... (Fig. 3A). Three of the ligands,OD2 of Asp165, NE2 of His79 and NE2 of His169,formed an equatorial plane. The other protein ligand,NE2 of His31, bound to the metal, in the company of a water oxygen, ... polypeptides consisted of sevena-helices, a three-stranded antiparallel b-sheet and loopsconnecting these secondary structure elements. The con-tents of the a-helix and b-strand were 50% and ... the conformationaround the active site of ApeSOD is independent of the presence of a metal cofactor.Figure 3D shows the superimposition of the activesite structures of apo, Mn-bound and Fe-bound...