A sharp thermal transition of fast aromatic-ring dynamics in ubiquitin

Kasinath, V., Fu, Y., Sharp, K. A. and Wand, A. J. (2015) A sharp thermal transition of fast aromatic-ring dynamics in ubiquitin. Angewandte Chemie (International Edition), 54(1), pp. 102-107. (doi: 10.1002/anie.201408220)

Abstract

Aromatic amino acid side chains have a rich role within proteins and are often central to their structure and function. Suitable isotopic-labelling strategies enable studies of sub-nanosecond aromatic-ring dynamics using solution NMR relaxation methods. Surprisingly, it was found that the three aromatic side chains in human ubiquitin show a sharp thermal dynamical transition at approximately 312 K. Hydrostatic pressure has little effect on the low-temperature behavior, but somewhat decreases the amplitude of motion in the high-temperature regime. Therefore, below the transition temperature, ring motion is largely librational. Above this temperature, a complete ring-rotation process that is fully consistent with a continuous diffusion not requiring the transient creation of a large activated free volume occurs. Molecular dynamics simulations qualitatively corroborate this view and reinforce the notion that the dynamical character of the protein interior has much more liquid-alkane-like properties than previously appreciated.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fu, Dr Yinan
• Authors: Kasinath, V., Fu, Y., Sharp, K. A., and Wand, A. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Angewandte Chemie (International Edition)
• Journal Abbr.: Angew Chem Int Ed Engl
• Publisher: Wiley - V C H Verlag GmbH & Co. KGaA
• ISSN: 1433-7851
• ISSN (Online): 1521-3773