Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
2  structures 1  species 0  interactions 1  sequence 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...

Insect toxins Edit Wikipedia article

Redirect to:

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

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

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:

  • Agriosphodrus dohrni (Assassin bug) toxin Ado1.
  • Isyndus obscurus (Assassin bug) toxin Iob1.
  • Peirates turpis (Assassin bug) toxin Ptu1.

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...

Loading domain graphics...

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 36 members:

ACI44 Agouti Albumin_I Albumin_I_a Antifungal_pept Antimicrobial25 Argos Atracotoxin CART CBM_1 Chi-conotoxin Conotoxin DUF5637 LEAP-2 Mu-conotoxin Omega-toxin Tachystatin_A Tachystatin_B Toxin_11 Toxin_12 Toxin_16 Toxin_18 Toxin_20 Toxin_21 Toxin_22 Toxin_23 Toxin_24 Toxin_27 Toxin_28 Toxin_30 Toxin_35 Toxin_7 Toxin_9 Tryp_inh UPF0506 Viral_cys_rich


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

View options

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.

Representative proteomes UniProt
Jalview View  View  View  View  View  View  View 
HTML View  View           
PP/heatmap 1 View           

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

Representative proteomes UniProt

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

Representative proteomes UniProt
Raw Stockholm Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download  

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

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...


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: Toxin_30; Toxin_30_;
Type: Family
Sequence Ontology: SO:0100021
Author: Lee SC
Number in seed: 2
Number in full: 1
Average length of the domain: 35.00 aa
Average identity of full alignment: 100 %
Average coverage of the sequence by the domain: 57.38 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 24.5 24.5
Trusted cut-off 24.9 52.0
Noise cut-off 24.2 23.5
Model length: 35
Family (HMM) version: 14
Download: download the raw HMM for this family

Species distribution

Sunburst controls


Weight segments by...

Change the size of the sunburst


Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


Align selected sequences to HMM

Generate a FASTA-format file

Clear selection

This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

Loading sunburst data...

Tree controls


The tree shows the occurrence of this domain across different species. More...


Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.


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 sequence.

Loading structure mapping...