FIGURE 5.

In vitro reconstitution of the Fe₂^III-Y^• cluster with purified recombinant wild-type and mutant β and β′ proteins. A, EPR analyses of 20 μm reconstituted ββ′ complex from WT β with WT β′ (blue), WT β with β′(Y323F) (red), β(Y376F) with WT β′ (green), and β-Y376F with β′(Y323F) (purple). B, enzyme activity assays of reconstituted WT and mutant ββ′ complexes using radioactive CDP as a substrate in the presence of an excess of α₂. C, specific activities of WT and mutant ββ′ complexes normalized by Y^• content.