Summary: Type II secretion system (T2SS), protein I
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Type II secretion system (T2SS), protein I Provide feedback
The Type II secretion system, also called Secretion-dependent pathway (SDP), is responsible for the transport of proteins across the outer membrane first exported to the periplasm by the Sec or Tat translocon in Gram-negative (diderm) bacteria. As members of the T2SJ family, members of the T2SI family are pseudopilins containing prepilin signal sequences .
Howard SP, Critch J, Bedi A; , J Bacteriol 1993;175:6695-6703.: Isolation and analysis of eight exe genes and their involvement in extracellular protein secretion and outer membrane assembly in Aeromonas hydrophila. PUBMED:8407845 EPMC:8407845
Desvaux M, Parham NJ, Scott-Tucker A, Henderson IR;, Trends Microbiol. 2004;12:306-309.: The general secretory pathway: a general misnomer?. PUBMED:15223057 EPMC:15223057
Peabody CR, Chung YJ, Yen MR, Vidal-Ingigliardi D, Pugsley AP, Saier MH Jr;, Microbiology. 2003;149:3051-3072.: Type II protein secretion and its relationship to bacterial type IV pili and archaeal flagella. PUBMED:14600218 EPMC:14600218
Desvaux M, Hebraud M, Talon R, Henderson IR;, Trends Microbiol. 2009;17:139-145.: Secretion and subcellular localizations of bacterial proteins: a semantic awareness issue. PUBMED:19299134 EPMC:19299134
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR003413
This entry represent the C-terminal domain of GspI, which is a pseudopilin component of the type II secretion system (T2SS). It contains the prepilin signal sequences [ PUBMED:8407845 ]. In Pseudomonas aeruginosa GspI homologue, known as XcpV, has been suggested to be the central component and initiator of pseudopilus formation [ PUBMED:19828448 ].
The type II secretion system (T2SS) is one of several extracellular secretion systems in gram-negative bacteria. It delivers toxins and a range of hydrolytic enzymes including proteases, lipases and carbohydrate-active enzymes to the cell surface or extracellular space [ PUBMED:30767847 ]. T2SS systems are composed of 11 to 15 different proteins, which are generally called GspA to GspO and GspS. The T2SS spans the two bacterial membranes and ensures secretion of folded proteins across the outer membrane pore formed by GspD. The inner membrane complex contains GspC, GspL, GspM, and GspF. The cytoplasmic domains of GspL and GspF interact with an ATPase, GspE. GspE is thought to energize the formation of a short pseudopilus by several pilin-like proteins, GspG to GspK [ PUBMED:22523076 ]. GspD has been shown to interact with the inner membrane component GspC [ PUBMED:19217396 ].
The T2SS pseudopilus is a periplasmic filament composed of the major pseudopilin, EpsG, and four minor pseudopilins, EpsH, EpsI, EpsJ and EpsK. Pseudopilus is assembled by the polymerization of GspG (also known as PulG) subunits. Pseudopilin proteins have a conserved N-terminal hydrophobic segment followed by a more variable C-terminal periplasmic and globular domain [ PUBMED:28258547 ].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||type II protein secretion system complex (GO:0015627)|
|Biological process||protein secretion by the type II secretion system (GO:0015628)|
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
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This family is a member of clan Pilus (CL0327), which has the following description:
This clan contains bacterial and archaeal systems involved in flagellar or twitching motility, adhesion, protein secretion, and DNA uptake, such as type II secretion system (T2SS), the type IV pilus or the competence pilus (Com) . Pili proteins enable the transfer of plasmid between bacteria. The families in this clan adopt an alpha helical structure which is packed against a beta sheet [2-3].
The clan contains the following 15 members:Arch_flagellin Bundlin ComP_DUS GspH PilA4 Pilin Pilin_GH Pilin_PilX PilJ_C PilM PilS T2SSG T2SSI T2SSJ TcpA
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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1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
Format an alignment
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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.
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Curation and family details
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|Seed source:||Pfam-B_2607 (release 5.4)|
|Previous IDs:||GSPII_IJ; T2SI;|
|Author:||Mian N , Bateman A , Desvaux M|
|Number in seed:||97|
|Number in full:||1194|
|Average length of the domain:||79.4 aa|
|Average identity of full alignment:||24 %|
|Average coverage of the sequence by the domain:||61.15 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||20|
|Download:||download the raw HMM for this family|
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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...
This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.
How the sunburst is generated
The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, its distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.
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Segments of the tree are coloured approximately according to their superkingdom. For example, archeal branches are coloured with shades of orange, eukaryotes in shades of purple, etc. The colour assignments are shown under the sunburst controls. Where space allows, the name of the taxonomic level will be written on the arc itself.
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Unmapped species names
The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.
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Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.
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The tree shows the occurrence of this domain across different species. More...
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For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.
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Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.
We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.
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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 T2SSI domain has been found. There are 17 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|
|A0A0H3GIF6||View 3D Structure||Click here|
|P45760||View 3D Structure||Click here|
|P45775||View 3D Structure||Click here|
|Q00516||View 3D Structure||Click here|
|Q32C41||View 3D Structure||Click here|
|Q9I5P5||View 3D Structure||Click here|