Backbone dynamics probed by ¹⁵N- relaxation rates.

<p><b>A, B, C. </b>¹⁵N spin-relaxation rates for ¹⁵N-perdeuterated hHP1β measured at a proton Larmor frequency of 600 MHz at 298 K. Residues with severe peak overlap or insufficient signal-to-noise ratio were excluded. R₁ (A), R₂ (B) and steady-state ¹H-¹⁵N heteronuclear NOE (C) are shown along the protein sequence. The R₂ rates were derived from R_1ρ measurements upon correction for the off-resonance tilted field as described in the Methods. <b>D.</b> Graphical analysis of reduced spectral density mapping. The solid line represents the theoretical function of J(ω_N) versus J(0) assuming a rigid single Lorentzian motion. Experimental values are plotted as points with labels specific for each hHP1β domain. <b>E.</b> The rotational correlation time τ_c, determined for each residue from the R₂/R₁ ratio, is shown as a function of residue number. <b>F.</b> Illustration of the diffusion tensor of CD (left, axially symmetric) and CSD (right, fully anisotropic) in full-length hHP1β. The x- and y-axes are shown as half-axes only for the fully anisotropic tensor. Pictures were prepared using MolMol <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060887#pone.0060887-Koradi1" target="_blank">[57]</a>.