20
Jun
(B) In the cryogenic structure, the C2 FG loop (yellow) adopts the unique, IgG4-like conformation and forms a 2882interface with a symmetry-related molecule (gray). FG loop in the other chain adopts the conformation previously observed in the cryogenic IgG4-Fc structures, despite both conformations being accessible. The room temperature human IgG4-Fc structure thus provides a more complete and physiologically relevant description of the conformation of this functionally critical C2 FG loop. == 1 . Introduction == IgG effector functions, such as antibody-dependent cell-mediated cytotoxicity, antibody-dependent cellular phagocytosis and complement activation, are mediated by the antibody Fc region (C2 and C3 domains).…