Glycoconjugate Journal

, Volume 27, Issue 1, pp 171–179

No direct binding of the heat-labile enterotoxin of Escherichia coli to E. coli lipopolysaccharides

  • Lena Jansson
  • Jonas Ångström
  • Michael Lebens
  • Susann Teneberg
Article

DOI: 10.1007/s10719-009-9264-7

Cite this article as:
Jansson, L., Ångström, J., Lebens, M. et al. Glycoconj J (2010) 27: 171. doi:10.1007/s10719-009-9264-7

Abstract

A novel carbohydrate binding site recognizing blood group A and B determinants in a hybrid of cholera toxin and Escherichia coli heat-labile enterotoxin B-subunits (termed LCTBK) has previously been described, and also the native heat-labile enterotoxin bind to some extent to blood group A/B terminated glycoconjugates. The blood group antigen binding site is located at the interface of the B-subunits. Interestingly, the same area of the B-subunits has been proposed to be involved in binding of the heat-labile enterotoxin to lipopolysaccharides on the bacterial cell surface. Binding of the toxin to lipopolysaccharides does not affect the GM1 binding capacity. The present study aimed at characterizing the relationship between the blood group A/B antigen binding site and the lipopolysaccharide binding site. However, no binding of the B-subunits to E. coli lipopolysaccharides in microtiter wells or on thin-layer chromatograms was obtained. Incubation with lipopolysaccharides did not affect the binding of the B-subunits of heat-labile enterotoxin of human isolates to blood group A-carrying glycosphingolipids, indicating that the blood group antigen site is not involved in LPS binding. However, the saccharide competition experiments showed that GM1 binding reduced the affinity for blood group A determinants and vice versa, suggesting that a concurrent occupancy of the two binding sites does not occur. The latter finding is related to a connection between the blood group antigen binding site and the GM1 binding site through residues interacting with both ligands.

Keywords

Carbohydrate binding E. coli heat-labile toxin lipopolysaccharide binding blood group A/B binding site GM1 binding site 

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Lena Jansson
    • 1
  • Jonas Ångström
    • 1
  • Michael Lebens
    • 2
  • Susann Teneberg
    • 1
  1. 1.Institute of Biomedicine, Department of Medical Biochemistry and Cell BiologyUniversity of GothenburgGöteborgSweden
  2. 2.Institute of Biomedicine, Department of Medical Microbiology and ImmunologyUniversity of GothenburgGöteborgSweden