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Protein

Hypoxanthine-guanine-xanthine phosphoribosyltransferase

Gene

HPRT

Organism
Toxoplasma gondii
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Catalyzes the transfer of a ribosyl phosphate group from 5-phosphoribose 1-diphosphate to the N9 of hypoxanthine, guanine or xanthine.1 Publication

Catalytic activityi

IMP + diphosphate = hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate.
GMP + diphosphate = guanine + 5-phospho-alpha-D-ribose 1-diphosphate.
XMP + diphosphate = 5-phospho-alpha-D-ribose 1-diphosphate + xanthine.

Cofactori

Mg2+1 PublicationNote: Binds 2 magnesium ions per subunit. The magnesium ions are essentially bound to the substrate and have few direct interactions with the protein.1 Publication

Pathwayi: GMP biosynthesis via salvage pathway

This protein is involved in step 1 of the subpathway that synthesizes GMP from guanine.
Proteins known to be involved in this subpathway in this organism are:
  1. Hypoxanthine-guanine-xanthine phosphoribosyltransferase (HPRT)
This subpathway is part of the pathway GMP biosynthesis via salvage pathway, which is itself part of Purine metabolism.
View all proteins of this organism that are known to be involved in the subpathway that synthesizes GMP from guanine, the pathway GMP biosynthesis via salvage pathway and in Purine metabolism.

Pathwayi: IMP biosynthesis via salvage pathway

This protein is involved in step 1 of the subpathway that synthesizes IMP from hypoxanthine.
Proteins known to be involved in this subpathway in this organism are:
  1. Hypoxanthine-guanine-xanthine phosphoribosyltransferase (HPRT)
This subpathway is part of the pathway IMP biosynthesis via salvage pathway, which is itself part of Purine metabolism.
View all proteins of this organism that are known to be involved in the subpathway that synthesizes IMP from hypoxanthine, the pathway IMP biosynthesis via salvage pathway and in Purine metabolism.

Pathwayi: XMP biosynthesis via salvage pathway

This protein is involved in step 1 of the subpathway that synthesizes XMP from xanthine.
Proteins known to be involved in this subpathway in this organism are:
  1. Hypoxanthine-guanine-xanthine phosphoribosyltransferase (HPRT)
This subpathway is part of the pathway XMP biosynthesis via salvage pathway, which is itself part of Purine metabolism.
View all proteins of this organism that are known to be involved in the subpathway that synthesizes XMP from xanthine, the pathway XMP biosynthesis via salvage pathway and in Purine metabolism.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei79GMP1
Active sitei150Proton acceptor2 Publications1
Binding sitei178GMP1
Metal bindingi206Magnesium1 Publication1
Binding sitei206GMP; via carbonyl oxygen1

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Nucleotide bindingi146 – 154GMP9
Nucleotide bindingi199 – 200GMP2

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Glycosyltransferase, Transferase

Keywords - Biological processi

Purine salvage

Keywords - Ligandi

Magnesium, Metal-binding, Nucleotide-binding

Enzyme and pathway databases

BRENDAi2.4.2.8. 6411.
UniPathwayiUPA00591; UER00648.
UPA00602; UER00658.
UPA00909; UER00887.

Names & Taxonomyi

Protein namesi
Recommended name:
Hypoxanthine-guanine-xanthine phosphoribosyltransferase (EC:2.4.2.22, EC:2.4.2.8)
Short name:
HGPRT
Short name:
HGXPRT
Short name:
HGXPRTase
Gene namesi
Name:HPRT
OrganismiToxoplasma gondii
Taxonomic identifieri5811 [NCBI]
Taxonomic lineageiEukaryotaAlveolataApicomplexaConoidasidaCoccidiaEucoccidioridaEimeriorinaSarcocystidaeToxoplasma

Subcellular locationi

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Cytoplasm

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi150D → A: Strongly reduced catalytic activity. 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00001395991 – 230Hypoxanthine-guanine-xanthine phosphoribosyltransferaseAdd BLAST230

Interactioni

Subunit structurei

Homodimer at low ionic strength and homotetramer at high ionic strength.2 Publications

Protein-protein interaction databases

STRINGi5811.TGME49_000320.

Structurei

Secondary structure

1230
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Helixi6 – 8Combined sources3
Beta strandi9 – 11Combined sources3
Helixi29 – 31Combined sources3
Turni36 – 41Combined sources6
Beta strandi44 – 47Combined sources4
Helixi49 – 67Combined sources19
Beta strandi72 – 78Combined sources7
Turni79 – 81Combined sources3
Helixi82 – 98Combined sources17
Beta strandi109 – 119Combined sources11
Beta strandi122 – 130Combined sources9
Helixi134 – 137Combined sources4
Beta strandi141 – 152Combined sources12
Helixi153 – 163Combined sources11
Beta strandi168 – 178Combined sources11
Beta strandi189 – 195Combined sources7
Beta strandi200 – 202Combined sources3
Turni208 – 213Combined sources6
Beta strandi215 – 219Combined sources5
Helixi222 – 228Combined sources7

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1DBRX-ray2.40A/B/C/D1-230[»]
1FSGX-ray1.05A/C1-230[»]
1QK3X-ray1.65A/B/C/D1-230[»]
1QK4X-ray1.90A/B/C/D1-230[»]
1QK5X-ray1.60A/B1-230[»]
ProteinModelPortaliQ26997.
SMRiQ26997.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiQ26997.

Family & Domainsi

Sequence similaritiesi

Phylogenomic databases

eggNOGiKOG3367. Eukaryota.
COG0634. LUCA.

Family and domain databases

CDDicd06223. PRTases_typeI. 1 hit.
Gene3Di3.40.50.2020. 1 hit.
InterProiIPR005904. Hxn_phspho_trans.
IPR000836. PRibTrfase_dom.
IPR029057. PRTase-like.
[Graphical view]
PfamiPF00156. Pribosyltran. 1 hit.
[Graphical view]
SUPFAMiSSF53271. SSF53271. 1 hit.
TIGRFAMsiTIGR01203. HGPRTase. 1 hit.
PROSITEiPS00103. PUR_PYR_PR_TRANSFER. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Q26997-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MASKPIEDYG KGKGRIEPMY IPDNTFYNAD DFLVPPHCKP YIDKILLPGG
60 70 80 90 100
LVKDRVEKLA YDIHRTYFGE ELHIICILKG SRGFFNLLID YLATIQKYSG
110 120 130 140 150
RESSVPPFFE HYVRLKSYQN DNSTGQLTVL SDDLSIFRDK HVLIVEDIVD
160 170 180 190 200
TGFTLTEFGE RLKAVGPKSM RIATLVEKRT DRSNSLKGDF VGFSIEDVWI
210 220 230
VGCCYDFNEM FRDFDHVAVL SDAARKKFEK
Length:230
Mass (Da):26,386
Last modified:November 1, 1996 - v1
Checksum:iC3784254EF96361D
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U09219 mRNA. Translation: AAA57068.1.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U09219 mRNA. Translation: AAA57068.1.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1DBRX-ray2.40A/B/C/D1-230[»]
1FSGX-ray1.05A/C1-230[»]
1QK3X-ray1.65A/B/C/D1-230[»]
1QK4X-ray1.90A/B/C/D1-230[»]
1QK5X-ray1.60A/B1-230[»]
ProteinModelPortaliQ26997.
SMRiQ26997.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

STRINGi5811.TGME49_000320.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Phylogenomic databases

eggNOGiKOG3367. Eukaryota.
COG0634. LUCA.

Enzyme and pathway databases

UniPathwayiUPA00591; UER00648.
UPA00602; UER00658.
UPA00909; UER00887.
BRENDAi2.4.2.8. 6411.

Miscellaneous databases

EvolutionaryTraceiQ26997.

Family and domain databases

CDDicd06223. PRTases_typeI. 1 hit.
Gene3Di3.40.50.2020. 1 hit.
InterProiIPR005904. Hxn_phspho_trans.
IPR000836. PRibTrfase_dom.
IPR029057. PRTase-like.
[Graphical view]
PfamiPF00156. Pribosyltran. 1 hit.
[Graphical view]
SUPFAMiSSF53271. SSF53271. 1 hit.
TIGRFAMsiTIGR01203. HGPRTase. 1 hit.
PROSITEiPS00103. PUR_PYR_PR_TRANSFER. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiHGXR_TOXGO
AccessioniPrimary (citable) accession number: Q26997
Entry historyi
Integrated into UniProtKB/Swiss-Prot: November 1, 1997
Last sequence update: November 1, 1996
Last modified: November 2, 2016
This is version 92 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)

Miscellaneousi

Keywords - Technical termi

3D-structure

Documents

  1. PATHWAY comments
    Index of metabolic and biosynthesis pathways
  2. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  3. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.