Aggregation of intramembrane particles in erythrocyte membranes treated with diamide

Abstract

Treatment of erythrocytes with diamide (diazene dicarboxylic acid bis-(N,N-dimethylamide)) results in oxidation of sulfhydryl groups of the membrane, and cross-linking of membrane proteins into high molecular weight complexes. Concomitant freeze-etching studies show aggregation of intramembrane particles on the protoplasmic fracture face of erythrocyte ghost membranes treated with the oxidant. Furthermore, after a 3 h incubation of erythrocytes with 10 mM diamide at 37 degrees C, cellular energy levels declined to about 70% of control values. The data suggest that disulfide cross-linking of the major membrane proteins releases the apparent physical occlusion of the band 3 proteins within the interstices of the cytoskeletal shell. This results in the translational mobility of band 3 proteins which is reflected ultra-structurally in the freeze-etch images.