3.5.4.33	Mg2+	optimum concentration2-5 mM, the enzyme does not require any cofactor, except magnesium ions, to deaminate adenosine 34 efficiently in tRNA. The dependence of the enzymatic reaction on magnesium ions probably reflects the need for a correct tRNA architecture	
3.5.4.33	Zn2+	TadA contains endogenous Zn2+ ions. Zn2+ is tetrahedrally coordinated by His52, Cys82, Cys85, and a water	
3.5.4.33	Zn2+	the active site contains a zinc ion coordinated to His53, Cys83 and Cys86	
3.5.4.33	Zn2+	the active site contains a zinc ion, which is coordinated by three strictly conserved amino acids, His53, Cys83, and Cys86	
3.5.4.33	Zn2+	wild type enzyme coordinates two Zn2+ per heterodimer. Mutation of one of the key Zn2+-coordinating cysteines in TbADAT2 yields a functional enzyme with a single bound zinc