5G3L

ESCHERICHIA COLI HEAT LABILE ENTEROTOXIN TYPE IIB B-PENTAMER COMPLEXED WITH SIALYLATED SUGAR

Summary for 5G3L

• Entry DOI: 10.2210/pdb5g3l/pdb
• Descriptor: HEAT-LABILE ENTEROTOXIN IIB, B CHAIN, N-acetyl-alpha-neuraminic acid-(2-3)-beta-D-galactopyranose, SODIUM ION, ... (6 entities in total)
• Functional Keywords: toxin, enterotoxin, ecoli, b subunit, sialic acid
• Biological source: ESCHERICHIA COLI; More
• Total number of polymer chains: 5
• Total formula weight: 56063.68

Authors

Zalem, D.,Benktander, J.,Ribeiro, J.P.,Varrot, A.,Lebens, M.,Imberty, A.,Teneberg, S. (deposition date: 2016-04-29, release date: 2016-09-14, Last modification date: 2024-01-10)

Primary citation

Zalem, D.,Ribeiro, J.P.,Varrot, A.,Lebens, M.,Imberty, A.,Teneberg, S.
Biochemical and Structural Characterization of the Novel Sialic Acid-Binding Site of Escherichia Coli Heat-Labile Enterotoxin Lt-Iib.
Biochem.J., 473:3923-, 2016

PubMed Abstract: The structurally related AB-type heat-labile enterotoxins of Escherichia coli and Vibrio cholerae are classified into two major types. The type I group includes cholera toxin (CT) and E. coli LT-I, whereas the type II subfamily comprises LT-IIa, LT-IIb and LT-IIc. The carbohydrate-binding specificities of LT-IIa, LT-IIb and LT-IIc are distinctive from those of cholera toxin and E. coli LT-I. Whereas CT and LT-I bind primarily to the GM1 ganglioside, LT-IIa binds to gangliosides GD1a, GD1b and GM1, LT-IIb binds to the GD1a and GT1b gangliosides, and LT-IIc binds to GM1, GM2, GM3 and GD1a. These previous studies of the binding properties of type II B-subunits have been focused on ganglio core chain gangliosides. To further define the carbohydrate binding specificity of LT-IIb B-subunits, we have investigated its binding to a collection of gangliosides and non-acid glycosphingolipids with different core chains. A high-affinity binding of LT-IIb B-subunits to gangliosides with a neolacto core chain, such as Neu5Gcα3- and Neu5Acα3-neolactohexaosylceramide, and Neu5Gcα3- and Neu5Acα3-neolactooctaosylceramide was detected. An LT-IIb-binding ganglioside was isolated from human small intestine and characterized as Neu5Acα3-neolactohexaosylceramide. The crystal structure of the B-subunit of LT-IIb with the pentasaccharide moiety of Neu5Acα3-neolactotetraosylceramide (Neu5Ac-nLT: Neu5Acα3Galβ4GlcNAcβ3Galβ4Glc) was determined providing the first information for a sialic-binding site in this subfamily, with clear differences from that of CT and LT-I.

PubMed: 27562297
DOI: 10.1042/BCJ20160575

Experimental method

X-RAY DIFFRACTION (1.72 Å)