Model of insertion and release of a large solute into and from a biopolymer complex

Insertion of a large solute into a biopolymer complex followed by release of the same solute from it is a principal function for sustaining life. We show that the switch from insertion to release is achieved by altering the solute conformation to reduce the excluded volume (EV) generated by the solute for solvent molecules and to increase the solute solvophilicity. The reduction in the EV weakens the insertion power induced by the entropic force, and the increase in the solvophilicity promotes preferential solvation not in the solvent confined within the complex cavity but in the bulk solvent.