A gene controlling variation in arabidopsis glucosinolate composition is part of the methionine chain elongation pathway
A gene controlling variation in arabidopsis glucosinolate composition is part of the methionine chain elongation pathway
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DOI：
10.1104/pp.010416
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发表时间：
2001-11-01
期刊：
影响因子：
7.4
通讯作者：
Mitchell-Olds, T
中科院分区：
文献类型：
--
作者：
Kroymann, J;Textor, S;Mitchell-Olds, T
拟南芥和其他十字花科植物产生大量的脂肪族硫代葡萄糖苷，这是一组蛋氨酸（Met）衍生的植物二级化合物，含有p -硫代葡萄糖部分，磺化肟和可变侧链。我们精细绘制了控制脂肪族硫代葡萄糖苷侧链长度变异的基因座GSL-ELONG。在该位点内，鉴定出一个多态性基因，该基因决定Met是否主要由一个或两个亚甲基延伸，以产生具有三碳或四碳侧链的脂肪族硫代葡萄糖苷。两个缺乏四碳侧链硫代葡萄糖苷的等位突变被证明在该基因中含有独立的错义突变。在无细胞酶实验中，来自该位点的异源表达cDNA能够与乙酰辅酶a凝聚2-氧-4-甲基硫代丁酸，这是Met链延伸的初始反应。甲基硫代烷基苹果酸合成酶1 （MAM1）是一个基因家族的成员，与2-异丙基苹果酸合成酶（一种亮氨酸生物合成酶，与乙酰辅酶a缩合2-氧-3-甲基丁酸酯）具有约60%的氨基酸序列相似性。
Arabidopsis and other Brassicaceae produce an enormous diversity of aliphatic glucosinolates, a group of methionine (Met)-derived plant secondary compounds containing a P-thio-glucose moiety, a sulfonated oxime, and a variable side chain. We fine-scale mapped GSL-ELONG, a locus controlling variation in the side-chain length of aliphatic glucosinolates. Within this locus, a polymorphic gene was identified that determines whether Met is extended predominantly by either one or by two methylene groups to produce aliphatic glucosinolates with either three- or four-carbon side chains. Two allelic mutants deficient in four-carbon side-chain glucosinolates were shown to contain independent missense mutations within this gene. In cell-free enzyme assays, a heterologously expressed cDNA from this locus was capable of condensing 2-oxo-4-methylthiobutanoic acid with acetyl-coenzyme A, the initial reaction in Met chain elongation. The gene methylthioalkylmalate synthase1 (MAM1) is a member of a gene family sharing approximately 60% amino acid sequence similarity with 2-isopropylmalate synthase, an enzyme of leucine biosynthesis that condenses 2-oxo-3-methylbutanoate with acetylcoenzyme A.