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Shiga toxin

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Shiga Toxin acts as an N-glycosidase, removing an adenine from the 28S ribosomal rRNA of a target cell which leads to inhibition of protein elongation and ultimately cellular apoptosis.<ref name=Di>PMID: 21184769</ref> The B subunit is necessary for binding to globo series glycolipid globotriaosylceramide (Gb<sub>3</sub>), a eukaryotic membrane receptor, where it is then endocytosed and proteolytically cleaved into an active A subunit and a B subunit.<ref name=Lenz>PMID: 2170899</ref> The B subunit is not active in the depurination of of 28S rRNA, but is essential for GB<sub>3</sub> binding and therefore essential for toxicity. Once in the cytosol the A subunit is free to interact with and inactivate 28S rRNA. On the A subunit <scene name='Shiga_toxin_1/Active_site_zoomed_in/1'>Tyr77, Tyr114, Glu167, Arg170, and Trp203</scene> are all essential in glycosidic activity.<ref name=Di>PMID: 21184769</ref> This mechanism (B subunit binding to globotriaosylceramide and A subunit depurinating 28S rRNA) is conserved amongst the Stx family as well as the ricin toxin.
Shiga Toxin acts as an N-glycosidase, removing an adenine from the 28S ribosomal rRNA of a target cell which leads to inhibition of protein elongation and ultimately cellular apoptosis.<ref name=Di>PMID: 21184769</ref> The B subunit is necessary for binding to globo series glycolipid globotriaosylceramide (Gb<sub>3</sub>), a eukaryotic membrane receptor, where it is then endocytosed and proteolytically cleaved into an active A subunit and a B subunit.<ref name=Lenz>PMID: 2170899</ref> The B subunit is not active in the depurination of of 28S rRNA, but is essential for GB<sub>3</sub> binding and therefore essential for toxicity. Once in the cytosol the A subunit is free to interact with and inactivate 28S rRNA. On the A subunit <scene name='Shiga_toxin_1/Active_site_zoomed_in/1'>Tyr77, Tyr114, Glu167, Arg170, and Trp203</scene> are all essential in glycosidic activity.<ref name=Di>PMID: 21184769</ref> This mechanism (B subunit binding to globotriaosylceramide and A subunit depurinating 28S rRNA) is conserved amongst the Stx family as well as the ricin toxin.
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</StructureSection>
 
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__NOTOC__
 
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==3D structures of shiga toxin==
==3D structures of shiga toxin==
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[[Shiga toxin 3D structures]]
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Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}
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</StructureSection>
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{{#tree:id=OrganizedByTopic|openlevels=0|
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*Shiga toxin
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**[[1dm0]], [[1r4q]] – SdStx α+β chains – ''Shigella dysenteriae''<br />
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**[[4m1u]] – EcStx2 α+β chains + disaccharide – ''Escherichia coli''<br />
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*Shiga-like toxin 1
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**[[1czw]], [[1czg]] – pHStx1 β chain (mutant) – phage H30<br />
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**[[4ull]] – pHStx1 β chain – NMR<br />
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**[[1c48]] - pHStx1 β chain receptor-binding domain (mutant)<br />
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**[[1bos]], [[1qnu]] – pHStx1 β chain receptor-binding domain + GB3 analog<br />
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**[[2xsc]] – EcStx1 β chain <br />
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**[[1d1i]], [[1cqf]] – EcStx1 β chain (mutant) + GB3 analog <br />
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**[[1c4q]], [[1d1k]] – EcStx1 β chain receptor-binding domain (mutant) + GB3 analog
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*Shiga-like toxin 2
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**[[2c5c]] - pHStx2 β chain + inhibitor<br />
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**[[1r4p]] – EcStx2 α+β chains<br />
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**[[3mxg]] – EcStx2 β chain (mutant)<br />
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**[[4p2c]] - EcStx2 α+β chains (mutant) + nanobody<br />
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**[[2bos]], [[1qoh]] – EcStx2 β chain receptor-binding domain (mutant) + GB3 analog<br />
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**[[2ga4]] - epStx2 α+β chains – enterobacteria phage 933W<br />
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**[[6fe4]] - epStx2 β chain +NB113<br />
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}}
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==References==
==References==
{{Reflist}}
{{Reflist}}
[[Category:Topic Page]]
[[Category:Topic Page]]

Current revision

E. coli Shiga-like toxin 1 subunit B complex with Zn+2 (grey (PDB code 2xsc)

Drag the structure with the mouse to rotate

References

  1. ↑ 1.0 1.1 Wagner PL, Livny J, Neely MN, Acheson DW, Friedman DI, Waldor MK. Bacteriophage control of Shiga toxin 1 production and release by Escherichia coli. Mol Microbiol. 2002 May;44(4):957-70. PMID:12010491
  2. ↑ 2.0 2.1 2.2 Herold S, Karch H, Schmidt H. Shiga toxin-encoding bacteriophages--genomes in motion. Int J Med Microbiol. 2004 Sep;294(2-3):115-21. PMID:15493821
  3. ↑ Asakura H, Makino S, Kobori H, Watarai M, Shirahata T, Ikeda T, Takeshi K. Phylogenetic diversity and similarity of active sites of Shiga toxin (stx) in Shiga toxin-producing Escherichia coli (STEC) isolates from humans and animals. Epidemiol Infect. 2001 Aug;127(1):27-36. PMID:11561972
  4. ↑ Russell JB, Jarvis GN. Practical mechanisms for interrupting the oral-fecal lifecycle of Escherichia coli. J Mol Microbiol Biotechnol. 2001 Apr;3(2):265-72. PMID:11321582
  5. ↑ Nishikawa K. Recent progress of Shiga toxin neutralizer for treatment of infections by Shiga toxin-producing Escherichia coli. Arch Immunol Ther Exp (Warsz). 2011 Aug;59(4):239-47. Epub 2011 Jun 5. PMID:21644029 doi:10.1007/s00005-011-0130-5
  6. ↑ 6.0 6.1 6.2 Fraser ME, Chernaia MM, Kozlov YV, James MN. Crystal structure of the holotoxin from Shigella dysenteriae at 2.5 A resolution. Nat Struct Biol. 1994 Jan;1(1):59-64. PMID:7656009
  7. ↑ 7.0 7.1 Di R, Kyu E, Shete V, Saidasan H, Kahn PC, Tumer NE. Identification of amino acids critical for the cytotoxicity of Shiga toxin 1 and 2 in Saccharomyces cerevisiae. Toxicon. 2011 Mar 15;57(4):525-39. Epub 2010 Dec 22. PMID:21184769 doi:10.1016/j.toxicon.2010.12.006
  8. ↑ Roman F, Santa A, Rimanoczky A, Toldi Z, Pataki L. [Isotope study of in vitro K(+) uptake and release of erythrocytes in juvenile diabetes with 86Rb]. Padiatr Grenzgeb. 1990;29(4):339-45. PMID:2170899

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