Summary: ADP-ribosyltransferase exoenzyme
This is the Wikipedia entry entitled "AB toxin". More...
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AB toxin Edit Wikipedia article
crystal structure of the enzymatic componet of iota-toxin from clostridium perfringens with nadh
crystal structure of the anthrax toxin protective antigen heptameric prepore
The AB toxins are two-component protein complexes secreted by a number of pathogenic bacteria. They can be classified as Type III toxins because they interfere with internal cell function. They are named AB toxins due to their components: the "A" component is usually the "active" portion, and the "B" component is usually the "binding" portion. The "A" subunit possesses enzyme activity, and is transferred to the host cell following a conformational change in the membrane-bound transport "B" subunit. Among the toxins produced by certain Clostridium spp. are the binary exotoxins. These proteins consist of two independent polypeptides, which correspond to the A/B subunit moieties. The enzyme component (A) enters the cell through endosomes produced by the oligomeric binding/translocation protein (B), and prevents actin polymerisation through ADP-ribosylation of monomeric G-actin.
Members of the "A" binary toxin family include C. perfringens iota toxin Ia, C. botulinum C2 toxin CI, and Clostridium difficile ADP-ribosyltransferase . Other homologous proteins have been found in Clostridium spiroforme.
Members of the "B" binary toxin family include the Bacillus anthracis protective antigen (PA) protein, most likely due to a common evolutionary ancestor. B. anthracis, a large Gram-positive spore-forming rod, is the causative agent of anthrax. Its two virulence factors are the poly-D-glutamate polypeptide capsule, and the actual anthrax exotoxin. The toxin comprises three factors: the protective antigen (PA); the oedema factor (EF); and the lethal factor (LF). Each is a thermolabile protein of ~80kDa. PA forms the "B" part of the exotoxin and allows passage of the "A" moiety (consisting of EF and LF) into target cells. PA protein forms the central part of the complete anthrax toxin, and translocates the B moiety into host cells after assembling as a heptamer in the membrane.
The AB5 toxins are usually considered a type of AB toxin, characterized by B pentamers. Less commonly, the term "AB toxin" is used to emphasize the monomeric character of the B component.
- "Bacterial Pathogenesis: Bacterial Factors that Damage the Host - Producing Exotoxins - A-B Toxins". Retrieved 2008-12-13.
- De Haan L, Hirst TR (2004). "Cholera toxin: a paradigm for multi-functional engagement of cellular mechanisms (Review)". Mol. Membr. Biol. 21 (2): 77–92. doi:10.1080/09687680410001663267. PMID 15204437.
- Perelle S, Gibert M, Boquet P, Popoff MR (December 1993). "Characterization of Clostridium perfringens iota-toxin genes and expression in Escherichia coli". Infect. Immun. 61 (12): 5147–56. PMC 281295. PMID 8225592.
- Fujii N, Kubota T, Shirakawa S, Kimura K, Ohishi I, Moriishi K, Isogai E, Isogai H (March 1996). "Characterization of component-I gene of botulinum C2 toxin and PCR detection of its gene in clostridial species". Biochem. Biophys. Res. Commun. 220 (2): 353–9. doi:10.1006/bbrc.1996.0409. PMID 8645309.
- Stubbs S, Rupnik M, Gibert M, Brazier J, Duerden B, Popoff M (May 2000). "Production of actin-specific ADP-ribosyltransferase (binary toxin) by strains of Clostridium difficile". FEMS Microbiol. Lett. 186 (2): 307–12. doi:10.1111/j.1574-6968.2000.tb09122.x. PMID 10802189.
- Pezard C, Berche P, Mock M (October 1991). "Contribution of individual toxin components to virulence of Bacillus anthracis". Infect. Immun. 59 (10): 3472â7. PMC 258908. PMID 1910002.
- Welkos SL, Lowe JR, Eden-McCutchan F, Vodkin M, Leppla SH, Schmidt JJ (September 1988). "Sequence and analysis of the DNA encoding protective antigen of Bacillus anthracis". Gene 69 (2): 287–300. doi:10.1016/0378-1119(88)90439-8. PMID 3148491.
ADP-ribosyltransferase exoenzyme Provide feedback
This is a family of bacterial and viral bi-glutamic acid ADP-ribosyltransferases, where, in Q93Q17 E403 is the catalytic residue and E401 contributes to the transfer of ADP-ribose to the target protein. In clostridial species it is actin that is being ADP-ribosylated; this result is lethal and dermonecrotic in infected mammals.
Tsuge H, Nagahama M, Nishimura H, Hisatsune J, Sakaguchi Y, Itogawa Y, Katunuma N, Sakurai J;, J Mol Biol. 2003;325:471-483.: Crystal structure and site-directed mutagenesis of enzymatic components from Clostridium perfringens iota-toxin. PUBMED:12498797 EPMC:12498797
Internal database links
|Similarity to PfamA using HHSearch:||ART|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR003540
ADP-ribosylation is a posttranslational modification of proteins involving the addition of one or more ADP-ribose moieties [PUBMED:17161604, PUBMED:10712584]. These reactions are involved in cell signaling and the control of many cell processes, including DNA repair and apoptosis [PUBMED:15003268, PUBMED:12727863].
This entry represents an ADP-ribosyltransferase domain found in various proteins, including bacterial and viral toxins.
|Cellular component||extracellular region (GO:0005576)|
|Biological process||pathogenesis (GO:0009405)|
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- the UniProt description of the protein sequence
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The members of this clan all represent ADP-ribosylating catalytic domains. The structurally conserved regions are located at the NAD binding region . According to SCOP, the ADP-ribosylation domain is thought to have an "unusual fold".
The clan contains the following 6 members:ADPrib_exo_Tox ART Diphtheria_C Enterotoxin_a PARP Pertussis_S1
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
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Curation and family details
|Number in seed:||26|
|Number in full:||558|
|Average length of the domain:||184.60 aa|
|Average identity of full alignment:||17 %|
|Average coverage of the sequence by the domain:||40.09 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||9|
|Download:||download the raw HMM for this family|
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There are 2 interactions for this family. More...
For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the ADPrib_exo_Tox domain has been found. There are 74 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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