Selection of D‐Amino‐Acid Peptides That Bind to Alzheimer's Disease Amyloid Peptide Aβ1–42 by Mirror Image Phage Display

Abstract

A mirror image phage display approach was used to identify novel and highly specific ligands for Alzheimer's disease amyloid peptide Aβ(1–42). A randomized 12‐mer peptide library presented on M13 phages was screened for peptides with binding affinity for the mirror image of Aβ(1–42). After four rounds of selection and amplification the peptides were enriched with a dominating consensus sequence. The mirror image of the most representative peptide (D‐pep) was shown to bind Aβ(1–42) with a dissociation constant in the submicromolar range. Furthermore, in brain tissue sections derived from patients that suffered from Alzheimer's disease, amyloid plaques and leptomeningeal vessels containing Aβ amyloid were stained specifically with a fluorescence‐labeled derivative of D‐pep. Fibrillar deposits derived from other amyloidosis were not labeled by D‐pep. Possible applications of this novel and highly specific Aβ ligand in diagnosis and therapy of Alzheimer's disease are discussed.