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. Author manuscript; available in PMC: 2010 Jul 8.
Published in final edited form as: Biochemistry. 1991 Apr 30;30(17):4257–4261. doi: 10.1021/bi00231a022

FIGURE 1.

FIGURE 1

Binding of Ca(II) and Sr(II) to the D-glucose-occupied, F5-Trp-labeled receptor: 19F NMR spectra. In each case the 5- fluorotryptophan (5F-Trp) incorporation was 65 ± 10% (Luck & Falke, 1991). Samples contained 200–500 μM 5F-Trp-labeled receptor depleted of metal ions, 100 mM KCl, 10 mM Tris, pH 7.1 with HCl,1mM D-glucose, 10% D2O, and (A) 20 mM EDTA, (B) 0.25 mM CaCl2, (C) 2 mM Srcl2, or (D) 0.1 mM CaCl2 and 2.0 mM SrCl2. Spectra were recorded at 470 MHz, 25 °C. Frequencies are relative to 3F-Phe as an internal standard, and the indicated assignments are from the preceding article.