Plant Terpene Cyclases, Class 1; This CD includes a diverse group of monomeric plant terpene ...
321-797
2.60e-84
Plant Terpene Cyclases, Class 1; This CD includes a diverse group of monomeric plant terpene cyclases (Tspa-Tspf) that convert the acyclic isoprenoid diphosphates, geranyl diphosphate (GPP), farnesyl diphosphate (FPP), or geranylgeranyl diphosphate (GGPP) into cyclic monoterpenes, diterpenes, or sesquiterpenes, respectively; a few form acyclic species. Terpnoid cyclases are soluble enzymes localized to the cytosol (sesquiterpene synthases) or plastids (mono- and diterpene synthases). All monoterpene and diterpene synthases have restrict substrate specificity, however, some sesquiterpene synthases can accept both FPP and GPP. The catalytic site consists of a large central cavity formed by mostly antiparallel alpha helices with two aspartate-rich regions located on opposite walls. These residues mediate binding of prenyl diphosphates, via bridging Mg2+ ions (K+ preferred by gymnosperm cyclases), inducing conformational changes such that an N-terminal region forms a cap over the catalytic core. Loss of diphosphate from the enzyme-bound substrate (GPP, FPP, or GGPP) results in an allylic carbocation that electrophilically attacks a double bond further down the terpene chain to effect the first ring closure. Unlike monoterpene, sesquiterene, and macrocyclic diterpenes synthases, which undergo substrate ionization by diphosphate ester scission, Tpsc-like diterpene synthases catalyze cyclization reactions by an initial protonation step producing a copalyl diphosphate intermediate. These enzymes lack the aspartate-rich sequences mentioned above. Most diterpene synthases have an N-terminal, internal element (approx 210 aa) whose function is unknown.
Pssm-ID: 173832 [Multi-domain] Cd Length: 542 Bit Score: 278.69 E-value: 2.60e-84
Terpene synthase, N-terminal domain; It has been suggested that this gene family be designated ...
269-476
4.60e-51
Terpene synthase, N-terminal domain; It has been suggested that this gene family be designated tps (for terpene synthase). It has been split into six subgroups on the basis of phylogeny, called tpsa-tpsf. tpsa includes vetispiridiene synthase, 5-epi- aristolochene synthase, and (+)-delta-cadinene synthase. tpsb includes (-)-limonene synthase. tpsc includes kaurene synthase A. tpsd includes taxadiene synthase, pinene synthase and myrcene synthase. tpse includes kaurene synthase B. tpsf includes linalool synthase.
Pssm-ID: 460194 [Multi-domain] Cd Length: 190 Bit Score: 177.01 E-value: 4.60e-51
squalene-hopene cyclase; SHC is an essential prokaryotic gene in hopanoid (triterpenoid) ...
104-152
9.39e-03
squalene-hopene cyclase; SHC is an essential prokaryotic gene in hopanoid (triterpenoid) biosynthesis. Squalene hopene cyclase, an integral membrane protein, directly cyclizes squalene into hopanoid products. [Fatty acid and phospholipid metabolism, Other]
Pssm-ID: 273661 [Multi-domain] Cd Length: 635 Bit Score: 39.49 E-value: 9.39e-03
Plant Terpene Cyclases, Class 1; This CD includes a diverse group of monomeric plant terpene ...
321-797
2.60e-84
Plant Terpene Cyclases, Class 1; This CD includes a diverse group of monomeric plant terpene cyclases (Tspa-Tspf) that convert the acyclic isoprenoid diphosphates, geranyl diphosphate (GPP), farnesyl diphosphate (FPP), or geranylgeranyl diphosphate (GGPP) into cyclic monoterpenes, diterpenes, or sesquiterpenes, respectively; a few form acyclic species. Terpnoid cyclases are soluble enzymes localized to the cytosol (sesquiterpene synthases) or plastids (mono- and diterpene synthases). All monoterpene and diterpene synthases have restrict substrate specificity, however, some sesquiterpene synthases can accept both FPP and GPP. The catalytic site consists of a large central cavity formed by mostly antiparallel alpha helices with two aspartate-rich regions located on opposite walls. These residues mediate binding of prenyl diphosphates, via bridging Mg2+ ions (K+ preferred by gymnosperm cyclases), inducing conformational changes such that an N-terminal region forms a cap over the catalytic core. Loss of diphosphate from the enzyme-bound substrate (GPP, FPP, or GGPP) results in an allylic carbocation that electrophilically attacks a double bond further down the terpene chain to effect the first ring closure. Unlike monoterpene, sesquiterene, and macrocyclic diterpenes synthases, which undergo substrate ionization by diphosphate ester scission, Tpsc-like diterpene synthases catalyze cyclization reactions by an initial protonation step producing a copalyl diphosphate intermediate. These enzymes lack the aspartate-rich sequences mentioned above. Most diterpene synthases have an N-terminal, internal element (approx 210 aa) whose function is unknown.
Pssm-ID: 173832 [Multi-domain] Cd Length: 542 Bit Score: 278.69 E-value: 2.60e-84
Terpene synthase, N-terminal domain; It has been suggested that this gene family be designated ...
269-476
4.60e-51
Terpene synthase, N-terminal domain; It has been suggested that this gene family be designated tps (for terpene synthase). It has been split into six subgroups on the basis of phylogeny, called tpsa-tpsf. tpsa includes vetispiridiene synthase, 5-epi- aristolochene synthase, and (+)-delta-cadinene synthase. tpsb includes (-)-limonene synthase. tpsc includes kaurene synthase A. tpsd includes taxadiene synthase, pinene synthase and myrcene synthase. tpse includes kaurene synthase B. tpsf includes linalool synthase.
Pssm-ID: 460194 [Multi-domain] Cd Length: 190 Bit Score: 177.01 E-value: 4.60e-51
Terpene cyclases, Class 1; Terpene cyclases, Class 1 (C1) of the class 1 family of isoprenoid ...
533-781
2.97e-07
Terpene cyclases, Class 1; Terpene cyclases, Class 1 (C1) of the class 1 family of isoprenoid biosynthesis enzymes, which share the 'isoprenoid synthase fold' and convert linear, all-trans, isoprenoids, geranyl (C10)-, farnesyl (C15)-, or geranylgeranyl (C20)-diphosphate into numerous cyclic forms of monoterpenes, diterpenes, and sesquiterpenes. Also included in this CD are the cis-trans terpene cyclases such as trichodiene synthase. The class I terpene cyclization reactions proceed via electrophilic alkylations in which a new carbon-carbon single bond is generated through interaction between a highly reactive electron-deficient allylic carbocation and an electron-rich carbon-carbon double bond. The catalytic site consists of a large central cavity formed by mostly antiparallel alpha helices with two aspartate-rich regions located on opposite walls. These residues mediate binding of prenyl phosphates via bridging Mg2+ ions, inducing proposed conformational changes that close the active site to solvent, stabilizing reactive carbocation intermediates. Mechanistically and structurally distinct, class II terpene cyclases and cis-IPPS are not included in this CD. Taxonomic distribution includes bacteria, fungi and plants.
Pssm-ID: 173837 [Multi-domain] Cd Length: 284 Bit Score: 52.75 E-value: 2.97e-07
Terpene synthase family, metal binding domain; It has been suggested that this gene family be ...
520-593
1.40e-03
Terpene synthase family, metal binding domain; It has been suggested that this gene family be designated tps (for terpene synthase). It has been split into six subgroups on the basis of phylogeny, called tpsa-tpsf. tpsa includes vetispiridiene synthase, 5-epi- aristolochene synthase, and (+)-delta-cadinene synthase. tpsb includes (-)-limonene synthase. tpsc includes kaurene synthase A. tpsd includes taxadiene synthase, pinene synthase, and myrcene synthase. tpse includes kaurene synthase B. tpsf includes linalool synthase.
Pssm-ID: 461096 [Multi-domain] Cd Length: 266 Bit Score: 41.35 E-value: 1.40e-03
squalene-hopene cyclase; SHC is an essential prokaryotic gene in hopanoid (triterpenoid) ...
104-152
9.39e-03
squalene-hopene cyclase; SHC is an essential prokaryotic gene in hopanoid (triterpenoid) biosynthesis. Squalene hopene cyclase, an integral membrane protein, directly cyclizes squalene into hopanoid products. [Fatty acid and phospholipid metabolism, Other]
Pssm-ID: 273661 [Multi-domain] Cd Length: 635 Bit Score: 39.49 E-value: 9.39e-03
Database: CDSEARCH/cdd Low complexity filter: no Composition Based Adjustment: yes E-value threshold: 0.01
References:
Wang J et al. (2023), "The conserved domain database in 2023", Nucleic Acids Res.51(D)384-8.
Lu S et al. (2020), "The conserved domain database in 2020", Nucleic Acids Res.48(D)265-8.
Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.", Nucleic Acids Res.45(D)200-3.
of the residues that compose this conserved feature have been mapped to the query sequence.
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