Effect of ConA-receptor interaction on the structure of cell membrane
DAI JIANWU, QUN DONG, YAXIANSU,AND KECHUN LIN Department of Cell Biology & Biophysics, Beijing Medical University, Beijing 100083, China
Recently, the effect of ligand receptor interaction on the membrane structure of liposomes has been studied extensively. However, little is known about how it exists on biological membranes. In this paper, the effect of Con-canavalin A (ConA) receptor interaction on the structure of cell membranes was studied by Circular Dichroism (CD) and 3lP Nuclear Magnetic Resonance (NMR). CD results of both the purified macrophage membranes and human erythrocyte ghosts (EG) showed that the conformation of membrane proteins changed after ConA bind ing. For further research, 31P-NMR was used to detect the organization of phospholipid molecules on macrophage mem branes. After ConA binding, the tendency to form non bi-layer structure increased with the amount of ConA. The changes of 31P-NMR spectra of living macrophages might be partly due to the above stated reason too. In addition, ConA-receptor interaction also induced similar results of 31P-NMR spectra in EG. In contrast, wheat germ agglutinin (WGA ), another kind of lectin, rarely showed the same influence.