| 1. |
- Tabiri, S, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
| 2. |
- Bravo, L, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Holmner, Åsa, et al.
(författare)
-
Blood group antigen recognition by Escherichia coli heat-labile enterotoxin
- 2007
-
Ingår i: Journal of Molecular Biology. - London : Elsevier BV. - 0022-2836 .- 1089-8638. ; 371:3, s. 754-764
-
Tidskriftsartikel (refereegranskat)abstract
- In a number of bacterial infections, such as Helicobacter pylori, Campylobacter jejuni and Vibrio cholerae infections, a correlation between the severity of disease and blood group phenotype of infected individuals has been observed. In the present investigation, we have studied the molecular basis of this effect for enterotoxigenic Escherichia coli (ETEC) infections. ETEC are non-invasive bacteria, which act through second messenger pathways to cause diarrhea. It has been suggested that the major virulence factor of ETEC from human isolates, i.e. the human heat-labile enterotoxin (hLT), recognizes certain blood group epitopes, although the molecular basis of blood group antigen recognition is unknown. The 2.5 angstrom crystal structure of the receptor-binding B-subunit of hLT in complex with the blood group A antigen analog GalNAc alpha 3(Fuc alpha-2)Gal beta 4(Fuc alpha-3)Glc beta provides evidence of a previously unknown binding site in the native toxin. The structure reveals the molecular interactions underlying blood group antigen recognition and suggests how this protein can discriminate between different blood group epitopes. These results support the previously debated role of hLT in the blood group dependence of ETEC infections. Similar observations regarding the closely related cholera toxin in V. cholera infections are also discussed. (c) 2007 Elsevier Ltd. All rights reserved.
|
|
| 7. |
- Holmner, Åsa, et al.
(författare)
-
Crystal Structures Exploring the Origins of the Broader Specificity of Escherichia coli Heat-Labile Enterotoxin Compared to Cholera Toxin.
- 2011
-
Ingår i: Journal of molecular biology. - : Elsevier BV. - 1089-8638 .- 0022-2836. ; 406:3, s. 387-402
-
Tidskriftsartikel (refereegranskat)abstract
- Cholera toxin (CT) and Escherichia coli heat-labile enterotoxin (LT) are structurally and functionally related and share the same primary receptor, the GM1 ganglioside. Despite their extensive similarities, these two toxins exhibit distinct ligand specificities, with LT being more promiscuous than CT. Here, we have attempted to rationalize the broader binding specificity of LT and the subtle differences between the binding characteristics of LTs from human and porcine origins (mediated by their B subunit pentamers, hLTB and pLTB, respectively). The analysis is based on two crystal structures of pLTB in complexes with the pentasaccharide of its primary ligand, GM1, and with neolactotetraose, the carbohydrate determinant of a typical secondary ligand of LTs, respectively. Important molecular determinants underlying the different binding specificities of LTB and CTB are found to be contributed by Ser95, Tyr18 and Thr4 (or Ser4 of hLTB), which together prestabilize the binding site by positioning Lys91, Glu51 and the adjacent loop region (50-61) containing Ile58 for ligand binding. Glu7 and Ala1 may also play an important role. Many of these residues are closely connected with a recently identified second binding site, and there appears to be cross-talk between the two binding sites. Binding to N-acetyllactosamine-terminated receptors is further augmented by Arg13 (present in pLT and some hLT variants), as previously predicted.
|
|
