pH Dependence of Amide Chemical Shifts in Natively Disordered Polypeptides Detects Medium-Range Interactions with Ionizable Residues

ABSTRACT

A growing number of natively disordered proteins undergo a folding/binding process that is essential for their biological function. An interesting question is whether these proteins have incompletely solvated regions that drive the folding/ binding process. Although the presence of predominantly hydrophobic buried regions can be easily ascertained by high-sensitivity differential scanning calorimetry analysis, the identification of those residues implicated in the burial requires NMR analysis. We have selected a partially solvated natively disordered fragment of Escherichia coli, thioredoxin, C37 (38-108), for full NMR spectral assignment. The secondary chemical shifts, …