Triple resonance NMR relaxation experiments for studies of intrinsically disordered proteins
|Year of publication
|Article in Periodical
|Magazine / Source
|Journal of Biomolecular NMR
|MU Faculty or unit
|Nuclear magnetic resonance; Relaxation; Non-uniform sampling; Intrinsically disordered proteins
|Description of protein dynamics is known to be essential in understanding their function. Studies based on a well established NMR relaxation methodology have been applied to a large number of systems. However, the low dispersion of chemical shifts very often observed within intrinsically disordered proteins complicates utilization of standard 2D HN correlated spectra because a limited number of amino acids can be characterized. Here we present a suite of triple resonance HNCO-type NMR experiments for measurements of five relaxation parameters (, , NOE, cross-correlated relaxation rates and ) in doubly ,-labeled proteins. We show that the third spectral dimension combined with non-uniform sampling provides relaxation rates for almost all residues of a protein with extremely poor chemical shift dispersion, the C terminal domain of -subunit of RNA polymerase from Bacillus subtilis. Comparison with data obtained using a sample labeled by only showed that the presence of has a negligible effect on , , and on the cross-relaxation rate (calculated from NOE and ), and that these relaxation rates can be used to calculate accurate spectral density values. Partially -labeled sample was used to test if the observed increase of in the presence of corresponds to the dipole-dipole interactions in the ,-labeled sample.