2.5.1.27 Mg2+ dependent on 660100 2.5.1.27 Mg2+ required 721952, 739429 2.5.1.27 MgCl2 dependent on presence of divalent cation, addition of 2 mM MnCl2 is 1.3 times more effective than that of 10 mM MgCl2 671796 2.5.1.27 MnCl2 dependent on presence of divalent cation, addition of 2 mM MnCl2 is 1.3 times more effective than that of 10 mM MgCl2 671796 2.5.1.27 Zn2+ two Zn2+ ions are present in the crystal. One is coordinated with the hydroxyl group of Thr-15. The other is located near AMP and is coordinated to the side chains of Asp-173, Glu-213, and His-214 689799