title: Determining binding sites of polycyclic aromatic small molecule-based amyloid-beta peptide aggregation modulators using sequence-specific antibodies.
abstract: Numerous aromatic small molecule modulators of amyloid-beta peptide (Aβ) monomer aggregation and neurotoxicity have been identified with the ultimate goal of Alzheimer's disease (AD) treatment. Determining binding sites of these modulators on Aβ monomer is an important topic in the mechanistic understanding of AD pathology and drug development. However, Aβ monomer binding sites have been reported for only a very limited number of Aβ modulators. In this article, we present a convenient method for determining aggregation-modulating polycyclic aromatic small molecule ligand binding sites on Aβ monomer using immunostaining with a panel of Aβ sequence-specific antibodies. To validate our technique, we first examined one modulating aromatic ligand, Congo Red, with known binding sites, which yielded consistent results with previous findings. Then, using the same technique, binding sites on Aβ of four known Aβ monomer aggregation modulators, Erythrosin B, Eosin Y, Phloxine B, and Rose Bengal, were determined. The identified ligand binding sites were also confirmed by a separate fluorescence quenching-based assay using a panel of overlapping Aβ sub-fragments. The technique described here greatly increases researchers' ability to determine the Aβ monomer binding site(s) of aggregation-modulating aromatic small molecule ligands and to screen for new ligands that bind specific regions on Aβ.
authors.affiliation: Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Irwin
authors.affiliation: Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: H
authors.initials: H
authors.lastname: Edward Wong
authors.affiliation: Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904, USA; School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea. Electronic address: inchan@gist.ac.kr.
authors.forename: Inchan
authors.initials: I
authors.lastname: Kwon
mesh_terms: D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D001665:Binding Sites; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D055503:Protein Multimerization / Q000187:drug effects*; D017433:Protein Structure, Secondary; D054852:Small Molecule Libraries / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D010446:Peptide Fragments; D054852:Small Molecule Libraries; C078592:amyloid beta-protein (1-40)
keywords: Alzheimer’s disease; Amyloid-beta peptide; Binding site; Ligand; Sequence-specific antibodies