FIGURE 4.

Specificity of the redox effects as a function of the location of double-cysteine mutations. The time course of the hERG current tail variations was followed upon the addition of 2 mm TbHO₂ and 5 mm DTT as indicated. Oocytes were bathed in standard OR-2 medium, except for the P2C/Y542C mutant, for which high-K⁺ OR-2 medium (see “Experimental Procedures”) was used because of the low expression level of this construct. Monoexponential fits are shown superimposed on the data during the TbHO₂ treatment. ○ (panels corresponding to mutants V3C/Y542C and V8C/Y542C), current level in a second set of oocytes following an oxidation period of 3 min in which test pulses were not applied to follow the evolution of the currents.