Including the Ensemble of Unstructured Conformations in the Analysis of Protein's Native State by High‐Pressure NMR Spectroscopy

This is the authors' abstract. We don't add key points for this paper.

The analysis of pressure induced changes in the chemical shift of proteins allows statements on structural fluctuations proteins exhibit at ambient pressure. The inherent issue of separating general pressure effects from structural related effects on the pressure dependence of chemical shifts has so far been addressed by considering the characteristics of random coil peptides on increasing pressure. In this work, chemically and pressure denatured states of the cold shock protein B from Bacillus subtilis ( Bs CspB) have been assigned in 2D 1 H‐ 15 N HSQC NMR spectra and their dependence on increasing hydrostatic pressure has been evaluated. The pressure denatured polypeptide chain has been used to separate general from structural related effects on 1 H and 15 N chemical shifts of native Bs CspB and the implications on the interpretation of pressure induced changes in the chemical shift regarding the structure of Bs CspB are discussed. It has been found that the ensemble of unstructured conformations of Bs CspB shows different responses to increasing pressure than random coil peptides do. Thus, the approach used for considering the general effects that arise when hydrostatic pressure increases changes the structural conclusions that are drawn from high pressure NMR spectroscopic experiments that rely on the analysis of chemical shifts.