Fig. 6.

NvErg1 exhibits reduced divalent cation sensitivity. Normalized G–V curves for NvErg1 WT (A) and NvErg1 E478D (B) at pH 8 (red) and pH 6 (blue) with either 100 μmol l⁻¹ Ca²⁺ (solid lines and symbols) or 1 mmol l⁻¹ Ca²⁺/1 mmol l⁻¹ Mg²⁺ (dashed lines and open symbols). (C) Comparison of pH 8 to pH 6 V₅₀ shifts for NvErg1 WT and NvErg1 E478D at 100 μmol l⁻¹ Ca²⁺ and 1 mmol l⁻¹ Ca²⁺/1 mmol l⁻¹ Mg²⁺. Shifts were calculated as the differences in average V₅₀ values at pH 8 and pH 6. Data points are means ± s.e.m. (n=6–11) and smooth curves show fits with a single Boltzmann distribution (parameters in Table 1).