Figure 8.

Specific activities and [Fe₂S₂]²⁺ cluster-content of different types of AtDHAD samples. Specific activity and [Fe₂S₂]²⁺ cluster-content are presented as a % of maximal values. The samples from bottom-to-top are as follows: as-purified DHAD containing substoichiometric [Fe₂S₂]²⁺ clusters; reconstituted DHAD containing near-stoichiometric [Fe₄S₄]²⁺ clusters and only trace amounts of [Fe₂S₂]²⁺ clusters; DHAD reconstituted in the presence of apo-NFU2 containing near-stoichiometric [Fe₂S₂]²⁺ clusters; DHAD reconstituted with stoichiometric [Fe₂S₂]²⁺ clusters by cluster transfer from [Fe₂S₂]²⁺ cluster–bound NFU2; DHAD with stoichiometric [Fe₂S₂]²⁺ clusters treated with 20-fold excess of DTT (+ DTT); and DHAD with stoichiometric [Fe₂S₂]²⁺ clusters treated with 20-fold excess of DTT followed by dialysis to remove DTT (−DTT).