  Magnetoferritin, a synthetic derivate of iron storage protein - ferritin, has
been synthesized with different iron oxide loading values. Small-angle neutron
scattering experiments were applied to study the structure of magnetoferritin
solutions using contrast variation method by varying the light to heavy water
ratio of the solvent. Higher iron loading leads to increasing of the neutron
scattering length density of magnetoferritin and also to the increase of the
polydispersity of complexes. The formation of the magnetic core and the
variation of the protein shell structure upon iron loading are concluded.
