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.
50  structures 7171  species 0  interactions 8837  sequences 61  architectures

Family: IGPS (PF00218)

Summary: Indole-3-glycerol phosphate synthase

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 "Indole-3-glycerol-phosphate synthase". More...

Indole-3-glycerol-phosphate synthase Edit Wikipedia article

In enzymology, an indole-3-glycerol-phosphate synthase (EC is an enzyme that catalyzes the chemical reaction

1-(2-carboxyphenylamino)-1-deoxy-D-ribulose 5-phosphate 1-C-(indol-3-yl)-glycerol 3-phosphate + CO2 + H2O

Hence, this enzyme has one substrate, 1-(2-carboxyphenylamino)-1-deoxy-D-ribulose 5-phosphate, but 3 products: 1-C-(indol-3-yl)-glycerol 3-phosphate, CO2, and H2O.

This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is 1-(2-carboxyphenylamino)-1-deoxy-D-ribulose-5-phosphate carboxy-lyase [cyclizing 1-C-(indol-3-yl)glycerol-3-phosphate-forming]. Other names in common use include indoleglycerol phosphate synthetase, indoleglycerol phosphate synthase, indole-3-glycerophosphate synthase, 1-(2-carboxyphenylamino)-1-deoxy-D-ribulose-5-phosphate, and carboxy-lyase (cyclizing). This enzyme participates in phenylalanine, tyrosine and tryptophan biosynthesis and two-component system - general. It employs one cofactor, pyruvate.

Structural studies

As of late 2007, 11 structures have been solved for this class of enzymes, with PDB accession codes 1A53, 1I4N, 1J5T, 1JCM, 1JUK, 1JUL, 1LBF, 1LBL, 1PII, 1VC4, and 2C3Z.


Template:Enzyme references

  • Creighton TE, Yanofsky C (1966). "Indole-3-glycerol phosphate synthetase of Escherichia coli, an enzyme of the tryptophan operon". J. Biol. Chem. 241: 4616–24. PMID 5332729.
  • Creighton TE and Yanofsky C (1970). "Chorismate to tryptophan (Escherichia coli) - Anthranilate synthetase, PR transferase, PRA isomerase, InGP synthetase, tryptophan synthetase". Methods Enzymol. 17A: 365–380.
  • Kung CC, Huang WN, Huang YC, Yeh KC (2006). "Proteomic survey of copper-binding proteins in Arabidopsis roots by immobilized metal affinity chromatography and mass spectrometry". Proteomics. 6: 2746–58. PMID 16526091.{{cite journal}}: CS1 maint: multiple names: authors list (link)

External links

The CAS registry number for this enzyme class is Template:CAS registry.

Template:Enzyme links

Gene Ontology (GO) codes

Template:GO code links

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.

Indole-3-glycerol phosphate synthase Provide feedback

No Pfam abstract.

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR013798

Indole-3-glycerol phosphate synthase ( EC ) (IGPS) catalyses the fourth step in the biosynthesis of tryptophan, the ring closure of 1-(2-carboxy-phenylamino)-1-deoxyribulose into indol-3-glycerol-phosphate. In some bacteria, IGPS is a single chain enzyme. In others, such as Escherichia coli, it is the N-terminal domain of a bifunctional enzyme that also catalyses N-(5'-phosphoribosyl)anthranilate isomerase ( EC ) (PRAI) activity (see INTERPRO ), the third step of tryptophan biosynthesis. In fungi, IGPS is the central domain of a trifunctional enzyme that contains a PRAI C-terminal domain and a glutamine amidotransferase ( EC ) (GATase) N-terminal domain.

A structure of the IGPS domain of the bifunctional enzyme from the mesophilic bacterium E. coli (eIGPS) has been compared with the monomeric indole-3-glycerol phosphate synthase from the hyperthermophilic archaeon Sulfolobus solfataricus (sIGPS). Both are single-domain (beta/alpha)8 barrel proteins, with one (eIGPS) or two (sIGPS) additional helices inserted before the first beta strand [ PUBMED:8747452 ].

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...


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             
PP/heatmap 1            

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: Prosite
Previous IDs: none
Type: Domain
Sequence Ontology: SO:0000417
Author: Finn RD
Number in seed: 16
Number in full: 8837
Average length of the domain: 249.2 aa
Average identity of full alignment: 39 %
Average coverage of the sequence by the domain: 74.89 %

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 27.0 27.0
Trusted cut-off 27.0 27.3
Noise cut-off 26.9 26.7
Model length: 254
Family (HMM) version: 24
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.


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 IGPS domain has been found. There are 50 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.

Loading structure mapping...

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
A0A077ZCP1 View 3D Structure Click here
A0A0D2GEH8 View 3D Structure Click here
A0A0H3GW36 View 3D Structure Click here
A0A0P0XEA1 View 3D Structure Click here
A0A175W6V1 View 3D Structure Click here
A0A1C1CAE8 View 3D Structure Click here
A0A1D8PFC8 View 3D Structure Click here
A0A5K1K8R3 View 3D Structure Click here
A0JVL1 View 3D Structure Click here
A0LA39 View 3D Structure Click here
A0LJ58 View 3D Structure Click here
A0QX95 View 3D Structure Click here
A1BDW1 View 3D Structure Click here
A1KAT2 View 3D Structure Click here
A1R5S7 View 3D Structure Click here
A1SL44 View 3D Structure Click here
A1T8X3 View 3D Structure Click here
A1TJQ2 View 3D Structure Click here
A1UHJ6 View 3D Structure Click here
A1VTG7 View 3D Structure Click here
A1W2Z8 View 3D Structure Click here
A1WH73 View 3D Structure Click here
A3CLL9 View 3D Structure Click here
A3DDS7 View 3D Structure Click here
A3PED0 View 3D Structure Click here
A4FLL0 View 3D Structure Click here
A4G1P4 View 3D Structure Click here
A4J147 View 3D Structure Click here
A4SG41 View 3D Structure Click here
A4VHK1 View 3D Structure Click here
A4XZC5 View 3D Structure Click here
A4YHD8 View 3D Structure Click here
A4YVD6 View 3D Structure Click here
A5EVG3 View 3D Structure Click here
A5GMK4 View 3D Structure Click here
A5GRL0 View 3D Structure Click here
A5N7N8 View 3D Structure Click here
A5USQ4 View 3D Structure Click here
A5VBA0 View 3D Structure Click here
A6Q3P0 View 3D Structure Click here