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8  structures 1233  species 0  interactions 1471  sequences 15  architectures

Family: LonB_AAA-LID (PF20436)

Summary: Archaeal LonB, AAA+ ATPase LID domain

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 "AAA proteins". More...

AAA proteins Edit Wikipedia article

AAA or AAA+ is an abbreviation for ATPases Associated with various cellular Activities. It is a protein superfamily in which the member proteins share a highly conserved module of approximately 230 amino acid residues.

The characteristic of AAA proteins is the coupling of chemical energy, provided by Adenosine triphosphate hydrolysis, to mechanical force exerted on some macromolecular substrate. This usually requires a conformational change in the AAA protein in question.

Members of the AAA family are found in all organisms and they are essential for many cellular functions.

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.

Archaeal LonB, AAA+ ATPase LID domain Provide feedback

The species-specific Lon-insertion domain (LID) is characteristic of Lon proteases (also known as endopeptidase La) and is fused to the AAA+ module [1]. Bacterial and eukaryotic Lons (LonA) have a LID at the N-terminal of AAA+ module; in archaeal Lons (LonB) the LID, represented in this entry, is inserted within the AAA+ module in a series of transmembrane segments known as the membrane-anchoring region (MA). In the Lon-like protease LonC, which does not have ATPase activity, the LID is also within the AAA-like module similar to LonBs; in this case, it is predicted to contain coiled-coil regions rather than transmembrane segments [1].

Literature references

  1. Liao JH, Ihara K, Kuo CI, Huang KF, Wakatsuki S, Wu SH, Chang CI;, Acta Crystallogr D Biol Crystallogr. 2013;69:1395-1402.: Structures of an ATP-independent Lon-like protease and its complexes with covalent inhibitors. PUBMED:23897463 EPMC:23897463

Internal database links

This tab holds annotation information from the InterPro database.

No InterPro data for this Pfam family.

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 AAA_lid (CL0671), which has the following description:

Many AAA+ proteins have a C-terminal alpha-helical bundle in addition to the AAA core [1]. The functional roles of the helical bundle are varied and include the formation of a lid over the nucleotide binding site and mediation of subunit interactions in oligomeric protein complexes [1].

The clan contains the following 23 members:

AAA_assoc_2 AAA_lid_1 AAA_lid_10 AAA_lid_11 AAA_lid_2 AAA_lid_3 AAA_lid_4 AAA_lid_5 AAA_lid_6 AAA_lid_7 AAA_lid_8 AAA_lid_9 CbbQ_C ClpB_D2-small Dpoe2NT LonB_AAA-LID MCM_lid Mg_chelatase_C ORC4_C PCP_red TIP49_C UVR Vps4_C


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...

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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.

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

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Representative proteomes UniProt

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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.

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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

This family is new in this Pfam release.

Seed source: Jackhmmer:C6QHL0
Previous IDs: none
Type: Domain
Sequence Ontology: SO:0000417
Author: Chuguransky S
Number in seed: 176
Number in full: 1471
Average length of the domain: 64.6 aa
Average identity of full alignment: 30 %
Average coverage of the sequence by the domain: 8.37 %

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 22.4 22.4
Trusted cut-off 22.4 22.4
Noise cut-off 22.3 22.3
Model length: 65
Family (HMM) version: 1
Download: download the raw HMM for this family

Species distribution

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Colour assignments

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


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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...

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


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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 LonB_AAA-LID domain has been found. There are 8 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.

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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
O26878 View 3D Structure Click here
O29883 View 3D Structure Click here
Q8NKS6 View 3D Structure Click here
Q9HJ89 View 3D Structure Click here
Q9HSC3 View 3D Structure Click here
Q9HVK8 View 3D Structure Click here