FIG 9.

Possible electron transfer pathway from the Rieske cluster of CumDO-F to the non-heme iron of CumDO-O. The hydrogen bonds that mediate the electron transfer are indicated by red dashed lines. The atoms involved in the electron transfer and in the coordination with the iron ions are shown in a stick model. Nitrogen, oxygen, sulfur, and iron atoms are colored blue, red, yellow, and orange, respectively. Carbon atoms in CumDO-F are colored cyan, and those in α-subunits 1 and 2 of CumDO-O are colored green and brown, respectively. Distances among three electron transfer centers, two Rieske clusters, and an active site iron are shown by black dotted lines.