Once the molecule file is fully loaded, the image at right will become live. At that time the "activate 3-D" icon will disappear.

---

Lactoferrin and Ferritin

This page shows some interactive JSmol views of lactoferrin and ferritin. Explore the structures for yourself:

The picture shows the structure of human lactoferrin, a single protein with two similar domains each capable of binding one iron ion - with a carbonate co-factor.
Compare the structure of the apoprotein with the equivalent metalloprotein. Note the "pac-man" structural change on iron binding. Zoom in on the iron centre at the lower right and note the ligation about the metal ion, particularly the coordinated carbonate anion.

The picture shows the structure of a partly-loaded derivative of human ferritin. It may take a few moments to load, it is a very large molecule.
The protein chains are shown in ribbon form. There are 24 equivalent sub-units making up the near-spherical protein shell. In vivo, the central cavity can contain up to 4500 iron ions, mostly as Fe(III) oxides.
There are two types of channel through the protein, at the 3-fold and 4-fold intersections between sub-units.

The last figure shows a partially iron-loaded ferritin molecule (exposed to Fe for approx. 5 minutes). The iron ions appear to sit in the channels with 3- and 4-fold symmetry and also slowly aggregate in 4-helix channels. (Fe ions shown as very large spheres for clarity.)

Return to the index page.