Protein tyrosine phosphatase oligomerization studied by a combination of [super 15]N NMR relaxation and [super 129]Xe NMR: Effect of buffer containing arginine and glutamic acid

[super 15]N NMR relaxation and [super 129]Xe NMR chemical shift measurements are used to study weak protein-protein interactions, which is used to analyze the oligomerization equilibrium of a low-molecular-weight protein tyrosine phosphatase in the presence of arginine and glutamic acid. The results have shown that the multiple effects of arginine and glutamic acid are related to their effective excluded volume that favors specific protein association and the destabilization of partially unfolded forms that interact with xenon and are responsible for nonspecific protein aggregation.