Summary: Bacterial extracellular solute-binding proteins, family 3
The Pfam group coordinates the annotation of Pfam families in Wikipedia, but we have not yet assigned a Wikipedia article to this family. If you think that a particular Wikipedia article provides good annotation, please let us know.
Bacterial extracellular solute-binding proteins, family 3 Provide feedback
No Pfam abstract.
Internal database links
|Similarity to PfamA using HHSearch:||Lig_chan SBP_bac_7 NMT1 Lig_chan-Glu_bd DUF3834 Phosphonate-bd SBP_bac_11 YhfZ_C|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR001638
Bacterial high affinity transport systems are involved in active transport of solutes across the cytoplasmic membrane. The protein components of these traffic systems include one or two transmembrane protein components, one or two membrane-associated ATP-binding proteins (ABC transporters; see INTERPRO) and a high affinity periplasmic solute-binding protein. The latter are thought to bind the substrate in the vicinity of the inner membrane, and to transfer it to a complex of inner membrane proteins for concentration into the cytoplasm.
In Gram-positive bacteria which are surrounded by a single membrane and have therefore no periplasmic region, the equivalent proteins are bound to the membrane via an N-terminal lipid anchor. These homologue proteins do not play an integral role in the transport process per se, but probably serve as receptors to trigger or initiate translocation of the solute throught the membrane by binding to external sites of the integral membrane proteins of the efflux system.
In addition, at least some solute-binding proteins function in the initiation of sensory transduction pathways.
On the basis of sequence similarities, the vast majority of these solute-binding proteins can be grouped [PUBMED:8336670] into eight families or clusters, which generally correlate with the nature of the solute bound.
Family 3 groups together specific amino acids and opine-binding periplasmic proteins and a periplasmic homologue with catalytic activity.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||outer membrane-bounded periplasmic space (GO:0030288)|
|Molecular function||transporter activity (GO:0005215)|
|Biological process||transport (GO:0006810)|
- 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...
Periplasmic binding proteins (PBPs) consist of two large lobes that close around the bound ligand. This architecture is reiterated in transcriptional regulators, such as the lac repressors. In the process of evolution, genes encoding the PBPs have fused with genes for integral membrane proteins. Thus, diverse mammalian receptors contain extracellular ligand binding domains that are homologous to the PBPs; these include glutamate/glycine-gated ion channels such as the NMDA receptor, G protein-coupled receptors, including metabotropic glutamate, GABA-B, calcium sensing, and pheromone receptors, and atrial natriuretic peptide-guanylate cyclase receptors .
The clan contains the following 23 members:DUF3834 HisG Lig_chan-Glu_bd Lipoprotein_8 Lipoprotein_9 LysR_substrate Mycoplasma_p37 NMT1 NMT1_2 OpuAC PBP_like PBP_like_2 Phosphonate-bd SBP_bac_1 SBP_bac_11 SBP_bac_3 SBP_bac_5 SBP_bac_6 SBP_bac_7 SBP_bac_8 TctC Transferrin VitK2_biosynth
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
|Number in seed:||483|
|Number in full:||31454|
|Average length of the domain:||223.60 aa|
|Average identity of full alignment:||19 %|
|Average coverage of the sequence by the domain:||63.80 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null --hand HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||15|
|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 SBP_bac_3 domain has been found. There are 113 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...