β Scribed by O. B. Ptitsyn; T. M. Birshtein
No coin nor oath required. For personal study only.
A general approach to the determination of relative stability of any pair of conformational state of biological macromolecules or their complexes (in particular, to the determination of relative stability of native and disordered states of the macromolecule) has been augpested. For determining the free energy ditFerence of the two states under the conditions when one of them is considerably more advantageous than the other, it is necessary for the macromolecule to be influenced by the transforming agent which levels free energies of both the conformational states, and to determine the external parameter derivative of the free energy dzerence in the region of the conformational transition induced by the change in this parameter. If the character of the dependence of this derivative on the external parameter (temperature, solvent composition, etc.) is known, then this allows the determination of the free energy difTerence of the two states under the conditions considered, even including conditions far from the transition region. The value of the derivative of the free energy diffewnce in the transition region in many cases can be measured directly (in particular, when using calorimetry), while in cases when a direct measurement of the derivative is impmible, it can often be estimated experimentally from the steepneea of the conformational transition. The methods of this estimation and also a possible character of the change of the considered derivative during variation of the external parameter are considered for the case when the transforming agent is one of the components of the solvent and, c o wquently, the derivative of the free energy dflerence is equal to the difTerence of number of molecules of thia component bound with the macromolecule in two conformational states.
* From here on, we shall simply speak of conformational states of macromolecules, understanding by this also the states of their complexes (e.g., associated and dissociated).
π SIMILAR VOLUMES