Figure 1.

Immunoglobulin heavy chain constant domains. The protein structure was deduced from the mRNA coding for transmembrane IgM (IgM-TM), secreted IgM (IgM-S) and transmembrane IgD (IgD-TM) forms. The putative cysteines that establish bonds with light chains (L) and heavy chains (H) to form multimers (J) are shown. Potential glycosylation sites are indicated with Gly.