Identification of an amino acid determinant of pH regiospecificity in a seed lipoxygenase from Momordica charantia

Hornung, Ellen; Kunze, Susan; Liavonchanka, Alena; Zimmermann, Grit; Kühn, Diana; Fritsche, Kathrin; Renz, Andreas; Kühn, Hartmut; Feußner, Ivo

doi:10.1016/j.phytochem.2008.09.006

Cited by 18 publications

(14 citation statements)

References 24 publications

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“…The feasibility of a PUFA inserting with head-to-tail orientation has been discussed because of the negative cost of burying a polar carboxyl group inside a non-polar active site (Browner et al 1998); this hypothesis may remain the best model available. It is supported by studies showing the formation of either 9S-hydro(pero)xy octadecadienoic acid (H(P)ODE) or 13S-H(P)ODE by the Cucumis sativus lipid body lipoxygenase (Cs-LBLOX) after a point mutation (Hornung et al 1999), as well as by Momordica charantia LOX1 (MoLOX1; Hornung et al 2008) and Glycine max LOX1 (GmLOX1), showing a pH-dependent product formation (Gardner 1989). Moreover, accepting two different orientations of the substrate makes it possible to explain the variability of positional oxidations of known iron-LOX with a few variables.…”

Section: Regiospecificity Of Hydrogen Abstractionmentioning

confidence: 88%

“…Consistent with previous findings (Gardner ; Hornung et al . ; Walther et al . ), all products formed requiring a head‐to‐tail orientation are preferentially formed at acidic pH.…”

Section: Discussionmentioning

confidence: 99%

“…), as well as by Momordica charantia LOX1 (MoLOX1; Hornung et al . ) and Glycine max LOX1 (GmLOX1), showing a pH‐dependent product formation (Gardner ). Moreover, accepting two different orientations of the substrate makes it possible to explain the variability of positional oxidations of known iron‐LOX with a few variables.…”

Section: Introductionmentioning

confidence: 99%

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The green microalga Lobosphaera incisa harbours an arachidonate 15S‐lipoxygenase

Djian¹,

Hornung²,

Ischebeck

et al. 2018

Plant Biol J

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The green microalga Lobosphaera incisa is an oleaginous eukaryotic alga that is rich in arachidonic acid (20:4). Being rich in this polyunsaturated fatty acid ( PUFA ), however, makes it sensitive to oxidation. In plants, lipoxygenases ( LOX s) are the major enzymes that oxidise these molecules. Here, we describe, to our best knowledge, the first characterisation of a cDNA encoding a LOX (Li LOX ) from a green alga. To obtain first insights into its function, we expressed it in E. coli , purified the recombinant enzyme and analysed its enzyme activity. The protein sequence suggests that Li LOX and plastidic LOX s from bryophytes and flowering plants may share a common ancestor. The fact that Li LOX oxidises all PUFA s tested with a consistent oxidation on the carbon n‐6, suggests that PUFA s enter the substrate channel through their methyl group first (tail first). Additionally, Li LOX form the fatty acid hydroperoxide in strict S configuration. Li LOX may represent a good model to study plastid LOX , because it is stable after heterologous expression in E. coli and highly active in vitro . Moreover, as the first characterised LOX from green microalgae, it opens the possibility to study endogenous LOX pathways in these organisms.

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Section: Regiospecificity Of Hydrogen Abstractionmentioning

confidence: 88%

“…Consistent with previous findings (Gardner ; Hornung et al . ; Walther et al . ), all products formed requiring a head‐to‐tail orientation are preferentially formed at acidic pH.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The green microalga Lobosphaera incisa harbours an arachidonate 15S‐lipoxygenase

Djian¹,

Hornung²,

Ischebeck

et al. 2018

Plant Biol J

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show abstract

“…However, this classification scheme is not comprehensive and encountered difficulty because many LOXs are found to yield a mixture of 9-or 13-hydroperoxide (Brash 1999;Hornung et al 1999Hornung et al , 2008. According to the phylogenetic analysis, which is more comprehensive, animal and plant LOXs can be divided to two distinct groups (Brash 1999).…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of a novel type of lipoxygenase (LOX) gene from common wheat (Triticum aestivum L.)

Feng

Dong

et al. 2011

Mol Breeding

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Lipoxygenases (LOXs) are key enzymes catalyzing the oxidation of polyunsaturated fatty acids, and play an important role in grain storage, seed vigor and bread-making. In this study, we report cloning and characterization of TaLOX3, the homolog gene of barley LoxB, from common wheat (Triticum aestivum L.). The full-length cDNA sequence of TaLOX3 had an open reading frame of 2,634 bp encoding a deduced polypeptide of 878 amino acid residues with a predicted molecular weight of 99,549.79 Da and an estimated isoelectric point of 6.26. TaLOX3 was assigned to chromosome 4A. The multiple alignment result showed that TaLOX3 protein had an identity of 91.3% to barley LOX3 (encoded by LoxB). Profile analyses revealed that the three TaLOX genes are expressed in unique patterns in various organs. Furthermore, the expression profiles of the TaLOX3 gene were determined by q-PCR using the high and low seed LOX activity of different wheat varieties. The result showed that TaLOX3 transcript levels increased significantly during the development of wheat grain. Further analysis indicated genotypes with high LOX activity were associated with higher expression levels than the low LOX activity ones. This indicates that TaLOX3 may contribute to the total LOX activity in common wheat seeds. Phylogenetic analysis conducted with LOXs from rice, maize, Brachypodium distachyon genome, barley and wheat seeds (TaLOX1, TaLOX2 and TaLOX3) revealed that LOXs could be well resolved into two clades (G1 and G2). Moreover, G1 can be divided to three subgroups, with each TaLOX in one subgroup. Collectively, these results can extent our knowledge of the molecular characterization of LOXs, and will provide a valuable resource for wheat quality improvement and breeding.

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“…Plant LOXs have been divided into two types, 9-LOXs and 13-LOXs, which catalyze oxygenation at the carbon atoms 9 and 13 of the hydrocarbon backbone of LA, respectively. However, this classification scheme has encountered difficulty because more and more animal and plant LOXs are found to yield a mixture of products upon catalysis (Brash, 1999;Hornung et al, 1999Hornung et al, , 2008. Phylogenetic analysis suggests that the LOX superfamily contains at least two distinct families, which are composed of the LOXs from animals and plants, respectively (Brash, 1999).…”

Section: Introductionmentioning

confidence: 99%

Molecular analysis of lipoxygenase (LOX) genes in common wheat and phylogenetic investigation of LOX proteins from model and crop plants

Feng

Dong

et al. 2010

Journal of Cereal Science

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Identification of an amino acid determinant of pH regiospecificity in a seed lipoxygenase from Momordica charantia

Cited by 18 publications

References 24 publications

The green microalga Lobosphaera incisa harbours an arachidonate 15S‐lipoxygenase

The green microalga Lobosphaera incisa harbours an arachidonate 15S‐lipoxygenase

Molecular characterization of a novel type of lipoxygenase (LOX) gene from common wheat (Triticum aestivum L.)

Molecular analysis of lipoxygenase (LOX) genes in common wheat and phylogenetic investigation of LOX proteins from model and crop plants

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