Correlation between Shiga toxin B‐subunit stability and antigen crosspresentation: A mutational analysis

Pina, David G.; Stechmann, Bahne; Shnyrov, Valery L.; Cabanié, Lucien; Haicheur, Nacilla; Tartour, Éric; Johannes, Ludger

doi:10.1016/j.febslet.2007.11.086

Cited by 3 publications

(4 citation statements)

References 32 publications

(47 reference statements)

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“…Explicit N mer unfolding models are well developed for trimeric and tetrameric systems; however, higher-order models that explicitly describe oligomer dissociation linked to monomer unfolding are too complex to resolve using CD t-melts [36]. Previous studies of Stx1B thermostability have reported no improvement in fits with models that include folded monomer as an intermediate [28], [46], [47]. This does not preclude the presence of folded monomer, but merely indicates that folded monomer may be indistinguishable from folded pentamer species in the CD spectra.…”

Section: Discussionmentioning

confidence: 99%

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Molecular Basis of Differential B-Pentamer Stability of Shiga Toxins 1 and 2

et al. 2010

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Escherichia coli strain O157:H7 is a major cause of food poisoning that can result in severe diarrhea and, in some cases, renal failure. The pathogenesis of E. coli O157:H7 is in large part due to the production of Shiga toxin (Stx), an AB5 toxin that consists of a ribosomal RNA-cleaving A-subunit surrounded by a pentamer of receptor-binding B subunits. There are two major isoforms, Stx1 and Stx2, which differ dramatically in potency despite having 57% sequence identity. Animal studies and epidemiological studies show Stx2 is associated with more severe disease. Although the molecular basis of this difference is unknown, data suggest it is associated with the B-subunit. Mass spectrometry studies have suggested differential B-pentamer stability between Stx1 and Stx2. We have examined the relative stability of the B-pentamers in solution. Analytical ultracentrifugation using purified B-subunits demonstrates that Stx2B, the more deadly isoform, shows decreased pentamer stability compared to Stx1B (EC50 = 2.3 µM vs. EC50 = 0.043 µM for Stx1B). X-ray crystal structures of Stx1B and Stx2B identified a glutamine in Stx2 (versus leucine in Stx1) within the otherwise strongly hydrophobic interface between B-subunits. Interchanging these residues switches the stability phenotype of the B-pentamers of Stx1 and Stx2, as demonstrated by analytical ultracentrifugation and circular dichroism. These studies demonstrate a profound difference in stability of the B-pentamers in Stx1 and Stx2, illustrate the mechanistic basis for this differential stability, and provide novel reagents to test the basis for differential pathogenicity of these toxins.

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Section: Discussionmentioning

confidence: 99%

“…Mutation of Stx1B residue L41 has previously been used to destabilize inter-subunit packing [46]. Stx1B-L41W decreased the T m by 6°C in CD thermal melts.…”

Section: Discussionmentioning

confidence: 99%

Molecular Basis of Differential B-Pentamer Stability of Shiga Toxins 1 and 2

et al. 2010

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“…Similar to primary mature DCs, mature D1 cells produce IL-12p75 in response to TNF [20] and efficiently stimulate T cells [20]. In addition, D1 cells can present peptides derived from exogenous antigens in the context of MHC class I molecules [51][52][53], a mechanism known as crosspresentation, which is considered to be essential for the induction of cytotoxic T cell (CTL) responses. To summarize, Raw264.7, J774 as well as D1 cells can take up antigen, however, only the Raw264.7 and D1 cells have the capacity to process and present antigen to T cells.…”

Section: Antigen Up-take and Presentationmentioning

confidence: 99%

Human and murine model cell lines for dendritic cell biology evaluated

Helden¹,

Leeuwen²,

Figdor³

2008

Immunology Letters

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“…Shiga toxin producing E. coli (STEC) [1], including serogroups O157:H7 and non-O157, are one of the leading causes of food poisoning worldwide [2]. Ingestion of as few as 30 bacteria is enough to produce disease symptoms [3].…”

Section: Introductionmentioning

confidence: 99%

Glycolipid Binding Preferences of Shiga Toxin Variants

Karve

Weiss

2014

PLoS ONE

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The major virulence factor of Shiga toxin producing E. coli, is Shiga toxin (Stx), an AB5 toxin that consists of a ribosomal RNA-cleaving A-subunit surrounded by a pentamer of receptor-binding B subunits. The two major isoforms, Stx1 and Stx2, and Stx2 variants (Stx2a-h) significantly differ in toxicity. The exact reason for this toxicity difference is unknown, however different receptor binding preferences are speculated to play a role. Previous studies used enzyme linked immunosorbent assay (ELISA) to study binding of Stx1 and Stx2a toxoids to glycolipid receptors. Here, we studied binding of holotoxin and B-subunits of Stx1, Stx2a, Stx2b, Stx2c and Stx2d to glycolipid receptors globotriaosylceramide (Gb3) and globotetraosylceramide (Gb4) in the presence of cell membrane components such as phosphatidylcholine (PC), cholesterol (Ch) and other neutral glycolipids. In the absence of PC and Ch, holotoxins of Stx2 variants bound to mixtures of Gb3 with other glycolipids but not to Gb3 or Gb4 alone. Binding of all Stx holotoxins significantly increased in the presence of PC and Ch. Previously, Stx2a has been shown to form a less stable B-pentamer compared to Stx1. However, its effect on glycolipid receptor binding is unknown. In this study, we showed that even in the absence of the A-subunit, the B-subunits of both Stx1 and Stx2a were able to bind to the glycolipids and the more stable B-pentamer formed by Stx1 bound better than the less stable pentamer of Stx2a. B-subunit mutant of Stx1 L41Q, which shows similar stability as Stx2a B-subunits, lacked glycolipid binding, suggesting that pentamerization is more critical for binding of Stx1 than Stx2a.

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Correlation between Shiga toxin B‐subunit stability and antigen crosspresentation: A mutational analysis

Cited by 3 publications

References 32 publications

Molecular Basis of Differential B-Pentamer Stability of Shiga Toxins 1 and 2

Molecular Basis of Differential B-Pentamer Stability of Shiga Toxins 1 and 2

Human and murine model cell lines for dendritic cell biology evaluated

Glycolipid Binding Preferences of Shiga Toxin Variants

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