A sharp thermal transition of fast aromatic-ring dynamics in ubiquitin. Academic Article uri icon


  • 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 312K. 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.

published proceedings

  • Angew Chem Int Ed Engl

altmetric score

  • 0.75

author list (cited authors)

  • Kasinath, V., Fu, Y., Sharp, K. A., & Wand, A. J.

citation count

  • 27

complete list of authors

  • Kasinath, Vignesh||Fu, Yinan||Sharp, Kim A||Wand, A Joshua

publication date

  • January 2015