title: The effect of sugar removal on the structure of the Fc region of an IgG antibody as observed with single molecule Förster Resonance Energy Transfer.
abstract: The deglycosylation of immunoglobulin G (IgG) antibodies leads to a diminished immune response. This reduction in immune response is thought to arise from weakened binding of IgG antibodies to effector molecules as a result of a conformational change in the antibody. The nature of this structural alteration is uncertain due to the conflicting results obtained from different experimental methods. We have examined the impact of deglycosylation by the endoglycosidase PNGase F on the structure of the Fc region of a human IgG antibody using single molecule Förster Resonance Energy Transfer (FRET). The FRET efficiency histograms obtained indicate that the structure of the Fc region becomes more flexible upon deglycosylation. This is demonstrated by a change in the width of the energy transfer efficiency peak, which increases from 0.19 ± 0.02 to 0.6 ± 0.1 upon deglycosylation.
authors.affiliation: DePaul University, Department of Chemistry, 1110 W. Belden Avenue, Chicago, IL 60614, United States.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Kelliher
authors.affiliation: DePaul University, Department of Chemistry, 1110 W. Belden Avenue, Chicago, IL 60614, United States.
authors.forename: Ramiah D
authors.initials: RD
authors.lastname: Jacks
authors.affiliation: DePaul University, Department of Chemistry, 1110 W. Belden Avenue, Chicago, IL 60614, United States.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Piraino
authors.affiliation: DePaul University, Department of Chemistry, 1110 W. Belden Avenue, Chicago, IL 60614, United States. Electronic address: csouthe2@depaul.edu.
authors.forename: Cathrine A
authors.initials: CA
authors.lastname: Southern
mesh_terms: D000906:Antibodies / Q000737:chemistry* / Q000276:immunology; D002241:Carbohydrates / Q000737:chemistry* / Q000276:immunology; D002460:Cell Line; D018360:Crystallography, X-Ray; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D057809:HEK293 Cells; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000737:chemistry* / Q000276:immunology; D007074:Immunoglobulin G / Q000737:chemistry* / Q000276:immunology; D008958:Models, Molecular; D013329:Structure-Activity Relationship
chemical_list: D000906:Antibodies; D002241:Carbohydrates; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G
keywords: Fc degylcosylation; Förster Resonance Energy Transfer; IgG structure; Single molecule