Extending Native Top-Down Electron Capture Dissociation to MDa Immunoglobulin Complexes Provides Useful Sequence Tags Covering Their Critical Variable Complementarity-Determining Regions.

ABSTRACT: Native top-down mass spectrometry (MS) is gaining traction for the analysis and sequencing of intact proteins and protein assemblies, giving access to their mass and composition, as well as sequence information useful for identification. Herein, we extend and apply native top-down MS, using electron capture dissociation, to two submillion Da IgM- and IgG-based oligomeric immunoglobulins. Despite structural similarities, these two systems are quite different. The ∼895 kDa noncovalent IgG hexamer consists of six IgG subunits hexamerizing in solution due to three specifically engineered mutations in the Fc region, whereas the ∼935 kDa IgM oligomer results from the covalent assembly of one joining (J) chain and 5 IgM subunits into an asymmetric "pentamer" stabilized by interchain disulfide bri

SUBMITTER: Greisch JF 

PROVIDER: S-EPMC8655740 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature