Biopolymers and cell. 2005; 21 (4): 319 - 325

Study on carbohydrate specificity of hemolytic lectin from death-cap mushroom (Amanita phalloides (Vaill. Fr.) Secr)

V. O. Antonyuk

Purification and some physical and chemical properties of a hemolytic lectin from death-cap mushroom (A. phalloides (Vaill. Fr.) Secr) are described. According to the SDS-PAGE data, the polypeptide chain of phallolysin consists of one component with molecular weight of approximately 18 kDa. The molecular weight of the lectin as determined by gel filtration on Toyopearl HW-55 is 35 kDa. Phallolysin is thermolabile, the heating during 30 min at 65 ⁰C removes completely its hemolytic and hemaglutinating activity. Phallolysin is not Ca²⁺-dependent lectin. The sensitivity of erythrocyte of different species to the hemolysis decreases in the following sequence: rabbit>rat>man. Osmotic protection experiments were performed using rabbit erythrocytes. When the erythrocytes were incubated together with phallolysin in the presence of polyethylene glycols of different molecular weight, the lysis was inhibited increasingly as the size of the molecules increased. The obtained results indicate that phallolysin forms ion-permeable pores with a functional diameter smaller than 2.3 nm (but big ger than 1.6 nm) in the cell membranes of rabbit erythrocytes. At the same time the presence of polyethylene glycols does not influence the hemaglutinating activity that allows to study carbohydrate specificity of the death-cap mushroom lectin. The lectin interaction with D-galactose and its b-derivatives is the strongest as revealed by study on carbohydrate specificity of phallolysin. The data on the phallolysin interaction with glycoproteins do not show any preference towards either N- or O-glycan type.

Key words: Amanita phalloides, phallolysin, hemotys, osmotic protect, carbohydrate specificity.