Structural heterogeneity of reconstituted complexes of DNA with typical and intermediate protamines

The binding of the intermediate proteins φ1 and φ3 from the mussel Mytilus edulis to DNA was studied in comparison with the typical protamine from the squid Loligo vuigaris using precipitation curves, thermal denaturation and X-ray diffraction techniques. The properties of protein φ1 appear to be very close to those of typical protamines while the properties of protein φ3 are notably different. The method of reconstitution influences the structural properties of the complexes. This effect is most pronounced in the case of protein φ3. The structural heterogeneity of the protein component in the complexes is discussed in the light of these observations.