Summary: PPE family
PPE family Provide feedback
This family named after a PPE motif near to the amino terminus of the domain. The PPE family of proteins all contain an amino-terminal region of about 180 amino acids. The carboxyl terminus of this family are variable, and on the basis of this region fall into at least three groups. The MPTR subgroup has tandem copies of a motif NXGXGNXG. The second subgroup contains a conserved motif at about position 350. The third group are only related in the amino terminal region. The function of these proteins is uncertain but it has been suggested that they may be related to antigenic variation of Mycobacterium tuberculosis .
Cole ST, Brosch R, Parkhill J, Garnier T, Churcher C, Harris D, Gordon SV, Eiglmeier K, Gas S, Barry CE 3rd, Tekaia F, Badcock K, Basham D, Brown D, Chillingworth T, Connor R, Davies R, Devlin K, Feltwell T, Gentles S, Hamlin N, Holroyd S, Hornsby T, Jage, Nature 1998;393:537-544.: Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence. PUBMED:9634230 EPMC:9634230
Strong M, Sawaya MR, Wang S, Phillips M, Cascio D, Eisenberg D; , Proc Natl Acad Sci U S A. 2006;103:8060-8065.: Toward the structural genomics of complexes: crystal structure of a PE/PPE protein complex from Mycobacterium tuberculosis. PUBMED:16690741 EPMC:16690741
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR000030
The human pathogen Mycobacterium tuberculosis harbours a large number of genes that encode proteins whose N-termini contain the characteristic motifs Pro-Glu (PE) or Pro-Pro-Glu (PPE). A subgroup of the PE proteins contains polymorphic GC-rich sequences (PGRS), while a subgroup of the PPE proteins contains major polymorphic tandem repeats (MPTR). The function of most of these proteins remains unknown [PUBMED:19602151]. However, the PE_PGRS proteins from Mycobacterium marinum are secreted by components of the ESX-5 system that belongs to the recently defined type VII secretion systems [PUBMED:18981138]. It has also been reported that the PE_PGRS family of proteins contains multiple calcium-binding and glycine-rich sequence motifs GGXGXD/NXUX. This sequence repeat constitutes a calcium-binding parallel beta-roll or parallel beta-helix structure and is found in RTX toxins secreted by many Gram-negative bacteria [PUBMED:18267304].This mycobacterial family is named after a conserved amino-terminal region of about 180 amino acids, the PPE motif. The carboxy termini of proteins belonging to the PPE family are variable, and on the basis of this region at least three groups can be distinguished. The MPTR subgroup is characterised by tandem copies of a motif NXGXGNXG. The second subgroup contains a conserved motif at about position 350. The third group shares only similarity in the amino terminal region. The function of these proteins is uncertain but it has been suggested that they may be related to antigenic variation of Mycobacterium tuberculosis [PUBMED:9634230].
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- the UniProt description of the protein sequence
- the number of residues in the sequence
- the Pfam graphic itself.
Loading domain graphics...
The WXG100 protein secretion system (Wss) is responsible for the secretion of WXG100 proteins (PF06013), such as ESAT-10 (6 kDa early secreted antigenic target) and CFP-10 (10 kDa culture filtrate protein) in Mycobacterium tuberculosis or EsxA (ESAT-6-like extracellularly secreted protein A) and EsxB in Staphylococcus aureus. These two proteins, generally encoded in the same gene cluster, form a 1:1 heterodimeric complex. These proteins are virulence factors involved in host-pathogen interaction , as demonstrated in Mycobacterium tuberculosis, Staphylococcus aureus or Bacillus anthracis. The Wss is encoded in many other Gram-positive (monoderm) bacteria. This superfamily contains a number of DUFs which are closely related and may or may not represent the same family of proteins.
The clan contains the following 6 members:DUF2563 DUF2580 LXG PE PPE WXG100
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
- the alignment generated by searching the sequence database using the HMM
- Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
- alignment generated by searching the NCBI sequence database using the family HMM
- alignment generated by searching the metagenomics sequence database using the family HMM
You can see the alignments as HTML or in three different sequence viewers:
- Pfam viewer
- an HTML-based viewer that uses DAS to retrieve alignment fragments on request
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
Format an alignment
If you find these logos useful in your own work, please consider citing the following article:
Note: You can also download the data file for the tree.
Curation and family details
|Seed source:||Pfam-B_297 (release 3.0)|
|Number in seed:||146|
|Number in full:||3533|
|Average length of the domain:||151.60 aa|
|Average identity of full alignment:||45 %|
|Average coverage of the sequence by the domain:||28.01 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||14|
|Download:||download the raw HMM for this family|
Weight segments by...
Change the size of the sunburst
selected sequences to HMM
a FASTA-format file
- 0 sequences
- 0 species
How the sunburst is generated
Colouring and labels
Anomalies in the taxonomy tree
Missing taxonomic levels
Unmapped species names
Too many species/sequences
The tree shows the occurrence of this domain across different species. More...
You can use the tree controls to manipulate how the interactive tree is displayed:
- show/hide the summary boxes
- highlight species that are represented in the seed alignment
- expand/collapse the tree or expand it to a given depth
- select a sub-tree or a set of species within the tree and view them graphically or as an alignment
- save a plain text representation of the tree
There is 1 interaction for this family. More...
We determine these interactions using iPfam, which considers the interactions between residues in three-dimensional protein structures and maps those interactions back to Pfam families. You can find more information about the iPfam algorithm in the journal article that accompanies the website.
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 PPE 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.
Loading structure mapping...