2.5.1.27	Mg2+	required	
2.5.1.27	Mg2+	dependent on	
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	
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	
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