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Biochim Biophys Acta. 2015 Feb;1848(2):463-8. doi: 10.1016/j.bbamem.2014.10.037. Epub 2014 Nov 4.

Phospholipases a2 from Viperidae snakes: Differences in membranotropic activity between enzymatically active toxin and its inactive isoforms.

Author information

1
Orbeli Institute of Physiology, Orbely str. 22, 0019 Yerevan, Armenia.
2
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, GSP-7, Ul. Miklukho-Maklaya, 16/10, 117997 Moscow, Russian Federation.
3
Instituto Clodomiro Picado, Universidad de Costa Rica, 11501 San José, Costa Rica.
4
Orbeli Institute of Physiology, Orbely str. 22, 0019 Yerevan, Armenia. Electronic address: taipan@ysu.am.

Abstract

We describe the interaction of various phospholipases A2 (PLA2) from snake venoms of the family Viperidae (Macrovipera lebetina obtusa, Vipera ursinii renardi, Bothrops asper) with giant unilamellar vesicles (GUVs) composed of natural brain phospholipids mixture, visualized through fluorescence microscopy. The membrane fluorescent probes 8-anilino-1-naphthalenesulfonicacid (ANS), LAUDRAN and PRODAN were used to assess the state of the membrane and specifically mark the lipid packing and membrane fluidity. Our results have shown that the three PLA2s which contain either of aspartic acid, serine, or lysine residues at position 49 in the catalytic center, have different effects on the vesicles. The PLA2 with aspartic acid at this position causes the oval deformation of the vesicles, while serine and lysine-containing enzymes lead to an appreciable increase of fluorescence intensity in the vesicles membrane, wherein the shape and dimensions of GUVs have not changed, but in this case GUV aggregation occurs. LAURDAN and PRODAN detect the extent of water penetration into the bilayer surface. We calculated generalized polarization function (GP), showing that for all cases (D49 PLA2, S49 PLA2 and K49 PLA2) both LAUDRAN and PRODAN GP values decrease. A higher LAURDAN GP is indicative of low water penetration in the lipid bilayer in case of K49 PLA2 compared with D49 PLA2, whereas the PRODAN mainly gives information when lipid is in liquid crystalline phase.

KEYWORDS:

Fluorescent probes; GUV; LAURDAN; PRODAN; Phospholipase A2; Snake venom

PMID:
25450350
DOI:
10.1016/j.bbamem.2014.10.037
[Indexed for MEDLINE]
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