Structural characterization of mouse monoclonal antibody 13-1 against a porphyrin derivative: identification of a disulfide bond in CDR-H3 of Mab 13-1.
The amino acid sequence of a mouse monoclonal antibody Mab13-1, a catalytic antibody against TCPP (meso-tetrakis(4-carboxyphenyl)porphyrin), was confirmed by mass spectrometric (MS) peptide mapping. The amino-terminal sequence of the heavy chain was established by MS/MS analysis of the isolated N-terminal peptide. The presence of a unique disulfide bond between Cys93H and Cys102H was identified by MS peptide mapping and sequence analysis of an S-S containing peptide. Positions of other disulfide bonds were identified to be conserved. The non-conserved disulfide bridge was found to be resistant as other intra-chain disulfide bonds against reduction under non-denaturing condition, and to be buried inside the molecule. This extra disulfide bond is expected to support antigen-binding by restricting the flexibility of CDR-H3 loop, and it might be favorable for the recognition of a plane antigen, a porphyrin derivative.
Akashi
S
S
Division of Biomolecular Characterization, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan. akashi@postman.riken.go.jp
Kato
K
K
Torizawa
T
T
Dohmae
N
N
Yamaguchi
H
H
Kamachi
M
M
Harada
A
A
Imanaka
T
T
Shimada
I
I
Takio
K
K
D000595:Amino Acid Sequence; D000818:Animals; D017151:Antibodies, Catalytic / Q000737:chemistry* / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology; D058846:Antibodies, Monoclonal, Murine-Derived; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry*; D007135:Immunoglobulin Variable Region / Q000737:chemistry* / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010449:Peptide Mapping; D011166:Porphyrins / Q000276:immunology*; D017421:Sequence Analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D017151:Antibodies, Catalytic; D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D004220:Disulfides; D007135:Immunoglobulin Variable Region; C109583:Mab13-1 monoclonal antibody; D010446:Peptide Fragments; D011166:Porphyrins; C018395:tetracarboxyphenylporphine; D003545:Cysteine