Figure 5

Effect of Zn²⁺ on the tryptophan fluorescence yield of NBCs. (a) Zn²⁺ titration into ntcNDCBE at different pH values. Individual runs are shown in Supplementary Figure S2. (b) Zn²⁺ titration into, ntcNCBE at pH 7.2. The Trp fluorescence yield increases faster in ntcNDCBE when exposed to Zn²⁺ as compared with ntcNCBE. Individual runs are shown in Supplementary Figure S4. (c) Zn²⁺ titration into the different ntcNDCBE constructs at pH 7.2. The ntcNDCBE mutants show little response to Zn²⁺ titration. Individual runs are shown in Supplementary Figure S2. (d) Mg²⁺ and Zn²⁺ (in the absence and presence of 1 mM Mg²⁺) titration into ntcNDCBE at pH 7.2. Individual runs are shown in Supplementary Figure S2. The fits (lines) were calculated with equation (2).