PMID: 25003391

Authors:

Menzel A, Neumann P, Schwieger C, Stubbs MT

Title:

Thermodynamic signatures in macromolecular interactions involving conformational flexibility.

Journal:

Biol Chem. 2014 Jul 1;395(7-8):905-11. doi: 10.1515/hsz-2014-0177.

Abstract:

Abstract The energetics of macromolecular interactions are complex, particularly where protein flexibility is involved. Exploiting serendipitous differences in the plasticity of a series of closely related trypsin variants, we analyzed the enthalpic and entropic contributions accompanying interaction with L45K-eglin C. Binding of the four variants show significant differences in released heat, although the affinities vary little, in accordance with the principle of enthalpy-entropy compensation. Binding of the most disordered variant is almost entirely enthalpically driven, with practically no entropy change. As structures of the complexes reveal negligible differences in protein-inhibitor contacts, we conclude that solvent effects contribute significantly to binding affinities.