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Literature summary for 4.2.3.55 extracted from

  • Köllner, T.G.; Schnee, C.; Li, S.; Svatos, A.; Schneider, B.; Gershenzon, J.; Degenhardt, J.
    Protonation of a neutral (S)-beta-bisabolene intermediate is involved in (S)-beta-macrocarpene formation by the maize sesquiterpene synthases TPS6 and TPS11 (2008), J. Biol. Chem., 283, 20779-20788.
    View publication on PubMedView publication on EuropePMC
Search for more literature for 4.2.3.55

Cloned(Commentary)

Cloned (Comment) Organism
overexpression in Escherichia coli Zea mays

Protein Variants

Protein Variants Comment Organism
D526N mutation inactivates the enzyme completely Zea mays
Y522F mutation reduces the production of (S)-beta-macrocarpene to trace amounts, the enzyme forms (S)-beta-bisabolene almost exclusively, the overall activity of the mutated enzyme is dramatically reduced Zea mays

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0021
-
 (2E,6E)-farnesyl diphosphate 30°C Zea mays

Localization

Localization Comment Organism GeneOntology No. Textmining
cytoplasm
-
 Zea mays 5737
-

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ TPS6 requires a divalent metal ion, with Mg2+ and Mn2+ being effective, optimum activity with 5 mM Mg2+ and 5 mM Mn2+. Although the Km for Mn2+ is significantly lower than for Mg2+, the enzyme is more likely to operate with a Mg2+ cofactor in planta, because the concentration of Mg2+ in plant cells is about 2 orders of magnitudes higher than Mn2+. In the presence of Mn2+, the product spectrum of TPS6 is shifted toward an increased production of (S)-beta bisabolene and a decreased production of (S)-beta-macrocarpene. KM-value for Mg2+ measured with 0.01 mM farnesyl diphosphate: 0.131 mM Zea mays
Mn2+ TPS6 requires a divalent metal ion, with Mg2+ and Mn2+ being effective, optimum activity with 5 mM Mg2+ and 5 mM Mn2+. Although the Km for Mn2+ is significantly lower than for Mg2+, the enzyme is more likely to operate with a Mg2+ cofactor in planta, because the concentration of Mg2+ in plant cells is about 2 orders of magnitudes higher than Mn2+. In the presence of Mn2+, the product spectrum of TPS6 is shifted toward an increased production of (S)-beta bisabolene and a decreased production of (S)-beta-macrocarpene. KM-value for Mn2+ measured with 0.01 mM farnesyl diphosphate: 0.0234 mM Zea mays

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
(2E,6E)-farnesyl diphosphate Zea mays the enzyme may be involved in plant defense (S)-beta-bisabolene + diphosphate
-
 ?
(2E,6E)-farnesyl diphosphate Zea mays the enzyme may be involved in plant defense (S)-beta-bisabolene + diphosphate i.e. ((4S)-1-methyl-4-(5-methyl-1-methylidenehex-4-en-1-yl)cyclohexene ?

Organism

Organism UniProt Comment Textmining
Zea mays Q1EG72 L. variety B73
-
Zea mays Q5GJ60 L. variety B73
-

Purification (Commentary)

Purification (Comment) Organism
partial Zea mays

Reaction

Reaction Comment Organism Reaction ID
(2E,6E)-farnesyl diphosphate = (S)-beta-bisabolene + diphosphate (S)-beta-bisabolene is a stable intermediate. (S)-beta-Macrocarpene formation requires a protonation of the intermediate Zea mays
a
(2E,6E)-farnesyl diphosphate = (S)-beta-bisabolene + diphosphate The synthesis of (S)-beta-macrocarpene from (2E,6E)-farnesyl diphosphate proceeds in two steps. The first step is the cyclization to (S)-beta-bisabolene. The second steps is the isomerization to (S)-beta-macrocarpene (c.f. EC 5.5.1.a, (S)-beta-macrocarpene synthase). The enzyme requires Mg2+ or Mn2+ for activity. Zea mays
a

Source Tissue

Source Tissue Comment Organism Textmining
root the enzyme is predominantly active in the roots Zea mays
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
(2E,6E)-farnesyl diphosphate
-
 Zea mays (S)-beta-bisabolene + diphosphate The synthesis of (S)-beta-macrocarpene from (2E,6E)-farnesyl diphosphate proceeds in two steps. The first step is the cyclization to (S)-beta-bisabolene. The second step is the isomerization to (S)-beta-macrocarpene ((S)-beta-macrocarpene synthase). Product is identified by GC-MS ?
(2E,6E)-farnesyl diphosphate the enzyme may be involved in plant defense Zea mays (S)-beta-bisabolene + diphosphate
-
 ?
(2E,6E)-farnesyl diphosphate the enzyme may be involved in plant defense Zea mays (S)-beta-bisabolene + diphosphate i.e. ((4S)-1-methyl-4-(5-methyl-1-methylidenehex-4-en-1-yl)cyclohexene ?
(2Z,6E)-farnesyl diphosphate
-
 Zea mays (S)-beta-bisabolene + diphosphate The synthesis of (S)-beta-macrocarpene from (2E,6E)-farnesyl diphosphate proceeds in two steps. The first step is the cyclization to (S)-beta-bisabolene. The second step is the isomerization to (S)-beta-macrocarpene ((S)-beta-macrocarpene synthase). Product is identified by GC-MS ?
additional information no activity with geranylgeranyl diphosphate. TPS6 accepts the monoterpene precursor geranyl diphosphate but the monoterpene products are produced at a lower velocity Zea mays ?
-
 ?

Synonyms

Synonyms Comment Organism
TPS11
-
 Zea mays
TPS6
-
 Zea mays

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
30
-
 assay at Zea mays

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7
-
 in presence of 5 mM Mg2+ Zea mays

pH Range

pH Minimum pH Maximum Comment Organism
6.2 8.6 half-maximal activity at pH 6.2 and at pH 8.6, in presence of 5 mM Mg2+. Within a pH range from 5.0 to 8.0, the major product is (S)-beta-macrocarpene, but higher pH values favor the formation of (S)-beta-bisabolene Zea mays

General Information

General Information Comment Organism
physiological function the enzyme may be involved in plant defense Zea mays