Powering down the Pfam website
On October 5th, we began redirecting traffic from Pfam (pfam.xfam.org) to InterPro (www.ebi.ac.uk/interpro). The Pfam website will remain available at pfam-legacy.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.
1087  structures 5340  species 0  interactions 542927  sequences 15591  architectures

Family: Ank_2 (PF12796)

Summary: Ankyrin repeats (3 copies)

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 "Ankyrin repeat". More...

Ankyrin repeat 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.

Ankyrin repeats (3 copies) Provide feedback

No Pfam abstract.

Internal database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR020683

This entry represents the ankyrin repeat-containing domain. These domains contain multiple repeats of a beta(2)-alpha(2) motif. The ankyrin repeat is one of the most common protein-protein interaction motifs in nature. Ankyrin repeats are tandemly repeated modules of about 33 amino acids. They occur in a large number of functionally diverse proteins mainly from eukaryotes. The few known examples from prokaryotes and viruses may be the result of horizontal gene transfers [ PUBMED:8108379 ]. The repeat has been found in proteins of diverse function such as transcriptional initiators, cell-cycle regulators, cytoskeletal, ion transporters and signal transducers. The ankyrin fold appears to be defined by its structure rather than its function since there is no specific sequence or structure which is universally recognised by it.

The conserved fold of the ankyrin repeat unit is known from several crystal and solution structures [ PUBMED:8875926 , PUBMED:9353127 , PUBMED:9461436 , PUBMED:9865693 ]. Each repeat folds into a helix-loop-helix structure with a beta-hairpin/loop region projecting out from the helices at a 90 o angle. The repeats stack together to form an L-shaped structure [ PUBMED:8875926 , PUBMED:12461176 ].

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 Ank (CL0465), which has the following description:

The ankyrin repeat is a short sequence region that is about 30-34 amino-acids in length. Multiple copies of the repeat composed of two beta strands and two alpha helices combine to form long arrays. In general these repeats are involved in protein-protein interactions. This superfamily also includes some families that are arrays of several repeats.

The clan contains the following 8 members:

Ank Ank_2 Ank_3 Ank_4 Ank_5 AnkUBD DUF3420 DUF3447


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             
PP/heatmap 1            

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        
Gzipped 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: Jackhmmer:Q183I8_CLOD6
Previous IDs: none
Type: Repeat
Sequence Ontology: SO:0001068
Author: Bateman A
Number in seed: 184
Number in full: 542927
Average length of the domain: 86.4 aa
Average identity of full alignment: 24 %
Average coverage of the sequence by the domain: 29.24 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild --amino -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 27.3 27.3
Trusted cut-off 27.3 27.3
Noise cut-off 27.2 27.2
Model length: 83
Family (HMM) version: 10
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


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 Ank_2 domain has been found. There are 1087 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...

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
A0A044QQ57 View 3D Structure Click here
A0A044QX08 View 3D Structure Click here
A0A044QZU4 View 3D Structure Click here
A0A044R6C0 View 3D Structure Click here
A0A044R8S5 View 3D Structure Click here
A0A044RAS7 View 3D Structure Click here
A0A044RCW9 View 3D Structure Click here
A0A044RD22 View 3D Structure Click here
A0A044RGU8 View 3D Structure Click here
A0A044RME6 View 3D Structure Click here
A0A044RW64 View 3D Structure Click here
A0A044RZE7 View 3D Structure Click here
A0A044S0A6 View 3D Structure Click here
A0A044S346 View 3D Structure Click here
A0A044S3J6 View 3D Structure Click here
A0A044S3W2 View 3D Structure Click here
A0A044S4N9 View 3D Structure Click here
A0A044S708 View 3D Structure Click here
A0A044SLY9 View 3D Structure Click here
A0A044SQ63 View 3D Structure Click here
A0A044SUL1 View 3D Structure Click here
A0A044SV50 View 3D Structure Click here
A0A044SXK6 View 3D Structure Click here
A0A044SXL3 View 3D Structure Click here
A0A044T0J9 View 3D Structure Click here
A0A044T6G0 View 3D Structure Click here
A0A044T7Q9 View 3D Structure Click here
A0A044T811 View 3D Structure Click here
A0A044T9C1 View 3D Structure Click here
A0A044TEL5 View 3D Structure Click here
A0A044TF70 View 3D Structure Click here
A0A044THC9 View 3D Structure Click here
A0A044TLP9 View 3D Structure Click here
A0A044TMZ2 View 3D Structure Click here
A0A044TNJ5 View 3D Structure Click here
A0A044TV22 View 3D Structure Click here
A0A044U730 View 3D Structure Click here
A0A044UCH5 View 3D Structure Click here
A0A044UCX7 View 3D Structure Click here
A0A044UL68 View 3D Structure Click here