What drives 15N spin relaxation in disordered proteins? Combined NMR/MD study of the H4 histone tail (Biophysical Journal)

Backbone (15N) NMR relaxation is one of the main sources of information on dynamics of disordered proteins. Yet we do not know very well what drives 15N relaxation in such systems, i.e. how different forms of motion contribute to the measurable relaxation rates. To address this problem, we have investigated, both experimentally and via MD simulations, the dynamics of a 26-residue peptide imitating the N-terminal portion of the histone protein H4. One part of the peptide was found to be fully flexible, while the other part features some transient structure (a hairpin stabilized by hydrogen bonds).