[NMR paper] Internal protein dynamics on ps to ?s timescales as studied by multi-frequency (15)N solid-state NMR relaxation.

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Internal protein dynamics on ps to ?s timescales as studied by multi-frequency (15)N solid-state NMR relaxation.

Related Articles Internal protein dynamics on ps to ?s timescales as studied by multi-frequency (15)N solid-state NMR relaxation.

J Biomol NMR. 2013 Sep 19;

Authors: Zinkevich T, Chevelkov V, Reif B, Saalwächter K, Krushelnitsky A


Abstract
A comprehensive analysis of the dynamics of the SH3 domain of chicken alpha-spectrin is presented, based upon (15)N T 1 and on- and off-resonance T 1? relaxation times obtained on deuterated samples with a partial back-exchange of labile protons under a variety of the experimental conditions, taking explicitly into account the dipolar order parameters calculated from (15)N-(1)H dipole-dipole couplings. It is demonstrated that such a multi-frequency approach enables access to motional correlation times spanning about 6 orders of magnitude. We asses the validity of different motional models based upon orientation autocorrelation functions with a different number of motional components. We find that for many residues a "two components" model is not sufficient for a good description of the data and more complicated fitting models must be considered. We show that slow motions with correlation times on the order of 1-10*?s can be determined reliably in spite of rather low apparent amplitudes (below 1*%), and demonstrate that the distribution of the protein backbone mobility along the time scale axis is pronouncedly non-uniform and non-monotonic: two domains of fast (?*