1.3.99.31: phytoene desaturase (lycopene-forming)
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For detailed information about phytoene desaturase (lycopene-forming), go to the full flat file.
Reaction
+ 4 acceptor = + 4 reduced acceptor
Synonyms
CarB, CrtI, crtI-type phytoene desaturase, lycopene synthase, PDS, PGT, PGTG_19044, phytoene desaturase, Rru_A0493
ECTree
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General Information
General Information on EC 1.3.99.31 - phytoene desaturase (lycopene-forming)
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evolution
malfunction
metabolism
physiological function
additional information
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CRTI-type phytoene desaturases prevailing in bacteria and fungi can form lycopene directly from phytoene while plants employ two distinct desaturases and two cis-tans isomerases for the same purpose
evolution
carotenoid biosynthesis and the evolution of carotenogenesis genes in rust fungi, phylogenetic analysis, detailed overview. A part of the carotenoid biosynthesis pathway in rust fungi is elucidated, with only two genes, CrtYB and CrtI, catalysing the reactions from geranyl-geranyl diphosphate (GGPP) to gamma-carotene. The CrtI gene encodes a phytoene desaturase carries out four successive desaturations of phytoene, through the intermediates phytofluene and neurosporene to lycopene. The CrtYB gene encodes a bifunctional lycopene cyclase/phytoene synthase, which catalyses the condensation of two GGPP into phytoene, as well as the cyclisation of the Psi-end of lycopene to form gamma-carotene
evolution
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
evolution
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
evolution
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
evolution
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
evolution
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, formingtetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
evolution
the nucleotide sequence of the crtI gene compared with that of other species, including Kocuria rhizophila and Myxococcus xanthus, proves well conserved during evolution
evolution
-
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
-
evolution
-
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
-
evolution
-
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
-
evolution
Puccinia graminis f. sp. tritici race SCCL
-
carotenoid biosynthesis and the evolution of carotenogenesis genes in rust fungi, phylogenetic analysis, detailed overview. A part of the carotenoid biosynthesis pathway in rust fungi is elucidated, with only two genes, CrtYB and CrtI, catalysing the reactions from geranyl-geranyl diphosphate (GGPP) to gamma-carotene. The CrtI gene encodes a phytoene desaturase carries out four successive desaturations of phytoene, through the intermediates phytofluene and neurosporene to lycopene. The CrtYB gene encodes a bifunctional lycopene cyclase/phytoene synthase, which catalyses the condensation of two GGPP into phytoene, as well as the cyclisation of the Psi-end of lycopene to form gamma-carotene
-
evolution
-
carotenoid biosynthesis and the evolution of carotenogenesis genes in rust fungi, phylogenetic analysis, detailed overview. A part of the carotenoid biosynthesis pathway in rust fungi is elucidated, with only two genes, CrtYB and CrtI, catalysing the reactions from geranyl-geranyl diphosphate (GGPP) to gamma-carotene. The CrtI gene encodes a phytoene desaturase carries out four successive desaturations of phytoene, through the intermediates phytofluene and neurosporene to lycopene. The CrtYB gene encodes a bifunctional lycopene cyclase/phytoene synthase, which catalyses the condensation of two GGPP into phytoene, as well as the cyclisation of the Psi-end of lycopene to form gamma-carotene
-
evolution
-
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
-
evolution
-
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
-
evolution
-
the enzyme belongs to the CrtI family of enzymes, analysis of the phylogenetic tree of a subset of phytoene desaturases from the CrtI family, overview. Recombinant expression of eight codon optimized CrtI enzymes from different clades in a bacterial system reveals that three CrtI enzymes can catalyse up to six desaturations, forming tetradehydrolycopene. Existence of characteristic patterns of desaturated molecules associated with various CrtI clades. Variations in the reaction rates and binding constants can explain the various carotene patterns observed. Relationship between genetic and functional evolution of certain CrtI enzymes, overview
-
-
a mutant of Rubrivivax gelatinosus lacking the crtI gene produces only phytoene, indicating that this organism has no other phytoene desaturases. When the crtI deletion mutant is complemented by the three-step phytoene desaturase of Rhodobacter capsulatus, spirilloxanthin and its precursors are not synthesized, although spheroidene and OH-spheroidene are accumulated
malfunction
wild-type Pgt produces reddish-brown urediniospores with yellow cytoplasmic carotenoid pigment and brownish spore wall pigments. Ethyl methanesulfonate (EMS)-induced mutants produce chocolate-coloured and yellow-coloured urediniospores, the mutants lack detectable cytoplasmic carotenoid pigments and sporewall pigments, respectively, viability and infection efficiency of these mutants compared to the corresponding wild-type forms, overview. Reduced fitness is found in the two colour mutants compared to the wild-type isolate, supporting a virulence function for carotenoid pigments in rust fungi, phenotypes, overview
malfunction
Puccinia graminis f. sp. tritici race SCCL
-
wild-type Pgt produces reddish-brown urediniospores with yellow cytoplasmic carotenoid pigment and brownish spore wall pigments. Ethyl methanesulfonate (EMS)-induced mutants produce chocolate-coloured and yellow-coloured urediniospores, the mutants lack detectable cytoplasmic carotenoid pigments and sporewall pigments, respectively, viability and infection efficiency of these mutants compared to the corresponding wild-type forms, overview. Reduced fitness is found in the two colour mutants compared to the wild-type isolate, supporting a virulence function for carotenoid pigments in rust fungi, phenotypes, overview
-
malfunction
-
wild-type Pgt produces reddish-brown urediniospores with yellow cytoplasmic carotenoid pigment and brownish spore wall pigments. Ethyl methanesulfonate (EMS)-induced mutants produce chocolate-coloured and yellow-coloured urediniospores, the mutants lack detectable cytoplasmic carotenoid pigments and sporewall pigments, respectively, viability and infection efficiency of these mutants compared to the corresponding wild-type forms, overview. Reduced fitness is found in the two colour mutants compared to the wild-type isolate, supporting a virulence function for carotenoid pigments in rust fungi, phenotypes, overview
-
-
CrtI produces lycopene exclusively as an end product, not as an intermediate in spirilloxanthin, carotenoid biosynthesis pathway in Rhodospirillum rubrum, overview
metabolism
the enzyme is involved catalyzing several steps in the beta-carotene biosynthetic pathway via phytoene, zeta-carotene, and lycopene, overview
metabolism
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Pantoea ananatis CrtI produces lycopene in vivo, but also tetradehydrolycopene in vitro
metabolism
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Mycolicibacterium aurum CrtI produces lycopene in vivo and in vitro
metabolism
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Rhodospirillum rubrum CrtI produces lycopene in vivo and in vitro
metabolism
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Blakeslea trispora CrtI produces lycopene in vivo and in vitro, but also didehydrolycopene in vivo (see also EC 1.3.99.30)
metabolism
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Enterobacter agglomerans CrtI produces lycopene in vivo and in vitro, but also tetradehydrolycopene in vitro
metabolism
the carotenoid biosynthesis pathway of Pgt is deduced from the results of the carotenoid pigment analysis and the gene complementation assay: the first C40 carotenoid, phytoene, is synthesised via the condensation of two molecules of GGPP, catalysed by the bifunctional lycopene cyclase/phytoene synthase encoded by the CrtYB gene. Subsequently, phytoene undergoes four steps of desaturation catalysed by the phytoene desaturase encoded by CrtI, through the intermediates phytofluene and neurosporene to lycopene. The CrtYB bifunctional lycopene cyclase/phytoene synthase then catalyses the cyclisation of one Psi-end of lycopene into gamma-carotene. beta-Carotene is not detected in the gene complementation assay
metabolism
the enzyme is involved in the lycopene biosynthetic pathway, overview
metabolism
-
CrtI produces lycopene exclusively as an end product, not as an intermediate in spirilloxanthin, carotenoid biosynthesis pathway in Rhodospirillum rubrum, overview
-
metabolism
-
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Rhodospirillum rubrum CrtI produces lycopene in vivo and in vitro
-
metabolism
-
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Rhodospirillum rubrum CrtI produces lycopene in vivo and in vitro
-
metabolism
-
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Rhodospirillum rubrum CrtI produces lycopene in vivo and in vitro
-
metabolism
Puccinia graminis f. sp. tritici race SCCL
-
the carotenoid biosynthesis pathway of Pgt is deduced from the results of the carotenoid pigment analysis and the gene complementation assay: the first C40 carotenoid, phytoene, is synthesised via the condensation of two molecules of GGPP, catalysed by the bifunctional lycopene cyclase/phytoene synthase encoded by the CrtYB gene. Subsequently, phytoene undergoes four steps of desaturation catalysed by the phytoene desaturase encoded by CrtI, through the intermediates phytofluene and neurosporene to lycopene. The CrtYB bifunctional lycopene cyclase/phytoene synthase then catalyses the cyclisation of one Psi-end of lycopene into gamma-carotene. beta-Carotene is not detected in the gene complementation assay
-
metabolism
-
the carotenoid biosynthesis pathway of Pgt is deduced from the results of the carotenoid pigment analysis and the gene complementation assay: the first C40 carotenoid, phytoene, is synthesised via the condensation of two molecules of GGPP, catalysed by the bifunctional lycopene cyclase/phytoene synthase encoded by the CrtYB gene. Subsequently, phytoene undergoes four steps of desaturation catalysed by the phytoene desaturase encoded by CrtI, through the intermediates phytofluene and neurosporene to lycopene. The CrtYB bifunctional lycopene cyclase/phytoene synthase then catalyses the cyclisation of one Psi-end of lycopene into gamma-carotene. beta-Carotene is not detected in the gene complementation assay
-
metabolism
-
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Rhodospirillum rubrum CrtI produces lycopene in vivo and in vitro
-
metabolism
-
carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Rhodospirillum rubrum CrtI produces lycopene in vivo and in vitro
-
metabolism
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carotenoid biosynthesis starts with the symmetrical condensation of two geranylgeranyl diphosphate molecules, forming phytoene. A series of successive desaturation reactions convert phytoene into phytofluene, zeta-carotene, neurosporene, lycopene. These desaturation reactions can be accomplished by a single enzyme (poly-trans pathway) or through a cascade of different enzymes (poly-cis pathway). In algae and plants, four different enzymes are necessary to form the final product (all-trans-lycopene). The phytoene and the zeta-carotene desaturases (PDS and ZDS, respectively) add double bonds in the cis-conformation. ZISO (zeta-carotene isomerase) and CRTISO (prolycopene isomerase) convert the cis-carotenes into di-cis-zeta-carotene and all-trans-lycopene, respectively. By contrast to other phytoene desaturases, CrtI are versatile enzymes classified into four enzymatic subgroups (EC 1.3.99.28, EC 1.3.99.29, EC 1.3.99.30, and EC 1.3.99.31) based on the last product they presumably produce (from zeta-carotene to didehydrolycopene). Carotene diversity can be further expanded in later steps with the addition of one or two rings by lycopene cyclases, thereby producing an extensive variety of symmetrical or asymmetrical cyclised carotenes, such as beta-zeacarotene, dehydro-beta-carotene, gamma-carotene, beta-carotene, and the fungi-specific torulene. When expressed in heterologous hosts, CrtI enzymes exhibit distinct desaturation patterns, CrtI enzyme activities may depend on the experimental conditions and thus be inconsistent with the patterns generated in the natural host. Rhodospirillum rubrum CrtI produces lycopene in vivo and in vitro
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the enzyme is involved in carotenoid biosynthesis
physiological function
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the enzyme simultaneously catalyzes a three- and four-step desaturation of phytoene producing both neurosporene and lycopene
physiological function
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the enzyme simultaneously catalyzes a three- and four-step desaturation of phytoene producing both neurosporene and lycopene. These carotenes are intermediates for the synthesis of spheroidene and spirilloxanthin, respectively
physiological function
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CRTI is a membrane-peripheral oxidoreductase which utilizes FAD as the sole redox-active cofactor. Oxygen, replaceable by quinones in its absence, is needed as the terminal electron acceptor. FAD, besides its catalytic role also displays a structural function by enabling the formation of enzymatically active CRTI membrane associates. Under anaerobic conditions the enzyme can act as a carotene cis-trans isomerase. In silico-docking experiments yielded information on substrate binding sites, potential catalytic residues and is in favor of single half-site recognition of the symmetrical C40 hydrocarbon substrate
physiological function
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in vivo, lycopene is incorporated into the light-harvesting complex 1 as efficiently as the methoxylated carotenoids spirilloxanthin (in the wild-type) and 3,4,3',4'-tetrahydrospirilloxanthin (in a crtD mutant), both under semiaerobic, chemoheterotrophic, and photosynthetic, anaerobic conditions, quantitative growth experiments, overview
physiological function
the expression product of crtI is essential for phytoene conversion to lycopene and 3,4-didehydrolycopene
physiological function
phytoene desaturase (CrtI), encoded by the gene crtI, catalyzes lycopene formation from phytoene and is an essential enzyme in the early steps of carotenoid biosynthesis. CrtI is one of the key enzymes regulating carotenoid biosynthesis and has been implicated as a rate-limiting enzyme of the pathway in various carotenoid synthesizing organisms
physiological function
the CrtI gene encodes a phytoene desaturase carries out four successive desaturations of phytoene, through the intermediates phytofluene and neurosporene to lycopene
physiological function
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the enzyme simultaneously catalyzes a three- and four-step desaturation of phytoene producing both neurosporene and lycopene. These carotenes are intermediates for the synthesis of spheroidene and spirilloxanthin, respectively
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physiological function
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in vivo, lycopene is incorporated into the light-harvesting complex 1 as efficiently as the methoxylated carotenoids spirilloxanthin (in the wild-type) and 3,4,3',4'-tetrahydrospirilloxanthin (in a crtD mutant), both under semiaerobic, chemoheterotrophic, and photosynthetic, anaerobic conditions, quantitative growth experiments, overview
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physiological function
Puccinia graminis f. sp. tritici race SCCL
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the CrtI gene encodes a phytoene desaturase carries out four successive desaturations of phytoene, through the intermediates phytofluene and neurosporene to lycopene
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physiological function
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the CrtI gene encodes a phytoene desaturase carries out four successive desaturations of phytoene, through the intermediates phytofluene and neurosporene to lycopene
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physiological function
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the expression product of crtI is essential for phytoene conversion to lycopene and 3,4-didehydrolycopene
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Rhodobacter azotoformans contains a carotenogenesis gene cluster with an unusual organization and a phytoene desaturase catalyzing both three- and four-step desaturations. CrtI from Rhodobacter azotoformans CGMCC 6086 can produce three-step desaturated neurosporene and four-step desaturated lycopene as major products, see also EC 1.3.99.28, together with small amounts of five-step desaturated 3,4-didehydrolycopene, EC 1.3.99.30
additional information
comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
additional information
comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
additional information
comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
additional information
comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
additional information
comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
additional information
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comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
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additional information
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comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
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additional information
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comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
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additional information
Cereibacter azotoformans CGMCC 6086
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Rhodobacter azotoformans contains a carotenogenesis gene cluster with an unusual organization and a phytoene desaturase catalyzing both three- and four-step desaturations. CrtI from Rhodobacter azotoformans CGMCC 6086 can produce three-step desaturated neurosporene and four-step desaturated lycopene as major products, see also EC 1.3.99.28, together with small amounts of five-step desaturated 3,4-didehydrolycopene, EC 1.3.99.30
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additional information
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comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
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additional information
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comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
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additional information
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comparison of the natural evolution and kinetic properties of selected CrtI enzymes expressed and assayed under standardised conditions. Potentially all CrtI enzymes can catalyse desaturation reactions that progress beyond the already observed end-products and the pattern of products formed originates from variations in the reaction rates rather than affinity constants
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