Intramolecular Interactions Overcome Hydration to Drive the Collapse Transition of Gly₁₅.

ABSTRACT: Simulations and experiments show oligo-glycines, polypeptides lacking any side chains, can collapse in water. We assess the hydration thermodynamics of this collapse by calculating the hydration free energy at each of the end points of the reaction coordinate, here taken as the end-to-end distance (r) in the chain. To examine the role of the various conformations for a given r, we study the conditional distribution, P(R_g|r), of the radius of gyration for a given value of r. The free energy change versus R_g, -k_BT ln P(R_g|r), is found to vary more gently compared to the corresponding variation in the excess hydration free energy. Using this observation within a multistate generalization of the potential distribution theorem, we calculate a tight up

SUBMITTER: Asthagiri D 

PROVIDER: S-EPMC5912879 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature