Letunic et al. (2017) Nucleic Acids Res doi: 10.1093/nar/gkx922
Letunic et al. (2020) Nucleic Acids Res doi: 10.1093/nar/gkaa937

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AIRC AIR carboxylase

SMART accession number:	SM01001
Description:	Members of this family catalyse the decarboxylation of 1-(5-phosphoribosyl)-5-amino-4-imidazole-carboxylate (AIR). This family catalyse the sixth step of de novo purine biosynthesis. Some members of this family contain two copies of this domain.
Interpro abstract (IPR000031):	The novo purine biosynthesis proceeds by two divergent paths. In bacteria, yeasts, and plants, 5-aminoimidazole ribonucleotide (AIR) is converted to 4-carboxy-AIR (CAIR) by two enzymes: N5-carboxy-AIR (N5-CAIR) synthetase (PurK) and N5-CAIR mutase (class I PurE). In animals, the conversion of AIR to CAIR requires a single enzyme, AIR carboxylase (class II PurE) [ (PUBMED:7918411) ]. Class I and class II PurEs are mechanistically related but bind different substrates. In yeast and plants PurE is found in PurK-class I PurE fusion proteins, known as ADE2 [ (PUBMED:8111040) (PUBMED:9500840) ], while animal class II PurEs are found in PurC-PurE fusion proteins, also known as ADE2 or PAICS [ (PUBMED:7918410) ].
GO process:	'de novo' IMP biosynthetic process (GO:0006189)
Family alignment:	View or CHROMA formatHMM/Web logoCLUSTALW formatMSF formatFASTA formatPIR format

There are 23473 AIRC domains in 23424 proteins in SMART's nrdb database.

Click on the following links for more information.

• Evolution (species in which this domain is found)

• Taxonomic distribution of proteins containing AIRC domain.

  This tree includes only several representative species. The complete taxonomic breakdown of all proteins with AIRC domain is also avaliable.

  • Proteins%Domains%
  • Archaea12785.4613225.44
    • undefined kingdom12785.4613225.44
  • Bacteria2029486.642029886.46
    • undefined kingdom2029486.642029886.46
  • Eukaryota16296.9516306.94
    • Fungi6652.846662.83
    • Metazoa6542.796542.79
    • Viridiplantae2250.962250.96
    • undefined kingdom850.36850.36
  • Viruses20.0120.01
    • undefined kingdom20.0120.01
  • undefined superkingdom2210.942210.94
    • undefined kingdom2210.942210.94

  Click on the protein counts, or double click on taxonomic names to display all proteins containing AIRC domain in the selected taxonomic class.

• Cellular role (predicted cellular role)

• Cellular role: metabolism
  

• Literature (relevant references for this domain)

• Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.

  • Mathews II, Kappock TJ, Stubbe J, Ealick SE
  • Crystal structure of Escherichia coli PurE, an unusual mutase in thepurine biosynthetic pathway.
  • Structure. 1999; 7: 1395-406
  • Display abstract

  • BACKGROUND: Conversion of 5-aminoimidazole ribonucleotide (AIR) to4-carboxyaminoimidazole ribonucleotide (CAIR) in Escherichia coli requirestwo proteins - PurK and PurE. PurE has recently been shown to be a mutasethat catalyzes the unusual rearrangement of N(5)-carboxyaminoimidazoleribonucleotide (N(5)-CAIR), the PurK reaction product, to CAIR. PurEs fromhigher eukaryotes are homologous to E. coli PurE, but use AIR and CO(2) assubstrates to produce CAIR directly. RESULTS: The 1.50 A crystal structureof PurE reveals an octameric structure with 422 symmetry. A centralthree-layer (alphabetaalpha) sandwich domain and a kinked C-terminal helixform the folded structure of the monomeric unit. The structure reveals acleft at the interface of two subunits and near the C-terminal helix of athird subunit. Co-crystallization experiments with CAIR confirm this to bethe mononucleotide-binding site. The nucleotide is bound predominantly toone subunit, with conserved residues from a second subunit making up onewall of the cleft. CONCLUSIONS: The crystal structure of PurE reveals aunique quaternary structure that confirms the octameric nature of theenzyme. An analysis of the native crystal structure, in conjunction withsequence alignments and studies of co-crystals of PurE with CAIR, revealsthe location of the active site. The environment of the active site andthe analysis of conserved residues between the two classes of PurEssuggests a model for the differences in their substrate specificities andthe relationship between their mechanisms.

• Structure (3D structures containing this domain)

• 3D Structures of AIRC domains in PDB

  PDB code	Main view	Title
  1d7a		CRYSTAL STRUCTURE OF E. COLI PURE-MONONUCLEOTIDE COMPLEX.
  1o4v		Crystal structure of the catalytic subunit of a phosphoribosylaminoimidazole mutase (tm0446) from thermotoga maritima at 1.77 A resolution
  1qcz		CRYSTAL STRUCTURE OF E. COLI PURE, AN UNUSUAL MUTASE THAT CATALYZES THE CONVERSION OF N5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (N5-CAIR) TO 4-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE (CAIR) IN THE PURINE BIOSYNTHETIC PATHWAY
  1u11		PurE (N5-carboxyaminoimidazole Ribonucleotide Mutase) from the acidophile Acetobacter aceti
  1xmp		Crystal Structure of PurE (BA0288) from Bacillus anthracis at 1.8 Resolution
  2ate		Structure of the complex of PurE with NitroAIR
  2fw1		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) from the acidophilic bacterium Acetobacter aceti, at pH 8.5
  2fw6		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) mutant H59N from the acidophilic bacterium Acetobacter aceti, at pH 5.4
  2fw7		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59N from the acidophilic bacterium Acetobacter aceti, at pH 8
  2fw8		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H89G from the acidophilic bacterium Acetobacter aceti, at pH 8
  2fw9		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59F from the acidophilic bacterium Acetobacter aceti, at pH 8
  2fwa		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H89N from the acidophilic bacterium Acetobacter aceti, at pH 7
  2fwb		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H89F from the acidophilic bacterium Acetobacter aceti, at pH 8
  2fwi		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59D, from the acidophilic bacterium Acetobacter aceti, complexed with 5-aminoimidazole ribonucleotide (AIR)
  2fwj		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) from the acidophilic bacterium Acetobacter aceti, complexed with AIR (5-aminoimidazole ribonucleotide)
  2fwp		Structure of PurE (N5-carboxyaminoimidazole ribonucleotide mutase) H59N from the acidophilic bacterium Acetobacter aceti, bound to isocair
  2h31		Crystal structure of human PAICS, a bifunctional carboxylase and synthetase in purine biosynthesis
  2nsh		E. coli PurE H45Q mutant complexed with nitro-AIR
  2nsj		E. coli PurE H45Q mutant complexed with CAIR
  2nsl		E. coli PurE H45N mutant complexed with CAIR
  2ywx		Crystal structure of phosphoribosylaminoimidazole carboxylase catalytic subunit from Methanocaldococcus jannaschii
  3kuu		Structure of the PurE Phosphoribosylaminoimidazole Carboxylase Catalytic Subunit from Yersinia pestis
  3lp6		Crystal Structure of Rv3275c-E60A from Mycobacterium tuberculosis at 1.7A resolution
  3oow		Octameric structure of the phosphoribosylaminoimidazole carboxylase catalytic subunit from Francisella tularensis subsp. tularensis SCHU S4.
  3opq		Phosphoribosylaminoimidazole carboxylase with fructose-6-phosphate bound to the central channel of the octameric protein structure.
  3ors		Crystal Structure of N5-Carboxyaminoimidazole Ribonucleotide Mutase from Staphylococcus aureus
  3rg8		Crystal structure of Treponema denticola PurE
  3rgg		Crystal structure of Treponema denticola PurE bound to AIR
  3trh		Structure of a phosphoribosylaminoimidazole carboxylase catalytic subunit (purE) from Coxiella burnetii
  4ay3		Crystal structure of Bacillus anthracis PurE
  4ay4		crystal structure of Bacillus anthracis PurE
  4b4k		Crystal structure of Bacillus anthracis PurE
  4grd		Crystal structure of Phosphoribosylaminoimidazole carboxylase catalytic subunit from Burkholderia cenocepacia J2315
  4ja0		Crystal structure of the invertebrate bi-functional purine biosynthesis enzyme PAICS at 2.8 A resolution
  4ycb		4YCB
  4ycc		4YCC
  4ycd		4YCD
  4ycj		4YCJ
  4z7j		4Z7J
  4zc8		4ZC8
  4zjy		4ZJY
  4zk2		4ZK2
  4zmb		4ZMB
  5bor		5BOR
  5bos		5BOS
  5c5d		5C5D
  5clf		5CLF
  5clg		5CLG
  5clh		5CLH
  5cli		5CLI
  5clj		5CLJ
  5ctj		5CTJ
  5cvt		5CVT

• Links (links to other resources describing this domain)

• PFAM	AIRC
  INTERPRO	IPR000031

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