Hydrostatic Pressure of 100 MPa Facilitates the Cross-Linking between Lysine-539 and Lysine-851 by Anion Transport Inhibitor in Band 3

Human erythrocyte band 3 is an anion exchanger and comprised of 14 transmembrane segments (TMs). Its function is inhibited by the modification of Lys-539 on TM 5 using 4,4’-diisothiocyanatodihydrostilbene 2,2’-disulfonate (H2DIDS). Upon exposure of band 3 to alkaline pH, another isothiocyanate group of H2DIDS can react with Lys-851 on TM 13. Thus, Lys-539 on TM 5 and Lys-851 on TM13 are cross-linked by H2DIDS. Such cross-linking was facilitated by a pressure of 100 MPa and suppressed the 200 MPa-induced hemolysis of erythrocytes pre-exposed to alkaline pH. Thus, the cross-linkage between TMs by H2DIDS stabilizes bilayer-cytoskeleton interactions and results in the reduction in the volume of band 3.