Discovery of a Novel Linoleate Dioxygenase of Fusarium oxysporum and Linoleate Diol Synthase of Colletotrichum graminicola
作者:Linda Sooman、Ernst H. Oliw
DOI:10.1007/s11745-015-4078-9
日期:2015.12
(cyclooxygenase) superfamily. The objective was to characterize the enzymatic activities of the DOX-CYP homologue of Colletotrichumgraminicola (EFQ34869) and the DOX homologue of F. oxysporum (EGU79548). The former oxidized oleic and linoleic acids in analogy with 7,8-linoleate diolsynthases (LDSs), but with the additional biosynthesis of 8,11-dihydroxylinoleic acid. The latter metabolized fatty acids
Linolenate 9
<i>R</i>
‐Dioxygenase and Allene Oxide Synthase Activities of
<i>Lasiodiplodia theobromae</i>
作者:Fredrik Jernerén、Felipe Eng、Mats Hamberg、Ernst H. Oliw
DOI:10.1007/s11745-011-3622-5
日期:2012.1
sequential action of 13-lipoxygenase, alleneoxidesynthase (AOS), and alleneoxide cyclase. The fungus Lasiodiplodiatheobromae can produce large amounts of JA and was recently reported to form the JA precursor 12-oxophytodienoic acid. The objective of our study was to characterize the fatty acid dioxygenaseactivities of this fungus. Two strains of L. theobromae with low JA secretion (~0.2 mg/L medium)
linoleic acid esterified to a bulky phosphatidylcholine molecule as a substrate suggested a tail-fist binding orientation of the substrate. Site directed mutagenesis of the alanine to glycine did not cause alterations in the stereospecificity of the products, while mutation of the alanine to valine or isoleucine modified both regio- and enantioselectivity of the enzyme. Kinetic measurements revealed
脂氧合酶 (LOX) 由一类催化多不饱和脂肪酸的区域和立体定向双加氧的酶组成。目前的报道提出,R-脂肪氧化酶活性位点的保守甘氨酸残基和S-脂肪氧化酶相应位置的丙氨酸残基在决定产物的立体化学方面起着至关重要的作用。最近,来自 Nostoc sp. 的具有亚油酸二醇合酶活性的双功能脂肪氧化酶。鉴定了具有 R 立体特异性的 PCC7120 和迄今为止在手性特异性序列决定簇位置携带丙氨酸而不是保守甘氨酸的独特特征。在大肠杆菌中表达后纯化重组羧基末端结构域。该酶使用酯化为庞大的磷脂酰胆碱分子的亚油酸作为底物的能力表明底物的尾拳结合方向。将丙氨酸定点诱变为甘氨酸不会引起产物立体特异性的改变,而将丙氨酸突变为缬氨酸或异亮氨酸改变了酶的区域选择性和对映选择性。动力学测量表明,用 Gly 或 Val 取代 Ala 不会显着影响反应特性,而 A162I 突变体显示 vmax 降低。根据获得的诱变数据,