Comparison of the structures of β amyloid peptide (25-35) and substance P in trifluoroethanol/water solution

The three-dimensional structure of beta amyloid peptide (25-35) in aqueous solution with 50% (vol/vol) 2,2,2-trifluoroethanol was determined by NMR spectroscopy. beta Amyloid peptide(A beta) is the major component of senile plaques found in the brain of patient of Alzheimer's disease. A beta 25-35 is biologically active fragment of A beta and exhibits some sequence homology with the tachykinin family. In this study, we present the structural similarity between AP25-35 and substance P which is a member of tachykinin family in order to examine the possibility of sharing pathways mediated by tachykinin receptors. Both peptides have alpha-helical structures in their C-terminal regions and aromatic rings or hydrophobic side chains in the center of the helix protrude outside. These conformational features are expected to be the key for the interaction with the receptors.