title: Conversion of incomplete antibodies to direct agglutinins by mild reduction: evidence for segmental flexibility within the Fc fragment of immunoglobulin G.
abstract: Reduction of interchain disulfide bonds converted some IgG incomplete antibodies to direct hemagglutinins. This conversion occurred whether antibody was free in solution or bound to the red-cell surface. Reduced antibody permitted to reoxidize in air no longer behaved as a direct agglutinin; reversion to an incomplete antibody did not occur when reoxidation was prevented by S-alkylation. These results suggest that mild reduction of the antibody imparts sufficient freedom to permit bridging between cells and are interpreted as evidence that the interheavy-chain disulfide bonds restrict segmental flexibility within the Fc fragment of IgG.
mesh_terms: D001665:Binding Sites; D004220:Disulfides / Q000032:analysis; D004912:Erythrocytes / Q000276:immunology; D006386:Hemagglutination Tests; D006801:Humans; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G / Q000302:isolation & purification; D046911:Macromolecular Substances; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D004220:Disulfides; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D046911:Macromolecular Substances
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