Volume 79, Issue 6 pp. 1739-1746
Research Article

Cold unfolding of β-hairpins: A molecular-level rationalization

Angelo Riccio

Angelo Riccio

Dipartimento di Scienze Applicate, Università di Napoli “Parthenope”, Centro Direzionale Isola C4, 80143 Napoli, Italy

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Giuseppe Graziano

Corresponding Author

Giuseppe Graziano

Dipartimento di Scienze Biologiche ed Ambientali, Università del Sannio, Via Port'Arsa 11 - 82100 Benevento, Italy

Dipartimento di Scienze Biologiche ed Ambientali, Università del Sannio, Via Port'Arsa 11 – 82100 Benevento, Italy===Search for more papers by this author
First published: 21 January 2011
Citations: 13

Abstract

Isolated β-hairpins in water have a temperature dependence of their conformational stability qualitatively resembling that of globular proteins, showing both cold and hot unfolding transitions. It is shown that a molecular-level rationalization of this cold unfolding can be provided extending the approach devised for globular proteins (Graziano G. Phys Chem Chem Phys 2010; 12:14245-14252). The decrease in the solvent-excluded volume upon folding, measured by the decrease in the solvent accessible surface area, produces a gain in configurational/translational entropy of water molecules that is the main stabilizing contribution of the folded conformation. This always stabilizing Gibbs energy contribution has a parabolic-like temperature dependence in water and is exactly counterbalanced at two temperatures (i.e., the cold and hot unfolding temperatures) by the always destabilizing Gibbs energy contribution due to the loss in conformational degrees of freedom of the peptide chain. Proteins 2011; © 2011 Wiley-Liss, Inc.

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