Control of antibody-antigen interaction using anion-induced conformational change in antigen peptide.
The binding of a monoclonal antibody to an epitope peptide was controlled by the conformational change of the epitope peptide induced by anions. We synthesized peptides in which the epitope sequence DTYRYI for the monoclonal antibody AU1 is located between amphiphilic peptides (KKLL)n and (LLKK)n. In the absence of an appropriate anion, the peptide was in a random coil state and the epitope was linear. In contrast, in the presence of an appropriate anion, the peptide exhibited an anti-parallel alpha-helical structure and the epitope was subsequently 'bent'. In the presence of 41 microM triphosphate, the association constant between the antibody and the peptide was decreased by one order of magnitude in the case of n = 3 and at least three orders of magnitude in the case of n = 4 or 5. Oligo-DNAs, as anions, dissociated the antibody-peptide complex, whereas triphosphate did not. The DNA concentrations required for 50% dissociation of the antibody-peptide complex at pH 7.5 were 4x10(-8), 1x10(-7) and 6x10(-6) M for decamer, octamer and hexamer DNA, respectively.
Katakura
Y
Y
Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan. katakura@bio.eng.osaka-u.ac.jp
Miyazaki
T
T
Wada
H
H
Omasa
T
T
Kishimoto
M
M
Goto
Y
Y
Suga
K
K
D000595:Amino Acid Sequence; D000818:Animals; D000838:Anions / Q000494:pharmacology*; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000378:metabolism; D000936:Antigen-Antibody Complex / Q000737:chemistry* / Q000187:drug effects*; D000937:Antigen-Antibody Reactions / Q000187:drug effects*; D000941:Antigens / Q000737:chemistry / Q000187:drug effects; D002942:Circular Dichroism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects; D017433:Protein Structure, Secondary / Q000187:drug effects
D000838:Anions; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000941:Antigens; D009838:Oligodeoxyribonucleotides; D010710:Phosphates