A Sharp Thermal Transition of Fast Aromatic-Ring Dynamics in Ubiquitin

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 arom...

Full description

Saved in:
Bibliographic Details
Published in:Angewandte Chemie International Edition 2015-01, Vol.54 (1), p.102-107
Main Authors: Kasinath, Vignesh, Fu, Yinan, Sharp, Kim A., Wand, A. Joshua
Format: Article
Language:English
Subjects:
Activated
Alkanes
Amino acids
Chains
conformational analysis
Diffusion
Dynamics
Human
Humans
Hydrostatic pressure
Labeling
Molecular dynamics
Molecular Dynamics Simulation
NMR
NMR spectroscopy
Nuclear magnetic resonance
Nuclear Magnetic Resonance, Biomolecular
Pressure effects
Protein Conformation
protein dynamics
Protein folding
Proteins
relaxation
Strategy
Structure-function relationships
Temperature
thermal activation
Transition temperature
Transition temperatures
Ubiquitin
Ubiquitin - chemistry
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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. NMR relaxation methods revealed that the three aromatic side chains in human ubiquitin show a sharp thermal dynamical transition at approximately 312 K. Below the transition temperature, ring motion is largely librational whereas above this temperature, a complete ring‐rotation process that is fully consistent with continuous diffusion not requiring the transient creation of a large activated free volume occurs.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201408220