Editing Enterotoxin (section)

=== Bacterial ===

Enterotoxins can be formed by the bacterial pathogens ''Staphylococcus aureus'' and ''Bacillus cereus'' and can cause [[Staphylococcal food poisoning|Staphylococcal Food Poisoning]] and ''Bacillus cereus'' diarrheal disease, respectively. Staphylococcal enterotoxins and streptococcal [[exotoxin]]s constitute a family of biologically and structurally related pyrogenic [[superantigen]]s.<ref>{{Cite journal|last1=Dinges|first1=M. M.|last2=Orwin|first2=P. M.|last3=Schlievert|first3=P. M.|date=2000|title=Exotoxins of Staphylococcus aureus|journal=Clinical Microbiology Reviews|volume=13|issue=1|pages=16–34, table of contents|issn=0893-8512|pmid=10627489|pmc=88931|doi=10.1128/CMR.13.1.16}}</ref> 25 staphylococcal enterotoxins (SEs), mainly produced by ''[[Staphylococcus aureus]]'', have been identified to date and named alphabetically (SEA – SEZ).<ref>{{cite journal |last1=Etter |first1=Danai |last2=Schelin |first2=Jenny |last3=Schuppler |first3=Markus |last4=Johler |first4=Sophia |title=Staphylococcal Enterotoxin C—An Update on SEC Variants, Their Structure and Properties, and Their Role in Foodborne Intoxications |journal=Toxins |date=2020-09-10 |volume=12 |issue=9 |pages=584 |doi=10.3390/toxins12090584 |pmid=32927913 | pmc=7551944 |hdl=20.500.11850/441345 |hdl-access=free |doi-access=free }}</ref> It has been suggested that ''staphylococci'' other than ''S. aureus'' can contribute to Staphylococcal Food Poisoning by forming enterotoxins.<ref>{{Cite journal|last1=Fetsch|first1=Alexandra|last2=Johler|first2=Sophia|date=2018-04-27|title=Staphylococcus aureus as a Foodborne Pathogen|journal=Current Clinical Microbiology Reports|language=en|volume=5|issue=2|pages=88–96|doi=10.1007/s40588-018-0094-x|s2cid=13668423|issn=2196-5471}}</ref> Streptococcal exotoxins are produced by ''[[Streptococcus pyogenes]]''.<ref name="pmid2679358">{{cite journal | author = Iandolo JJ | title = Genetic analysis of extracellular toxins of Staphylococcus aureus | journal = Annu. Rev. Microbiol. | volume = 43 | pages = 375–402 | year = 1989 | pmid = 2679358 | doi = 10.1146/annurev.mi.43.100189.002111 }}</ref><ref name="pmid2185544">{{cite journal |vauthors=Marrack P, Kappler J | title = The staphylococcal enterotoxins and their relatives | journal = Science | volume = 248 | issue = 4956 | pages = 705–11 |date=May 1990 | pmid = 2185544 | doi = 10.1126/science.2185544| bibcode = 1990Sci...248..705M | s2cid = 33752378 }}</ref> These toxins share the ability to [[Molecular binding|bind]] to the [[major histocompatibility complex]] proteins of their hosts. A more distant relative of the family is the ''S. aureus ''[[toxic]] shock syndrome toxin, which shares only a low level of [[sequence (biology)|sequence]] similarity with this group.

All of these toxins share a similar two-domain [[protein folding|fold]] (N and [[C-terminal domain]]s) with a long [[alpha-helix]] in the middle of the molecule, a characteristic [[beta-barrel]] known as the "oligosaccharide/oligonucleotide fold" at the N-terminal [[Domain (biology)|domain]] and a beta-grasp [[protein motif|motif]] at the C-terminal domain. An example is [[Staphylococcal Enterotoxin B|staphylococcal enterotoxin B]]. Each superantigen possesses slightly different [[binding (molecular)|binding]] mode(s) when it [[protein–protein interaction|interact]]s with [[MHC class II]] molecules or the [[T-cell receptor]].<ref name="pmid9514739">{{cite journal |vauthors=Papageorgiou AC, Tranter HS, Acharya KR | title = Crystal structure of microbial superantigen staphylococcal enterotoxin B at 1.5 A resolution: implications for superantigen recognition by MHC class II molecules and T-cell receptors | journal = J. Mol. Biol. | volume = 277 | issue = 1 | pages = 61–79 |date=March 1998 | pmid = 9514739 | doi = 10.1006/jmbi.1997.1577 }}</ref>

The beta-grasp domain has some [[secondary structure|structural]] similarities to the beta-grasp [[sequence motif|motif]] present in immunoglobulin-binding domains, [[ubiquitin]], 2Fe-2 S [[ferredoxin]] and [[Translation (genetics)|translation]] [[Eukaryotic initiation factor|initiation factor]] 3 as identified by the [[SCOP database]].

* ''[[Clostridioides difficile (bacteria)|Clostridioides difficile]]''
* ''[[Clostridium perfringens]]'' ([[Clostridium enterotoxin]])<ref name="pmid9334247">{{cite journal |vauthors=Katahira J, Sugiyama H, Inoue N, Horiguchi Y, Matsuda M, Sugimoto N |title=Clostridium perfringens enterotoxin utilizes two structurally related membrane proteins as functional receptors in vivo |journal=The Journal of Biological Chemistry |volume=272 |issue=42 |pages=26652–8 |date=October 1997 |pmid=9334247 |doi= 10.1074/jbc.272.42.26652|doi-access=free }}</ref>
* ''[[Vibrio cholerae]]'' ([[Cholera toxin]])<ref name="Mesh">{{MeshName|Enterotoxins}}</ref>
* ''[[Staphylococcus aureus]]'' ([[Staphylococcal enterotoxin B]])<ref name=eMedicine830715>{{EMedicine|article|830715|CBRNE - Staphylococcal Enterotoxin B}}</ref>
* ''[[Yersinia enterocolitica]]''
* ''[[Shigella dysenteriae]]'' ([[Shiga toxin]])<ref name="Mesh"/>