C8VSZ2 · XANA_EMENI

Function

function

Alpha-ketoglutarate-dependent xanthine dioxygenase is a non-heme mononuclear Fe2+ enzyme that decarboxylates alpha-ketoglutarate to succinate and CO2 while hydroxylating xanthine to generate uric acid (PubMed:15948966, PubMed:17429948, PubMed:18036331).
Allows xanthine utilization as a nitrogen source (PubMed:15948966).
Whereas xanA is highly specific for xanthine, alpha-ketoadipic acid can replace alpha-ketoglutarate as a cosubstrate (PubMed:17429948).
Exhibits ferroxidase activity in the absence of substrates (PubMed:18036331).

Catalytic activity

Cofactor

Fe2+ (UniProtKB | Rhea| CHEBI:29033 )

Note: Binds 1 Fe2+ ion per subunit.

Activity regulation

Cu2+ and Zn2+ completely inhibit the xanthine dioxygenase activity, whereas Co2+, Mn2+, and Ni2+ partially inhibit the activity. The inactive metal ions are presumed to compete for the Fe2+-binding site (PubMed:17429948).
N-oxalylglycine (NOG), a known inhibitor of several Fe2+/alpha-ketoglutarate-dependent dioxygenase family members, competes with alpha-ketoglutarate and provides a Ki of 0.12 uM for inhibition (PubMed:17429948).
6,8-dihydroxypurine acts as a slow-binding competitive inhibitor (PubMed:18036331).
The thiol-specific inhibitors 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and iodoacetamide, inhibit also the catalytic activity (PubMed:18036331).

Kinetics

KM SUBSTRATE pH TEMPERATURE[C] NOTES EVIDENCE
31.1 μM2-oxoglutarate25
50 μM2-oxoglutarate30
45.2 μMxanthine25
46 μMxanthine30
0.16 mMalpha-ketoadipic acid25
0.4 mM9-methylxanthine25

pH Dependence

Optimum pH is 6.5 to 7.4.

Features

Showing features for binding site.

TypeIDPosition(s)Description
Binding site107substrate
Binding site149Fe cation (UniProtKB | ChEBI); catalytic
Binding site151Fe cation (UniProtKB | ChEBI); catalytic
Binding site1952-oxoglutarate (UniProtKB | ChEBI)
Binding site3252-oxoglutarate (UniProtKB | ChEBI)
Binding site340Fe cation (UniProtKB | ChEBI); catalytic
Binding site3522-oxoglutarate (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentcytosol
Molecular Functionalpha-ketoglutarate-dependent xanthine dioxygenase activity
Molecular Functionmetal ion binding

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Alpha-ketoglutarate-dependent xanthine dioxygenase xanA
  • EC number

Gene names

    • Name
      xanA
    • ORF names
      AN0488, ANIA_10081

Organism names

Accessions

  • Primary accession
    C8VSZ2
  • Secondary accessions
    • Q5BG42

Proteomes

Organism-specific databases

Subcellular Location

Keywords

Phenotypes & Variants

Features

Showing features for mutagenesis.

TypeIDPosition(s)Description
Mutagenesis101Leads to elevated ferroxidase activity in the absence of substrates.
Mutagenesis122Affects the binding of 2-oxoglutarate.
Mutagenesis137Exhibits relatively enhanced activity and affects the inhibition by 6,8-dihydroxypurine.
Mutagenesis138Exhibits relatively enhanced activity and affects the inhibition by 6,8-dihydroxypurine.
Mutagenesis149Impairs catalytic activity.
Mutagenesis151Impairs catalytic activity.
Mutagenesis167In xanA1; impairs catalytic activity.
Mutagenesis340Exhibits only 0.17% of the wild-type enzyme activity.
Mutagenesis356Leads to elevated ferroxidase activity in the absence of substrates and affects the inhibition by 6,8-dihydroxypurine.
Mutagenesis357Exhibits relatively enhanced activity, resistance to thiol-specific inhibitors such as DTNB or iodoacetamide, and elevated ferroxidase activity in the absence of substrates.
Mutagenesis358Exhibits a 23-fold decrease in kcat/Km and affects the inhibition by 6,8-dihydroxypurine.

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00004460051-370Alpha-ketoglutarate-dependent xanthine dioxygenase xanA

Post-translational modification

Glycosylated (PubMed:17429948).
Is subject to both N- and O-linked glycosylation (PubMed:17429948).
Phosphorylated.

Expression

Induction

Expression is induced by uric acid which is mediated by the transcription factor UaY, together with the AreA GATA factor (PubMed:17367381).
The promoter contains 4 A/CGATAR areA-binding sites (PubMed:17367381).

Interaction

Protein-protein interaction databases

Structure

Family & Domains

Sequence similarities

Belongs to the TfdA dioxygenase family.

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    370
  • Mass (Da)
    41,305
  • Last updated
    2019-01-16 v2
  • Checksum
    5E3A746FDBFAC33A
MPAITVKPLTPPAGSAIDFGAVITDVDLEHLTDGDFSTIRSALYTHLVVVLKNQHQLTPKAQYELTRRFDPSATQYGHGKTLDAKRSILHPDLKTIPHQPQVQVIGHGFIDSYEGLENITLKHPHHRTFHRDPIPQEDDYDSTRFYRWHIDAALYGLNPPIVTTLLAVKVPGGRRQTVRYDDGSGETMDVPLGTTAFASGERMFELLSEEDKEFALSSRVEYAPHPYIWMSPARSLPTGLGLHSDDLELPLSELPPIDESAIQILPMVWKNPATGKPALQIHPSAVRKIHCGDGTVIDDLKKVREIAYKLQRPAISPQYVYAHDWEEGDLVLFHNRGVLHSVVGAFGEGEVRLFRQCNLAAGEGVVPYRE

Sequence caution

The sequence CBF89386.1 differs from that shown. Reason: Erroneous gene model prediction
The sequence EAA66587.1 differs from that shown. Reason: Erroneous gene model prediction

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AACD01000007
EMBL· GenBank· DDBJ
EAA66587.1
EMBL· GenBank· DDBJ
Genomic DNA Sequence problems.
BN001308
EMBL· GenBank· DDBJ
CBF89386.1
EMBL· GenBank· DDBJ
Genomic DNA Sequence problems.

Genome annotation databases

Similar Proteins

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