Conformational particularities of beta-amyloid peptide 25-35

Abstract

In Alzheimer's disease, beta-amyloid peptide (Ав) plays an important role in the mechanism of neurodegeneration. A small fragment of Лв(25-35) (with the sequence GSNKGAIIGLLM) is regarded to be the functional domain of Лв, responsible for its neurotoxic properties and represents the biological active region of Лв. Conformational analysis of each C-terminal segment of the peptide by the method of molecular mechanics revealed a limited number of most probable conformations and quite clearly helped to clarify what forces stabilize the structures. The obtained results showed that Лв(25-35) energetically has a propensity for adopting alpha-helix conformation of the C-terminal octapeptide segment. A molecular dynamics method was used to build a model of intramolecular mobility in the Лв(25-35) molecule. It was demonstrated that in low-energy conformations, Лв(25-35), the orientation of flexible structures of the N-terminal region with respect to the structures of the C-terminal region is different.