ULTRACENTRIFUGATION STUDIES ON THE TRANSMEMBRANE DOMAIN OF THE HUMAN ERYTHROCYTE ANION TRANSPORTER BAND-3 IN THE DETERGENT C12E8

The dilute solution behaviour of the transmembrane domain (TMD) of the human erythrocyte anion exchanger Band 3 was studied by analytical ul tracentrifugation. Sedimentation velocity and equilibrium studies of t he TMD solubilized with the detergent C12E8 demonstrate that the prote in is a stable dimer in the concentration range 0.1 to 1 mg/ml. There is no evidence of a dissociation at low concentrations or of an associ ation at higher concentrations, Hydrodynamic calculations applying a p rolate ellipsoid of revolution and assuming a hydration of w = 0.35 re sult in an asymmetrical particle with an axial ratio (a/b) of similar to 3.5.