Details

Autor(en) / Beteiligte

• Zalem, Dani
• Juhás, Martin
• Terrinoni, Manuela
• King-Lyons, Natalie
• Lebens, Michael
• Varrot, Annabelle
• Connell, Terry D
• Teneberg, Susann

Titel

Characterization of the ganglioside recognition profile of Escherichia coli heat-labile enterotoxin LT-IIc

Ist Teil von

• Glycobiology (Oxford), 2022-04, Vol.32 (5), p.391-403

Ort / Verlag

England: Oxford University Press

Erscheinungsjahr

2022

Quelle

Oxford Journals 2020 Medicine

Beschreibungen/Notizen

• Abstract The heat-labile enterotoxins of Escherichia coli and cholera toxin of Vibrio cholerae are related in structure and function. Each of these oligomeric toxins is comprised of one A polypeptide and five B polypeptides. The B-subunits bind to gangliosides, which are followed by uptake into the intoxicated cell and activation of the host’s adenylate cyclase by the A-subunits. There are two antigenically distinct groups of these toxins. Group I includes cholera toxin and type I heat-labile enterotoxin of E. coli; group II contains the type II heat-labile enterotoxins of E. coli. Three variants of type II toxins, designated LT-IIa, LT-IIb and LT-IIc have been described. Earlier studies revealed the crystalline structure of LT-IIb. Herein the carbohydrate binding specificity of LT-IIc B-subunits was investigated by glycosphingolipid binding studies on thin-layer chromatograms and in microtiter wells. Binding studies using a large variety of glycosphingolipids showed that LT-IIc binds with high affinity to gangliosides with a terminal Neu5Acα3Gal or Neu5Gcα3Gal, e.g. the gangliosides GM3, GD1a and Neu5Acα3-/Neu5Gcα3--neolactotetraosylceramide and Neu5Acα3-/Neu5Gcα3-neolactohexaosylceramide. The crystal structure of LT-IIc B-subunits alone and with bound LSTd/sialyl-lacto-N-neotetraose d pentasaccharide uncovered the molecular basis of the ganglioside recognition. These studies revealed common and unique functional structures of the type II family of heat-labile enterotoxins.