The amino acid sequence of a lambda light chain presenting abnormal physicochemical and antigenic features.
The amino acid sequence of the light chain of a human monoclonal IgA1 (Mem) was established, in part by analogy with already known sequences. By homology its variable part was shown to belong to the V lambda I subgroup while the isotype-associated amino acid residues characterized it as Mcg+, Kern+ and Oz-. The normal primary structure of this chain was in contrast to its abnormal physical and antigenic properties: (a) its apparent molecular mass estimated by SDS/polyacrylamide gel electrophoresis, by gel filtration chromatography and by gradient ultracentrifugation was found to be lower by approximately equal to 10% than the values (23.5 kDa) of 'normal' light chain used as controls; (b) the lambda I chain Mem, when tested in native state was not antigenically reactive. These abnormalities were reverted when the chain was treated with 8 M urea. These data suggest that the abnormal behaviour of lambda I chain Mem is at a conformational level.
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Mihaesco
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JP
Roy
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Congy
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Peran-Rivat
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Mihaesco
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis*; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000032:analysis*; D007146:Immunoglobulin lambda-Chains / Q000032:analysis* / Q000276:immunology; D011487:Protein Conformation; D014783:Viscosity
D000596:Amino Acids; D000939:Epitopes; D007147:Immunoglobulin Light Chains; D007146:Immunoglobulin lambda-Chains