   1.8.1.19 | Fe-S center |
the alpha-subunit carries a [2Fe-2S]2+,+ prosthetic group. It exhibits EPR g-values, 2.035, 1.908, 1.786, and reduction potential, Em,8 = +80 mV, reminiscent of Rieske-type clusters. Comparative sequence analysis indicates that this cluster is coordinated by a novel motif of one Asp and three Cys ligands. The beta-subunit carries a [3Fe-4S]+,0 cluster, and a [4Fe-4S]2+,+ cluster. The 3Fe cluster has an unusually high reduction potential, Em,8 = +230 mV. The reduced 4Fe cluster exhibits a complex EPR signal, presumably resulting from magnetic interaction of its S = 1/2 spin with the S=2 spin of the reduced 3Fe cluster. The 4Fe cluster can be reduced with deazaflavin/EDTA/light but not with sodium dithionite, however, it is readily reduced with NADPH |
722825 |
