The effect of salt on the conformations of three model proteins is revealed by variable temperature ion mobility mass spectrometry

► We examine the effect of sodium iodide on three model proteins using nESI-IM-MS. ► The number of iodides correlates to the number of available basic sites. ► The conformational space occupied by each protein is altered due to the presence of salt and columbic effects. ► Thermally induced unfolding is lessened in the presence of adducted iodide. ► Proteins have lower collision cross sections at 300 K than at 260 K.