Publications by authors named "Ernst Oliw"

The X-ray crystal structures of soybean lipoxygenase (LOX) and rabbit 15-LOX were reported in the 1990s. Subsequent 3D structures demonstrated a conserved U-like shape of the substrate cavities as reviewed here. The 8-LOX:arachidonic acid (AA) complex showed AA bound to the substrate cavity carboxylate-out with C10 at 3.

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Analyses of fungal genomes of escalate from biological and evolutionary investigations. The biochemical analyses of putative enzymes will inevitably lag behind and only a selection will be characterized. Plant-pathogenic fungi secrete manganese-lipoxygenases (MnLOX), which oxidize unsaturated fatty acids to hydroperoxides to support infection.

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Lipoxygenases (LOX) contain catalytic iron (FeLOX), but fungi also produce LOX with catalytic manganese (MnLOX). In this review, the 3D structures and properties of fungal LOX are compared and contrasted along with their associations with pathogenicity. The 3D structures and properties of two MnLOX (Magnaporthe oryzae, Geaumannomyces graminis) and the catalysis of four additional MnLOX have provided information on the metal centre, substrate binding, oxygenation, tentative O channels, and biosynthesis of exclusive hydroperoxides.

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Oxylipins designate oxygenated unsaturated C fatty acids. Many filamentous fungi pathogens contain dioxygenases (DOX) in oxylipin biosynthesis with homology to human cyclooxygenases. They contain a DOX domain, which is often fused to a functional cytochrome P450 at the C-terminal end.

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Histoplasma capsulatum is an ascomyceteous fungus and a human lung pathogen, which is present in river valleys of the Americas and other continents. H. capsulatum and two related human pathogens, Blasmomyces dermatitidis and Paracoccidioides brasiliensis, belongs to the Ajellomycetaceae family.

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Filamentous fungi differentiate along complex developmental programs directed by abiotic and biotic signals. Currently, intrinsic signals that govern fungal development remain largely unknown. Here we show that an endogenously produced and secreted fungal oxylipin, 5,8-diHODE, induces fungal cellular differentiation, including lateral branching in pathogenic Aspergillus fumigatus and Aspergillus flavus, and appressorium formation in the rice blast pathogen Magnaporthe grisea.

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Rationale: Jasmonates are formed from 12-oxo-10,15(Z)-phytodienoic acid (12-OPDA) in plants and also from 12-oxo-10-phytoenoic acid (12-OPEA) in fungi. Collision-induced dissociation (CID) of [M-H] generates characteristic product anions at m/z 165 [C H O] . Our goal was to investigate the structure and mode of formation of this anion by CID of 12-OPDA, 12-OPEA, and 12-oxophytonoic acid (12-OPA).

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Fusarium oxysporum f. sp. tulipae (FOT) secretes (+)-7-iso-jasmonoyl-(S)-isoleucine ((+)-JA-Ile) to the growth medium together with about 10 times less 9,10-dihydro-(+)-7-iso-JA-Ile.

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The fungal linoleate diol synthase (LDS) family contains over twenty characterized 8-, 9-, and 10-dioxygenases (DOX), usually fused to catalytically competent cytochromes P450. Crystal structures are not available, but indirect evidence suggests that linoleic acid enters the active site of 8R-DOX-LDS headfirst and enters 9S-DOX-allene oxide synthase (AOS) with the ω-end (tail) first. Fatty acids derivatized with amino acids can conceivably be used to study oxidation in tail first position by enzymes, which bind natural fatty acids headfirst.

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Oxylipin biosynthesis by fungi is catalyzed by both the lipoxygenase (LOX) family and the linoleate diol synthase (LDS) family of the peroxidase-cyclooxygenase superfamily. Rhizoctonia solani, a pathogenic fungus, infects staple crops such as potato and rice. The genome predicts three genes with 9-13 introns, which code for tentative dioxygenase (DOX)-cytochrome P450 fusion enzymes of the LDS family, and one gene, which might code for a 13-LOX.

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Pathogenic fungi express fatty acid dioxygenases (DOX) fused to cytochromes P450 with diol or allene oxide synthase activities. The orientation of the fatty acids in the active sites of DOX was investigated with amino acid conjugates of 18:3n-3 and 18:2n-6. 9S-DOX-allene oxide synthase (AOS) oxidized the Gly, Ile, and Trp derivatives at C-9, which suggests that these conjugates enter the substrate recognition site with the omega end in analogy with fatty acids bound to cyclooxygenases and coral 8R-lipoxygenase (8R-LOX).

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Fungi can produce jasmonic acid (JA) and its isoleucine conjugate in large quantities, but little is known about the biosynthesis. Plants form JA from 18:3-3 by 13-lipoxygenase (LOX), allene oxide synthase, and allene oxide cyclase. Shaking cultures of f.

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Plants and fungi form jasmonic acid from α-linolenic acid. The first two steps of biosynthesis in plants occur by sequential transformation by 13S-lipoxygenase and allene oxide synthase (AOS). The biosynthesis in fungi may follow this classical scheme, but the only fungal AOS discovered so far are cytochromes P450 (CYP) fused to 8- and 9-dioxygenases (DOX).

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The crystal structure of 13R-manganese lipoxygenase (MnLOX) of Gaeumannomyces graminis (Gg) in complex with zonadhesin of Pichia pastoris was solved by molecular replacement. Zonadhesin contains β-strands in two subdomains. A comparison of Gg-MnLOX with the 9S-MnLOX of Magnaporthe oryzae (Mo) shows that the protein fold and the geometry of the metal ligands are conserved.

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Linoleate dioxygenase-cytochrome P450 (DOX-CYP) fusion enzymes are common in pathogenic fungi. The DOX domains form hydroperoxy metabolites of 18:2n-6, which can be transformed by the CYP domains to 1,2- or 1,4-diols, epoxy alcohols, or to allene oxides. We have characterized two novel allene oxide synthases (AOSs), namely, recombinant 8R-DOX-AOS of Coccidioides immitis (causing valley fever) and 8S-DOX-AOS of Zymoseptoria tritici (causing septoria tritici blotch of wheat).

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Lipoxygenases (LOX) are non-heme metal enzymes, which oxidize polyunsaturated fatty acids to hydroperoxides. All LOX belong to the same gene family, and they are widely distributed. LOX of animals, plants, and prokaryotes contain iron as the catalytic metal, whereas fungi express LOX with iron or with manganese.

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The genome of Aspergillus niger codes for a fusion protein (EHA25900), which can be aligned with ~50% sequence identity to 9S-dioxygenase (DOX)-allene oxide synthase (AOS) of Fusarium oxysporum, homologues of the Fusarium and Colletotrichum complexes and with over 62% sequence identity to homologues of Aspergilli, including (DOX)-9R-AOS of Aspergillus terreus. The aims were to characterize the enzymatic activities of EHA25900 and to identify crucial amino acids for the stereospecificity. Recombinant EHA25900 oxidized 18:2n-6 sequentially to 9R-hydroperoxy-10(E),12(Z)-octadecadienoic acid (9R-HPODE) and to a 9R(10)-allene oxide.

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Fungal pathogens constitute serious threats for many forms of life. The pathogenic fungi Fusarium and Colletotrichum and their formae speciales (f. spp.

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Magnaporthe oryzae causes rice blast disease and has become a model organism of fungal infections. M. oryzae can oxygenate fatty acids by 7,8-linoleate diol synthase, 10R-dioxygenase-epoxy alcohol synthase, and by a putative manganese lipoxygenase (Mo-MnLOX).

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The biosynthesis of jasmonates in plants is initiated by 13S-lipoxygenase (LOX), but details of jasmonate biosynthesis by fungi, including Fusarium oxysporum, are unknown. The genome of F. oxysporum codes for linoleate 13S-LOX (FoxLOX) and for F.

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Fatty acid oxygenases are often characterized by steric analysis of their hydroxy or hydroperoxy metabolites. Chiral phase-HPLC (CP-HPLC) can be used to separate enantiomeric hydroperoxyoctadecenoic acids. This method is based on analysis of seven octadecenoic fatty acids with double bonds at positions 6Z to 13Z, which were oxidized to hydroperoxides by photooxidation.

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The genome of the rice blast fungus Magnaporthe oryzae codes for two proteins with N-terminal dioxygenase (DOX) and C-terminal cytochrome P450 (CYP) domains, respectively. One of them, MGG_13239, was confirmed as 7,8-linoleate diol synthase by prokaryotic expression. The other recombinant protein (MGG_10859) possessed prominent 10R-DOX and epoxy alcohol synthase (EAS) activities.

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Lipoxygenases (LOX) oxidize polyunsaturated fatty acids to hydroperoxides, which are generated by proton coupled electron transfer to the metal center with FeIIIOH- or MnIIIOH-. Hydrogen abstraction by FeIIIOH- of soybean LOX-1 (sLOX-1) is associated with a large deuterium kinetic isotope effect (D-KIE). Our goal was to compare the D-KIE and other kinetic parameters at different temperatures of sLOX-1 with 13R-LOX with catalytic manganese (13R-MnLOX).

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Lipoxygenases constitute a family of nonhaem metal enzymes with catalytic iron or, occasionally, catalytic manganese. Lipoxygenases oxidize polyunsaturated fatty acids with position specificity and stereospecificity to hydroperoxides, which contribute to inflammation and the development of cancer. Little is known about the structural differences between lipoxygenases with Fe or Mn and the metal-selection mechanism.

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