title: Design and Optimization of Anti-amyloid Domain Antibodies Specific for β-Amyloid and Islet Amyloid Polypeptide.
abstract: Antibodies with conformational specificity are important for detecting and interfering with polypeptide aggregation linked to several human disorders. We are developing a motif-grafting approach for designing lead antibody candidates specific for amyloid-forming polypeptides such as the Alzheimer peptide (Aβ). This approach involves grafting amyloidogenic peptide segments into the complementarity-determining regions (CDRs) of single-domain (VH) antibodies. Here we have investigated the impact of polar mutations inserted at the edges of a large hydrophobic Aβ42 peptide segment (Aβ residues 17-42) in CDR3 on the solubility and conformational specificity of the corresponding VH domains. We find that VH expression and solubility are strongly enhanced by introducing multiple negatively charged or asparagine residues at the edges of CDR3, whereas other polar mutations are less effective (glutamine and serine) or ineffective (threonine, lysine, and arginine). Moreover, Aβ VH domains with negatively charged CDR3 mutations show significant preference for recognizing Aβ fibrils relative to Aβ monomers, whereas the same VH domains with other polar CDR3 mutations recognize both Aβ conformers. We observe similar behavior for a VH domain grafted with a large hydrophobic peptide from islet amyloid polypeptide (residues 8-37) that contains negatively charged mutations at the edges of CDR3. These findings highlight the sensitivity of antibody binding and solubility to residues at the edges of CDRs, and provide guidelines for designing other grafted antibody fragments with hydrophobic binding loops.
authors.affiliation: From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and.
authors.forename: Christine C
authors.initials: CC
authors.lastname: Lee
authors.affiliation: From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Julian
authors.affiliation: From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Tiller
authors.affiliation: From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and.
authors.forename: Fanling
authors.initials: F
authors.lastname: Meng
authors.affiliation: From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: DuConge
authors.affiliation: the Department of Chemistry, Stony Brook University, Stony Brook, New York 11794.
authors.forename: Rehana
authors.initials: R
authors.lastname: Akter
authors.affiliation: the Department of Chemistry, Stony Brook University, Stony Brook, New York 11794.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Raleigh
authors.affiliation: From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and tessier@rpi.edu.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Tessier
mesh_terms: D019943:Amino Acid Substitution; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000235:genetics; D001666:Binding Sites, Antibody; D022801:Complementarity Determining Regions; D006801:Humans; D058228:Islet Amyloid Polypeptide / Q000737:chemistry* / Q000235:genetics; D020125:Mutation, Missense; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics; D057127:Single-Chain Antibodies / Q000737:chemistry* / Q000235:genetics
chemical_list: D016229:Amyloid beta-Peptides; D022801:Complementarity Determining Regions; D058228:Islet Amyloid Polypeptide; D010446:Peptide Fragments; D057127:Single-Chain Antibodies; C075222:amyloid beta-protein (1-42)
keywords: aggregation; amyloid-beta (AB); antibody engineering; conformation-specific; fibril; islet amyloid polypeptide; monomer; oligomer; protein stability; solubility