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99  structures 1661  species 0  interactions 2280  sequences 3  architectures

Family: Arabinose_Isome (PF02610)

Summary: L-arabinose isomerase

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This is the Wikipedia entry entitled "L-arabinose isomerase". More...

L-arabinose isomerase Edit Wikipedia article

L-arabinose isomerase
L-arabinose isomerase hexamer, Geobacillus kaustophilus
EC number5.3.1.4
CAS number9023-80-7
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
Arabinose isomerase
PDB 2ajt EBI.jpg
crystal structure of l-arabinose isomerase from e.coli

In enzymology, a L-arabinose isomerase (EC is an enzyme that catalyzes the chemical reaction

L-arabinose L-ribulose

Hence, this enzyme has one substrate, L-arabinose, and one product, L-ribulose.

This enzyme belongs to the family of isomerases, specifically those intramolecular oxidoreductases interconverting aldoses and ketoses. The systematic name of this enzyme class is L-arabinose aldose-ketose-isomerase. This enzyme participates in pentose and glucuronate interconversions.

This enzyme catalyses the conversion of L-arabinose to L-ribulose as the first step in the pathway of L-arabinose utilization as a carbon source.[1]

Structural studies

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 2AJT and 2HXG.


  1. ^ Sa-Nogueira I, Nogueira TV, Soares S, de Lencastre H (March 1997). "The Bacillus subtilis L-arabinose (ara) operon: nucleotide sequence, genetic organization and expression". Microbiology. 143 (3): 957–69. doi:10.1099/00221287-143-3-957. PMID 9084180.

Further reading

  • HEATH EC, HORECKER BL, SMYRNIOTIS PZ, TAKAGI Y (1958). "Pentose fermentation by Lactobacillus plantarum. II. L-arabinose isomerase". J. Biol. Chem. 231 (2): 1031–7. PMID 13539034.
  • Nakamatu T, Yamanaka K (1969). "Crystallization and properties of L-arabinose isomerase from Lactobacillus gayonii". Biochim. Biophys. Acta. 178 (1): 156–65. doi:10.1016/0005-2744(69)90142-9. PMID 5773448.
This article incorporates text from the public domain Pfam and InterPro: IPR003762

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.

L-arabinose isomerase Provide feedback

This is a family of L-arabinose isomerases, AraA, EC: These enzymes catalyse the reaction: L-arabinose <=> L-ribulose. This reaction is the first step in the pathway of L-arabinose utilisation as a carbon source after entering the cell L-arabinose is converted into L-ribulose by the L-arabinose isomerases enzyme [1].

Literature references

  1. Sa-Nogueira I, Nogueira TV, Soares S, de Lencastre H; , Microbiology 1997;143:957-969.: The Bacillus subtilis L-arabinose (ara) operon: nucleotide sequence, genetic organization and expression. PUBMED:9084180 EPMC:9084180

This tab holds annotation information from the InterPro database.

InterPro entry IPR003762

The Escherichia coli araBAD operon consists of three genes encoding three enzymes that convert L-arabinose to D-xylulose-5 phosphate. L-arabinose isomerase (AraA) EC catalyses the conversion of L-arabinose to L-ribulose as the first step in the pathway of L-arabinose utilization as a carbon source [ PUBMED:9084180 ].

Gene Ontology

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Domain organisation

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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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Seed source: COG2160
Previous IDs: none
Type: Family
Sequence Ontology: SO:0100021
Author: Bashton M , Bateman A
Number in seed: 125
Number in full: 2280
Average length of the domain: 340.80 aa
Average identity of full alignment: 39 %
Average coverage of the sequence by the domain: 69.80 %

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 29.4 29.4
Trusted cut-off 29.4 29.4
Noise cut-off 29.1 29.1
Model length: 356
Family (HMM) version: 18
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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 Arabinose_Isome domain has been found. There are 99 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
P08202 View 3D Structure Click here