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Title: | A new class of fatty acid allene oxide formed by the DOX-P450 fusion proteins of human and plant pathogenic fungi, C. immitis and Z. tritic |
Author: | Oliw, Ernst H. Aragó Belenguer, Marc Chen, Yang Jernerén, Fredrik |
Keywords: | Metabolisme dels lípids Enzims Dioxines Proteïnes Fongs patògens Lipid metabolism Enzymes Dioxins Proteins Pathogenic fungi |
Issue Date: | Aug-2016 |
Publisher: | American Society for Biochemistry and Molecular Biology |
Abstract: | 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). The 8R-DOX-AOS oxidized 18:2n-6 sequentially to 8R-hydroperoxy-9Z,12Z-octadecadienoic acid (8R-HPODE) and to an allene oxide, 8R(9)-epoxy-9,12Z-octadecadienoic acid, as judged from the accumulation of the α-ketol, 8S-hydroxy-9-oxo-12Z-octadecenoic acid. The 8S-DOX-AOS of Z. tritici transformed 18:2n-6 sequentially to 8S-HPODE and to an α-ketol, 8R-hydroxy-9-oxo-12Z-octadecenoic acid, likely formed by hydrolysis of 8S(9)-epoxy-9,12Z-octadecadienoic acid. The 8S-DOX-AOS oxidized [8R-2H]18:2n-6 to 8S-HPODE with retention of the 2H-label, suggesting suprafacial hydrogen abstraction and oxygenation in contrast to 8R-DOX-AOS. Both enzymes oxidized 18:1n-9 and 18:3n-3 to α-ketols, but the catalysis of the 8R- and 8S-AOS domains differed. 8R-DOX-AOS transformed 9R-HPODE to epoxy alcohols, but 8S-DOX-AOS converted 9S-HPODE to an α-ketol (9-hydroxy-10-oxo-12Z-octadecenoic acid) and epoxy alcohols in a ratio of ∼1:2. Whereas all fatty acid allene oxides described so far have a conjugated diene impinging on the epoxide, the allene oxides formed by 8-DOX-AOS are unconjugated. |
Note: | Reproducció del document publicat a: https://doi.org/10.1194/jlr.M068981 |
It is part of: | Journal of Lipid Research, 2016, vol. 57, num. 8, p. 1518-1528 |
URI: | http://hdl.handle.net/2445/125188 |
Related resource: | https://doi.org/10.1194/jlr.M068981 |
ISSN: | 0022-2275 |
Appears in Collections: | Articles publicats en revistes (Ciències Fisiològiques) |
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