The influence of calcium ions on fibrinogen conformation

The conformation of fibrinogen has been examined using the techniques of dye-photosensitized surface labelling and cross-linking. The results obtained suggest that fibrinogen is a flexible molecule and its conformation is influenced by the concentration of calcium ions. These effects are mediated through binding to the low-affinity calcium binding sites of fibrinogen. In particular the C-terminal regions of the [A]alpha chain are more exposed at higher calcium concentrations creating a molecule which is more liable to form inter-molecular interactions.