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6  structures 3717  species 0  interactions 13052  sequences 51  architectures

Family: SSF (PF00474)

Summary: Sodium:solute symporter family

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This is the Wikipedia entry entitled "Sodium-solute symporter". More...

Sodium-solute symporter Edit Wikipedia article

Sodium:solute symporter family
PDB 3dh4 EBI.png
Structure of Sodium/Sugar symporter with bound Galactose from vibrio parahaemolyticus.[1]
Identifiers
Symbol SSF
Pfam PF00474
InterPro IPR001734
PROSITE PDOC00429
TCDB 2.A.21
OPM superfamily 67
OPM protein 3dh4

Sodium/substrate symport (or co-transport) is a widespread mechanism of solute transport across cytoplasmic membranes of pro- and eukaryotic cells. Thereby the energy stored in an inwardly directed electrochemical sodium gradient (sodium motive force, SMF) is used to drive solute accumulation against a concentration gradient. The SMF is generated by primary sodium pumps (e.g. sodium/potassium ATPases, sodium translocating respiratory chain complexes) or via the action of sodium/proton antiporters. Sodium/substrate transporters are grouped in different families based on sequence similarities.[2][3]

One of these families, known as the sodium:solute symporter family (SSSF), contains over a hundred members of pro- and eukaryotic origin.[4] The average hydropathy plot for SSSF proteins predicts 11 to 15 putative transmembrane domains (TMs) in alpha-helical conformation. A secondary structure model of PutP from Escherichia coli suggests the protein contains 13 TMs with the N-terminus located on the periplasmic side of the membrane and the C-terminus facing the cytoplasm. The results support the idea of a common topological motif for members of the SSSF. Transporters with a C-terminal extension are proposed to have an additional 14th TM.

An ordered binding model of sodium/substrate transport suggests that sodium binds to the empty transporter first, thereby inducing a conformational alteration which increases the affinity of the transporter for the solute. The formation of the ternary complex induces another structural change that exposes sodium and substrate to the other site of the membrane. Substrate and sodium are released and the empty transporter re-orientates in the membrane allowing the cycle to start again.

Subfamilies[edit]

Human proteins containing this domain[edit]

AIT; SLC5A1; SLC5A10; SLC5A11; SLC5A12; SLC5A2; SLC5A3; SLC5A4; SLC5A5; SLC5A6; SLC5A7; SLC5A8; SLC5A9;

References[edit]

  1. ^ Faham S, Watanabe A, Besserer GM, et al. (August 2008). "The crystal structure of a sodium galactose transporter reveals mechanistic insights into Na+/sugar symport". Science 321 (5890): 810–4. doi:10.1126/science.1160406. PMID 18599740. 
  2. ^ Reizer J, Reizer A, Saier Jr MH (1990). "The Na+/pantothenate symporter (PanF) of Escherichia coli is homologous to the Na+/proline symporter (PutP) of E. coli and the Na+/glucose symporters of mammals". Res. Microbiol. 141 (9): 1069–1072. doi:10.1016/0923-2508(90)90080-A. PMID 1965458. 
  3. ^ Reizer J, Reizer A, Saier Jr MH (1994). "A functional superfamily of sodium/solute symporters". Biochim. Biophys. Acta 1197 (2): 133–136. doi:10.1016/0304-4157(94)90003-5. PMID 8031825. 
  4. ^ Jung H (2002). "The sodium/substrate symporter family: structural and functional features". FEBS Lett. 529 (1): 73–77. doi:10.1016/S0014-5793(02)03184-8. PMID 12354616. 

This article incorporates text from the public domain Pfam and InterPro IPR001734

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Sodium:solute symporter family Provide feedback

This family includes P33413 which is not in the Prosite entry. Membership of this family is supported by a significant blast score.

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001734

Sodium/substrate symport (or co-transport) is a widespread mechanism of solute transport across cytoplasmic membranes of pro- and eukaryotic cells. Thereby the energy stored in an inwardly directed electrochemical sodium gradient (sodium motive force, SMF) is used to drive solute accumulation against a concentration gradient. The SMF is generated by primary sodium pumps (e.g. sodium/potassium ATPases, sodium translocating respiratory chain complexes) or via the action of sodium/proton antiporters. Sodium/substrate transporters are grouped in different families based on sequence similarities [PUBMED:1965458, PUBMED:8031825].

One of these families, known as the sodium:solute symporter family (SSSF), contains over a hundred members of pro- and eukaryotic origin [PUBMED:12354616]. The average hydropathy plot for SSSF proteins predicts 11 to 15 putative transmembrane domains (TMs) in alpha-helical conformation. A secondary structure model of PutP from Escherichia coli suggests the protein contains 13 TMs with the N terminus located on the periplasmic side of the membrane and the C terminus facing the cytoplasm. The results support the idea of a common topological motif for members of the SSSF. Transporters with a C-terminal extension are proposed to have an additional 14th TM.

An ordered binding model of sodium/substrate transport suggests that sodium binds to the empty transporter first, thereby inducing a conformational alteration which increases the affinity of the transporter for the solute. The formation of the ternary complex induces another structural change that exposes sodium and substrate to the other site of the membrane. Substrate and sodium are released and the empty transporter re-orientates in the membrane allowing the cycle to start again.

Gene Ontology

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Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan APC (CL0062), which has the following description:

This large superfamily contains a variety of transporters including amino acid permeases that according to TCDB belong to the APC (Amino acid-Polyamine-organoCation) superfamily.

The clan contains the following 18 members:

AA_permease AA_permease_2 AA_permease_C Aa_trans BenE Branch_AA_trans CstA HCO3_cotransp K_trans Na_Ala_symp Nramp Spore_permease SSF Sulfate_tra_GLY Sulfate_transp Transp_cyt_pur Trp_Tyr_perm Xan_ur_permease

Alignments

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 using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics 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.

  Seed
(10)
Full
(13052)
Representative proteomes NCBI
(10595)
Meta
(8262)
RP15
(1309)
RP35
(2409)
RP55
(3400)
RP75
(4094)
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

  Seed
(10)
Full
(13052)
Representative proteomes NCBI
(10595)
Meta
(8262)
RP15
(1309)
RP35
(2409)
RP55
(3400)
RP75
(4094)
Alignment:
Format:
Order:
Sequence:
Gaps:
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Download options

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.

  Seed
(10)
Full
(13052)
Representative proteomes NCBI
(10595)
Meta
(8262)
RP15
(1309)
RP35
(2409)
RP55
(3400)
RP75
(4094)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

Pfam alignments:

HMM logo

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...

Trees

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.

Curation View help on the curation process

Seed source: Prosite
Previous IDs: none
Type: Family
Author: Finn RD
Number in seed: 10
Number in full: 13052
Average length of the domain: 353.80 aa
Average identity of full alignment: 21 %
Average coverage of the sequence by the domain: 74.16 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 19.8 19.8
Trusted cut-off 19.8 19.8
Noise cut-off 19.7 19.6
Model length: 406
Family (HMM) version: 12
Download: download the raw HMM for this family

Species distribution

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Structures

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 SSF domain has been found. There are 6 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.

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