Related Experiment Video

Updated: Jun 24, 2026

Characterization of Glycoproteins with the Immunoglobulin Fold by X-Ray Crystallography and Biophysical Techniques
08:58

Characterization of Glycoproteins with the Immunoglobulin Fold by X-Ray Crystallography and Biophysical Techniques

Published on: July 5, 2018

The immunoglobulin-binding Eib proteins from Escherichia coli are receptors for IgG Fc

Jack C Leo1, Adrian Goldman

  • 1Macromolecular Crystallography Group, Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.

Molecular Immunology
|March 24, 2009
PubMed

The immunoglobulin-binding proteins from Escherichia coli (Eibs) comprise a family of six proteins homologous to the Yersinia adhesin YadA. These proteins are postulated to bind to the Fc portion of immunoglobulin G (IgG) in a non-immune manner. However, a recent study [Ghumra, A., Pleass, R.J., 2007. Escherichia coli do not express Fc-receptors for human immunoglobulin G (IgG). Mol. Immunol. 44, 2144-2146] appeared to show that these proteins do not bind Fc and suggested that the binding seen in earlier studies is due to the polyclonal preparations used in the assays containing antibodies specific to epitopes in the Eib proteins. To resolve this matter, we produced purified, recombinant Eibs for the first time and investigated their binding to intact antibodies and Fc fragments by immunoblot and ELISA techniques. We were able to purify four members of the family, EibA, -C, -D and -F, and show conclusively that these bind IgG Fc. We were also able to block the binding of full-length antibody with IgG Fc, but not with IgG Fab. Binding to IgG Fab was not detectable by surface plasmon resonance, whereas the affinities of Eibs to IgG and IgG Fc were in the range of 50-200 nM. We further demonstrate that deglycosylating IgG Fc does not affect Eib binding. Our results show that the Eib proteins do indeed bind human IgG Fc and that IgG Fc receptors are present in E. coli.

More Related Videos

Producing Gene Deletions in Escherichia coli by P1 Transduction with Excisable Antibiotic Resistance Cassettes08:13

Producing Gene Deletions in Escherichia coli by P1 Transduction with Excisable Antibiotic Resistance Cassettes

Published on: September 1, 2018

Covalent Binding of Antibodies to Cellulose Paper Discs and Their Applications in Naked-eye Colorimetric Immunoassays09:04

Covalent Binding of Antibodies to Cellulose Paper Discs and Their Applications in Naked-eye Colorimetric Immunoassays

Published on: October 21, 2016

Related Concept Videos

Antibody Structure01:10

Antibody Structure

Overview
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
Antibody Structure01:10

Antibody Structure

Overview
Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.
The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains
Antibodies consist of four polypeptide chains: two identical heavy...
Immunoglobulin-like Cell Adhesion Molecules01:31

Immunoglobulin-like Cell Adhesion Molecules

Immunoglobulin-like cell adhesion molecules or Ig-CAMs are a versatile group of cell surface glycoproteins belonging to the immunoglobulin protein superfamily. Ig-CAMs possess the characteristic immunoglobulin protein domains and other domains such as the fibronectin type III domain. The Ig domains are glycosylated to varying degrees in different Ig-CAMs.
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Transcytosis of IgG01:15

Transcytosis of IgG

Transcytosis is the process in which molecules are internalized by endocytosis, transported across the cell, and released through exocytosis from the opposite end of the cell. Molecules such as insulin, immunoglobulins, and certain nutrients are transferred through the recycling endosomes by recycling and transcytosis.
IgG molecules from a mother undergo transcytosis starting around 13 weeks of gestation. The amount of IgG transferred and entering the fetal blood circulation increases with...
Antibody Structure and Classes01:25

Antibody Structure and Classes

Antibodies, also known as immunoglobulins, are produced by B cells in response to foreign substances, such as bacteria and viruses. These proteins are critical for recognizing and neutralizing these substances, protecting the body from potential harm.
The basic structure of an antibody consists of four protein chains: two identical heavy chains and two identical light chains. These chains are held together by disulfide bonds and other non-covalent interactions, forming a Y-shaped structure.
Single-Strand DNA Binding Proteins01:03

Single-Strand DNA Binding Proteins

For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...