Class of enzymes
6-Phosphogluconate dehydrogenase (6PGD ) is an enzyme in the pentose phosphate pathway . It forms ribulose 5-phosphate from 6-phosphogluconate :
6-phospho-D-gluconate + NAD(P)+
⇌ ⇌ -->
{\displaystyle \rightleftharpoons }
+ It is an oxidative carboxylase that catalyses the oxidative decarboxylation of 6-phosphogluconate into ribulose 5-phosphate in the presence of NADP . This reaction is a component of the hexose mono-phosphate shunt and pentose phosphate pathways (PPP).[ 2] [ 3] Prokaryotic and eukaryotic 6PGD are proteins of about 470 amino acids whose sequences are highly conserved .[ 4] homodimer in which the monomers act independently:[ 3] alpha-helical domain and a smaller beta-alpha-beta domain, containing a mixed parallel and anti-parallel 6-stranded beta sheet .[ 3] substrate binding in an adjacent pocket.[ 3]
Biotechnological significance
Recently, 6PGD was demonstrated to catalyze also the reverse reaction (i.e. reductive carboxylation ) in vivo .[ 5] Escherichia coli selection strains revealed that this reaction was efficient enough to support the formation of biomass based solely on CO2 and pentose sugars . In the future, this property could be exploited for synthetic carbon fixation routes.
Clinical significance
Mutations within the gene coding this enzyme result in 6-phosphogluconate dehydrogenase deficiency , an autosomal hereditary disease affecting the red blood cells.
As a possible drug target
6PGD is involved in cancer cell metabolism so 6PGD inhibitors have been sought.[ 6]
See also
References
^ PDB : 1PGQ Adams MJ, Ellis GH, Gover S, Naylor CE, Phillips C (July 1994). "Crystallographic study of coenzyme, coenzyme analogue and substrate binding in 6-phosphogluconate dehydrogenase: implications for NADP specificity and the enzyme mechanism". Structure . 2 (7): 651–68. doi :10.1016/s0969-2126(00)00066-6 . PMID 7922042 . ^ Broedel SE, Wolf RE (July 1990). "Genetic tagging, cloning, and DNA sequence of the Synechococcus sp. strain PCC 7942 gene (gnd) encoding 6-phosphogluconate dehydrogenase" . J. Bacteriol . 172 (7): 4023–31. doi :10.1128/jb.172.7.4023-4031.1990 . PMC 213388 PMID 2113917 . ^ a b c d Adams MJ, Archibald IG, Bugg CE, Carne A, Gover S, Helliwell JR , Pickersgill RW, White SW (1983). "The three dimensional structure of sheep liver 6-phosphogluconate dehydrogenase at 2.6 A resolution" . EMBO J . 2 (6): 1009–14. doi :10.1002/j.1460-2075.1983.tb01535.x . PMC 555222 PMID 6641716 . ^ Reizer A, Deutscher J, Saier MH, Reizer J (May 1991). "Analysis of the gluconate (gnt) operon of Bacillus subtilis". Mol. Microbiol . 5 (5): 1081–9. doi :10.1111/j.1365-2958.1991.tb01880.x . PMID 1659648 . S2CID 2006623 . ^ Satanowski A, Dronsella B, Noor E, Vögeli B, He H, Wichmann P, et al. (November 2020). "Awakening a latent carbon fixation cycle in Escherichia coli" . Nature Communications . 11 (1): 5812. Bibcode :2020NatCo..11.5812S . doi :10.1038/s41467-020-19564-5 . PMC 7669889 PMID 33199707 . ^ 6-Phosphogluconate dehydrogenase links oxidative PPP, lipogenesis and tumour growth by inhibiting LKB1–AMPK signalling. 2015
Further reading
Activity Regulation Classification Kinetics Types
