Long-term metastable conformation of human Fcγ subunit

Abstract It was found that the human (hu) myeloma IgG1 Ser, its Fcγ fragment and the chimeric mouse-human monoclonal antibody (chim-mAb), containing the constant part of hu-γ1-chain, can exist in a long-term metastable conformational state. This state arises as a result of short incubation of IgG molecules and their Fcγ fragments at pH γ 2 domains is unfolded, but rapidly refolds after neutralisation. At the same time, non-covalent interactions between C γ 2 and C γ 3 domains are restored very slowly. A metastable state of IgG keeps 70% of complement-binding ability in comparison with the native state.