Primary structure of a human IgA1 immunoglobulin. V. Amino acid sequence of a human IgA lambda light chain (Bur).

The sequence of the lambda light chain of the Bur IgA1 molecule has been determined. It comprises 214 amino acid residues with a blocked NH2 terminus and lacks carbohydrate. The V-region sequence is of the VlambdaII subgroup and contains the coupled interchanges Arg-7 and Cys-87. The Lv3 region is comparatively short and hydrophobic in nature and lends support for the designation of this area as a hypervariable deletion region. The C-region exhibits the Mcg+ Kren+ Oz- isotypes. These appear coupled with substitution at position 100 (in the V-region). The pattern of nonrandom association of V- and C-regions and H and L chains is discussed in terms of the generation of antibody diversity. With the companion papers in this series, the complete primary structure of a human IgA1 molecule is established.