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2  structures 3  species 0  interactions 3  sequences 1  architecture

Family: Toxin_30 (PF08117)

Summary: Ptu family

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Insect toxins". More...

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This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Ptu family Provide feedback

This family consists of toxic peptides that are isolated from the saliva of assassin bugs. The saliva contains a complex mixture of proteins that are used by the bug either to immobilise the prey or to digest it. One of the proteins (Ptu1) has been purified and shown to block reversibly the N-type calcium channels and to be less specific for the L- and P/Q- type calcium channels expressed in BHK cells [1].

Literature references

  1. Bernard C, Corzo G, Mosbah A, Nakajima T, Darbon H; , Biochemistry 2001;40:12795-12800.: Solution structure of Ptu1, a toxin from the assassin bug Peirates turpis that blocks the voltage-sensitive calcium channel N-type. PUBMED:11669615 EPMC:11669615


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR012325

Assassin bugs (Arthropoda:Insecta:Hemiptera:Reduviidae), sometimes known as conenoses or kissing bugs, are one of the largest and morphologically diverse families of true bugs feeding on crickets, caterpillars and other insects. Some assassin bug species are bloodsucking parasites of mammals, even of human. They can be commonly found throughout most of the world and their size varies from a few millimetres to as much as 3 or 4 centimetres. The toxic saliva of the predatory assassin bugs contains a complex mixture of small and large peptides for diverse uses such as immobilizing and pre-digesting their prey, and defence against competitors and predators. Assassin bug toxins are small peptides with disulphide connectivity that target ion-channels. They are relatively homologous to the calcium channel blockers omega-conotoxins from marine cone snails and belong to the four-loop cysteine scaffold structural class [PUBMED:11423127], [PUBMED:11669615].

One of these small proteins, Ptu1, blocks reversibly the N-type calcium channels, but at the same time is less specific for the L- or P/Q-type calcium channels [PUBMED:11423127]. Ptu1 is 34 amino acid residues long and is cross-linked by three disulphide bridges. Ptu1 contains a beta-sheet region made of two antiparallel beta-strands and consists of a compact disulphide-bonded core from which four loops emerge as well as N- and C-termini [PUBMED:11669615]. Some assassin bug toxins are listed below:

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan Omega_toxin (CL0083), which has the following description:

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 [1].

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

Alignments

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We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Short protein clustering
Previous IDs: none
Type: Family
Author: Lee SC
Number in seed: 2
Number in full: 3
Average length of the domain: 34.70 aa
Average identity of full alignment: 57 %
Average coverage of the sequence by the domain: 99.05 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 24.5 24.5
Trusted cut-off 24.9 79.1
Noise cut-off 24.2 23.5
Model length: 35
Family (HMM) version: 6
Download: download the raw HMM for this family

Species distribution

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Structures

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_30 domain has been found. There are 2 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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