Comparative study of the interaction of CHAPS and Triton X-100 with the erythrocyte membrane

Abstract

The zwitterionic detergent CHAPS, a derivative of the bile salts, is widely used in membrane protein solubilization. It is a "facial" detergent, having a hydrophilic side and a hydrophobic back. The objective of this work is to characterize the interaction of CHAPS with a cell membrane. To this aim, erythrocytes were incubated with a wide range of detergent concentrations in order to determine CHAPS partition behavior, and its effects on membrane lipid order, hemolytic effects, and the solubilization of membrane phospholipids and cholesterol. The results were compared with those obtained with the nonionic detergent Triton X-100. It was found that CHAPS has a low affinity for the erythrocyte membrane (partition coefficient K=0.06mM(-1)), and at sub-hemolytic concentrations it causes little effect on membrane lipid order. CHAPS hemolysis and phospholipid solubilization are closely correlated. On the other side, binding of Triton X-100 disorders the membrane at all levels, and has independent mechanisms for hemolysis and solubilization. Differential behavior was observed in the solubilization of phospholipids and cholesterol. Thus, the detergent resistant membranes (DRM) obtained with the two detergents will have different composition. The behaviors of the two detergents are related to the differences in their molecular structures, suggesting that CHAPS does not penetrate the lipid bilayer but binds in a flat position on the erythrocyte surface, both in intact and cholesterol depleted erythrocytes. A relevant result for Triton X-100 is that hemolysis is not directly correlated with the solubilization of membrane lipids, as it is usually assumed.

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“…have also reported that hemoglobin release and solubilization of phospholipids/cholesterol evoked by TX-100 were processes not directly correlated, once hemoglobin release preceded solubilization. They confirmed our hypothesis that hemoglobin is released from erythrocytes through holes created by the partition and fast segregation of TX-100 to cholesterol poor (liquid disordered, Ld) regions of the membrane, while most of the lipids remained insoluble (Rodi et al 2014). Those authors have found different results with the zwitterionic and weak solubilizer CHAPS, to which hemoglobin release and lipid solubilization occurred at the same detergent concentration range.…”

“…TX-100 is known to preferentially solubilize phospholipids from the inner leaflet of the cell membrane (Ingelmo-Torres et al 2009;Koumanov et al 2005;Lichtenberg et al 2005) while Brij detergents are not as selective as TX-100 (Schuck et al 2003). Rodi et al (2014) have also demonstrated that TX-100 incorporates and solubilize lipid components from the erythrocyte membranes in a different way compared with CHAPS (a zwitterionic detergent). Those results also indicate that TX-100 is able to flip to the inner leaflet and incorporate in poor cholesterol regions of the membrane, while CHAPS probably due to its charges is prevented from flip-flop and thus acts on the surface of the erythrocyte membrane (Rodi et al 2014).…”

“…Rodi et al (2014) have also demonstrated that TX-100 incorporates and solubilize lipid components from the erythrocyte membranes in a different way compared with CHAPS (a zwitterionic detergent). Those results also indicate that TX-100 is able to flip to the inner leaflet and incorporate in poor cholesterol regions of the membrane, while CHAPS probably due to its charges is prevented from flip-flop and thus acts on the surface of the erythrocyte membrane (Rodi et al 2014). Given that Brij detergents do not selectively solubilize components from the inner and outer leaflets, Brij-DRMs can reflect important aspects regarding membrane domains.…”

“…EPR spectra taken from such membrane systems-doped with spin labels-are sensitive to changes in molecular organization caused by the partitioning of amphiphiles, phase separation, bilayer/micelle transition, etc. For instance, detergent incorporation into erythrocytes decreases the molecular order and increases the mobility of the phospholipid hydrocarbon chains (Galembeck et al 1998;Preté et al 2011;Rodi et al 2006Rodi et al , 2014 and induces phase separation (Crepaldi Domingues et al 2009;Domingues et al 2010;Preté et al 2011;Rodi et al 2006Rodi et al , 2014Casadei et al 2014a). …”

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“…The damage of plasma membrane following a TX-100 exposure was further evaluated using the hemolysis and solubilized phospholipids (PLs) assay as standard techniques. [31] Trends were similar between the hemolytic activity and the amount of solubilized PLs on challenge by TX-100 (Figure 5(C) and 5(D)). The concentration dependence of these values was fitted by the logistic function.…”