A structural model of human erythrocyte band 2.1: alignment of chemical and functional domains.
Protein 2.1 is a 210-kilodalton protein that connects erythrocyte spectrin to the NH2-terminal cytoplasmic domain of band 3 and thereby functions as the essential linkage between the membrane skeleton and the bilayer. We cleaved this protein into specific chemical domains by limited digestion with trypsin and alpha-chymotrypsin at 0 degrees C. Intermediate-sized peptides were separated by two-dimensional isoelectric focusing/NaDodSO4/polyacrylamide gel electrophoresis and characterized by high resolution peptide mapping. We have established a provisional structural model of protein 2.1 by comparing the peptide maps of these chemical domains to maps obtained from larger overlapping chymotryptic fragments as well as fragments obtained from 2-nitro-5-thiocyanobenzoic acid cleavage. In addition to providing a provisional structural map of protein 2.1, we have identified two functional domains of protein 2.1, an 83-kilodalton tryptic peptide (T-83) which binds band 3 and a 65-kilodalton tryptic peptide (T-65) which binds spectrin. We have therefore localized the functional domains along our linear map of protein 2.1.
D001457:Anion Exchange Protein 1, Erythrocyte / Q000502:physiology; D017487:Ankyrins; D001798:Blood Proteins / Q000302:isolation & purification / Q000502:physiology*; D002918:Chymotrypsin; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000502:physiology*; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D013049:Spectrin / Q000502:physiology; D014357:Trypsin
C110202:ANK1 protein, human; D001457:Anion Exchange Protein 1, Erythrocyte; D017487:Ankyrins; D001798:Blood Proteins; D010446:Peptide Fragments; D013049:Spectrin; D002918:Chymotrypsin; D014357:Trypsin