Glucose-6-phosphate isomerase

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Not to be confused with D-xylose isomerase.
Glucose-6-phosphate isomerase
Glucose-6-phosphate isomerase 1GZV wpmp.png
Identifiers
EC number 5.3.1.9
CAS number 9001-41-6
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
Bacterial phospho-glucose isomerase C-terminal region
PDB 1x9h EBI.jpg
crystal structure of phosphoglucose/phosphomannose isomerase from pyrobaculum aerophilum in complex with fructose 6-phosphate
Identifiers
Symbol bact-PGI_C
Pfam PF10432
InterPro IPR019490
Phosphoglucose isomeras
Identifiers
Symbol PGI
Pfam PF00342
SCOP 1pgi
SUPERFAMILY 1pgi
Glucose-6-phosphate isomerase
Protein GPI PDB 1dqr.png
PDB rendering based on 1dqr.
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
Symbols GPI ; AMF; GNPI; NLK; PGI; PHI; SA-36; SA36
External IDs OMIM172400 MGI95797 HomoloGene145 GeneCards: GPI Gene
EC number 5.3.1.9
RNA expression pattern
PBB GE GPI 208308 s at tn.png
More reference expression data
Orthologs
Species Human Mouse
Entrez 2821 14751
Ensembl ENSG00000105220 ENSMUSG00000036427
UniProt P06744 P06745
RefSeq (mRNA) NM_000175 NM_008155
RefSeq (protein) NP_000166 NP_032181
Location (UCSC) Chr 19:
34.85 – 34.89 Mb
Chr 7:
34.2 – 34.23 Mb
PubMed search [1] [2]

Glucose-6-phosphate isomerase (alternatively known as phosphoglucose isomerase or phosphohexose isomerase) is an enzyme that catalyzes the conversion of glucose-6-phosphate into fructose 6-phosphate in the second step of glycolysis.

The human variant of this enzyme is encoded by the GPI gene.[1]

Structure[edit]

PGI monomers are made of two domains, one made of two separate segments called the large domain and the other made of the segment in between called the small domain.[2] The two domains are each αβα sandwiches, with the small domain containing a five-strand β-sheet surrounded by α-helices while the large domain has a six-stranded β-sheet.[3] The large domain and the C-terminal of each monomer also contain "arm-like" protrusions.[2]

Functional PGI is a dimer composed of two identical monomers. The two monomers interact notably through the two protrusions in a hugging embrace. The active site of each monomer is formed by a cleft between the two domains and the dimer interface.[3]

Mechanism[edit]

The mechanism that PGI uses to interconvert glucose 6-phosphate and fructose 6-phosphate consists of three major steps: opening the glucose ring, isomerizing glucose into fructose through an enediol intermediate, and closing the fructose ring.[4]

Glucose 6 phosphate binds to PGI as a hemiacetal ring. The ring is opened in a "push-pull" mechanism by His388, which protonates the C5 oxygen, and Lys518, which deprotonates the C1 hydroxyl group. This creates an open chain aldose. Then, the substrated is rotated about the C3-C4 bond to position it for isomerization. At this point, Glu357 deprotonates C2 to create a cis-enediolate intermediate stabilized by Arg272. To complete the isomerization, Glu357 donates its proton to C1, the C2 hydroxyl group loses its proton and the open-chain ketose, Fructose 6-phosphate is formed. Finally, the ring is closed by rotating the substrate about the C3-C4 bond again and deptrotonating the C5 hydroxyl with Lys518 to cause to the opposite of the ring opening mechanism used to start the reaction.[5]

Function[edit]

This gene belongs to the GPI family whose members encode multifunctional phosphoglucose isomerase proteins involved in energy pathways. The protein encoded by this gene is a dimeric enzyme that catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate.

glucose 6-phosphate <=> fructose 6-phosphate

The protein has different functions inside and outside the cell. In the cytoplasm, the protein is involved in glycolysis and gluconeogenesis, while outside the cell it functions as a neurotrophic factor for spinal and sensory neurons. The same protein is also secreted by cancer cells, where it is called autocrine motility factor[6] and stimulates metastasis.[7] Defects in this gene are the cause of nonspherocytic hemolytic anemia and a severe enzyme deficiency can be associated with hydrops fetalis, immediate neonatal death and neurological impairment.[1]

Glycolysis[edit]

α-D-Glucose 6-phosphate Phosphoglucose isomerase β-D-Fructose 6-phosphate
Alpha-D-glucose-6-phosphate wpmp.png   Beta-D-fructose-6-phosphate wpmp.png
Biochem reaction arrow reversible NNNN horiz med.png
 
  Phosphoglucose isomerase

Compound C00668 at KEGG Pathway Database. Enzyme 5.3.1.9 at KEGG Pathway Database. Compound C05345 at KEGG Pathway Database. Reaction R00771 at KEGG Pathway Database.

Click on genes, proteins and metabolites below to link to respective articles. [§ 1]

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GlycolysisGluconeogenesis_WP534 go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to Entrez go to article go to article go to article go to article go to article go to WikiPathways go to article go to Entrez go to article
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Glycolysis and Gluconeogenesis edit
  1. ^ The interactive pathway map can be edited at WikiPathways: "GlycolysisGluconeogenesis_WP534". 

Isomerization of glucose[edit]

D-Glucose Phosphoglucose isomerase D-Fructose
D-glucose wpmp.png   Alpha-d-fructose.svg
Biochem reaction arrow reversible NNNN horiz med.png
 
  Phosphoglucose isomerase

Neuroleukin[edit]

Though originally treated as separate proteins, cloning technology demonstrated that PGI is almost identical to the protein neuroleukin.[8] Neuroleukin is a neurotrophic factor for spinal and sensory neurons. It is found in large amounts in muscle, brain, heart, and kidneys.[9]

Neuroleukin also acts as a lymphokine secreted by T cells stimulated by lectin. It induces immunoglobulin secretion in B cells as part of a response that activates antibody-secreting cells.[10]

Tumor Cell Autocrine Motility Factor[edit]

Cloning experiments also revealed that PGI is identical to the protein known as autocrine motility factor.[11] Autocrine motility factor produced and secreted by cancer cells and stimulates cell growth and motility as a growth factor.[12] Autocrine motility factor is thought to play a key role in cancer metastasis.[13]

Prokaryotic bifunctional glucose-6-phosphate isomerase[edit]

In some archaea and bacteria glucose-6-phosphate isomerase (PGI) activity occurs via a bifunctional enzyme that also exhibits phosphomannose isomerase (PMI) activity. Though not closely related to eukaryotic PGIs, the bifunctional enzyme is similar enough that the sequence includes the cluster of threonines and serines that forms the sugar phosphate-binding site in conventional PGI. The enzyme is thought to use the same catalytic mechanisms for both glucose ring-opening and isomerisation for the interconversion of glucose 6-phosphate to fructose 6-phosphate.[14]

Clinical significance[edit]

A deficiency of phosphoglucose isomerase is responsible for 4% of the hemolytic anemias due to glycolytic enzyme deficiencies.[15][16][17]

Several cases of glucose phosphate isomerase deficiency have recently been identified.[18]

References[edit]

  1. ^ a b "Entrez Gene: GPI glucose phosphate isomerase". 
  2. ^ a b Sun YJ, Chou CC, Chen WS, Wu RT, Meng M, Hsiao CD (May 1999). "The crystal structure of a multifunctional protein: phosphoglucose isomerase/autocrine motility factor/neuroleukin". Proc Natl Acad Sci U S A 96 (10): 5412–5417. doi:10.1073/pnas.96.10.5412. PMC 21873. PMID 10318897. 
  3. ^ a b Jeffery CJ, Bahnson BJ, Chien W, Ringe D, Petsko GA (February 2000). "Crystal structure of rabbit phosphoglucose isomerase, a glycolytic enzyme that moonlights as neuroleukin, autocrine motility factor, and differentiation mediator". Biochemistry 39 (5): 955–64. doi:10.1021/bi991604m. PMID 10653639. 
  4. ^ Read J, Pearce J, Li X, Muirhead H, Chirgwin J, Davies C (June 2001). "The crystal structure of human phosphoglucose isomerase at 1.6 A resolution: implications for catalytic mechanism, cytokine activity and haemolytic anaemia". J Mol Biol. 309 (2): 447–63. doi:10.1006/jmbi.2001.4680. PMID 11371164. 
  5. ^ Graham Solomons JT, Zimmerly EM, Burns S, Krishnamurthy N, Swan MK, Krings S, Muirhead H, Chirgwin J, Davies C (September 2004). "The crystal structure of mouse phosphoglucose isomerase at 1.6A resolution and its complex with glucose 6-phosphate reveals the catalytic mechanism of sugar ring opening". J Mol Biol. 342 (3): 847–60. doi:10.1016/j.jmb.2004.07.085. PMID 15342241. 
  6. ^ Dobashi Y, Watanabe H, Sato Y, et al. (December 2006). "Differential expression and pathological significance of autocrine motility factor/glucose-6-phosphate isomerase expression in human lung carcinomas". J. Pathol. 210 (4): 431–40. doi:10.1002/path.2069. PMID 17029220. 
  7. ^ Watanabe H, Takehana K, Date M, Shinozaki T, Raz A (1 July 1996). "Tumor cell autocrine motility factor is the neuroleukin/phosphohexose isomerase polypeptide". Cancer Res. 56 (13): 2960–3. PMID 8674049. 
  8. ^ Chaput M, Claes V, Portetelle D, Cludts I, Cravador A, Burny A, Gras H, Tartar A (March 1988). "The neurotrophic factor neuroleukin is 90% homologous with phosphohexose isomerase". Nature 332 (6163): 454–5. doi:10.1038/332454a0. PMID 3352744. 
  9. ^ Gurney ME, Heinrich SP, Lee MR, Yin HS (October 1986). "Molecular cloning and expression of neuroleukin, a neurotrophic factor for spinal and sensory neurons". Science 234 (4776): 566–74. doi:10.1126/science.3764429. PMID 3764429. 
  10. ^ Gurney ME, Apatoff BR, Spear GT, Baumel MJ, Antel JP, Bania MB, Reder AT (October 1986). "Neuroleukin: a lymphokine product of lectin-stimulated T cells". Science 234 (4776): 574–81. doi:10.1126/science.3020690. PMID 3020690. 
  11. ^ Watanabe H, Takehana K, Date M, Shinozaki T, Raz A (July 1996). "Tumor cell autocrine motility factor is the neuroleukin/phosphohexose isomerase polypeptide". Cancer Res. 56 (13): 2960–3. PMID 8674049. 
  12. ^ Silletti S, Raz A (July 1993). "Autocrine motility factor is a growth factor". Biochem Biophys Res Commun. 194 (1): 454–5. doi:10.1006/bbrc.1993.1840. PMID 8392842. 
  13. ^ Liotta LA, Mandler R, Murano G, Katz DA, Gordon RK, Chiang PK, Schiffmann E (May 1986). "Tumor cell autocrine motility factor". Proc Natl Acad Sci U S A 83 (10): 3302–6. doi:10.1073/pnas.83.10.3302. PMID 3085086. 
  14. ^ Swan MK, Hansen T, Schonheit P, Davies C (September 2004). "A novel phosphoglucose isomerase (PGI)/phosphomannose isomerase from the crenarchaeon Pyrobaculum aerophilum is a member of the PGI superfamily: structural evidence at 1.16-A resolution". J. Biol. Chem. 279 (38): 39838–45. doi:10.1074/jbc.M406855200. PMID 15252053. 
  15. ^ Walker JI, Layton DM, Bellingham AJ, Morgan MJ, Faik P (March 1993). "DNA sequence abnormalities in human glucose 6-phosphate isomerase deficiency". Hum. Mol. Genet. 2 (3): 327–9. doi:10.1093/hmg/2.3.327. PMID 8499925. 
  16. ^ Kanno H, Fujii H, Hirono A, Ishida Y, Ohga S, Fukumoto Y, Matsuzawa K, Ogawa S, Miwa S (September 1996). "Molecular analysis of glucose phosphate isomerase deficiency associated with hereditary hemolytic anemia". Blood 88 (6): 2321–5. PMID 8822954. 
  17. ^ Kugler W, Lakomek M (March 2000). "Glucose-6-phosphate isomerase deficiency". Baillieres Best Pract. Res. Clin. Haematol. 13 (1): 89–101. doi:10.1053/beha.1999.0059. PMID 10916680. 
  18. ^ "GPI Deficiency". 

Further reading[edit]

  • Walker JI, Faik P, Morgan MJ (1990). "Characterization of the 5' end of the gene for human glucose phosphate isomerase (GPI).". Genomics 7 (4): 638–43. doi:10.1016/0888-7543(90)90212-D. PMID 2387591. 
  • Brownstein BH, Silverman GA, Little RD, et al. (1989). "Isolation of single-copy human genes from a library of yeast artificial chromosome clones.". Science 244 (4910): 1348–51. doi:10.1126/science.2544027. PMID 2544027. 
  • Mizrachi Y (1989). "Neurotrophic activity of monomeric glucophosphoisomerase was blocked by human immunodeficiency virus (HIV-1) and peptides from HIV-1 envelope glycoprotein.". J. Neurosci. Res. 23 (2): 217–24. doi:10.1002/jnr.490230212. PMID 2547084. 
  • Gurney ME, Apatoff BR, Spear GT, et al. (1986). "Neuroleukin: a lymphokine product of lectin-stimulated T cells.". Science 234 (4776): 574–81. doi:10.1126/science.3020690. PMID 3020690. 
  • Faik P, Walker JI, Redmill AA, Morgan MJ (1988). "Mouse glucose-6-phosphate isomerase and neuroleukin have identical 3' sequences.". Nature 332 (6163): 455–7. doi:10.1038/332455a0. PMID 3352745. 
  • Zanella A, Izzo C, Rebulla P, et al. (1981). "The first stable variant of erythrocyte glucose-phosphate isomerase associated with severe hemolytic anemia.". Am. J. Hematol. 9 (1): 1–11. doi:10.1002/ajh.2830090102. PMID 7435496. 
  • Faik P, Walker JI, Morgan MJ (1994). "Identification of a novel tandemly repeated sequence present in an intron of the glucose phosphate isomerase (GPI) gene in mouse and man.". Genomics 21 (1): 122–7. doi:10.1006/geno.1994.1233. PMID 7545951. 
  • Xu W, Beutler E (1995). "The characterization of gene mutations for human glucose phosphate isomerase deficiency associated with chronic hemolytic anemia.". J. Clin. Invest. 94 (6): 2326–9. doi:10.1172/JCI117597. PMC 330061. PMID 7989588. 
  • Xu W, Lee P, Beutler E (1996). "Human glucose phosphate isomerase: exon mapping and gene structure.". Genomics 29 (3): 732–9. doi:10.1006/geno.1995.9944. PMID 8575767. 
  • Baronciani L, Zanella A, Bianchi P, et al. (1996). "Study of the molecular defects in glucose phosphate isomerase-deficient patients affected by chronic hemolytic anemia.". Blood 88 (6): 2306–10. PMID 8822952. 
  • Beutler E, West C, Britton HA, et al. (1998). "Glucosephosphate isomerase (GPI) deficiency mutations associated with hereditary nonspherocytic hemolytic anemia (HNSHA).". Blood Cells Mol. Dis. 23 (3): 402–9. doi:10.1006/bcmd.1997.0157. PMID 9446754. 
  • Kanno H, Fujii H, Miwa S (1998). "Expression and enzymatic characterization of human glucose phosphate isomerase (GPI) variants accounting for GPI deficiency.". Blood Cells Mol. Dis. 24 (1): 54–61. doi:10.1006/bcmd.1998.0170. PMID 9616041. 
  • Kugler W, Breme K, Laspe P, et al. (1998). "Molecular basis of neurological dysfunction coupled with haemolytic anaemia in human glucose-6-phosphate isomerase (GPI) deficiency.". Hum. Genet. 103 (4): 450–4. doi:10.1007/s004390050849. PMID 9856489. 
  • Belyaeva OV, Balanovsky OP, Ashworth LK, et al. (1999). "Fine mapping of a polymorphic CA repeat marker on human chromosome 19 and its use in population studies.". Gene 230 (2): 259–66. doi:10.1016/S0378-1119(99)00056-6. PMID 10216265. 
  • Yakirevich E, Naot Y (2000). "Cloning of a glucose phosphate isomerase/neuroleukin-like sperm antigen involved in sperm agglutination.". Biol. Reprod. 62 (4): 1016–23. doi:10.1095/biolreprod62.4.1016. PMID 10727272. 
  • Haga A, Niinaka Y, Raz A (2000). "Phosphohexose isomerase/autocrine motility factor/neuroleukin/maturation factor is a multifunctional phosphoprotein.". Biochim. Biophys. Acta 1480 (1-2): 235–44. doi:10.1016/s0167-4838(00)00075-3. PMID 11004567. 

External links[edit]

This article incorporates text from the public domain Pfam and InterPro IPR019490