UniProtKB - P0A9M2 (HPRT_ECOLI)
Protein
Hypoxanthine phosphoribosyltransferase
Gene
hpt
Organism
Escherichia coli (strain K12)
Status
Functioni
Purine salvage pathway enzyme which catalyzes the transfer of the ribosyl-5-phosphate group from 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) to the N9 position of hypoxanthine to yield IMP (inosine 5'-monophosphate). To a lesser extent, can also act on guanine leading to GMP, but shows a highly less efficient activity with xanthine.1 Publication
Miscellaneous
E.coli cells express two distinct 6-oxopurine PRTases, with very different specificities for hypoxanthine, guanine, and xanthine. Salvage enzymes allow a more energy efficient synthesis of purine nucleoside monophosphates compared with the de novo pathway. The kinetic analysis suggests that E.coli HPRT is mainly responsible for the synthesis of IMP and that XGPRT primarily salvages guanine and xanthine.1 Publication
Catalytic activityi
- EC:2.4.2.81 PublicationThis reaction proceeds in the backward1 Publication direction.
- EC:2.4.2.81 PublicationThis reaction proceeds in the backward1 Publication direction.
Cofactori
Mg2+1 Publication
Activity regulationi
Inhibited by the product IMP (PubMed:12070315). Highly inhibited by nucleoside phosphonates, which are product analogs (PubMed:23927482, Ref. 6).3 Publications
Kineticsi
kcat is 59.0 sec(-1) with hypoxanthine as substrate. kcat is 10.2 sec(-1) with guanine as substrate. kcat is 0.008 sec(-1) with xanthine as substrate (at pH 8.5 and 25 degrees Celsius).1 Publication
- KM=12.5 µM for hypoxanthine (at pH 8.5 and 25 degrees Celsius)1 Publication
- KM=294 µM for guanine (at pH 8.5 and 25 degrees Celsius)1 Publication
- KM=25 µM for xanthine (at pH 8.5 and 25 degrees Celsius)1 Publication
- KM=192 µM for 5-phospho-alpha-D-ribose 1-diphosphate (at pH 8.5 and 25 degrees Celsius)1 Publication
: IMP biosynthesis via salvage pathway Pathwayi
This protein is involved in step 1 of the subpathway that synthesizes IMP from hypoxanthine.1 PublicationProteins known to be involved in this subpathway in this organism are:
- Hypoxanthine phosphoribosyltransferase (FAZ83_06800), Hypoxanthine phosphoribosyltransferase (hpt)
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.
Sites
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Metal bindingi | 99 | MagnesiumCombined sources1 Publication | 1 | |
Binding sitei | 99 | IMP or GMPCombined sources1 Publication | 1 | |
Metal bindingi | 100 | MagnesiumCombined sources1 Publication | 1 | |
Active sitei | 103 | Proton acceptor1 Publication | 1 | |
Binding sitei | 131 | IMP or GMPCombined sources1 Publication | 1 | |
Binding sitei | 159 | GMP; via carbonyl oxygenCombined sources1 Publication | 1 | |
Binding sitei | 165 | DiphosphateBy similarity | 1 |
Regions
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Nucleotide bindingi | 103 – 108 | IMP or GMPCombined sources1 Publication | 6 |
GO - Molecular functioni
- guanine phosphoribosyltransferase activity Source: EcoCyc
- guanosine tetraphosphate binding Source: EcoCyc
- hypoxanthine phosphoribosyltransferase activity Source: EcoCyc
- magnesium ion binding Source: EcoCyc
GO - Biological processi
- adenine salvage Source: GO_Central
- GMP salvage Source: EcoliWiki
- guanine salvage Source: GO_Central
- hypoxanthine metabolic process Source: GO_Central
- IMP salvage Source: EcoliWiki
- protein homotetramerization Source: EcoCyc
Keywordsi
Molecular function | Glycosyltransferase, Transferase |
Biological process | Purine salvage |
Ligand | Magnesium, Metal-binding, Nucleotide-binding |
Enzyme and pathway databases
BioCyci | EcoCyc:HYPOXANPRIBOSYLTRAN-MONOMER MetaCyc:HYPOXANPRIBOSYLTRAN-MONOMER |
UniPathwayi | UPA00591;UER00648 |
Names & Taxonomyi
Protein namesi | Recommended name: Hypoxanthine phosphoribosyltransferase1 Publication (EC:2.4.2.81 Publication)Short name: HPRT1 Publication Alternative name(s): 6-oxopurine phosphoribosyltransferase1 Publication Short name: 6-oxopurine PRTase1 Publication |
Gene namesi | Name:hpt Ordered Locus Names:b0125, JW5009 |
Organismi | Escherichia coli (strain K12) |
Taxonomic identifieri | 83333 [NCBI] |
Taxonomic lineagei | Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacterales › Enterobacteriaceae › Escherichia › |
Proteomesi |
|
Subcellular locationi
Cytoplasm and Cytosol
Cytosol
- cytosol Source: EcoCyc
Keywords - Cellular componenti
CytoplasmPTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
ChainiPRO_0000139632 | 1 – 178 | Hypoxanthine phosphoribosyltransferaseAdd BLAST | 178 |
Proteomic databases
jPOSTi | P0A9M2 |
PaxDbi | P0A9M2 |
PRIDEi | P0A9M2 |
2D gel databases
SWISS-2DPAGEi | P0A9M2 |
Interactioni
Subunit structurei
Homotetramer.
1 PublicationProtein-protein interaction databases
BioGRIDi | 4261679, 26 interactors 850970, 3 interactors |
DIPi | DIP-47994N |
IntActi | P0A9M2, 5 interactors |
STRINGi | 511145.b0125 |
Structurei
Secondary structure
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details3D structure databases
SMRi | P0A9M2 |
ModBasei | Search... |
PDBe-KBi | Search... |
Miscellaneous databases
EvolutionaryTracei | P0A9M2 |
Family & Domainsi
Region
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Regioni | 43 – 44 | DiphosphateBy similarity | 2 |
Sequence similaritiesi
Belongs to the purine/pyrimidine phosphoribosyltransferase family.Curated
Phylogenomic databases
eggNOGi | COG0634, Bacteria |
HOGENOMi | CLU_073615_0_0_6 |
InParanoidi | P0A9M2 |
PhylomeDBi | P0A9M2 |
Family and domain databases
CDDi | cd06223, PRTases_typeI, 1 hit |
Gene3Di | 3.40.50.2020, 1 hit |
InterProi | View protein in InterPro IPR005904, Hxn_phspho_trans IPR000836, PRibTrfase_dom IPR029057, PRTase-like |
Pfami | View protein in Pfam PF00156, Pribosyltran, 1 hit |
SUPFAMi | SSF53271, SSF53271, 1 hit |
TIGRFAMsi | TIGR01203, HGPRTase, 1 hit |
PROSITEi | View protein in PROSITE PS00103, PUR_PYR_PR_TRANSFER, 1 hit |
i Sequence
Sequence statusi: Complete.
P0A9M2-1 [UniParc]FASTAAdd to basket
10 20 30 40 50
MKHTVEVMIP EAEIKARIAE LGRQITERYK DSGSDMVLVG LLRGSFMFMA
60 70 80 90 100
DLCREVQVSH EVDFMTASSY GSGMSTTRDV KILKDLDEDI RGKDVLIVED
110 120 130 140 150
IIDSGNTLSK VREILSLREP KSLAICTLLD KPSRREVNVP VEFIGFSIPD
160 170
EFVVGYGIDY AQRYRHLPYI GKVILLDE
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | U00096 Genomic DNA Translation: AAC73236.2 AP009048 Genomic DNA Translation: BAB96700.2 |
RefSeqi | NP_414667.4, NC_000913.3 WP_000683335.1, NZ_STEB01000010.1 |
Genome annotation databases
EnsemblBacteriai | AAC73236; AAC73236; b0125 BAB96700; BAB96700; BAB96700 |
GeneIDi | 58463620 946624 |
KEGGi | ecj:JW5009 eco:b0125 |
PATRICi | fig|1411691.4.peg.2157 |
Similar proteinsi
Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | U00096 Genomic DNA Translation: AAC73236.2 AP009048 Genomic DNA Translation: BAB96700.2 |
RefSeqi | NP_414667.4, NC_000913.3 WP_000683335.1, NZ_STEB01000010.1 |
3D structure databases
Select the link destinations: PDBei RCSB PDBi PDBji Links Updated | PDB entry | Method | Resolution (Å) | Chain | Positions | PDBsum |
1G9S | X-ray | 2.80 | A/B | 1-178 | [»] | |
1G9T | X-ray | 2.80 | A/B | 1-178 | [»] | |
1GRV | X-ray | 2.90 | A/B | 1-178 | [»] | |
5KNR | X-ray | 2.86 | A/B | 1-178 | [»] | |
5KNS | X-ray | 2.79 | A/B | 1-178 | [»] | |
5KNT | X-ray | 2.55 | A/B | 1-178 | [»] | |
5KNU | X-ray | 2.81 | A/B | 1-178 | [»] | |
5KNV | X-ray | 2.86 | A/B | 1-178 | [»] | |
5KNX | X-ray | 2.40 | A/B | 1-178 | [»] | |
SMRi | P0A9M2 | |||||
ModBasei | Search... | |||||
PDBe-KBi | Search... |
Protein-protein interaction databases
BioGRIDi | 4261679, 26 interactors 850970, 3 interactors |
DIPi | DIP-47994N |
IntActi | P0A9M2, 5 interactors |
STRINGi | 511145.b0125 |
Chemistry databases
DrugBanki | DB04566, Inosinic Acid |
2D gel databases
SWISS-2DPAGEi | P0A9M2 |
Proteomic databases
jPOSTi | P0A9M2 |
PaxDbi | P0A9M2 |
PRIDEi | P0A9M2 |
Genome annotation databases
EnsemblBacteriai | AAC73236; AAC73236; b0125 BAB96700; BAB96700; BAB96700 |
GeneIDi | 58463620 946624 |
KEGGi | ecj:JW5009 eco:b0125 |
PATRICi | fig|1411691.4.peg.2157 |
Organism-specific databases
EchoBASEi | EB4143 |
Phylogenomic databases
eggNOGi | COG0634, Bacteria |
HOGENOMi | CLU_073615_0_0_6 |
InParanoidi | P0A9M2 |
PhylomeDBi | P0A9M2 |
Enzyme and pathway databases
UniPathwayi | UPA00591;UER00648 |
BioCyci | EcoCyc:HYPOXANPRIBOSYLTRAN-MONOMER MetaCyc:HYPOXANPRIBOSYLTRAN-MONOMER |
Miscellaneous databases
EvolutionaryTracei | P0A9M2 |
PROi | PR:P0A9M2 |
Family and domain databases
CDDi | cd06223, PRTases_typeI, 1 hit |
Gene3Di | 3.40.50.2020, 1 hit |
InterProi | View protein in InterPro IPR005904, Hxn_phspho_trans IPR000836, PRibTrfase_dom IPR029057, PRTase-like |
Pfami | View protein in Pfam PF00156, Pribosyltran, 1 hit |
SUPFAMi | SSF53271, SSF53271, 1 hit |
TIGRFAMsi | TIGR01203, HGPRTase, 1 hit |
PROSITEi | View protein in PROSITE PS00103, PUR_PYR_PR_TRANSFER, 1 hit |
ProtoNeti | Search... |
MobiDBi | Search... |
Entry informationi
Entry namei | HPRT_ECOLI | |
Accessioni | P0A9M2Primary (citable) accession number: P0A9M2 Secondary accession number(s): P36766 | |
Entry historyi | Integrated into UniProtKB/Swiss-Prot: | July 19, 2005 |
Last sequence update: | July 19, 2005 | |
Last modified: | April 7, 2021 | |
This is version 125 of the entry and version 1 of the sequence. See complete history. | ||
Entry statusi | Reviewed (UniProtKB/Swiss-Prot) | |
Annotation program | Prokaryotic Protein Annotation Program |
Miscellaneousi
Keywords - Technical termi
3D-structure, Reference proteomeDocuments
- PATHWAY comments
Index of metabolic and biosynthesis pathways - PDB cross-references
Index of Protein Data Bank (PDB) cross-references - SIMILARITY comments
Index of protein domains and families