Physical Origin of Anharmonic Dynamics in Proteins: New Insights From Resolution-Dependent Neutron Scattering on Homomeric Polypeptides

Antonio Cupane, Giorgio Schiro', Francesca Natali

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

Neutron scattering reveals a complex dynamics in polypeptide chains, with two main onsets of anharmonicity whose physical origin and biological role are still debated. In this study the dynamicsof strategically selected homomeric polypeptides is investigated with elastic neutron scattering using different energy resolutions and compared with that of a real protein. Our data spotlight the dependence ofanharmonic transition temperatures and fluctuation amplitudes on energy resolution, which we quantitatively explain in terms of a two-site model for the protein-hydration water energy landscape.Experimental data strongly suggest that the protein dynamical transition is not a mere resolution effect but is due to a real physical effect. Activation barriers and free energy values obtained for the proteindynamical transition allow us to make a connection with the two-well interaction potential of supercooledconfined water proposed to explain a low-density -- high-density liquid-liquid transition.
Original languageEnglish
Pages (from-to)128102-1-128102-5
Number of pages5
JournalPhysical Review Letters
Volume109
Publication statusPublished - 2012

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy

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