Information on EC 4.1.99.16 - geosmin synthase

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The expected taxonomic range for this enzyme is: Streptomyces

EC NUMBER
COMMENTARY
4.1.99.16
-
RECOMMENDED NAME
GeneOntology No.
geosmin synthase
-
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
(1E,4S,5E,7R)-germacra-1(10),5-dien-11-ol + H2O = (-)-geosmin + acetone
show the reaction diagram
-
-
-
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(1E,4S,5E,7R)-germacra-1(10),5-dien-11-ol + H2O = (-)-geosmin + acetone
show the reaction diagram
conversion of germacradienol to geosmin results in the release of the three-carbon side chain as acetone and involves a 1,2-hydride shift of the bridgehead hydrogen exclusively into ring B of geosmin
Q9X839
PATHWAY
KEGG Link
MetaCyc Link
Biosynthesis of secondary metabolites
-
geosmin biosynthesis
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Sesquiterpenoid and triterpenoid biosynthesis
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SYSTEMATIC NAME
IUBMB Comments
germacradienol geosmin-lyase (acetone forming)
Requires Mg2+. Geosmin is the cause of the characteristic smell of moist soil. It is a bifunctional enzyme. The N-terminal part of the enzyme is EC 4.2.3.22, germacradienol synthase, and forms germacradienol from FPP. The C-terminal part of the enzyme catalyses the conversion of germacradienol to geosmin via (1S,4aS,8aS)-1,4a-dimethyl-1,2,3,4,4a,5,6,8a-octahydronaphthalene.
SYNONYMS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
spterp13
B0F2N6
gene name
spterp13
B0F2N6
gene name
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ORGANISM
COMMENTARY
LITERATURE
SEQUENCE CODE
SEQUENCE DB
SOURCE
germacradienol/geosmin synthase
UniProt
Manually annotated by BRENDA team
C-terminal domain; germacradienol/germacrene D synthase
UniProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
physiological function
Q82L49
mutants with a deleted geoA are unable to produce either germacradienol or geosmin
physiological function
B0F2N6, -
deletion of the doxorubicin gene cluster results in increased cell growth rate along with detectable production of geosmin. Overexpression of the spterp13 gene in the Streptomyecs peucetius doxorubicin mutant leads to 2.4fold enhanced production of geosmin
physiological function
-
deletion of the doxorubicin gene cluster results in increased cell growth rate along with detectable production of geosmin. Overexpression of the spterp13 gene in the Streptomyecs peucetius doxorubicin mutant leads to 2.4fold enhanced production of geosmin
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SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
(1E,4S,5E,7R)-germacra-1(10),5-dien-11-ol + H2O
(-)-geosmin + acetone
show the reaction diagram
Q9X839
catalysed by the C-terminal domain of the bifunctional enzyme
-
-
?
(2E,6E)-farnesyl diphosphate + H2O
(4S,7R)-germacra-1(10)E,5E-diene-11-ol + (7S)-germacrene D + geosmin + ?
show the reaction diagram
Q82L49
overall reaction of germacradienol/geosmin synthase
presence of Mg2+, synthesis of 66% (4S,7R)-germacra-1(10)E,5E-diene-11-ol, 24% (7S)-germacrene D, 8% geosmin, and 2% of a hydrocarbon, tentatively assigned the structure of octalin
-
?
additional information
?
-
Q9X839
conversion of germacradienol to geosmin results in the release of the three-carbon side chain as acetone and involves a 1,2-hydride shift of the bridgehead hydrogen exclusively into ring B of geosmin
-
-
-
additional information
-
-
Q82L49
nerolidyl diphosphate is excluded as an intermediate in the enzymatic formation of germacradienol, germacrene D, and geosmin
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-
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METALS and IONS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
Co2+
Q82L49
10-20% of the activity with Mg2+
Cu2+
Q82L49
10-20% of the activity with Mg2+
Fe2+
Q82L49
50% of the activity with Mg2+
Mg2+
Q82L49
preferred divalent cation, maximum activity at 10 mM
Zn2+
Q82L49
50% of the activity with Mg2+
Mn2+
Q82L49
10-20% of the activity with Mg2+
additional information
Q82L49
absolute requirement for a divalent cation. No activity with Ni2+ or Ca2+
KM VALUE [mM]
KM VALUE [mM] Maximum
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.000075
-
(2E,6E)-farnesyl diphosphate
Q82L49
pH 8.2, 30°C
TURNOVER NUMBER [1/s]
TURNOVER NUMBER MAXIMUM[1/s]
SUBSTRATE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.0031
-
(2E,6E)-farnesyl diphosphate
Q82L49
pH 8.2, 30°C
pH OPTIMUM
pH MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
Cloned/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
expression in Escherichia coli
Q82L49