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).
2+ centre in Complex III and then donates an electron to a Cu2+ centre in cytochrome C oxidase in Complex IV.
3+ ion in a heme C group (Fe-porphyrin) surrounded by the protein chain shown as a ribbon with helical regions coloured in blue.
3+ to Fe2+ and back again. Here the Fe3+ is octahedral with Fe-N and Fe-S bond lengths of 1.99 Å and 2.37 Å, respectively.
2+ are longer. The Fe-N and Fe-S bond lengths are 2.18 Å and 2.43 Å, respectively, compared with 1.99 and 2.37 Å for Fe3+. Nature minimizes such structural changes to make electron transfer fast.