scholarly journals Ionic-strength-dependent changes in the structure of the major protein of the human erythrocyte membrane

1977 ◽  
Vol 161 (1) ◽  
pp. 131-138 ◽  
Author(s):  
R E Jenkins ◽  
M J A Tanner
Keyword(s):  
Ionic Strength ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Polypeptide Chain ◽  
Trypsin Digestion ◽  
Major Protein ◽  
Human Erythrocyte Membrane ◽  
Extracellular Region ◽  
The Individual ◽  
Intracellular Region

The effect of ionic strength on the proteolysis by trypsin of the major membrane-penetrating protein (polypeptide 3) in the erythrocyte membrane was studied. Both the intracellular and extracellular regions of the protein are susceptible to trypsin proteolysis under hypo-osmotic conditions, whereas under iso-osmotic conditions the extracellular region of the protein is resistant to trypsin, and the intracellular region yields only two cleavage products with trypsin. Studies of the fragments obtained from polypeptide 3 by trypsin digestion under iso-osmotic conditions of ‘ghosts’ radioiodinated with lactoperoxidase confirmed our earlier conclusions that the polypeptide chain of polypeptide 3 traverses the membrane twice. Ionic-strength-dependent changes were also observed in the incorporation of iodine by lactoperoxidase into the individual extracellular tyrosine sites of the protein. These results show that polypeptide 3 undergoes ionic-strength-dependent changes in structure.

scholarly journals The major human erythrocyte membrane protein. Evidence for an S-shaped structure which traverses the membrane twice and contains a duplicated set of sites.

1975 ◽  
Vol 147 (3) ◽  
pp. 393-399 ◽  
Author(s):  
R E Jenkins ◽  
J A Tanner
Keyword(s):  
Membrane Protein ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Polypeptide Chain ◽  
Native Protein ◽  
Human Erythrocyte Membrane ◽  
Erythrocyte Membrane Protein ◽  
Tyrosine Residues ◽  
Extracellular Region ◽  
Intracellular Region

The structure of the major human erythrocyte membrane protein (protein E) was investigated by studying the products of proteolysis of the native protein in the membrane. The distribution and location of the tyrosine residues labelled by radioiodination by lactoperoxidase was determined. Proteolysis of the extracellular region of the protein by thermolysin released four tyrosine-containing peptides, all of which were also found to remain in the major fragment that is retained in the membrane. The presence of these duplicated sites in the extracellular region of the protein was confirmed by limited trypsin digestion of the intracellular region of the protein. Two groups of fragments were obtained. Both groups contained a set of the extracellular labelled sites, but they differed in containing distinct groups of intracellular sites, showing that the two sets of extracellular sites are linked by an intracellular region of the protein. The polypeptide chain thus traverses the membrane twice. An S-shaped model which is consistent with these data is proposed.

scholarly journals The structure of the major protein of the human erythrocyte membrane. Characterization of the intact protein and major fragments

1977 ◽  
Vol 161 (1) ◽  
pp. 139-147 ◽  
Author(s):  
R E Jenkins ◽  
M J A Tanner
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Group Analysis ◽  
Terminal Group ◽  
Terminal Region ◽  
Intact Protein ◽  
Major Protein ◽  
Human Erythrocyte Membrane ◽  
Terminal Part ◽  
Extracellular Region

Polypeptide 3, the major membrane-penetrating protein of the human erythrocyte membrane, was characterized, together with two major fragments derived by specific proteolysis of the native protein in the membrane. One fragment (fragment 3f) was obtained from thermolysin cleavage in the extracellular region of the protein, and the other (fragment T1) was derived from tryptic cleavage in the intracellular region of the protein. The results of N- and C-terminal group analysis suggest that fragment 3f contains the N-terminal region of polypeptide 3 and fragment T1 contains the C-terminal part of the molecule. The carbohydrate contents of the polypeptides suggest that carbohydrates are present in three regions of the molecule, much of this carbohydrate being present in the C-terminal part of the molecule. This region of the protein also contains the receptors for concanavalin and the lectins from Phaseolus vulgaris and Ricinis communis, and our results suggest that there is heterogeneity in the carbohydrate chains present in the C-terminal region of polypeptide 3. These data are related to the folding of polypeptide 3 in the erythrocyte membrane.

scholarly journals Role of the reticulum in the stability and shape of the isolated human erythrocyte membrane

1982 ◽  
Vol 92 (3) ◽  
pp. 714-721 ◽  
Author(s):  
Y Lange ◽  
RA Hadesman ◽  
TL Steck
Keyword(s):  
Ionic Strength ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Time Course ◽  
Isotonic Saline ◽  
Human Erythrocyte Membrane ◽  
Wide Range ◽  
Cell Stability ◽  
Mechanically Stabilized ◽  
Low Ionic Strength

In order to examine the widely held hypothesis that the reticulum of proteins which covers the cytoplamsic surface of the human erythrocyte membrane controls cell stability and shape, we have assessed some of its properties. The reticulum, freed of the bilayer by extraction with Triton X-100, was found to be mechanically stable at physiological ionic strength but physically unstable at low ionic strength. The reticulum broke down after a characteristic lag period which decreased 500-fold between 0 degrees and 37 degrees C. The release of polypeptide band 4.1 from the reticulum preceded that of spectrin and actin, suggesting that band 4.1 might stabilize the ensemble but is not essential to its integrity. The time-course of breakdown was similar for ghosts, the reticulum inside of ghosts, and the isolated reticulum. However, at very low ionic strength, the reticulum was less stable within the ghost than when free; at higher ionic strength, the reverse was true. Over a wide range of conditions the membrane broke down to vesicles just as the reticulum disintegrated, presumably because the bilayer was mechanically stabilized by this network. The volume of both ghosts and naked reticula varied inversely and reversibly with ionic strength. The volume of the naked reticulum varied far more widely than the ghost, suggesting that its deformation was normally limited by the less extensible bilayer. The contour of the isolated reticulum was discoid and often dimpled or indented, as visualized in the fluorescence microscope after labeling of the ghosts with fluoroscein isothiocyanate. Reticula derived from ghosts which had lost the ability to crenate in isotonic saline were shriveled, even though the bilayer was smooth and expanded. Conversly, ghosts crenated by dinitrophenol yielded smooth, expanded reticula. We conclude that the reticulum is a durable, flexible, and elastic network which assumes and stabilizes the contour of the membrane but is not responsible for its crenation.

Further evidence for a membrane potential-dependent shape transformation of the human erythrocyte membrane

1986 ◽  
Vol 6 (11) ◽  
pp. 999-1006 ◽  
Author(s):  
Peter Müller ◽  
Andreas Herrmann ◽  
Roland Glaser
Keyword(s):  
Membrane Potential ◽  
Ionic Strength ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Transmembrane Potential ◽  
Sodium Gluconate ◽  
Human Erythrocyte Membrane ◽  
Shape Transformation

The influence of various factors (pH, temperature, sodium gluconate) on the ionic strength-dependent stomatocyte-discocyte-echinocyte transformation of the human erythrocyte membrane was investigated. The results give further evidence for a correlation between shape of erythrocyte membrane and the transmembrane potential of the cells.

scholarly journals The organization of the major protein of the human erythrocyte membrane

1974 ◽  
Vol 137 (3) ◽  
pp. 531-534 ◽  
Author(s):  
D. H. Boxer ◽  
R. E. Jenkins ◽  
M. J. A. Tanner
Keyword(s):  
Membrane Protein ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Intact Cell ◽  
The Other ◽  
Major Protein ◽  
Erythrocyte Ghosts ◽  
Human Erythrocyte Membrane ◽  
Cytoplasmic Surface ◽  
Peptide Maps

The enzyme lactoperoxidase was used to catalyse the radioiodination of membrane proteins in intact human erythrocytes and in erythrocyte ‘ghosts’. Two major proteins of the erythrocyte membrane were isolated after iodination of these two preparations, and the peptide ‘maps’ of each protein so labelled were compared. Peptides from both proteins are labelled in the intact cell. In addition, further mobile peptides derived from one of the proteins are labelled only in the ‘ghost’ preparation. Various sealed ‘ghost’ preparations were also iodinated, lactoperoxidase being present only at either the cytoplasmic or extra-cellular surface of the membrane. The peptide ‘maps’ of protein E (the major membrane protein) labelled in each case were compared. Two discrete sets of labelled peptides were consistently found. One group is obtained when lactoperoxidase is present at the extra-cellular surface and the other group is found when the enzyme is accessible only to the cytoplasmic surface of the membrane. The results support the assumption that the organization of protein E in the membrane of the intact erythrocyte is unaltered on making erythrocyte ‘ghosts’. They also confirm previous suggestions that both the sialoglycoprotein and protein E extend through the human erythrocyte membrane.

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