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39  structures 6864  species 0  interactions 9696  sequences 99  architectures

Family: GXGXG (PF01493)

Summary: GXGXG motif

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GXGXG motif Provide feedback

This domain is found in glutamate synthase, tungsten formylmethanofuran dehydrogenase subunit c (FwdC) and molybdenum formylmethanofuran dehydrogenase subunit c (FmdC). A repeated G-XX-G-XXX-G motif is seen in the alignment.

Literature references

  1. Hochheimer A, Hedderich R, Thauer RK; , Arch Microbiol 1998;170:389-393.: The formylmethanofuran dehydrogenase isoenzymes in Methanobacterium wolfei and Methanobacterium thermoautotrophicum: induction of the molybdenum isoenzyme by molybdate and constitutive synthesis of the tungsten isoenzyme. PUBMED:9818358 EPMC:9818358

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR002489

Glutamate synthase (GltS) is a complex iron-sulphur flavoprotein that catalyses the reductive synthesis of L-glutamate from 2-oxoglutarate and L-glutamine via intramolecular channelling of ammonia, a reaction in the bacterial, yeast and plant pathways for ammonia assimilation [ PUBMED:11188694 ]. GltS is a multifunctional enzyme that functions through three distinct active centres carrying out multiple reaction steps: L-glutamine hydrolysis, conversion of 2-oxoglutarate into L-glutamate, and electron uptake from an electron donor. The active centres are synchronised to avoid the wasteful consumption of L-glutamine [ PUBMED:11967268 ]. There are three classes of GltS, which share many functional properties: bacterial NADPH-dependent GltS, ferredoxin-dependent GltS from photosynthetic cells, and NAD(P)H-dependent GltS from yeast, fungi and lower animals.

The dimeric alpha subunits each consist of four domains: N-terminal amidotransferase domain, the central domain, the FMN binding domain and the C-terminal domain. The C-terminal domain forms a right-handed beta-helix that comprises seven helical turns [ PUBMED:11188694 ]. Each helical turn has a sharp bend that is associated with a repeated sequence motif consisting of G-XX-G-XXX-G. This domain does not contain any residues directly involved in catalysis, but has a crucial structural role.

This domain is also found in proteins such as subunit C of formylmethanofuran dehydrogenase, which catalyses the first step in methane formation from carbon dioxide in methanogenic archaea. There are two isoenzymes of formylmethanofuran dehydrogenase: a tungsten-containing isoenzyme (FwdC) and a molybdenum-containing isoenzyme (FmdC). The tungsten isoenzyme is constitutively transcribed, whereas transcription of the molybdenum operon is induced by molybdate [ PUBMED:9818358 ].

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...

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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.

Representative proteomes UniProt
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Representative proteomes UniProt

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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.

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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.

Curation View help on the curation process

Seed source: Pfam-B_428 (release 4.0)
Previous IDs: DUF14;
Type: Family
Sequence Ontology: SO:0100021
Author: Bashton M , Bateman A
Number in seed: 159
Number in full: 9696
Average length of the domain: 185.2 aa
Average identity of full alignment: 46 %
Average coverage of the sequence by the domain: 13.12 %

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 32.5 32.5
Trusted cut-off 32.5 32.5
Noise cut-off 32.4 32.4
Model length: 190
Family (HMM) version: 22
Download: download the raw HMM for this family

Species distribution

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Colour assignments

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


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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 adjacent tab. More...

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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 GXGXG domain has been found. There are 39 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.

Protein Predicted structure External Information
A0A077ZK91 View 3D Structure Click here
A0A077ZLA5 View 3D Structure Click here
A0A0A2V3X1 View 3D Structure Click here
A0A0D2DPU9 View 3D Structure Click here
A0A0H3GY60 View 3D Structure Click here
A0A0K0ESL4 View 3D Structure Click here
A0A0K0JM90 View 3D Structure Click here
A0A0N4UQG4 View 3D Structure Click here
A0A0R0EVI7 View 3D Structure Click here
A0A0R0JMI0 View 3D Structure Click here
A0A0R0KBX5 View 3D Structure Click here
A0A1C1CVH7 View 3D Structure Click here
A0A1D6G2B5 View 3D Structure Click here
A0A1D6IM18 View 3D Structure Click here
A0A1D6MBZ9 View 3D Structure Click here
A0A1D6NFK0 View 3D Structure Click here
A0A1D8PDU9 View 3D Structure Click here
A0A368UIE4 View 3D Structure Click here
A0A3P7FDR9 View 3D Structure Click here
A0A3Q0KL96 View 3D Structure Click here
A0A5K4EL52 View 3D Structure Click here
A0A5K4EM75 View 3D Structure Click here
C0NYC5 View 3D Structure Click here
E1V8I1 View 3D Structure Click here
I1MAK3 View 3D Structure Click here
I1N8S9 View 3D Structure Click here
K0EQD1 View 3D Structure Click here
K8F7V7 View 3D Structure Click here
M9NFH8 View 3D Structure Click here
O87391 View 3D Structure Click here
P09831 View 3D Structure Click here
P0CW43 View 3D Structure Click here
P23225 View 3D Structure Click here
P39812 View 3D Structure Click here
P55037 View 3D Structure Click here
P55038 View 3D Structure Click here
P82736 View 3D Structure Click here
P96218 View 3D Structure Click here
Q0DG35 View 3D Structure Click here
Q0JKD0 View 3D Structure Click here