EFFECT OF WHEAT GERM AGGLUTININ AND CONCANAVALIN A ON ERYTHROCYTE MEMBRANE SKELETON. THERMAL DIELECTROSCOPY STUDY

Abstract

Deformability and stability of erythrocyte membrane (EM) largely depend on spectrin-based membrane skeleton (MS) and its attachment to the lipid bilayer. Concanavalin A binds to band 3 without effect on EM deformability, while wheat germ agglutinin (WGA) binds to Glycophorin A decreasing the EM deformability by unclear mechanism. Here, the binding of these lectins was studied using the dielectric relaxation on MS which involves a piezo effect on spectrin, powered by the electrostriction of EM through the attachment sites of MS (Ivanov and Paarvanova, 2016). To bind lectins, erythrocytes were suspended in working medium of isotonic 10 mM NaCl and mannitol solution, containing the lectin, at 22 °C for 30 min, hematocrit 0.10. The erythrocytes were washed, suspended at hematocrit 0.45 in working medium and heated. At the spectrin denaturation temperature (49.5 °C) the C* = Cre + jCim changed by ΔC* = ΔCre + jΔCim. The dielectric loss curve of spectrin, ΔC"im, derived from ΔCim data, and the ΔCre vs Cre plot were used to study the dielectric relaxation, assuming the dielectric activity of denatured spectrin nil. Up to 0.25 mg/ml, WGA strongly subdued the ΔC"im curve and ΔCre vs Cre plot, while Concanavalin A was without effect. This outcome indicates that WGA, in contrast to Concanavalin A, could sever the bridges between MS and bilayer, such that implicate Glycophorin A.

Keywords

• thermal dielectroscopy
• spectrin skeleton detachment
• lectin
• erythrocyte deformability