Effects of Hydrophobic and Electrostatic Interactions on Change in Decapeptide Conformation in Micelle and Liposome Solution

Abstract

Examination was made of the title effects in water, methanol and aqueous solutions of micelles and liposomes. Lysine (Lys) scanning decapeptides each containing norleucine (Nle) and alanine (Ala) were synthesized and their conformations determined by circular dichroism (CD). Conformational transition from α-helix to β-structure was noted in nearly every decapeptide. Each decapeptide was examined for its capacity to form amyloids by fluorescence using Thioflavin T. Increase in fluorescence was clear indication of the high capacity of Ala-Nle-Ala-Lys-Ala-Ala-Ala-Ala-Nle-Ala (2-9X4K) to form amyloids. Decapeptide interactions with acidic liposome were assessed based on entrapped 5(6)-carboxyfluorescein (CF) leakage. Leakage capacity of Ala-Nle-Ala-Ala-Ala-Ala-Lys-Ala-Nle-Ala (2-9X7K) was found greater than that of 2-9X4K.