Anionic sites on the membrane intercalated particles of human erythrocyte ghost membranes. Freeze-etch localization

Abstract

Freeze-fracture and freeze-etching techniques disclose exclusive association of a ferritin derivative (with high isoelectric point, used as a marker for anionic sites) with the regions at the outer and inner surface of the membrane of human erythrocyte ghosts which correspond to the membraneintercalated particles. At the outer surface the sites include sialoglycoprotein. Exclusive association of anionic sites and membrane particles, and comparison of the number of sialic acid residues and intercalated particles implies clustering of acidic groups over discrete sites at the surface. Association of the label with the outer and inner surface regions which correspond to the membrane intercalated particles, provides further support for the concept of protein-containing structures which are intercalated and traverse the hydrophobic matrix of membrane regions with bilayer organization.