title: Cross-linkings between spectrin and band 3 in human erythroycte membranes.
abstract: A specific structural association between spectrin component 1 and band 3 in human erythrocyte membrane has been demonstrated by covalent cross-linkings, specific labeling, and the technique of two-dimensional gel electrophoresis. A complex of 330,000 daltons, representing 1 + 3, was produced in mildly oxidized membranes at physiologic pH and isotonic conditions but not at hypotonic conditions ( less than 10 mM KCl or NaCl). The yield of this complex decreased dramatically as the monovalent cation concentration decreased from 90 mM to 30 mM. The presence of Mg++ or Ca++ (2 mM) at low ionic strength promoted 1 + 3 cross-linking in an amount similar to that produced at isotonic conditions. The specific segment of band 3 involved in the cross-linking was also investigated by means of chymotrypsin digestion of band 3 in the intact red cells. The results showed the cross-links between spectrin component 1 and the 55,000-dalton fragment of band 3 at physiologic pH and isotonic conditions. This is consistent with the idea that band 3 is anchored on or contacted with the submembrane meshwork at the cytoplasmic membrane surface.
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000648:ultrastructure*; D004912:Erythrocytes / Q000648:ultrastructure*; D006801:Humans; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000097:blood; D008970:Molecular Weight; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D013049:Spectrin
chemical_list: D046911:Macromolecular Substances; D008565:Membrane Proteins; D013049:Spectrin