Powering down the Pfam website
On October 5th, we will start redirecting the traffic from Pfam (pfam.xfam.org) to InterPro (www.ebi.ac.uk/interpro). The Pfam website will be available at legacy.pfam.xfam.org until January 2023, when it will be decommissioned. You can read more about the sunset period in our blog post.

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.
0  structures 214  species 0  interactions 308  sequences 1  architecture

Family: Phage_TAC_12 (PF12363)

Summary: Phage tail assembly chaperone protein, TAC

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

The Pfam group coordinates the annotation of Pfam families in Wikipedia, but we have not yet assigned a Wikipedia article to this family. If you think that a particular Wikipedia article provides good annotation, please let us know.

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.

Phage tail assembly chaperone protein, TAC Provide feedback

This is a family of phage tail assembly chaperone proteins from Siphoviridae phages.

Literature references

  1. Pell LG, Cumby N, Clark TE, Tuite A, Battaile KP, Edwards AM, Chirgadze NY, Davidson AR, Maxwell KL;, J Mol Biol. 2013;425:2436-2449.: A conserved spiral structure for highly diverged phage tail assembly chaperones. PUBMED:23542344 EPMC:23542344

This tab holds annotation information from the InterPro database.

InterPro entry IPR024410

This is a family of phage tail assembly chaperone proteins from Siphoviridae phages. TACs are required for the morphogenesis of all long-tailed phages. The proposed function for the TAC is to coat the tape-measure protein to prevent it from forming unproductive complexes or precipitating before the tail tube protein has been incorporated [ PUBMED:23542344 ].

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 Phage_TACs (CL0567), which has the following description:

This superfamily is characterised by only distantly related families of tail assembly chaperones or TACs. Most bacteriophages possess a long tail that is either contractile as in the Siphoviridae family or contractile as in the Myoviridae family. TACs are required for the morphogenesis of all long-tailed phages. All the studied TACs form spiral quaternary rings that have arisen through diverging sequences and oligomerisation mechanisms. The proposed function in all cases, however, is for the TAC to coat the tape-measure protein to prevent it from forming unproductive complexes or precipitating before the tail tube protein has been incorporated [1,2].

The clan contains the following 14 members:

Phage_TAC_1 Phage_TAC_10 Phage_TAC_11 Phage_TAC_12 Phage_TAC_13 Phage_TAC_14 Phage_TAC_2 Phage_TAC_3 Phage_TAC_4 Phage_TAC_5 Phage_TAC_6 Phage_TAC_7 Phage_TAC_8 Phage_TAC_9


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: Prosite
Previous IDs: DUF3647;
Type: Family
Sequence Ontology: SO:0100021
Author: Gavin OL
Number in seed: 14
Number in full: 308
Average length of the domain: 110.4 aa
Average identity of full alignment: 24 %
Average coverage of the sequence by the domain: 81.8 %

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 26.2 26.2
Trusted cut-off 26.3 26.5
Noise cut-off 26.1 26.1
Model length: 111
Family (HMM) version: 11
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.

AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
Q2FX63 View 3D Structure Click here

trRosetta Structure

The structural model below was generated by the Baker group with the trRosetta software using the Pfam UniProt multiple sequence alignment.

The InterPro website shows the contact map for the Pfam SEED alignment. Hovering or clicking on a contact position will highlight its connection to other residues in the alignment, as well as on the 3D structure.

Improved protein structure prediction using predicted inter-residue orientations. Jianyi Yang, Ivan Anishchenko, Hahnbeom Park, Zhenling Peng, Sergey Ovchinnikov, David Baker Proceedings of the National Academy of Sciences Jan 2020, 117 (3) 1496-1503; DOI: 10.1073/pnas.1914677117;