7prs

Publication Abstract from PubMed

The heat-labile enterotoxins of Escherichia coli and cholera toxin of Vibrio cholerae are related in structure and function. Each of these oligomeric toxins are comprised of one A polypeptide and five B polypeptides. The B-subunits bind to gangliosides, which is 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 Neu5Ac<3Gal or Neu5Gc<3Gal sequence, e.g. the gangliosides GM3, GD1a and Neu5Ac<3-/Neu5Gc<3-neolactotetraosylceramide and Neu5Ac<3-/Neu5Gc<3-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.

Characterization of the ganglioside recognition profile of Escherichia coli heat-labile enterotoxin LT-IIc.,Zalem D, Juhas M, Terrinoni M, King-Lyons N, Lebens M, Varrot A, Connell TD, Teneberg S Glycobiology. 2021 Dec 24. pii: 6482028. doi: 10.1093/glycob/cwab133. PMID:34972864^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.