2,2,2-Trifluroethanol induces simultaneous increase in α-helicity and aggregation in alkaline unfolded state of bovine serum albumin

Abstract

Little work has been done to understand the folding of proteins at alkaline conditions. BSA acquires a partially reversible unfolded state at pH 13.0, devoid of any native structure. Introduction of methanol, ethanol and 2-propanol with the alkaline unfolded protein resulted in β-sheet-like structure formation, and 2,2,2-trifluroethanol found to enhance α-helical conformations with simultaneous increase in aggregation. The extent of secondary and tertiary structure formation is in the order of methanol < ethanol < 2-propanol < 2,2,2-trifluroethanol. Exposure of hydrophobic core of protein molecules in apolar environment of 2,2,2-trifluroethanol seems to promote intermolecular cluster formation. This is one of the very few reports that α-helical structures can also aggregate.