Thiaville2016 - Folate pathway model (PanB overexpression and THF regulation)

This model is described in the article:
Abstract:
Tetrahydrofolate (THF) and its one-carbon derivatives, collectively termed folates, are essential cofactors, but are inherently unstable. While it is clear that chemical oxidation can cleave folates or damage their pterin precursors, very little is known about enzymatic damage to these molecules or about whether the folate biosynthesis pathway responds adaptively to damage to its end-products. The presence of a duplication of the gene encoding the folate biosynthesis enzyme 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (FolK) in many sequenced bacterial genomes combined with a strong chromosomal clustering of the folK gene with panB, encoding the 5,10-methylene-THF-dependent enzyme ketopantoate hydroxymethyltransferase, led us to infer that PanB has a side activity that cleaves 5,10-methylene-THF, yielding a pterin product that is recycled by FolK. Genetic and metabolic analyses of Escherichia coli strains showed that overexpression of PanB leads to accumulation of the likely folate cleavage product 6-hydroxymethylpterin and other pterins in cells and medium, and-unexpectedly-to a 46% increase in total folate content. In silico modeling of the folate biosynthesis pathway showed that these observations are consistent with the in vivo cleavage of 5,10-methylene-THF by a side-activity of PanB, with FolK-mediated recycling of the pterin cleavage product, and with regulation of folate biosynthesis by folates or their damage products.
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Experimental and Metabolic Modeling Evidence for a Folate-Cleaving Side-Activity of Ketopantoate Hydroxymethyltransferase (PanB).
- Thiaville JJ, Frelin O, García-Salinas C, Harrison K, Hasnain G, Horenstein NA, Díaz de la Garza RI, Henry CS, Hanson AD, de Crécy-Lagard V
- Frontiers in microbiology , 0/ 2016 , Volume 7 , pages: 431 , PubMed ID: 27065985
- Department of Microbiology and Cell Science, University of Florida Gainesville, FL, USA.
- Tetrahydrofolate (THF) and its one-carbon derivatives, collectively termed folates, are essential cofactors, but are inherently unstable. While it is clear that chemical oxidation can cleave folates or damage their pterin precursors, very little is known about enzymatic damage to these molecules or about whether the folate biosynthesis pathway responds adaptively to damage to its end-products. The presence of a duplication of the gene encoding the folate biosynthesis enzyme 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (FolK) in many sequenced bacterial genomes combined with a strong chromosomal clustering of the folK gene with panB, encoding the 5,10-methylene-THF-dependent enzyme ketopantoate hydroxymethyltransferase, led us to infer that PanB has a side activity that cleaves 5,10-methylene-THF, yielding a pterin product that is recycled by FolK. Genetic and metabolic analyses of Escherichia coli strains showed that overexpression of PanB leads to accumulation of the likely folate cleavage product 6-hydroxymethylpterin and other pterins in cells and medium, and-unexpectedly-to a 46% increase in total folate content. In silico modeling of the folate biosynthesis pathway showed that these observations are consistent with the in vivo cleavage of 5,10-methylene-THF by a side-activity of PanB, with FolK-mediated recycling of the pterin cleavage product, and with regulation of folate biosynthesis by folates or their damage products.
Submitter of this revision: administrator
Modellers: administrator, Christopher Henry
Metadata information
isDescribedBy (2 statements)
hasTaxon (1 statement)
hasProperty (1 statement)
hasPart (2 statements)
Connected external resources
Name | Description | Size | Actions |
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Model files |
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BIOMD0000000690_url.xml | SBML L2V4 representation of Thiaville2016 - Folate pathway model (PanB overexpression and THF regulation) | 66.31 KB | Preview | Download |
Additional files |
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BIOMD0000000690-biopax2.owl | Auto-generated BioPAX (Level 2) | 31.80 KB | Preview | Download |
BIOMD0000000690-biopax3.owl | Auto-generated BioPAX (Level 3) | 44.10 KB | Preview | Download |
BIOMD0000000690.m | Auto-generated Octave file | 6.41 KB | Preview | Download |
BIOMD0000000690.pdf | Auto-generated PDF file | 165.73 KB | Preview | Download |
BIOMD0000000690.png | Auto-generated Reaction graph (PNG) | 85.53 KB | Preview | Download |
BIOMD0000000690.sci | Auto-generated Scilab file | 154.00 Bytes | Preview | Download |
BIOMD0000000690.svg | Auto-generated Reaction graph (SVG) | 23.75 KB | Preview | Download |
BIOMD0000000690.vcml | Auto-generated VCML file | 103.94 KB | Preview | Download |
BIOMD0000000690.xpp | Auto-generated XPP file | 4.52 KB | Preview | Download |
BIOMD0000000690_urn.xml | Auto-generated SBML file with URNs | 66.30 KB | Preview | Download |
MODEL1602280003.cps | Curated and annotated model COPASI file. | 79.84 KB | Preview | Download |
MODEL1602280003.sedml | SED-ML file for figure 7B of the reference publication. Parameter changes: FolA, 31,170 to 86,170 ; FolC, 6,184 to 10,000 ; FolK, 15.8 to 24.8 and FolP, 4,000 to 8,000. | 4.99 KB | Preview | Download |
- Model originally submitted by : Christopher Henry
- Submitted: Feb 28, 2016 9:45:47 PM
- Last Modified: Mar 13, 2018 5:14:53 PM
Revisions
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Version: 3
- Submitted on: Mar 13, 2018 5:14:53 PM
- Submitted by: administrator
- With comment: Model name updated using online editor.
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Version: 2
- Submitted on: May 31, 2017 11:42:28 AM
- Submitted by: Christopher Henry
- With comment: Current version of Thiaville2016 - Folate pathway model with induced PanB reaction and folate pathway
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Version: 1
- Submitted on: Feb 28, 2016 9:45:47 PM
- Submitted by: Christopher Henry
- With comment: Original import of Henry2016 Folate pathway model with induced PanB reaction and folate pathway
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: Variable used inside SBML models
Species | Initial Concentration/Amount |
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AMP AMP ; AMP |
2.8E-4 mmol |
Glycine glycine ; Glycine |
2.77E-4 mmol |
p ABA 4-Aminobenzoate ; 4-aminobenzoate |
1.0E-5 mmol |
H2 HMPterinPP 6-(Hydroxymethyl)-7,8-dihydropterin ; phosphorylation ; dihydropterin |
1.0E-5 mmol |
PPi Diphosphate |
5.0E-4 mmol |
L Glutamate L-Glutamate ; glutamate(2-) |
8.46E-4 mmol |
DHF Dihydrofolate ; dihydrofolate(2-) |
1.0E-5 mmol |
ATP ATP ; ATP |
0.0096 mmol |
THF tetrahydrofolate ; Tetrahydrofolate |
1.69E-4 mmol |
Reactions | Rate | Parameters |
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ATP + H2_HMPt => AMP + H2_HMPterinPP | compartment*k1*ATP*H2_HMPt | k1=24.8 |
THF + L_serine => CH2_THF + Glycine | compartment*(k1*THF*L_serine-k2*CH2_THF*Glycine) | k1=4080.0; k2=2000.0 |
p_ABA + H2_HMPterinPP => PPi + H2_Pteroate | compartment*k1*p_ABA*H2_HMPterinPP | k1=8000.0 |
CH2_THF => H2_HMPt + p_ABA | compartment*k1*CH2_THF | k1=0.008 |
L_Glutamate + ATP + H2_Pteroate => DHF + ADP + Phosphate | compartment*k1*L_Glutamate*ATP*H2_Pteroate | k1=10029.0 |
DHF + NADPH => NADP + THF | compartment*k1*DHF*NADPH | k1=86170.0 |
(added: 20 Mar 2018, 22:04:29, updated: 20 Mar 2018, 22:04:29)