Immunoglob.Fc (IGGI) complexed w. protein G

Fab (fragment antigen binding) fragments of antibody are produced when antibody molecules are cleaved with proteolytic enzymes. This model shows a ribbon diagram of an immunoglobulin Fc fragment (IGGI) with immunoglobulin G binding protein G (pdb code: 1pgx). G proteins are involved in cell signalling receptors and cascades.