title: Salt bridges in prion proteins are necessary for high-affinity binding to the monoclonal antibody T2.
abstract: We studied the role of the 2 salt bridges (Asp143-Arg147 and Asp146-Arg150) in helix 1 of mouse prion protein (PrP) on the formation of the complex between PrP and the monoclonal antibody T2. We introduced 6 charge-changing mutations to the amino acid residues associated with the salt bridges. Analysis of the circular dichroism spectra of the mutant PrPs showed that the salt bridge mutations did not change the secondary structures. We analyzed the kinetics of the association and dissociation of the PrPs with the T2 antibody. The results showed that the association kinetics were not significantly different among the variants except Arg150Lys, while the dissociation rate of the neutralized-charge variants was 2 orders of magnitude higher than that of the wild type. These results indicate that salt bridges make the interaction of PrP with T2 tighter by slowing down dissociation.
authors.affiliation: Molecular Composite Medicine Research Group, Biomedical Research Institute, Tsukuba-shi, Ibaraki, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Sasamori
authors.forename: Mieko
authors.initials: M
authors.lastname: Kato
authors.forename: Kosuke
authors.initials: K
authors.lastname: Maki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Tagawa
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Hanyu
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology; D002942:Circular Dichroism; D007700:Kinetics; D051379:Mice; D009154:Mutation; D000072002:Prion Proteins; D011328:Prions / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012492:Salts / Q000737:chemistry; D020349:Surface Plasmon Resonance
chemical_list: D000911:Antibodies, Monoclonal; D000072002:Prion Proteins; D011328:Prions; C512657:Prnp protein, mouse; D012492:Salts