Summary: Type VI secretion system/phage-baseplate injector OB domain
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Type VI secretion system/phage-baseplate injector OB domain Provide feedback
Family of bacterial and phage baseplate assembly proteins responsible for forming the small spike at the end of the tail or bacterial pathogenic needle-shaft . This entry represents the OB fold part of the structure. This structure contains an unusual extra beta hairpin that forms the foundation of the spike protein's beta helix .
Haggard-Ljungquist E, Jacobsen E, Rishovd S, Six EW, Nilssen O, Sunshine MG, Lindqvist BH, Kim KJ, Barreiro V, Koonin EV, et al.; , Virology 1995;213:109-121.: Bacteriophage P2: genes involved in baseplate assembly. PUBMED:7483254 EPMC:7483254
Internal database links
|Similarity to PfamA using HHSearch:||Phage_Mu_Gp45 DUF6484|
This tab holds annotation information from the InterPro database.
InterPro entry IPR006531
This domain occurs in a family of phage (and bacteriocin) proteins related to the phage P2 V gene product, which forms the small spike at the tip of the tail [ PUBMED:7483254 ]. Homologs in general are annotated as baseplate assembly protein V. At least one member is encoded within a region of Pectobacterium carotovorum (Erwinia carotovora) described as a bacteriocin, a phage tail-derived module able to kill bacteria closely related to the host strain.
It is also found in Vgr-related proteins. Genes encoding type VI secretion systems (T6SS) are widely distributed in pathogenic Gram-negative bacterial species. In Vibrio cholerae, T6SS have been found to secrete three related proteins extracellularly, VgrG-1, VgrG-2, and VgrG-3. VgrG-1 can covalently cross-link actin in vitro, and this activity was used to demonstrate that V. cholerae can translocate VgrG-1 into macrophages by a T6SS-dependent mechanism. VgrG-related proteins likely assemble into a trimeric complex that is analogous to that formed by the two trimeric proteins gp27 and gp5 that make up the baseplate "tail spike" of Escherichia coli bacteriophage T4. The VgrG components of the T6SS apparatus might assemble a "cell-puncturing device" analogous to phage tail spikes to deliver effector protein domains through membranes of target host cells [ PUBMED:17873062 ].
Gp5 is an integral component of the virion baseplate of bacteriophage T4. T4 Gp5 consists of 3 domains connected via long linkers: the N-terminal oligosaccharide/oligonucleotide-binding (OB)-fold domain, the middle lysozyme domain, and the C-terminal triplestranded-helix. The equivalent of the Gp5 OB-fold domain in the structure of VgrG is the domain of unknown function comprising residues 380-470 and conserved in all known VgrGs. This entry represents the OB-fold domain which consists of a 5-stranded antiparallel-barrel with a Greek-key topology [ PUBMED:19251641 ].
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
The graphic that is shown by default represents the longest sequence with a given architecture. Each row contains the following information:
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The OB (oligonucleotide/oligosaccharide binding) was defined by Murzin . The common part of the OB-fold, has a five-stranded beta-sheet coiled to form a closed beta-barrel. This barrel is capped by an alpha-helix located between the third and fourth strands .
The clan contains the following 113 members:BOF BRCA-2_OB1 BRCA-2_OB3 CcmE CDC13_N Cdc13_OB2 CDC24_OB1 CDC24_OB2 CDC24_OB3 CSD CSD2 CusF_Ec CysA_C_terminal DNA_ligase_A_C DNA_ligase_C DNA_ligase_OB DNA_ligase_OB_2 DNA_pol_D_N DUF1344 DUF1449 DUF2110 DUF223 DUF2815 DUF3127 DUF3217 DUF3299 DUF5666 DUF6484 DUF961 EFP eIF-1a eIF-5a Elong-fact-P_C EutN_CcmL EXOSC1 FbpC_C_terminal Fimbrial_PilY2 GlcV_C_terminal Gp138_N gp32 Gp5_OB HIN HROB ID MCM_OB mRNA_cap_C MRP-S35 NfeD NigD_N NlpE_C OB_aCoA_assoc OB_Dis3 OB_MalK OB_NTP_bind OB_RNB PCB_OB Phage_base_V Phage_DNA_bind Phage_SSB Pol_alpha_B_N POT1 POT1PC Prot_ATP_ID_OB Prot_ATP_OB_N RecG_wedge RecJ_OB RecO_N RecO_N_2 Rep-A_N Rep_fac-A_3 Rep_fac-A_C REPA_OB_2 Rho_RNA_bind Ribosom_S12_S23 Ribosomal_L2 Ribosomal_S17 Ribosomal_S28e Ribosomal_S4e RMI1_C RMI1_N RMI2 RNA_pol_Rbc25 RNA_pol_Rpb8 RNA_pol_RpbG RNase_II_C_S1 RPA43_OB Rrp44_CSD1 Rrp44_S1 RsgA_N RuvA_N S1 S1-like S1_2 SfsA_N SSB ssDBP Stn1 TEBP_beta Ten1 Ten1_2 TLP1_add_C TOBE TOBE_2 TOBE_3 TPP1 TRAM TRAM_2 tRNA_anti-codon tRNA_anti-like tRNA_anti_2 tRNA_bind TTC5_OB WCOB
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...
There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.
We make a range of alignments for each Pfam-A family:
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You can see the alignments as HTML or in three different sequence viewers:
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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.
Format an alignment
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.
You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.
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...
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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.
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.
|Seed source:||Pfam-B_5996 (release 7.5)|
|Author:||Waterfield DI , Finn RD , Bateman A|
|Number in seed:||57|
|Number in full:||5355|
|Average length of the domain:||74.70 aa|
|Average identity of full alignment:||30 %|
|Average coverage of the sequence by the domain:||12.72 %|
|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:||15|
|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:
Colouring and labels
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.
As you move your mouse across the sunburst, the current node will be highlighted. In the top section of the controls panel we show a summary of the lineage of the currently highlighed node. If you pause over an arc, a tooltip will be shown, giving the name of the taxonomic level in the title and a summary of the number of sequences and species below that node in the tree.
Anomalies in the taxonomy tree
There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.
Missing taxonomic levels
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.
Too many species/sequences
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.
Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.
If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.
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 Phage_base_V domain has been found. There are 38 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.