Characterization of a methyljasmonate-inducible lipoxygenase from barley (Hordeum vulgare cv. Salome) leaves.
Characterization of a methyljasmonate-inducible lipoxygenase from barley (Hordeum vulgare cv. Salome) leaves.
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大麦（Hordeum vulgare cv. Salome）叶中茉莉酸甲酯诱导型脂氧合酶的表征。
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发表时间：
1998
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通讯作者：
Claus Wasternack
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作者：
Kirsten Vörös;Ivo Feussner;Hartmut Kühn;Justin E. E. Lee;Andreas Graner;Marian Löbler;Benno Parthier;Claus Wasternack
我们发现了三种茉莉酸甲酯诱导的脂氧合酶，分子量分别为92 kDa、98 kDa和100 kDa (LOX-92、-98和-100)[Feussner， I., Hause， B., Vörös， K., Parthier， B. & Wasternack， C. (1995) Plant J. 7,949 -957]。其中至少有两个（LOX-92和LOX-100）定位于大麦叶片的叶绿体中。在这里，我们描述了一个编码LOX-100的cDNA （3073 bp）的分离，该蛋白由936个氨基酸残基组成，分子量为106 kDa。经序列比较，该脂加氧酶可鉴定为LOX2型脂加氧酶，因此命名为LOX2:Hv:1。重组脂氧合酶在大肠杆菌中表达，鉴定为亚油酸13-LOX和花生四烯酸15-LOX。该酶的最适pH值在7.0左右，对亚油酸有中等的底物偏好。该基因在外源施用茉莉酸甲酯后短暂表达，表达量在12 ~ 18 h之间达到最大值，不受外源施用脱落酸的影响。山梨糖醇胁迫导致的内源茉莉酸的增加也没有诱导LOX2:Hv:1，这表明与大麦中其他茉莉酸诱导的蛋白相比，它有一个单独的信号通路。本文讨论了LOX2:Hv:1的性质，以及它可能参与茉莉酸的生物合成和迄今为止发现的其他LOX形式的大麦。
We found three methyl jasmonate-induced lipoxygenases with molecular masses of 92 kDa, 98 kDa, and 100 kDa (LOX-92, -98 and -100) [Feussner, I., Hause, B., Vörös, K., Parthier, B. & Wasternack, C. (1995) Plant J. 7, 949-957]. At least two of them (LOX-92 and LOX-100), were shown to be localized within chloroplasts of barley leaves. Here, we describe the isolation of a cDNA (3073 bp) coding for LOX-100, a protein of 936 amino acid residues and a molecular mass of 106 kDa. By sequence comparison this lipoxygenase could be identified as LOX2-type lipoxygenase and was therefore designated LOX2:Hv:1. The recombinant lipoxygenase was expressed in Escherichia coli and characterized as linoleate 13-LOX and arachidonate 15-LOX, respectively. The enzyme exhibited a pH optimum around pH 7.0 and a moderate substrate preference for linoleic acid. The gene was transiently expressed after exogenous application of jasmonic acid methyl ester with a maximum between 12 h and 18 h. Its expression was not affected by exogenous application of abscisic acid. Also a rise of endogenous jasmonic acid resulting from sorbitol stress did not induce LOX2:Hv:1, suggesting a separate signalling pathway compared with other jasmonate-induced proteins of barley. The properties of LOX2:Hv:1 are discussed in relation to its possible involvement in jasmonic acid biosynthesis and other LOX forms of barley identified so far.