Figure 2.

HyperW HMQC sensitivity enhancements calculated for resolved residues in the ¹⁵N-labeled PhoA4 protein fragment. The sensitivity enhancements were extracted by comparing peak volumes between the HyperW HMQC spectrum (e.g., Figure 1, red) and thermal equilibrium spectra measured in an 82.5% H₂O buffer (Figure S3). The values are averaged for three HyperW HMQC experiments, after normalizing to the H₂O proton enhancement in each experiment; the “error bars” reflect the scattering obtained over the course of these repeated injections for each residue. Sensitivity enhancements compared against SSP scores (gray bars) given in the literature¹⁸ based on NMR ¹³C_α and ¹³C_β chemical shifts. Charged residues are also mapped on the sequence with orange (positively charged) and red (negatively charged) squares.