REPULSIVE INTERPARTICLE INTERACTIONS IN A DENATURED PROTEIN SOLUTION REVEALED BY SMALL-ANGLE NEUTRON-SCATTERING

In order to investigate the effect of concentration in biological proc esses such as protein folding, small angle neutron scattering measurem ents were used to determine the second virial coefficient of solutions of both native and strongly denatured phosphoglycerate kinase and the radius of gyration of the protein at zero concentration. The value of the second virial coefficient is a good probe of the non-ideality of a solution. The present results show that the unfolding of the protein leads to a drastic change in the repulsive intermolecular interaction s. We conclude that these interactions are due mainly to the behaviour of the denatured polypeptide chain as an excluded volume polymer, (C) 1998 Federation of European Biochemical Societies.