Oxylipin formation in Nostoc punctiforme (PCC73102)

Lang, Imke; Feußner, Ivo

doi:10.1016/j.phytochem.2007.02.028

Cited by 36 publications

(36 citation statements)

References 32 publications

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“…For example, the two common classes of plant LOX form either the 9S-hydroperoxides of linoleic (18:26) and linolenic (18:33) acids, or the 13S-hydroperoxides (11). Similar LOX activities were described recently in two species of cyanobacteria (12,13). There are also specific LOX enzymes identified that produce 10 of the 12 possible regio-and stereoisomers of hydroperoxide from arachidonic acid (20:46) (3,14).…”

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confidence: 58%

A 49-kDa Mini-lipoxygenase from Anabaena sp. PCC 7120 Retains Catalytically Complete Functionality

Zheng¹,

Boeglin²,

Schneider

et al. 2008

Journal of Biological Chemistry

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Anabaena sp. PCC 7120 is one of the few prokaryotes harboring a lipoxygenase (LOX) gene. The sequence resides in an open reading frame encoding a fusion protein of a catalase-like hemoprotein with an unusually short LOX (ϳ49 kDa) at the C terminus. The recombinant mini-LOX contains a non-heme iron in the active site and is highly active with linoleic and ␣-linolenic acids (which occur naturally in Anabaena) giving the respective 9R-hydroperoxides, the mirror image of the 9S-LOX products of plants. Using stereospecifically labeled [11-3 H]linoleic acids we show that reaction is catalyzed via a typical antarafacial relationship of initial hydrogen abstraction and oxygenation. The mini-LOX oxygenated C 16 /C 18:2 -phosphatidylcholine with 9R specificity, suggesting a "tail first" mode of fatty acid binding. Site-directed mutagenesis of an active site Ala (Ala 215 ), typically conserved as Gly in R-LOX, revealed that substitution with Gly retained 9R specificity, whereas the larger Val substitution switched oxygenation to 13S, implying that Ala 215 represents the functional equivalent of the Gly in other R-LOX. Metabolism studies using a synthetic fatty acid with extended double bond conjugation, 9E,11Z,14Z-20:36, showed that the mini-LOX can control oxygenation two positions further along the fatty acid carbon chain. We conclude that the mini-LOX, despite lacking the ␤-barrel domain and much additional sequence, is catalytically complete. Interestingly, animal and plant LOX, which undoubtedly share a common ancestor, are related in sequence only in the catalytic domain; it is possible that the prokaryotic LOX represents a common link and that the ␤-barrel domain was then acquired independently in the animal and plant kingdoms. Lipoxygenases (LOX)3 oxygenate polyunsaturated fatty acids to specific hydroperoxide derivatives (1, 2). The enzymes occur widely in the eukaryotic world, being ubiquitous in plants and fungi, common in primitive animals such as corals and hydra, and again ubiquitous in higher animals (3, 4). The lipoxygenase proteins are comprised of a polypeptide chain of 75-80 kDa in animals, 94 -104 kDa in plants, and harbor a single non-heme iron in the active site. As shown by x-ray crystallography, the animal and plant LOX enzymes share the same overall topology, with the extra ϳ20 -30 kDa in the plant LOX being accounted for by extra loops between the otherwise well conserved sequences (5-8). Lipoxygenases have a two-domain structure, an N-terminal C2-like or ␤-barrel domain, and the larger, mainly ␣-helical, catalytic domain that holds the iron in the active site. In the catalytic domain the LOX enzymes share five well conserved amino acid ligands to the iron, four histidines (or three His and one Asn or Ser) and the carboxylate group of the very C-terminal amino acid, usually Ile. Analysis of the structure-function of LOX enzymes suggests that the ␤-barrel domain plays a role in membrane binding and/or substrate acquisition (9, 10), whereas the catalytic domain is involved in controlling the reactio...

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confidence: 58%

A 49-kDa Mini-lipoxygenase from Anabaena sp. PCC 7120 Retains Catalytically Complete Functionality

Zheng¹,

Boeglin²,

Schneider

et al. 2008

Journal of Biological Chemistry

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“…1b). The red alga (Phyropia haitanensis) and cyanobacteria (Nostoc punctiforme) also have lipoxygenase genes to form fatty acid hydroperoxides (Koeduka et al 2007;Lang and Feussner 2007;Zhu et al 2015). Both C18 and C20 fatty acid metabolic pathways have been reported and the database search to find the genes encoding to CYP74 enzymes are available in bryophytes and algae, but the enzymes have not been fully examined for the function and diversification of AOS, HPL, and DES activities, especially about the cleaving enzymes such as HPL that are responsible for the formation of C8 volatiles in liverworts.…”

Section: Introductionmentioning

confidence: 99%

Biochemical characterization of allene oxide synthases from the liverwort Marchantia polymorpha and green microalgae Klebsormidium flaccidum provides insight into the evolutionary divergence of the plant CYP74 family

Koeduka

Ishizaki

Mwenda

et al. 2015

Planta

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Allene oxide synthases (AOSs) were isolated from liverworts and charophytes. These AOSs exhibited enzymatic properties similar to those of angiosperms but formed a distinct phylogenetic clade. Allene oxide synthase (AOS) and hydroperoxide lyase (HPL) mediate the formation of precursors of jasmonates and carbon-six volatiles, respectively. AOS and HPL utilize fatty acid hydroperoxides and belong to the plant cytochrome P450 74 (CYP74) family that mediates plant defense against herbivores, pathogens, or abiotic stresses. Although members of the CYP74 family have been reported in mosses and other species, the evolution and function of multiple CYP74 genes in plants remain elusive. Here, we show that the liverwort Marchantia polymorpha belongs to a basal group in the evolution of land plants; has two closely related proteins (59% identity), MpAOS1 and MpAOS2, that are similar to moss PpAOS1 (49 and 47% identity, respectively); and exhibits AOS activity but not HPL activity. We also found that the green microalgae Klebsormidium flaccidum, consist of multicellular and non-branching filaments, contains an enzyme, KfAOS, that is similar to PpAOS1 (37% identity), and converts 13-hydroperoxide of linolenic acid to 12-oxo-phytodienoic acid in a coupled reaction with allene oxide cyclase. Phylogenetic analysis showed two evolutionarily distinct clusters. One cluster comprised AOS and HPL from charophytic algae, liverworts, and mosses, including MpAOSs and KfAOS. The other cluster was formed by angiosperm CYP74. Our results suggest that plant CYP74 enzymes with AOS, HPL, and divinyl ether synthase activities have arisen multiple times and in the two different clades, which occurred prior to the divergence of the flowering plant lineage.

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“…The deduced amino acid sequence showed that CspLOX2 consists only of a C-terminal catalytic LOX domain with highest homology to a putative arachidonate 15-LOX precursor from Microcystis aeruginosa and to NpLOX2, a linoleate 13-LOX from cyanobacterium Nostoc punctiforme. CspLOX2 showed 43% sequence identity and 60% similarity to the latter enzyme (32,33). Alignment of the amino acid sequence revealed that CspLOX2 harbors the conserved metal ligands (3 histidine residues, an asparagine, and the C-terminal isoleucine), but not the residues described to play a role in determining regiospecificity in either mammalian or plant LOXs.…”

Section: Resultsmentioning

confidence: 97%

A Bisallylic Mini-lipoxygenase from Cyanobacterium Cyanothece sp. That Has an Iron as Cofactor

Andreou¹,

Göbel²,

Hámberg

et al. 2010

Journal of Biological Chemistry

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Lipoxygenases are enzymes that are found ubiquitously in higher animals and plants, but have only recently been identified in a number of bacteria. The genome of the diazotrophic unicellular cyanobacterium Cyanothece sp. harbors two genes with homology to lipoxygenases. Here we describe the isolation of one gene, formerly named csplox2. It was cloned, and the protein was expressed in Escherichia coli and purified. The purified enzyme belongs to the group of prokaryotic mini lipoxygenases, because it had a molecular mass of 65 kDa. Interestingly, it catalyzed the conversion of linoleic acid, the only endogenously found polyunsaturated fatty acid, primarily to the bisallylic hydroperoxide 11R-hydroperoxyoctadecadienoic acid. This product had previously only been described for the manganese lipoxygenase from the take all fungus, Gaeumannomyces graminis. By contrast, CspLOX2 was shown to be an iron lipoxygenase. In addition, CspLOX2 formed a mixture of typical conjugated lipoxygenase products, e.g. 9R-and 13S-hydroperoxide. The conversion of linoleic acid took place with a maximum reaction rate of 31 s ؊1 . Incubation of the enzyme with [(11S)-2 H]linoleic acid led to the formation of hydroperoxides that had lost the deuterium label, thus suggesting that CspLOX2 catalyzes antarafacial oxygenation as opposed to the mechanism of manganese lipoxygenase. CspLOX2 could also oxidize diarachidonylglycerophosphatidylcholine with similar specificity as the free fatty acid, indicating that binding of the substrate takes place with a "tail-first" orientation. We conclude that CspLOX2 is a novel iron mini-lipoxygenase that catalyzes the formation of bisallylic hydroperoxide as the major product.

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Oxylipin formation in Nostoc punctiforme (PCC73102)

Cited by 36 publications

References 32 publications

A 49-kDa Mini-lipoxygenase from Anabaena sp. PCC 7120 Retains Catalytically Complete Functionality

A 49-kDa Mini-lipoxygenase from Anabaena sp. PCC 7120 Retains Catalytically Complete Functionality

Biochemical characterization of allene oxide synthases from the liverwort Marchantia polymorpha and green microalgae Klebsormidium flaccidum provides insight into the evolutionary divergence of the plant CYP74 family

A Bisallylic Mini-lipoxygenase from Cyanobacterium Cyanothece sp. That Has an Iron as Cofactor

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