-Met, l-Trp, l-Leu followed by l-His, l-Phe, l-Arg and l-Ile. Six substrates-Gly, l-Ser, l-Thr, l-Pro, l-Cys, l-Asp-were not oxidized. The enzyme has antimicrobial activity inhibiting the growth of both Gram-negative and Gram-positive bacteria. V. lebetina LAAO dose-dependently inhibited platelet aggregation induced by ADP or collagen. In case of ADP-induced aggregation the inhibitory effect was more pronounced on the second wave of aggregation.

Makarova YV, Osipov AV, Tsetlin VI, Utkin YN.

To determine whether the ability to induce neurite outgrowth in rat pheochromocytoma cell line PC12 is characteristic of phospholipases of different types, we have studied the influence of phospholipase A(2) (PLA2) from cobra Naja kaouthia venom and two PLA2s from viper Vipera nikolskii venom on PC12 cells. Phospholipases from the viper venom are heterodimers in which only one of the subunits is enzymatically active, while PLA2 from the cobra venom is a monomer. It was found that all three PLA2s induce neurite outgrowth in PC12. The PLA2 from cobra venom exhibits this effect at higher concentrations as compared to the viper enzymes. We have not observed such an activity for isolated subunits of viper PLA2s, since the enzymatically active subunits have very high cytotoxicity, while the other subunits are not active at all. However, co-incubation of active and inactive subunits before addition to the cells leads to a marked decrease in cytotoxicity and to restoration of the neurite-inducing activity. It has also been shown that all enzymatically active PLA2s are cytotoxic, the PLA2 from cobra venom being the least active. Thus, for the first time we have shown that PLA2s from snake venoms can induce neurite outgrowth in PC12 cells.