title: Behavior of fragmented band 3 from chymotrypsin-treated bovine erythrocyte membrane in nonionic detergent solution.
abstract: Bovine band 3 which had been cleaved into two membrane intercalated fragments by extracellular chymotryptic digestion was partially purified and the behavior of fragmented band 3 was compared with that of intact band 3 in nonionic detergent, C12E9, solution. The two fragments were always co-eluted with nearly a 1:1 molar ratio from ion-exchange and gel filtration columns, confirming the observation of Reithmeier ((1979) J. Biol. Chem. 254, 3054-3060) that the fragments are bound together. However, as shown by the molecular size of fragmented band 3 and its reactivity with dimethylmaleic anhydride and/or a cross-linking reagent, the fragmentation caused some change in gross conformation of the protein. Dissociation of the two fragments, though not complete, was found to occur on treatment of fragmented band 3 with dimethylmaleic anhydride, which is a dissociating reagent for band 3 oligomers into the monomers. The disruption of self-associated band 3 was accompanied with a disruption of helical structure. The results suggest that a mutual interaction between the chymotryptic fragments is of importance to form the folded structure maintaining a band 3 dimer.
mesh_terms: D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte; D001798:Blood Proteins / Q000302:isolation & purification; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D002918:Chymotrypsin; D003902:Detergents; D004910:Erythrocyte Membrane / Q000032:analysis*; D004912:Erythrocytes / Q000032:analysis*; D008299:Maleic Anhydrides; D010446:Peptide Fragments / Q000302:isolation & purification*; D011487:Protein Conformation; D012996:Solutions
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D001798:Blood Proteins; D003902:Detergents; D008299:Maleic Anhydrides; D010446:Peptide Fragments; D012996:Solutions; C007474:2,3-dimethylmaleic anhydride; D002918:Chymotrypsin