CYP175A1 from Thermus thermophilus HB27, the first �-carotene hydroxylase of the P450 superfamily

Blasco, Francesca; Kauffmann, Isabelle Melanie; Schmid, Rolf D.

doi:10.1007/s00253-003-1529-7

Cited by 68 publications

(37 citation statements)

References 16 publications

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“…The location of this single P450 gene on the thermophile's megaplasmid suggests that the gene may have been acquired through horizontal transfer and perhaps conferred some advantage to heat stress. The bacterial gene encodes a 44 kDa (9.72 pI) enzyme in comparison to the predicted mature 66 kDa (5.44 pI) plant Clan A enzyme [72,73], though they share 21% similar residues and cluster in a neighbor-joining tree [74]. While the plant and bacterial enzymes are sufficiently different, and perhaps cases of convergent evolution, they both functioned in E. coli.…”

Section: What Is the Structural Basis For Enzyme Specificity?mentioning

confidence: 99%

Escherichia coli as a platform for functional expression of plant P450 carotene hydroxylases

Quinlan

Jaradat

Wurtzel

2007

Archives of Biochemistry and Biophysics

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Carotenoids and their derivatives are essential for growth, development, and signaling in plants and have an added benefit as nutraceuticals in food crops. Despite the importance of the biosynthetic pathway, there remain open questions regarding some of the later enzymes in the pathway. The CYP97 family of P450 enzymes was predicted to function in carotene ring hydroxylation, to convert provitamin A carotenes to nonprovitamin A xanthophylls. However, substrate specificity was difficult to investigate directly in plants, which mask enzyme activities by a complex and dynamic metabolic network. To characterize the enzymes more directly, we amplified cDNAs from a model crop, Oryza sativa, and used functional complementation in Escherichia coli to test activity and specificity of members of Clans A and C. This heterologous system will be valuable for further study of enzyme interactions and substrate utilization needed to understand better the role of CYP97 hydroxylases in plant carotenoid biosynthesis.

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Section: What Is the Structural Basis For Enzyme Specificity?mentioning

confidence: 99%

Escherichia coli as a platform for functional expression of plant P450 carotene hydroxylases

Quinlan

Jaradat

Wurtzel

2007

Archives of Biochemistry and Biophysics

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“…Genes for both types of enzyme may have been acquired from carotenoid-producing bacteria. Plant CrtZ-type ␤-carotene hydroxylases are similar in amino acid sequence to certain bacterial and archaeal enzymes that serve the same function, and the cytochrome P450 class of carotenoid ␤-ring hydroxylases also has representatives in carotenoid-producing bacteria (6).…”

mentioning

confidence: 99%

“…6,2007 CAROTENOID BIOSYNTHESIS IN CYANIDIOSCHYZON MEROLAE 543 (41). Whether this approach is applicable to genes of the plastid genome, and to crtR in particular, is not known.…”

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confidence: 99%

Carotenoid Biosynthesis in the Primitive Red Alga Cyanidioschyzon merolae

2007

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Cyanidioschyzon merolae is considered to be one of the most primitive of eukaryotic photosynthetic organisms. To obtain insights into the origin and evolution of the pathway of carotenoid biosynthesis in eukaryotic plants, the carotenoid content of C. merolae was ascertained, genes encoding enzymes of carotenoid biosynthesis in this unicellular red alga were identified, and the activities of two candidate pathway enzymes of particular interest, lycopene cyclase and ␤-carotene hydroxylase, were examined. C. merolae contains perhaps the simplest assortment of chlorophylls and carotenoids found in any eukaryotic photosynthetic organism: chlorophyll a, ␤-carotene, and zeaxanthin. Carotenoids with -rings (e.g., lutein), found in many other red algae and in green algae and land plants, were not detected, and the lycopene cyclase of C. merolae quite specifically produced only ␤-ringed carotenoids when provided with lycopene as the substrate in Escherichia coli. Lycopene ␤-ring cyclases from several bacteria, cyanobacteria, and land plants also proved to be high-fidelity enzymes, whereas the structurally related -ring cyclases from several plant species were found to be less specific, yielding products with ␤-rings as well as -rings. C. merolae lacks orthologs of genes that encode the two types of ␤-carotene hydroxylase found in land plants, one a nonheme diiron oxygenase and the other a cytochrome P450. A C. merolae chloroplast gene specifies a polypeptide similar to members of a third class of ␤-carotene hydroxylases, common in cyanobacteria, but this gene did not produce an active enzyme when expressed in E. coli. The identity of the C. merolae ␤-carotene hydroxylase therefore remains uncertain.The unicellular red alga Cyanidioschyzon merolae, a resident of acidic hot springs, is considered to be one of the most primitive of photosynthetic eukaryotes (44,57,65). As such, the photosynthetic apparatus in this alga may provide the closest approximation to that of the prokaryotic ancestor of the modern-day chloroplast. We are especially interested in the ancestry and evolution of enzymes of the pathway that provides for the synthesis of the carotenoids, a family of isoprenoid pigments that are integral and essential constituents of the photosynthetic apparatus in all oxygenic photoautotrophs. In this work, we exploit the recent availability of the nuclear (39), mitochondrial (47), and plastid (46) genome sequences of C. merolae to address the origin of carotenoid pathway genes in this alga.The pathways of carotenoid biosynthesis in eukaryotic plants and in prokaryotic cyanobacteria, the latter of which are considered to be modern-day descendants of the ancestral plastid progenitor (40), are very much alike in their early stages. Reactions in plant chloroplasts that lead from the C 5 isoprenoid precursors isopentenyl diphosphate and dimethylallyl diphosphate to the linear C 40 carotenoid intermediate lycopene are catalyzed by enzymes similar in sequence to their cyanobacterial counterparts (53). Plant and cyanobacterial c...

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“…The carotenoid oxygenases identified to date are not heminic enzymes since the recent X-ray structure analysis of a carotenoid oxygenase showed the presence of 4 histidine residues chelating the iron center [60]. However, it was recently shown that carotenoid hydroxylation is catalyzed by CYP 450 in bacteria [69] and in plants [70,71]. A well-developed and elegant porphyrin model of a catalytic system has been used to mimic the central cleavage of carotenoids [72].…”

Section: Carail and C Caris-veyratmentioning

confidence: 99%

Carotenoid oxidation products: From villain to saviour?

Carail¹,

Caris-Veyrat²

2006

Pure and Applied Chemistry

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Carotenoid oxidation products have various structures, among which epoxides and apo-or seco-carotenoids are the two main families. Although both these compound types are widely found in the natural world, the sensitivity of carotenoids to oxidation means they can also be an unwanted presence in in vitro assays. On the other hand, carotenoid oxidation products have also provided chemists with useful chemical tools for the structural identification of carotenoids, and in the natural world they are important biological mediators for plants and animals. In vitro, carotenoid oxidation products have been found to exert various effects which are either potentially beneficial or, on the contrary, detrimental to human health. However, to date, few carotenoid oxidation products have been found in humans.In order to isolate and characterize carotenoid oxidation products and identify their mechanism of formation, we set up two chemical oxidation systems. Lycopene was oxidized with potassium permanganate in a biphasic system to produce the fullest possible range of apo-lycopenals and some diapocarotene-dials. Biomimetic chemical systems of a heminic enzyme center were shown to oxidize lycopene and β-carotene into different families of molecules. Analysis by high-performance liquid chromatography coupled with a diode array-UV/vis detector and a mass spectrometry detector (HPLC-DAD-MS) was used to gain insight into the possible mechanisms of formation of the carotenoid oxidation products formed by these biomimetic systems.

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CYP175A1 from Thermus thermophilus HB27, the first �-carotene hydroxylase of the P450 superfamily

Cited by 68 publications

References 16 publications

Escherichia coli as a platform for functional expression of plant P450 carotene hydroxylases

Escherichia coli as a platform for functional expression of plant P450 carotene hydroxylases

Carotenoid Biosynthesis in the Primitive Red Alga Cyanidioschyzon merolae

Carotenoid oxidation products: From villain to saviour?

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