Information on EC 4.2.3.118 - 2-methylisoborneol synthase

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The expected taxonomic range for this enzyme is: Bacteria

EC NUMBER
COMMENTARY
4.2.3.118
-
RECOMMENDED NAME
GeneOntology No.
2-methylisoborneol synthase
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REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
(E)-2-methylgeranyl diphosphate + H2O = 2-methylisoborneol + diphosphate
show the reaction diagram
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-
-
-
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
2-methylisoborneol biosynthesis
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SYSTEMATIC NAME
IUBMB Comments
(E)-2-methylgeranyl-diphosphate diphosphate-lyase (cyclizing, 2-methylisoborneol-forming)
The product, 2-methylisoborneol, is a characteristc odiferous compound with a musty smell produced by soil microorganisms.
SYNONYMS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
2-MIB cyclase
-
-
-
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MIB synthase
-
-
-
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MIBS
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-
-
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sco7700
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-
-
-
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
two adjacent genes, SAM-dependent methyltransferanse gene and monoterpene cyclase gene, are responsible for geranyl diphosphate methylation and subsequent cyclization to 2-methylisoborneol in cyanobacteria
UniProt
Manually annotated by BRENDA team
Pseudanabaena limnetica Castaic Lake
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UniProt
Manually annotated by BRENDA team
two adjacent genes, SAM-dependent methyltransferanse gene and monoterpene cyclase gene, are responsible for geranyl diphosphate methylation and subsequent cyclization to 2-methylisoborneol in cyanobacteria
UniProt
Manually annotated by BRENDA team
two adjacent genes, SAM-dependent methyltransferanse gene and monoterpene cyclase gene, are responsible for geranyl diphosphate methylation and subsequent cyclization to 2-methylisoborneol in cyanobacteria
UniProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
physiological function
E9NH28
biosynthesis of 2-methylisoborneol in cyanobacteria is a result of 2 key reactions, a S-adenosylmethionine-dependent methylation of the monoterpene precursor geranyl diphosphate to 2-methylgeranyl diphosphate catalyzed by geranyl diphosphate 2-methyltransferase, and further cyclization of 2-methylgeranyl diphosphate to 2-methylisoborneol catalyzed by 2-methylisoborneol synthase as part of a 2-methylisoborneol operon
physiological function
D3KYU2
biosynthetic pathway to 2-methylisoborneol involves the methylation of geranyl diphosphate by GPP methyltransferase and its subsequent cyclization by monoterpene cyclase to 2-methylisoborneol
physiological function
Pseudanabaena limnetica Castaic Lake
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biosynthesis of 2-methylisoborneol in cyanobacteria is a result of 2 key reactions, a S-adenosylmethionine-dependent methylation of the monoterpene precursor geranyl diphosphate to 2-methylgeranyl diphosphate catalyzed by geranyl diphosphate 2-methyltransferase, and further cyclization of 2-methylgeranyl diphosphate to 2-methylisoborneol catalyzed by 2-methylisoborneol synthase as part of a 2-methylisoborneol operon
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SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
(E)-2-methylgeranyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
D3KYU2
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-
-
?
(E)-2-methylgeranyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
G0YUP1
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-
-
?
(E)-2-methylgeranyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
G0YUP5
-
-
-
?
(E)-2-methylgeranyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
E9NH28
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major reaction product
-
?
(E)-2-methylgeranyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
Q9F1Y6
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plus trace amounts of 2-methylbornene
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?
(E)-2-methylgeranyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
G0YUP1
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-
-
?
(E)-2-methylgeranyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
Pseudanabaena limnetica Castaic Lake
E9NH28
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major reaction product
-
?
2-fluorolinalyl diphosphate + H2O
(1R)-(+)-camphor + HF + diphosphate
show the reaction diagram
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single cyclic product, obtained via the (4R)-alpha-2-fluoroterpinyl carbocation intermediate. The initially generated 2-fluoroisoborneol cyclization product is unstable and undergoes elimination of hydrogen fluoride to yield (1R)-(+)-camphor
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?
2-fluorolinalyl diphosphate + H2O
(1R)-(+)-camphor + HF + diphosphate
show the reaction diagram
Q9F1Y6
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single cyclic product, obtained via the (4R)-alpha-2-fluoroterpinyl carbocation intermediate. The initially generated 2-fluoroisoborneol cyclization product is unstable and undergoes elimination of hydrogen fluoride to yield (1R)-(+)-camphor
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?
2-methyllinalyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
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natural intermediate of the cyclization reaction
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-
?
2-methyllinalyl diphosphate + H2O
2-methylisoborneol + diphosphate
show the reaction diagram
Q9F1Y6
natural intermediate of the cyclization reaction
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-
?
geranyl diphosphate + H2O
limonene + diphosphate
show the reaction diagram
Q9F1Y6
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products are 6% alpha-pinene, 23% beta-pinene , 32% limonene, 29% gamma-terpinene, and 120% delta-terpinene
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?
additional information
?
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Q9F1Y6
cyclization of (E)-2-methylgeranyl diphosphate most likely occurs by a mechanism closely resembling that established for the conversion of geranyl diphosphate to bornyl diphosphate, except that the penultimate bornyl cation is quenched on the exo face by water, analogous to the formation of fenchol, rather than by internal return of the diphosphate to the endo face, no substrate: farnesyl diphosphate, geranylgeranyl diphosphate
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additional information
?
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no substrate: farnesyl diphosphate, geranylgeranyl diphosphate
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METALS and IONS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Mg2+
D3KYU2
required
Mg2+
-
three Mg2+ ions are presumed to be required for the cyclization reaction
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.026
(E)-2-methylgeranyl diphosphate
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pH 7.0, 30C
0.0028
geranyl diphosphate
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pH 7.0, 30C
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.039
(E)-2-methylgeranyl diphosphate
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pH 7.0, 30C
0.0003
geranyl diphosphate
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pH 7.0, 30C
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
1.45
(E)-2-methylgeranyl diphosphate
E9NH28
temperature not specified in the publication, pH not specified in the publication
8931
PDB
SCOP
CATH
ORGANISM
Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)
Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)
Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)
Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
80000 - 90000
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gel filtration
717263
150000
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PAGE
717263
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
?
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x * 49937, MALDI-TOF
?
D3KYU2
x * 52400, SDS-PAGE, His-tagged recombinant protein
multimer
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x * 47000, calculated
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
in complex with substrate analogues geranyl-S-thiolodiphosphate and 2-fluorogeranyl diphosphate at 1.80 and 1.95 A resolution, respectively. MIBS adopts the tertiary structure of a class I terpenoid cyclase. The dimeric quaternary structure is different, the active sites in the MIBS dimer are oriented in parallel fashion and the dimer interface in MIBS is formed by helices D1, D2
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in unliganded state and in complex with two Mg2+ ions and 2-fluoroneryl diphosphate at 1.85 and 2.00 A resolution, respectively. Cocrystallization with the fluorinated analogue of the tertiary allylic diphosphate intermediate, 2-fluorolinalyl diphosphate yields the crystal structure of the complex with the primary allylic diphosphate, 2-fluoroneryl diphosphate. The crystalline enzyme active site remains partially open, presumably due to the binding of only two Mg2+ ions
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
recombinant protein
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
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expression in Streptomyces avermitilis
D3KYU2
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
light is a crucial, but not the only, active regulatory factor for the transcription of 2-methylisoborneol synthesis genes. Under low light, there is a 30% increase in the transcription of methyltransferase and a 60% increase in methylisoborneol synthase transcription compared to controls within 312 h. Under high light intensity, however, transcription of these two genes decreases by 30% and 50%, respectively. Expression of both genes is inhibited when bacteria are cultured in the dark at 25C for 72 h
G0YUP5
the expression level decreases at 4C, compared with at 20C
U6C722
the expression level increases at 30C, compared with at 20C
U6C722
light is a crucial, but not the only, active regulatory factor for the transcription of 2-methylisoborneol synthesis genes. Under low light, there is a 30% increase in the transcription of methyltransferase and a 60% increase in methylisoborneol synthase transcription compared to controls within 312 h. Under high light intensity, however, transcription of these two genes decreases by 30% and 50%, respectively. Expression of both genes is inhibited when bacteria are cultured in the dark at 25C for 72 h
G0YUP1
light is a crucial, but not the only, active regulatory factor for the transcription of 2-methylisoborneol synthesis genes. Under low light, there is a 30% increase in the transcription of methyltransferase and a 60% increase in methylisoborneol synthase transcription compared to controls within 312 h. Under high light intensity, however, transcription of these two genes decreases by 30% and 50%, respectively. Expression of both genes is inhibited when bacteria are cultured in the dark at 25C for 72 h
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APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
nutrition
U6C722
2-methylisoborneol produced by cyanobacteria,, causes an unpleasant taste and odor in tap water. Bacterial cultures show higher accumulation of 2-methylisoborneol at 30C than at 4C or 20C after 24 h of culture