Information on EC 4.2.3.61 - 5-epiaristolochene synthase

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The expected taxonomic range for this enzyme is: Solanaceae

EC NUMBER
COMMENTARY
4.2.3.61
-
RECOMMENDED NAME
GeneOntology No.
5-epiaristolochene synthase
-
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
(2E,6E)-farnesyl diphosphate = (+)-5-epiaristolochene + diphosphate
show the reaction diagram
-
-
-
-
PATHWAY
KEGG Link
MetaCyc Link
capsidiol biosynthesis
-
Sesquiterpenoid and triterpenoid biosynthesis
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SYSTEMATIC NAME
IUBMB Comments
(2E,6E)-farnesyl-diphosphate diphosphate-lyase [(+)-5-epiaristolochene-forming]
Initial cyclization gives (+)-germacrene A in an enzyme bound form which is not released to the medium.
SYNONYMS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
EAS12
Q84LF2
gene name
EAS3
Q40577
gene name
EAS34
Q84LF1
gene name
EAS37
Q84LF0
gene name
EAS4
Q40577
gene name
g110
Q7X9A3
-
ORGANISM
COMMENTARY
LITERATURE
SEQUENCE CODE
SEQUENCE DB
SOURCE
isoform 5-epi-aristolochene synthase 34
UniProt
Manually annotated by BRENDA team
isoform 5-epi-aristolochene synthase 37
UniProt
Manually annotated by BRENDA team
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
(2E,6E)-farnesyl diphosphate
(+)-5-epiaristolochene + diphosphate
show the reaction diagram
-
-
-
-
?
(2E,6E)-farnesyl diphosphate
(+)-5-epiaristolochene + diphosphate
show the reaction diagram
-
-
(+)-5-epiaristolochene constitutes about 85% of hyxdrocarbon products
-
?
(2E,6E)-farnesyl diphosphate
(+)-5-epiaristolochene + diphosphate
show the reaction diagram
-
-
about 79% of hydrocarbon product, plus about 6% of (-)-4-epi-eremophilene, 3.6% of (+)-germacrene A and 22 hydrocarbons contributing about 12% of TEAS sesquiterpene products. The pathway to the by-products starts with a 1,6 cyclization of the (Z,E)-farnesyl cation, followed by a 1,2 hydride shift leading to a syn-6,10 ring closure which generates an acoradilyl cation. Elimination of a proton from either C12 or C13 of the isopropylidene tail of the acoradilyl cation readily explains the formation of ?-acoradiene. Alternatively, a 2,11 ring closure followed by elimination of a proton at C2 is the likely pathway to (-)-alpha-cedrene. A 3,11 ring closure of the acoradilyl cation is the most common event, based on the relative abundance of isomerization products observed, and is followed by Wagner-Meerwein rearrangement and proton elimination from C15 to produce isoprezizaene, the dominant (Z,E)-farnesyl cation-derived product
-
?
(2E,6E)-farnesyl diphosphate
(+)-5-epiaristolochene + diphosphate
show the reaction diagram
Q84LF0, Q84LF1, Q84LF2
-
single major sesquiterpene product
-
?
(2E,6E)-farnesyl diphosphate
(+)-5-epiaristolochene + diphosphate
show the reaction diagram
Q40577
reaction proceeds via geracrene A as an intermediate. Proton donation by residue Y520 is responsible for the activation of germacrene A to a eudesmane cation
-
-
?
(2E,6E)-farnesyl diphosphate
5-epi-aristolochene + diphosphate
show the reaction diagram
Q7X9A3
-
-
-
?
(2E,6Z)-6-fluorofarnesyl diphosphate
(-)-1-fluororogermacrene A
show the reaction diagram
-
the fluoro substitution at the C6 position of farnesyl diphosphate has negligible effects on enzyme binding, substrate orientation, diphosphate ionization, and the initial 1,10 ring closure catalyzed by TEAS
sole product, 58% yield
-
?
METALS and IONS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
Mg2+
-
presence of 2 Mg2+ ions
KM VALUE [mM]
KM VALUE [mM] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.0016
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(2E,6E)-farnesyl diphosphate
-
fusion construct epiaristolochene synthase/farnesyl diphosphate synthase, pH 8.0, 30C
0.0017
-
(2E,6E)-farnesyl diphosphate
-
wild-type, pH 8.0, 30C
0.0023
-
(2E,6E)-farnesyl diphosphate
-
wild-type, pH 7.5, 30C
0.0026
-
(2E,6E)-farnesyl diphosphate
-
fusion construct farnesyl diphosphate synthase/epiaristolochene synthase, pH 8.0, 30C
0.0081
-
(2E,6E)-farnesyl diphosphate
-
mutant Y520F, pH 7.5, 30C
0.0084
-
(2E,6E)-farnesyl diphosphate
-
pH 7.0, 22C
0.014
-
(2E,6E)-farnesyl diphosphate
-
pH 7.5, 22C
0.0197
-
(2E,6Z)-6-fluorofarnesyl diphosphate
-
pH 7.0, 22C
TURNOVER NUMBER [1/s]
TURNOVER NUMBER MAXIMUM[1/s]
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.005
-
(2E,6E)-farnesyl diphosphate
-
mutant Y520F, pH 7.5, 30C
0.042
-
(2E,6E)-farnesyl diphosphate
-
pH 7.0, 22C
0.048
-
(2E,6E)-farnesyl diphosphate
-
wild-type, pH 7.5, 30C
0.095
-
(2E,6E)-farnesyl diphosphate
-
pH 7.5, 22C
0.11
-
(2E,6Z)-6-fluorofarnesyl diphosphate
-
pH 7.0, 22C
kcat/KM VALUE [1/mMs-1]
kcat/KM VALUE [1/mMs-1] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
5
-
(2E,6E)-farnesyl diphosphate
-
pH 7.0, 22C
263972
6.7
-
(2E,6E)-farnesyl diphosphate
-
pH 7.5, 22C
263972
5.6
-
(2E,6Z)-6-fluorofarnesyl diphosphate
-
pH 7.0, 22C
253690
SOURCE TISSUE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
SOURCE
Q84LF0, Q84LF1, Q84LF2
constitutive expression
Manually annotated by BRENDA team
additional information
Q84LF0, Q84LF1, Q84LF2
no constitutive expression of EAS and capsidiol accumulation in shoots of rosette plants, but accumulation of transcripts can be induced in shoots by feeding of the tobacco hornworm, Manduca sexta
Manually annotated by BRENDA team
Crystallization/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
to 2.2-2.8 A resolution, of TEAS alone and in complexes with two different substrate analogs. TEAS consists entirely of alpha-helices and short connecting loops and turns, and is organized into two structural domains. Two Mg2+ ions are coordinated on opposite sides of the entrance to the active site pocket, and constitute a diphosphate binding site. Asp301 coordinates a Mg2+ in the native TEAS structure, and the side chain carboxyl of Glu379 provides a longer range interaction. Asp305 provides an additional coordination bond in the enzyme with substrate analogs bound. Asp301 and Asp305 are part of a -DDXXD- sequence. Asp301 directly contacts Mg2+, whereas Asp302 demonstrates no direct metal coordination. The side chains of Asp444, Thr448, Glu452, and one water molecule the second coordinate Mg2+. In the native TEAS structure, the A-C and J-K loops and the residues NH2-terminal of residue 36 are disordered
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Purification/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
recombinant protein
Q7X9A3
Cloned/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
expression in Oryza sativa
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expression in Escherichia coli
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expression in Petunia hybrida infiltrated with Agrobacterium tumefaciens harboring the enzyme gene
Q7X9A3
EXPRESSION
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
accumulation of transcripts can be induced in shoots by feeding of the tobacco hornworm, Manduca sexta; accumulation of transcripts can be induced in shoots by feeding of the tobacco hornworm, Manduca sexta; accumulation of transcripts can be induced in shoots by feeding of the tobacco hornworm, Manduca sexta
Q84LF0, Q84LF1, Q84LF2
ENGINEERING
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
Y520F
-
3% of wild-type catalytic efficiency, reaction prooduct is germacrene A
additional information
-
heterologous expression of EAS in transgenic rice does not interfere with the activities of endogenous squalene synthase or farnesyl diphosphatase. The induction of EAS enzyme activity is accompanied by an increase in EAS mRNA when challenged by the elicitor. The EAS ectopic expression in transgenic rice plants results in the synthesis of 5-epi-aristolochene in vivo upon elicitor treatment
additional information
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construction of fusion proteins with farnesyl diphosphate synthase FPPS from Artemisia annua. The fusion enzymes produce epi-aristolochene from isopentenyl diphosphate through a coupled reaction. The Km values of FPPS and eAS for isopentenyl diphosphate and farnesyl diphosphate, respectively, are essentially the same for the single and fused enzymes. The bifunctional enzymes show a more efficient conversion of isopentenyl diphosphate to epi-aristolochene than the corresponding amount of single enzymes
APPLICATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
analysis
Q7X9A3
method for the recovery of full-length cDNAs from predicted terpene synthase genes containing introns. The approach utilizes Agrobacterium-mediated transient expression coupled with a reverse transcription-polydeoxyribonucleotide chain reaction assay to facilitate expression cloning of processed transcripts. Subsequent expression of intronless cDNAs in a suitable prokaryotic host provides for direct functional testing of the encoded gene product
synthesis
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expression system in Escherichia coli, highest expression level after 3 h induction with low concentration of IPTG and incubation at 27C. Epiaristolochene synthase protein constitutes up to 35% of total Escherichia coli proteins
synthesis
-
construction of fusion proteins with farnesyl diphosphate synthase FPPS from Artemisia annua. The fusion enzymes produce epi-aristolochene from isopentenyl diphosphate through a coupled reaction. The Km values of FPPS and eAS for isopentenyl diphosphate and farnesyl diphosphate, respectively, are essentially the same for the single and fused enzymes. The bifunctional enzymes show a more efficient conversion of isopentenyl diphosphate to epi-aristolochene than the corresponding amount of single enzymes