Complete covalent structure of a human IgA1 immunoglobulin.

The complete covalent structure has been determined for a human myeloma IgA1 immunoglobulin. This protein has unique features in the amino acid sequence and disulfide bridge structure of the variable (V) and constant (C) regions of both the alpha heavy and the lambda light chains, and in the number and loci of oligosaccharides. Whereas C region domains of heavy chains have evolved independently over eons, recent isotypic variations have occured in lambda light chains and possibly in alpha heavy chains.