Please be patient while the structures in the left frame load. In order to display all of the structures in the tour properly, press 'View' buttons below in order (from 1 to the end).
This is a display of the X-ray structure of a [2Fe-2S] ferredoxin from the plant S. platensis.
In the ribbon display it can be seen that the protein consists of beta-sheets (red) and two small regions of alpha-helices (blue). The cluster [2Fe-2S] has two Fe3+ ions and two bridging S2- (sulfides) which is bound to the protein by coordination to four cysteine sulfurs. The sequence Cys-X-X-Cys is characteristic of iron-sulfur clusters. The two iron ions are in a tetrahedral coordination environment. The [Fe2S2(S-Cys)4]2- cluster serves as a simple electron carrier. The cluster is at the surface of this small protein to make electron transfer rapid.
This is the structure of oxidized cluster. The oxidation state of the iron ions in this environment varies between the reduced, mixed valence form {Fe(III),Fe(II)} and the oxidized form {Fe(III),Fe(III)}, shown here. The oxidized form has an Fe-Fe distance of 2.64 Å.
This is [2Fe-2S] ferredoxin. Feel free to play around with it and all the other molecules displayed in the previous pages.