Correction: Dihedral angle measurements for structure determination by biomolecular solid-state NMR spectroscopy

There was a mistake in the caption of Figure 6 as published. The caption erroneously stated “(C,D) NCCH-type measurements of the φ backbone angle based on the same design principle (Ladizhansky et al., 2002)”. This text should have been referring to the ψ backbone angle. The corrected caption of Figure 6 appears below.

“FIGURE 6 Transfer-based torsion angle measurements of backbone angle ψ. (A,B) NCCN pulse sequence implemented without ¹³C DQ generation, using rotor-synchronized ¹³C-¹³C transfer instead (Ladizhansky et al., 2003). Carbonyl (C′) polarization is created via a double CP scheme, followed by REDOR-based ¹³C-¹⁵N recoupling (time t_CN). The residual ¹³C′ signal is transferred to neighboring ¹³Cα via a short RFDR block, after which the ¹³Cα-¹⁵N recoupling is done (also for t_CN). Finally, the remaining ¹³C signal (as a function of t_CN) is recorded in a series of 1D or 2D N(CO)CA spectra (F). (C,D) NCCH-type measurements of the ψ backbone angle based on the same design principle (Ladizhansky et al., 2002). Here, ¹³C-¹H dipolar recoupling occurred during the LGCP period. Note that here the REDOR time (t_CN) and LGCP time (t_CH) are both incremented in parallel. Panels B and D illustrate the generic design of these experiments, with color-coding of the dipolar recoupling blocks. (E) Structure of α-spectrin SH3, with residues L8 and V9 in the first β-strand marked (Musacchio et al., 1992), prepared with UCSF ChimeraX (Pettersen et al., 2021). (F) 2D N(CO)CA spectrum for uniformly labeled α-spectrin SH3, showing peaks for ¹³Cα_i-¹⁵N_i+1 correlations between residues i and i+1. Peaks for the Cα of residues L8 and V9 are indicated with red ovals. (G) Example N(CO)CA NCCN data curves for L8 and V9, along with matching values of the ψ angle. (F,G) are adapted from (Ladizhansky et al., 2003) with permission, copyright American Chemical Society 2003.”

The original article has been updated.

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