Information on EC 1.3.99.28 - phytoene desaturase (neurosporene-forming) and Organism(s) Cereibacter sphaeroides and UniProt Accession P54980

all-trans-neurosporene

15-cis-phytoene

all-trans-neurosporene

15-cis-phytoene

all-trans-phytofluene

all-trans-phytofluene

all-trans-zeta-carotene

Synonyms

3-step phytoene desaturase, show all synonyms

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CrtI

741967, 759253

PDS

phytoene desaturase

CrtI

phytoene desaturase

Biosynthesis of secondary metabolites, Carotenoid biosynthesis

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KEGG

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15-cis-phytoene:acceptor oxidoreductase (neurosporene-forming)

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15-cis-phytoene + acceptor

all-trans-phytofluene + reduced acceptor

all-trans-phytofluene + acceptor

all-trans-zeta-carotene + reduced acceptor

all-trans-zeta-carotene + acceptor

all-trans-neurosporene + reduced acceptor

15-cis-phytoene + 3 acceptor

all-trans-neurosporene + 3 reduced acceptor

the enzyme is involved in carotenoid biosynthesis

15-cis-phytoene + acceptor

all-trans-zeta-carotene + reduced acceptor

all-trans-zeta-carotene + acceptor

all-trans-neurosporene + reduced acceptor

phytoene + acceptor

neurosporene + reduced acceptor

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15-cis-phytoene + acceptor

all-trans-phytofluene + reduced acceptor

all-trans-phytofluene + acceptor

all-trans-zeta-carotene + reduced acceptor

all-trans-zeta-carotene + acceptor

all-trans-neurosporene + reduced acceptor

15-cis-phytoene + 3 acceptor

all-trans-neurosporene + 3 reduced acceptor

the enzyme is involved in carotenoid biosynthesis

15-cis-phytoene + acceptor

all-trans-zeta-carotene + reduced acceptor

all-trans-zeta-carotene + acceptor

all-trans-neurosporene + reduced acceptor

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additional information

classical Michaelis-Menten kinetic model

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2 entries

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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

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. CrtI from Rhodobacter sphaeroides produced neurosporene in vitro and in vivo

evolution

homologous complementation of CrtI from Pantoea agglomerans with the Pantoea agglomerans carotenogenic module expressing CrtEPAG-CrtBPAG

metabolism

the enzyme is a pathway branch point enzyme in the carotenoid pathway

physiological function

involved in carotenoid biosynthesis

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

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F166I

mutation changes the product of phytoene desaturation from neurosporene to lycopene

H12Q

mutation has little effect on the product formation

M402T

mutation has a negative effect on percent lycopene production

V68D

mutation changes the product of phytoene desaturation from neurosporene to lycopene

additional information

3 entries

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gene crtI, sequence comparisons and phylogenetic analysis, recombinant expression in Escherichia coli

gene crtI, phylogenetic tree, co-expression with 5 other enzymes of the carotenoid pathway from Pantoea agglomerans, i.e. IPP isomerase, FPP synthase, GGPP synthase, phytoene synthase, lycopene cyclase, beta-carotene hydrolase, and zeaxanthin glucosyltransferase, in Escherichia coli, functional complementation by CrtI of Brevibacterium linens, CGI, CrtI of Corynebacterium glutamicum, RSI, CrtI of Rhodobacter sphaeroides RCI, CrtI of Rhodobacter capsulatus, and RBI, CrtI of Rhodopirellula baltica, and the homologous complementation of CrtI from Pantoea agglomerans with the Pantoea agglomerans carotenogenic module expressing CrtEPAG -CrtBPAG

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synthesis

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swapping the native three-step CrtI for the four-step Pantoea agglomerans enzyme, EC 1.3.99.31, reroutes carotenoid biosynthesis and culminates in the production of 2,2'-diketo-spirilloxanthin under semi-aerobic conditions. Premature termination of this pathway by inactivating crtC or crtD produces strains with lycopene or rhodopin as major carotenoids. All of the spirilloxanthin series carotenoids are accepted by the assembly pathways for light-harvesting 2 complex and reaction centre-light-harvesting 1-PufX complexes

741967

Wang, C.W.; Liao, J.C.

Alteration of product specificity of Rhodobacter sphaeroides phytoene desaturase by directed evolution

J. Biol. Chem.

276

41161-41164

2001

Cereibacter sphaeroides

11526111

Song, G.H.; Kim, S.H.; Choi, B.H.; Han, S.J.; Lee, P.C.

Heterologous carotenoid-biosynthetic enzymes: functional complementation and effects on carotenoid profiles in Escherichia coli

Appl. Environ. Microbiol.

610-618

2013

Brevibacterium linens, Brevibacterium linens DSM 20426, Cereibacter sphaeroides, Cereibacter sphaeroides KCTC 12085, Corynebacterium glutamicum, Corynebacterium glutamicum KCTC 1445, Pantoea agglomerans (K7WPN7), Pantoea agglomerans KCTC 2479 (K7WPN7), Rhodobacter capsulatus, Rhodobacter capsulatus KCTC 2583, Rhodopirellula baltica, Rhodopirellula baltica DSM 10527

23144136

741967

Chi, S.C.; Mothersole, D.J.; Dilbeck, P.; Niedzwiedzki, D.M.; Zhang, H.; Qian, P.; Vasilev, C.; Grayson, K.J.; Jackson, P.J.; Martin, E.C.; Li, Y.; Holten, D.; Neil Hunter, C.

Assembly of functional photosystem complexes in Rhodobacter sphaeroides incorporating carotenoids from the spirilloxanthin pathway

Biochim. Biophys. Acta

1847

189-201

2015

Cereibacter sphaeroides (P54980), Cereibacter sphaeroides DSM 158 (P54980)

25449968