Importance of Glycophorin A Protein Found in Red Blood Cells Essay
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Glycophorin A (GpA) is a protein found in the human membrane red blood cell. The GpA protein is obtained from the gene called glycophorin A (MNS blood group) or GpA. The GpA gene bears the antigenic determinants for the MN and Ss blood groups, and 40 related variants of the Miltenberger complex and several isoforms of Sta1. There are two classes of membrane glycoproteins, asialo and sialoglycoproteins (glycophorins). These glycoproteins are determined by the presence of sialic acid which is the negative charge on cell surface. GpA is the primary sialoglycoprotein of human erythrocyte membranes that forms noncovalent dimers by sequence-specific, reversible association of its single hydrophobic membrane-spanning domain2. The glycophorin…show more content… The glycosylated part of the N-terminus acts as receptors of MN blood group. The GpA protein is receptors for influenza virus, Hepatitis A virus, and Plasmodium falciparum erythrocyte-binding antigen 1751. It is also significant for the function and the activities of SLC4A1 (solute carrier family 4 (anion exchanger)) such as to translocate it to the plasma membrane.
Glycophorins contain high carbohydrates which link to polypeptide chain through O-glycosidic linkages either to serine or threonine residues and N-glycosidic linkage to asparagine residues of the protein4. Human has 15 linkages of O-glycosidic and 1 of N-glycosidic. The carbohydrates and the protein play important role in the antigenicity. If they are different then they will have different antigenic behavior. Two genes within the human glycophorin family, the GpB and GpE, are homologous to the GpA gene. These genes encode the GpB and GpE proteins which have the same functions as GpA protein. The difference between GpA, GpB, and GpE proteins is that GpE carry less blood group antigen than the other two.
Studies had shown that solution nuclear magnetic resonance (NMR) spectroscopy of a 40-residue peptide solubilized in aqueous detergent micelles2. The experiment demonstrates that even though some residues do not have the tendency to form alpha helices, hydrogen bonds are formed in the backbone to yield the helix. The unfavorable residues in one monomer were predicted to interact with the other monomer to