Coupled effect of salt and pH on proteins probed with NMR spectroscopy

- pKa values and chemical shifts as a function of salt concentration (50-400 mM NaCl).
- pKa values are more sensitive to conformational effects than elec. screening.
- 1HN chemical shift changes mainly come from the solvent bulk effect.
- Screening of inter-protein elec. interactions is negligible throughout the protein.
- Perturbation of hydrogen bond geometry is the main salt-induced effect on ΔG.