The Iron Storage Protein Ferritin - Entire Molecule


Ferritin stores the iron, which was transported into the cell by the transport protein transferrin, as Fe3+ ions which are surrounded by a hydrate shell.

The picture shows the iron-free form of ferritin, the apoferritin, which consists of 24 subunits.

It has a highly symmetrical, spherical structure (diameter 130 Å), which is punctuated by three- and fourfold channels. These connect the center of the protein with its surroundings.

The fourfold channels are lined with hydrophobic residues; the threefold channels are lined with hydrophilic residues (aspartate and glutamate residues).

For this reason it is assumed that iron ions reach the center of the apoferritin through the threefold channels.