Fine structure of the band 3 protein in human red cell membranes: Freeze-fracture studies

Ronald S Weinstein, J. K. Khodadad, T. L. Steck

Research output: Chapter in Book/Report/Conference proceedingChapter


The major red cell membrane protein, band 3, is a glycoprotein which extends across the membrane from the extracellular space into the cytoplasmic compartment. It is widely held that band 3 is a component of the intramembrane particles (IMP) which can be demonstrated by freeze-fracture electron microscopy. In this study, we find that the outer surface poles of the IMP can be seen by freeze-etching after they are unmasked by proteolysis under conditions which excise the surrounding sialopeptides from the membrane. The poles appear as distinctive projections, 30-50 Å in diameter, the 'ES particles.' The ES particles remain associated with the outer surface of the membrane following cleavage of the band 3 polypeptide by chymotrypsin or pronase. This is consistent with previous biochemical studies which have shown that the 38,000-dalton outer surface segment of band 3 is intercalated in the lipid bilayer. A granulofibrillar component at the inner surface of the membrane is provisionally identified as the 40,000-dalton inner-surface domain of band 3.

Original languageEnglish (US)
Title of host publicationProgress in Clinical and Biological Research
Number of pages11
VolumeNo 30
Publication statusPublished - 1979
Externally publishedYes


ASJC Scopus subject areas

  • Medicine(all)

Cite this

Weinstein, R. S., Khodadad, J. K., & Steck, T. L. (1979). Fine structure of the band 3 protein in human red cell membranes: Freeze-fracture studies. In Progress in Clinical and Biological Research (Vol. No 30, pp. 47-57)