Arg 901 in the AE1 C-terminal tail is involved in conformational change but not in substrate binding

► Kinetic parameters of anion transport of C-terminal AE1 mutants were evaluated. ► Vmax decreased as the hydrophobicities of C-terminal residues increased. ► Arg 901 modification with HPG or PG increased alkali and protease resistance. ► Increase of C-terminal hydrophobicity leads to inefficient conformational change.