Summary: Scorpion calcine family
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Scorpion calcine family Provide feedback
This family consists of the calcine family of scorpion toxins. The calcine family consists of Maurocalcine and Imperatoxin. These toxins have been shown to be potent effector of ryanodyne-sensitive calcium channel from skeletal muscles. These toxins are thus useful for dihydropyridine receptor/ryanodyne receptor interaction studies [1,2].
Mosbah A, Kharrat R, Fajloun Z, Renisio JG, Blanc E, Sabatier JM, El Ayeb M, Darbon H; , Proteins 2000;40:436-442.: A new fold in the scorpion toxin family, associated with an activity on a ryanodine-sensitive calcium channel. PUBMED:10861934 EPMC:10861934
Nabhani T, Zhu X, Simeoni I, Sorrentino V, Valdivia HH, Garcia J; , Biophys J 2002;82:1319-1328.: Imperatoxin a enhances Ca(2+) release in developing skeletal muscle containing ryanodine receptor type 3. PUBMED:11867448 EPMC:11867448
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR012632
Toxins of the scorpion calcine family bind directly to ryanodine receptors (RyRs), intracellular channel targets of the endoplasmic reticulum, and induce long lasting channel openings in a mode of smaller conductance. They have the ability to translocate into cells by crossing the plasma membrane [PUBMED:10075681, PUBMED:10713267, PUBMED:15653689].
Toxins of scorpion calcine family are highly basic 33-amino acid peptides that present three disulphide bridges (C1-C4, C2-C5, and C3-C6) and fold along a knottin or inhibitor cystine knot motif (http://knottin.cbs.cnrs.fr) [PUBMED:10075681, PUBMED:10713267, PUBMED:15653689]. Their three dimensional structure consists of a compact disulphide-bonded core from which emerge loops and the N terminus. The main element of regular secondary structure is a double-stranded antiparallel beta-sheet. A third peripheral extended strand is almost perpendicular to the double-stranded antiparallel beta-sheet [PUBMED:10713267, PUBMED:10861934]. Scorpion calcine mimic the activating segment of the dihydropyridine receptor II-III loop, which interacts with a region of the ryanodine receptor [PUBMED:10075681, PUBMED:10713267, PUBMED:12429019].
This family includes:
- Imperatoxin-A (IpTx A) from Pandinus imperator (Emperor scorpion).
- Opicalcin-1 and -2 from Opistophthalmus carinatus (African yellow leg scorpion).
- Maurocalcin (MCa) from Scorpio maurus palmatus (Chactoid scorpion).
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||extracellular region (GO:0005576)|
|Molecular function||calcium channel inhibitor activity (GO:0019855)|
|Biological process||pathogenesis (GO:0009405)|
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This clan contains a set of related small protein toxins and what appears to be the functionally distinct Albumin I domain. All members of this clan have a knottin-like fold. Additional information about this clan may be found from .
The clan contains the following 19 members:Agouti Albumin_I Conotoxin Mu-conotoxin Omega-toxin Tachystatin_B Toxin_11 Toxin_12 Toxin_16 Toxin_18 Toxin_21 Toxin_22 Toxin_23 Toxin_24 Toxin_27 Toxin_30 Toxin_7 Toxin_9 UPF0506
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Curation and family details
|Seed source:||Short protein clustering|
|Number in seed:||2|
|Number in full:||5|
|Average length of the domain:||33.00 aa|
|Average identity of full alignment:||83 %|
|Average coverage of the sequence by the domain:||60.66 %|
|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:||6|
|Download:||download the raw HMM for this family|
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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 Toxin_27 domain has been found. There are 1 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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