Fig. 1.

Differing sensitivity of Cys substitutions in aTMH2 and aTMH4 to Ag⁺ and NEM. A 160-μl aliquot of membranes at 10 mg/ml in TMG-acetate was treated with 5 mM NEM for 15 min at room temperature and then diluted into 3.2 ml of HMK buffer containing 0.3 μg/ml ACMA. Alternatively, membranes were diluted into HMK buffer and AgNO₃ added to 40 μM for 15 min at room temperature before addition of ACMA. ATP was added to 0.94 mM at 20 s, and the uncoupler nigericin was added to 0.5 μg/ml at 100 s. The traces indicate no treatment (green), NEM treatment (red), or Ag⁺ treatment (blue). The substitution tested is indicated.