Study of the Spatial Structure of β-Amyloid Peptide (25-35) from Circular Dichroism Spectroscopy in the Medium Close to Membrane Environment Conditions

Abstract

The spatial structure of β-amyloid peptide (25-35) was studied using circular dichroism spectroscopy in a medium close to the conditions of the membrane environment. The conformational preference of β-amyloid peptide (25-35) was first studied in dipalmitoylphosphatidylcholine (DPPC) solution with and without cholesterol using circular dichroism spectroscopy. It was found that the peptide adopts the structures of the a- helix, β-sheet, β-turn and irregular regions, and their relative proportions changed depending on the presence of cholesterol. The results of the spectral analysis of β-amyloid peptide (25-35) made it possible to unambiguously assume the secondary structure of the peptide in a lipid solvent. It has been shown that ordering of the secondary structure of the β-amyloid peptide (25-35) is observed in the solution with DPPC, which maximally simulates the environment on the surface of the plasma membrane.