Aggregation behaviors and their pH sensitivity of cholesterol-conjugated proteinoids composed of glutamic acid and aspartic acid matrix.

Abstract

Cholesterol-conjugated proteinoids and their aggregation behaviors were investigated with model proteinoid systems. Model proteinoids of molecular weights in the range of 4000 to 6000 were synthesized by anhydrous thermal condensation forming a matrix with glutamic acid and aspartic acid and of naturally occurring amino acids. Nuclear magnetic resonance and Fourier transform infrared spectra suggested that cholesterol was conjugated to carboxyl group-forming pendants. Native water-soluble proteinoids can form microspheres in acidified or heated conditions, but the cholesterol-conjugated proteinoids were found to form aggregates in water, regardless of the temperature or pH of the solutions. The hydrophobic pendant moieties come to a compact association in core, whereas the hydrophilic chains provide a shield layer.