Fluorescence spectra of the Tyr⁵⁷Trp mutant under different ligation conditions.

<p><b>A)</b> Enzyme under R-state conditions of ligation (5 mM F6P and 5 mM KPi) in the presence of various concentration of Ca²⁺ and Mg²⁺. <b>B)</b> Enzyme under R-state conditions of ligation (5 mM F6P and 5 mM KPi) in the presence of various concentration of Mg²⁺ and under T-state conditions of ligation (5 mM F6P, 5 mM KPi, and 2 µM AMP) in the presence of Mg²⁺. <b>C)</b> Enzyme under R-state conditions of ligation (5 mM F6P and 5 mM KPi) in the presence of various concentration of Zn²⁺ and under T-state conditions of ligation (5 mM F6P, 5 mM KPi, and 2 µM AMP) in the presence of Zn²⁺. The final emission spectra do not depend on the sequence of the ligands addition.