Difference between revisions of "DXS"

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(DXS parameters)
(DXS parameters)
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== DXS parameters ==
 
== DXS parameters ==
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[[File:DXS_Kcat.png | left |600px ]]
  
 
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Revision as of 15:07, 23 March 2017

You can go back to main page of the kinetic model here.


The DXS reaction (EC 2.2.1.7)


Pyruvate + G3P \rightleftharpoons DXP + CO2

Deoxyxylulose-5-phosphate synthase (DXS) catalyses the production of 1-deoxy-D-xylulose 5-phosphate (DXP) from pyruvate and glyceraldehyde 3-phosphate (G3P). This reaction is the first step in the MEP pathway.

Modelling DXS

In the kinetic model, the DXS reaction is modelled with reversible Michaelis-Menten using the Hanekom [1] bi-bi random order generic equation. In total, this reaction requires five kinetic parameters (Kms for all substrates and products, and a forward Kcat) and one thermodynamic parameter (Equilibrium constant, Keq).



V_\mathrm{DXS}= \cfrac{Kcat_\mathrm{forward} \bullet [DXS] \bullet \left( \cfrac{[Pyr]}{Km_\mathrm{DXS}} \right) \bullet \left( \cfrac{[G3P]}{Km_\mathrm{g3p}} \right) \bullet \left( 1 - \cfrac{\left( \cfrac{[DXP]\bullet[CO2]}{[Pyr]\bullet[G3P]} \right)}{K_\mathrm{eq}} \right)} {\left( 1 + \cfrac {[Pyr]}{Km_\mathrm{pyr}} + \cfrac{[CO2]}{Km_\mathrm{co2}}\right) \bullet \left( 1 + \cfrac{[G3P]}{Km_\mathrm{g3p}} + \cfrac{[DXP]}{KM_\mathrm{dxp}} \right)}

DXS parameters

DXS Kcat.png
Parameter Direction Substrate Value Unit Weight Description Reference
Kcat Forward DXS 229.7 1/min 16 from E. coli wild type DXS, with non-optimal buffer: 40mM Tris, pH 8, 37C ; Km_GAP:52.5 +/- 8.3 microM; Km_pyruvate: 86.3 +/- 16.2 microM, kcat: 145.50 +/- 12.7 1/min [2]
Kcat Forward DXS 153.6 1/min 16 from E. coli wild type DXS, with non-optimal buffer: 40mM Tris, pH 8, 37C ; Km_GAP:52.5 +/- 8.3 microM; Km_pyruvate: 86.3 +/- 16.2 microM, kcat: 145.50 +/- 12.7 1/min [2]
Kcat Forward DXS 145.5 1/min 16 from E. coli wild type DXS, with non-optimal buffer: 40mM Tris, pH 8, 37C ; Km_GAP:52.5 +/- 8.3 microM; Km_pyruvate: 86.3 +/- 16.2 microM, kcat: 145.50 +/- 12.7 1/min [2]
Kcat Forward DXS 209 1/min 16 from E. coli wild type DXS, with non-optimal buffer: 100mM Tris, pH 8, 37C ; Km_GAP:279.0+/- 7.2microM; Km_pyruvate: 74.70+/- 7.3 microM, kcat: 209.0 +/- 6.3 1/min [2]
Kcat Forward DXS 173 1/min 16 from E. coli wild type DXS, with non-optimal buffer: 100mM Tris, pH 8, 37C ; Km_GAP:279.0+/- 7.2microM; Km_pyruvate: 74.70+/- 7.3 microM, kcat: 209.0 +/- 6.3 1/min [2]
Kcat Forward DXS 246 1/min 16 from E. coli wild type DXS, with non-optimal buffer: 100mM Tris, pH 8, 37C ; Km_GAP:279.0+/- 7.2microM; Km_pyruvate: 74.70+/- 7.3 microM, kcat: 209.0 +/- 6.3 1/min [2]
Kcat Forward GAP 48 1/min 256 Taken from Cane 2001's ref20. E.coli DXS in 40mM Tris, pH7.5, 37¡C. Km pyruvate 2.9 ± 0.5 mM. [3]
Kcat Forward GAP 66 1/min 128 DXPS2; in vitro- S. coelicolor gene expressed in E. coli; pH 7.5, 47C. [4]
Kcat Forward GAP 114 1/min 8 from R. capsulatus, pH 7.4, 37C [5]
Kcat Forward GAP 660 1/min 64 from Plasmodium, expressed in E. coli. Look at Table 3. pH7-7.5;37C, Km_GAp:19 +/- 4 microM; Km_Pyruvate: 870 +/- 110 microM. [6]
Kcat Forward GAP 1608 1/min 8 dxs11 from Agrobacterium tumefaciens, pH8.0, 37¡C, expressed in E. coli [7]
Kcat Forward GAP 120 1/min 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]
Kcat Forward GAP 120 1/min 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]
Kcat Forward GAP 360 1/min 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]
Kcat Forward Pyruvate 570 1/min 64 from Plasmodium, expressed in E. coli. Look at Table 3. pH7-7.5;37C, Km_GAp:19 +/- 4 microM; Km_Pyruvate: 870 +/- 110 microM. [6]
Kcat Forward Pyruvate 144 1/min 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]
Kcat Forward Pyruvate 114 1/min 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]
Kcat Forward Pyruvate 312 1/min 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]
Parameter Direction Substrate Value Unit Weight Description Reference
Km Forward G3P 6.1 µM 8 pH 7.9, 37C (optimal), Mycobacterium tuberculosis, Km_G3P 6.1 microM, Km_Pyr 40 microM Bailey2002, Br658834
Km Forward G3P 1670 µM 64 from Vitis vinifera L. ; expressed in E. coli DH5a, pH 8.0; 37C; VvDXS N284 Battilana2011, Br720131
Km Forward G3P 1780 µM 64 from Vitis vinifera L. ; expressed in E. coli DH5a, pH 8.0; 37C; VvDXS N284 Battilana2011, Br720131
Km Forward G3P 900 µM 256 Taken from Cane 2001's ref20. E.coli DXS in 40mM Tris, pH7.5, 37¡C. Km pyruvate 2.9 ± 0.5 mM. Boronat1999
Km Forward G3P 750 µM 64 from Capsicum anuum; Km_pyruvate: 500 microM; Km_GAP: 750 microM Bouvier1998
Km Forward G3P 30.3 µM 16 from E. coli wild type DXS, Optimal buffer: 100 mM HEPES, pH 8, 37C ; Km_GAP:23.5 +/- 1.7 microM; Km_pyruvate: 48.7 +/- 8.0 microM, kcat: 153.6 +/- 6.8 1/min [2]
Km Forward G3P 23.5 µM 16 from E. coli wild type DXS, Optimal buffer: 100 mM HEPES, pH 8, 37C ; Km_GAP:23.5 +/- 1.7 microM; Km_pyruvate: 48.7 +/- 8.0 microM, kcat: 153.6 +/- 6.8 1/min. Kinetics were measured in different buffers (buffer optimization study). All buffers ph*, 37C [2]
Km Forward G3P 52.5 µM 16 from E. coli wild type DXS, Optimal buffer: 100 mM HEPES, pH 8, 37C ; Km_GAP:23.5 +/- 1.7 microM; Km_pyruvate: 48.7 +/- 8.0 microM, kcat: 153.6 +/- 6.8 1/min [2]
Km Forward G3P 600 µM 128 DXPS1; in vitro- S. coelicolor gene expressed in E. coli; pH 7.5, 47C. [4]
Km Forward G3P 200 µM 128 DXPS2; in vitro- S. coelicolor gene expressed in E. coli; pH 7.5, 47C. [4]
Km Forward G3P 68 µM 8 from Rhodobacter capsulatus, pH7.4, 37C, Km_GAP: 0.068 +/- 0.001 mM, Km_pyr: 0.44 +/- 0.05 mM. [5]
Km Forward G3P 111 µM 16 from Grey poplar leaves, pH 8.6; 45 C; Ghirardo2010
Km Forward G3P 150 µM 128 from Rhodobacter capsulatus, pH7.4, 37¡C; expressed in E. coli; recombinant isoenzyme-A; Km_pyruvate: 610 +/- 50 microM; Km_GAP: 150 +/- 10 microM; Vmax = 1.9 +/- 0.1 micrommol/min/mg; Hahn2001, Br395816
Km Forward G3P 120 µM 128 from Rhodobacter capsulatus, pH7.4, 37¡C; expressed in E. coli; recombinant isoenzyme-A; Km_pyruvate: 610 +/- 50 microM; Km_GAP: 150 +/- 10 microM; Vmax = 1.9 +/- 0.1 micrommol/min/mg; Hahn2001, Br395816
Km Forward G3P 19 µM 64 from Plasmodium, expressed in E. coli. Look at Table 3. pH7-7.5;37C, Km_GAp:19 +/- 4 microM; Km_Pyruvate: 870 +/- 110 microM. [6]
Km Forward G3P 120 µM 8 from Streptomyces sp. strain CL190, expressed in E. coli. pH 9.0, 42-44C. Table 1. Km_pyruvate: 65microM, Km_GAP: 120 microM Kuzuyama2000, Br395812
Km Forward G3P 240 µM 32 from E. coli. pH 7.5-8.0.0, 42-44C. Km_pyruvate: 65microM, Km_GAP: 120 microM. See Table 1. Measured to compare with DXS from streptomyces. Purified in Kuzuyama1998 study. Kuzuyama2000, Br395812
Km Forward G3P 23.2 µM 8 dxs11 from Agrobacterium tumefaciens, pH8.0, 37¡C, expressed in E. coli Lee2007, Br674982
Km Forward G3P 470 µM 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]
Km Forward G3P 870 µM 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]
Km Forward G3P 1000 µM 64 from Botrycoccus braunnii. Three recombinant enzymes used: DXS-I, DXS-II, DXS-III which are different by the digestion pattern using Xhol and BamHI. expressed in E. coli; pH 7.8 , 32 C; Km 1800 +/- 200 microM [8]

References

  1. Hanekom, A. J. 2006. "Generic kinetic equations for modelling multisubstrate reactions in computational systems biology", MSc Thesis submitted at the University of Stellenbosch
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Brammer, L.A. 2011 "1-FDeoxy-D-xylulose 5-phosphate synthase catalyzes a novel random sequential mechanism", JBioChem, 283(42):36522-36531.
  3. Brammer, L.A. 2011 "1-Deoxy-D-xylulose 5-phosphate synthase catalyzes a novel random sequential mechanism", JBioChem, 283(42):36522-36531.
  4. 4.0 4.1 4.2 Cane, D.E., et. al.. 2001 "Molecular cloning, expression and characterization of the first three genes in the mevalonate-independent isoprenoid pathway in Streptomyces coelicolor ", Bioorganic & Medicinal Chemistry, 9:1467-1477.
  5. 5.0 5.1 Eubanks, L.M. & Poulter, C.D. 2003. "Rhodobacter capsulatus 1-Deoxy-D-xylulose 5-Phosphate Synthase: Steady-State Kinetics and Substrate Binding† ", Biochemistry, 42:1140-1149.
  6. 6.0 6.1 6.2 Handa, S. et. al. 2013. "Production of recombinant 1-deoxy-d-xylulose-5-phosphate synthase from Plasmodium vivax in Escherichia coli", Biochemistry, 3:124-129. Cite error: Invalid <ref> tag; name "Handa2013" defined multiple times with different content
  7. Lee, J. et. al. 2007. "Cloning and characterization of the dxs gene, encoding 1-deoxy-d-xylulose 5-phosphate synthase from Agrobacterium tumefaciens, and its overexpression in Agrobacterium tumefaciens", JBiotech, 128:555-566.
  8. 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 Matsushima, D. et. al2012. "The single cellular green microalga Botryococcus braunii, race B possesses three distinct 1-deoxy-d-xylulose 5-phosphate synthases", PlantSci, 185-186:309-320.