Figure 62.

Measurement of site-specific proximity to mobile small molecules, water, lipids, and cholesterol. (a) Water-exposed residues in KcsA are highlighted based on a (H)NH spectrum after the sample is washed in acidic buffer. Proximity to water was recorded in the same study via H(H)N and H(H)CC spectra. Reprinted from ref (374). Copyright 2014 American Chemical Society. (b) Selected strips from a 4D H(H)(N)CANH spectrum highlighting cross-peaks to water and lipid moieties. Reprinted with permission from ref (375). Copyright 2019 John Wiley & Sons. Panel (c) shows cholesterol docked to the structure of VDAC, in agreement with the measured proximity to nearby residues as determined by transfer from the protons of cholesterol in a H(H)NH spectrum. Adjacent hydrophobic side-chains that form grooves on the outside of the protein are labeled. Reprinted with permission from ref (376). Copyright 2021 Springer Nature. (d) Sites of water exposure are mapped onto the structure of GLPG, based on a H(H)NH spectrum, shown in red. Reproduced from ref (230). Copyright 2019 American Chemical Society.