Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
0  structures 1551  species 0  interactions 2914  sequences 5  architectures

Family: DcuC (PF03606)

Summary: C4-dicarboxylate anaerobic carrier

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Anaerobic C4-dicarboxylate membrane transporter protein". More...

Anaerobic C4-dicarboxylate membrane transporter protein Edit Wikipedia article

Redirect to:

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.

C4-dicarboxylate anaerobic carrier Provide feedback

No Pfam abstract.

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR018385

Escherichia coli contains four different secondary carriers (DcuA, DcuB, DcuC, and DctA) for C4-dicarboxylates [ PUBMED:10482502 , PUBMED:1512189 , PUBMED:7961398 , PUBMED:8955408 ] DcuA is used for aerobic growth on C4-dicarboxylates [ PUBMED:10482502 , PUBMED:5541510 ], whereas the Dcu carriers (encoded by the dcuA, dcuB, and dcuC genes) are used under anaerobic conditions and form a distinct family of carriers [ PUBMED:1512189 , PUBMED:8020497 , PUBMED:9889977 , PUBMED:7961398 , PUBMED:9230919 , PUBMED:8955408 ]. Each of the Dcu carriers is able to catalyze the uptake, antiport, and possibly also efflux of C4-dicarboxylates. DcuB is the major C4-dicarboxylate carrier for fumarate respiration with high fumarate-succinate exchange activity. It is synthesized only in the absence of oxygen and nitrate and in the presence of C4-dicarboxylates [ PUBMED:1512189 , PUBMED:9973351 , PUBMED:9852003 , PUBMED:9765574 ]. DcuA is expressed constitutively in aerobic and anaerobic growth and can substitute for DcuB [ PUBMED:9852003 , PUBMED:7961398 ]. These proteins are members of the C4-dicarboxylate Uptake C (DcuC) family. DcuC has 12 GES predicted transmembrane regions, is induced only under anaerobic conditions, and is not repressed by glucose. DcuC may therefore function as a succinate efflux system during anaerobic glucose fermentation. However, when overexpressed, it can replace either DcuA or DcuB in catalyzing fumarate-succinate exchange and fumarate uptake [ PUBMED:8020497 , PUBMED:10368146 ]. DcuC shows the same transport modes as DcuA and DcuB (exchange, uptake, and presumably efflux of C4-dicarboxylates) [ PUBMED:8955408 ].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

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

Loading domain graphics...

Pfam Clan

This family is a member of clan IT (CL0182), which has the following description:

This superfamily of secondary carriers specific for cationic and anionic compounds, has been termed the ion transporter (IT) superfamily [1].

The clan contains the following 22 members:

ABG_transport ArsB ArsP_1 ArsP_2 CitMHS CitMHS_2 DctM DcuA_DcuB DcuC DUF1646 DUF401 EutH EXS GntP_permease Lactate_perm MatC_N Na_H_antiport_2 Na_H_antiport_3 Na_H_antiporter Na_sulph_symp NhaB SCFA_trans


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...

View options

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.

Representative proteomes UniProt
Jalview View  View  View  View  View  View  View 
HTML View  View           
PP/heatmap 1 View           

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

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

Format an alignment

Representative proteomes UniProt

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.

Representative proteomes UniProt
Raw Stockholm Download   Download   Download   Download   Download   Download   Download  
Gzipped 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.

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...


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: TIGRFAMs
Previous IDs: none
Type: Family
Sequence Ontology: SO:0100021
Author: TIGRFAMs, Griffiths-Jones SR
Number in seed: 12
Number in full: 2914
Average length of the domain: 434.90 aa
Average identity of full alignment: 23 %
Average coverage of the sequence by the domain: 96.26 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 23.1 23.1
Trusted cut-off 23.1 23.1
Noise cut-off 23.0 23.0
Model length: 461
Family (HMM) version: 18
Download: download the raw HMM for this family

Species distribution

Sunburst controls


Weight segments by...

Change the size of the sunburst


Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


Align selected sequences to HMM

Generate a FASTA-format file

Clear selection

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...

Loading sunburst data...

Tree controls


The tree shows the occurrence of this domain across different species. More...


Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.

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
P0ABP3 View 3D Structure Click here
P39263 View 3D Structure Click here
P45428 View 3D Structure Click here
Q2FZA8 View 3D Structure Click here

trRosetta Structure

The structural model below was generated by the Baker group with the trRosetta software using the Pfam UniProt multiple sequence alignment.

The InterPro website shows the contact map for the Pfam SEED alignment. Hovering or clicking on a contact position will highlight its connection to other residues in the alignment, as well as on the 3D structure.

Improved protein structure prediction using predicted inter-residue orientations. Jianyi Yang, Ivan Anishchenko, Hahnbeom Park, Zhenling Peng, Sergey Ovchinnikov, David Baker Proceedings of the National Academy of Sciences Jan 2020, 117 (3) 1496-1503; DOI: 10.1073/pnas.1914677117;