Effects of ethylammonium halides on helix formation of proteins

Helix formation in β-lactoglobulin (β-LG) and α-synuclein (α-Syn) was investigated in aqueous solutions of ethylammonium halides (EAX; X = Cl, Br, or I) at different concentrations using vibrational spectroscopy. It was found that EABr and EAI induced helix formation in both proteins; however, no helix-promoting ability was observed for EACl. Notably, particularly enhanced helix formation was detected in EAI. Moreover, no intermolecular β-sheet development (i.e., amyloid-like aggregation) was noted for either β-LG or α-Syn at any EAX concentration.