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On the conformation of antibodies in the presence and absence of antigen (small‐angle X‐ray studies)
Author(s) -
Pilz I.,
Kratky O.,
Licht A.,
Sela M.
Publication year - 1978
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889878013631
Subject(s) - hapten , chemistry , conformational change , antibody , immunoglobulin fab fragments , binding site , radius of gyration , crystallography , stereochemistry , biochemistry , biology , immunology , peptide sequence , organic chemistry , gene , complementarity determining region , polymer
The conformations of different IgG antibodies were studied before and after interaction with antigen (hapten). In every case a strong change of the conformation was observed. Binding of hapten caused a decrease of the radius of gyration by 2 to 8% and a decrease of the volume by 3 to 10%, depending on the degree of saturation with hapten. Two IgG antibodies (anti‐poly‐‐alanyl) were split by enzymes into fragments which contain one binding site (Fab′) and two binding sites (Fab′) 2 , respectively, for hapten. No changes of conformation were observed with these fragments upon the interaction with hapten. These findings lead to the conclusion that the conformation change does not take place within the area of the combining site but relatively far away, at the area of the hinge region and/or the Fc‐fragment.