Information on EC 4.2.3.152 - 2-epi-5-epi-valiolone synthase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
4.2.3.152
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RECOMMENDED NAME
GeneOntology No.
2-epi-5-epi-valiolone synthase
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REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
alpha-D-sedoheptulopyranose 7-phosphate = 2-epi-5-epi-valiolone + phosphate
show the reaction diagram
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Acarbose and validamycin biosynthesis
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Biosynthesis of antibiotics
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gadusol biosynthesis
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validamycin biosynthesis
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SYSTEMATIC NAME
IUBMB Comments
alpha-D-sedoheptulopyranose 7-phosphate phosphate-lyase (cyclizing; 2-epi-5-epi-valiolone-forming)
The enzyme is highly specific for alpha-D-sedoheptulopyranose 7-phosphate. It requires a divalent metal ion (Zn2+ or Co2+) and an NAD+ cofactor, which is transiently reduced during the reaction. The enzyme is involved in the biosynthesis of C7N-aminocyclitol natural products, such as the valienamine moiety of the antidiabetic drug acarbose and the crop protectant validamycin A. cf. EC 4.2.3.155, 2-epi-valiolone synthase and EC 4.2.3.154, demethyl-4-deoxygadusol synthase.
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
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UniProt
Manually annotated by BRENDA team
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SwissProt
Manually annotated by BRENDA team
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UniProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
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in-frame complete deletion of the 2-epi-5-epi-valiolone synthase gene has little effect on in vivo production of shinorine. Complete segregation of the 2-epi-5-epi-Valiolone synthase gene deletion mutant proves difficult and is achieved only when the mutant is grown in the dark and in a medium supplemented with fructose. The segregated mutant shows a striking colour change from native bluegreen to pale yellow-green, corresponding to substantial loss of the photosynthetic pigment phycocyanin, as evinced by combinations of absorbance and emission spectra. Transcriptional analysis of the mutant grown in the presence of fructose under dark or light conditions reveals downregulation of the cpcA gene that encodes the alpha subunit of phycocyanin, whereas the gene encoding nblA, a protease chaperone essential for phycobilisome degradation, is not expressed
metabolism
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2-epi-5-epi-valiolone synthase activity is essential for maintaining phycobilisome composition in the cyanobacterium Anabaena variabilis ATCC 29413 when grown in the presence of a carbon source
physiological function
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
D-sedoheptulose 7-phosphate
2-epi-5-epi-valiolone + phosphate
show the reaction diagram
sedoheptulose 7-phosphate
2-epi-5-epi-valiolone + phosphate
show the reaction diagram
additional information
?
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NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
D-sedoheptulose 7-phosphate
2-epi-5-epi-valiolone + phosphate
show the reaction diagram
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
50500
x * 50500, SDS-PAGE, His-tagged recombinant protein
50550
x * 50550, polyhistidine-tagged protein, SDS-PAGE
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
2.1 A resolution crystal structure of ValA in complex with NAD+ and Zn2+, hanging drop method at 4°C
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-20°C, AcbC extract can be stored for 3 months without major loss of activity
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
expression in Escherichia coli; overexpressed in Escherichia coli
overexpressed heterologously in Streptomyces lividans 66