Summary: Outer membrane usher protein
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This is the Wikipedia entry entitled "Fimbrial usher protein". More...
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Fimbrial usher protein Edit Wikipedia article
|Fimbrial Usher protein|
Structure of the type 1 pilus assembly platform FimD(25-139).
The fimbrial usher protein is involved in biogenesis of the pilus in Gram-negative bacteria. The biogenesis of fimbriae (or pili) requires a two-component assembly and transport system which is composed of a periplasmic chaperone and an outer membrane protein which has been termed a molecular 'usher'.
The usher protein has a molecular weight ranging from 86 to 100 kDa and is composed of a membrane-spanning 24-stranded beta barrel domain, reminiscent of porins, and of four periplasmic soluble domains: an N-terminal one of about 120 residues (NTD), a 'middle' domain of about 80 residues located as a soluble insertion within the beta barrel region of the sequence (plug domain) and two IG-like domains (each about 80 residues long) at the C-terminus (CTD1 and CTD2). Although the degree of sequence similarity of these proteins is not very high they share a number of characteristics. One of these is the presence of two pairs of disulfide bond-forming cysteines, the first one located in the NTD and the second in CTD2. The best conserved region of the sequence corresponds to the plug domain.
- Nishiyama M, Horst R, Eidam O, et al. (June 2005). "Structural basis of chaperoneâ€“subunit complex recognition by the type 1 pilus assembly platform FimD". EMBO J. 24 (12): 2075â€“86. doi:10.1038/sj.emboj.7600693. PMC 1150887. PMID 15920478.
- Hultgren SJ, Jacob-Dubuisson F, Striker R (1994). "Chaperone-assisted self-assembly of pili independent of cellular energy". J. Biol. Chem. 269 (17): 12447â€“12455. PMID 7909802.
- Schifferli DM, Alrutz MA (1994). "Permissive linker insertion sites in the outer membrane protein of 987P fimbriae of Escherichia coli". J. Bacteriol. 176 (4): 1099â€“1110. PMC 205162. PMID 7906265.
- Saier Jr MH, Van Rosmalen M (1993). "Structural and evolutionary relationships between two families of bacterial extracytoplasmic chaperone proteins which function cooperatively in fimbrial assembly". Res. Microbiol. 144 (7): 507â€“527. doi:10.1016/0923-2508(93)90001-I. PMID 7906046.
- Capitani G, Eidam O, GrÃ¼tter MG (2006). "Evidence for a novel domain of bacterial outer membrane ushers". Proteins. 65 (4): 816â€“23. doi:10.1002/prot.21147. PMID 17066380.
- Phan G, Remaut H, Wang T, Allen WJ, Pirker KF, Lebedev A, et al. (2011). "Crystal structure of the FimD usher bound to its cognate FimC-FimH substrate". Nature. 474 (7349): 49â€“53. doi:10.1038/nature10109. PMC 3162478. PMID 21637253.
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Outer membrane usher protein Provide feedback
In Gram-negative bacteria the biogenesis of fimbriae (or pili) requires a two- component assembly and transport system which is composed of a periplasmic chaperone and an outer membrane protein which has been termed a molecular 'usher' [1-3]. The usher protein is rather large (from 86 to 100 Kd) and seems to be mainly composed of membrane-spanning beta-sheets, a structure reminiscent of porins. Although the degree of sequence similarity of these proteins is not very high they share a number of characteristics. One of these is the presence of two pairs of cysteines, the first one located in the N-terminal part and the second at the C-terminal extremity that are probably involved in disulphide bonds. The best conserved region is located in the central part of these proteins [4-5].
Van Rosmalen M, Saier MH Jr;, Res Microbiol. 1993;144:507-527.: Structural and evolutionary relationships between two families of bacterial extracytoplasmic chaperone proteins which function cooperatively in fimbrial assembly. PUBMED:7906046 EPMC:7906046
Huang Y, Smith BS, Chen LX, Baxter RH, Deisenhofer J;, Proc Natl Acad Sci U S A. 2009;106:7403-7407.: Insights into pilus assembly and secretion from the structure and functional characterization of usher PapC. PUBMED:19380723 EPMC:19380723
Remaut H, Tang C, Henderson NS, Pinkner JS, Wang T, Hultgren SJ, Thanassi DG, Waksman G, Li H;, Cell. 2008;133:640-652.: Fiber formation across the bacterial outer membrane by the chaperone/usher pathway. PUBMED:18485872 EPMC:18485872
Internal database links
|Similarity to PfamA using HHSearch:||Usher_TcfC|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR000015
In Gram-negative bacteria the biogenesis of fimbriae (or pili) requires a two- component assembly and transport system which is composed of a periplasmic chaperone and an outer membrane protein which has been termed a molecular 'usher' [ PUBMED:7909802 , PUBMED:7906265 , PUBMED:7906046 ].
The usher protein is rather large (from 86 to 100kDa) and seems to be mainly composed of membrane-spanning beta-sheets, a structure reminiscent of porins. Although the degree of sequence similarity of these proteins is not very high, they share a number of characteristics. One of these is the presence of two pairs of cysteines, the first one located in the N-terminal part and the second at the C-terminal extremity that are probably involved in disulphide bonds. The best conserved region is located in the central part of these proteins [ PUBMED:19380723 , PUBMED:18485872 ].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||membrane (GO:0016020)|
|Molecular function||fimbrial usher porin activity (GO:0015473)|
|Biological process||pilus assembly (GO:0009297)|
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
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This clan gathers together a large set of beta barrel membrane proteins.Although these proteins have different numbers of beta strands in the barrel they have significant sequence similarity between families.
The clan contains the following 117 members:Ail_Lom Alginate_exp Attacin_C Attacin_N Autotransporter BBP2 BBP2_2 BBP7 BCSC_C Campylo_MOMP Caps_assemb_Wzi CBP_BcsS Channel_Tsx Chlam_OMP CopB CymA DcaP DUF1207 DUF1302 DUF1842 DUF2219 DUF2490 DUF2715 DUF2860 DUF3034 DUF3078 DUF3138 DUF3187 DUF3373 DUF3570 DUF3573 DUF3575 DUF3769 DUF3996 DUF4421 DUF4595 DUF481 DUF4840 DUF5020 DUF5686 DUF5723 DUF5777 DUF5916 DUF6048 DUF6089 DUF6268 Gcw_chp GrlR HP_OMP HP_OMP_2 HpuA IAT_beta KdgM LamB Legionella_OMP Lipoprot_C LptD LptD_2 MDM10 MipA MOSP_C MSP MtrB_PioB NfrA_C Omp85 Omp85_2 Omp_AT OMP_b-brl OMP_b-brl_2 OMP_b-brl_3 OmpA_like OmpA_membrane Omptin OmpW Opacity OpcA OprB OprD OprF PagL PagP Phenol_MetA_deg PLA1 Pom Porin_1 Porin_10 Porin_2 Porin_3 Porin_4 Porin_5 Porin_6 Porin_7 Porin_8 Porin_O_P Porin_OmpG Porin_OmpG_1_2 Porin_OmpL1 PorP_SprF PorV Serpulina_VSP ShlB SlipAM Surface_Ag_2 TbpB_B_D Toluene_X TonB_dep_Rec TraF_2 TraO TSA UPF0164 UPF0257 Usher Usher_TcfC YadA_anchor YaiO YfaZ YjbH
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.
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
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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
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.
|Seed source:||MRC-LMB Genome group and Prosite|
|Author:||Bateman A , Desvaux M , Eberhardt R|
|Number in seed:||17|
|Number in full:||1867|
|Average length of the domain:||449.50 aa|
|Average identity of full alignment:||22 %|
|Average coverage of the sequence by the domain:||63.97 %|
|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:||23|
|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 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.
In order to reduce the complexity of the representation, we reduce the number of taxonomic levels that we show. We consider only the following eight major taxonomic levels:
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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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Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.
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.
So that these nodes are not simply omitted from the sunburst tree, we group them together in a separate branch (or segment of the sunburst tree). Since we cannot determine the lineage for these unmapped species, we show all levels between the superkingdom and the species as "uncategorised".
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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For large species trees, you may see blank regions in the outer layers of the sunburst. These occur when there are large numbers of arcs to be drawn in a small space. If an arc is less than approximately one pixel wide, it will not be drawn and the space will be left blank. You may still be able to get some information about the species in that region by moving your mouse across the area, but since each arc will be very small, it will be difficult to accurately locate a particular species.
The tree shows the occurrence of this domain across different species. More...
We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.
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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.
We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.
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 Usher domain has been found. There are 15 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.