In close collaboration with Philip Anfinrud, novel hardware was designed and developed that makes it possible, for the first time, to obtain demonstrate that it is readily possible to monitor the folding of the protein chain in a residue-specific manner upon jumping the applied pressure. Pressure changes of up to 2.5 kbar, requiring 1-2 ms, are shown to feasible and compatible with the recording of high quality NMR data. Experiments have been demonstrated for a pressure-sensitized mutant of the protein ubiquitin, whose folding previously has been studied extensively by other methods. The appearance of the native, folded ubiquitin NMR spectrum shows the same time dependence for all its residues and is found to be quite slow. Remarkably, however, the disappearance of the unfolded NMR resonances is more than an order of magnitude faster and shows a large dispersion in rates, reflecting the transitioning of individual residues from full disorder into a partially ordered but not yet fully folded protein state. 15N relaxation rates measured during the folding process are consistent with the rates at which residues disappear from the unfolded NMR spectrum after switching to low pressure and are indicative of motions on a micro-second time scale.
| Charlier, Cyril; Alderson, T Reid; Courtney, Joseph M et al. (2018) Study of protein folding under native conditions by rapidly switching the hydrostatic pressure inside an NMR sample cell. Proc Natl Acad Sci U S A 115:E4169-E4178 |
| Alderson, T Reid; Lee, Jung Ho; Charlier, Cyril et al. (2018) Propensity for cis-Proline Formation in Unfolded Proteins. Chembiochem 19:37-42 |
| Charlier, Cyril; Courtney, Joseph M; Alderson, T Reid et al. (2018) Monitoring 15N Chemical Shifts During Protein Folding by Pressure-Jump NMR. J Am Chem Soc 140:8096-8099 |
