FIGURE 9.

Location of the arginine mutations that inhibit tariquidar rescue of misprocessed mutants and tariquidar-stimulated ATPase activity. Predicted structure of human P-gp in the open conformation as described in the legend to Fig. 1. The red balls show the positions of residues in the TM segments (His⁶¹, Gly⁶⁴, Leu⁶⁵, Met⁶⁸, Met⁶⁹, Phe⁷², Ala¹²⁹, Phe³⁰³, Ile³⁰⁶, Tyr³⁰⁷, Ser³⁰⁹, Tyr³¹⁰, Phe³³⁶, Phe³⁴³, Gln⁷²⁵, Phe⁷²⁸, Phe⁷³², Val⁸⁶⁵, Ile⁸⁶⁸, Gly⁸⁷², Phe⁹⁴², Thr⁹⁴⁵, Gln⁹⁴⁶, Met⁹⁴⁹, Tyr⁹⁵⁰, Ser⁹⁵², Tyr⁹⁵³, Leu⁹⁷⁵, Phe⁹⁷⁸, and Val⁹⁸²) that when changed to arginine significantly reduced both arginine rescue (Figs. 4 and 6) and tariquidar-stimulated ATPase activity (Fig. 8).