Structure determination and analysis of acyl-CoA oxidase (ACX1) from tomato.
Structure determination and analysis of acyl-CoA oxidase (ACX1) from tomato.
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DOI：
10.1107/s0907444906014107
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发表时间：
2006-06
期刊：
影响因子：
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通讯作者：
Rachel A. Powers;C. Rife;Anthony L. Schilmiller;Gregg A. Howe;R. Michael Garavito
中科院分区：
文献类型：
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作者：
Rachel A. Powers;C. Rife;Anthony L. Schilmiller;Gregg A. Howe;R. Michael Garavito
黄素酶酰基辅酶A氧化酶 (ACX) 催化 β-氧化的第一个关键步骤，是茉莉酸生物合成所必需的，茉莉酸是一种参与植物防御的信号分子。最近，番茄中发现了一种突变体，该突变体缺乏茉莉酸的产生，并且其伤口反应受到损害。这是由于 acx1 中的单点突变导致保守残基 Thr138 被异亮氨酸取代。为了了解该突变的结构基础，通过分子置换将 LeACX1 的晶体结构确定为 2.74 埃分辨率。出乎意料的是，观察到了不寻常的堆积排列，其中不对称单元中存在 LeACX1 的三个单体。尽管 LeACX1 的三级结构本质上与之前确定的 ACX 酶的结构相似，但晶胞内的堆积却明显不同。
The flavoenzyme acyl-CoA oxidase (ACX) catalyzes the first committed step in beta-oxidation and is required for the biosynthesis of jasmonic acid, a signaling molecule involved in plant defense. Recently, a mutant in tomato was identified that is deficient in jasmonic acid production and compromised in its wound response. This results from a single point mutation in acx1, which causes the conserved residue Thr138 to be substituted by isoleucine. To understand the structural basis for this mutation, the crystal structure of LeACX1 was determined to 2.74 Angstrom resolution by molecular replacement. Unexpectedly, an unusual packing arrangement was observed in which three monomers of LeACX1 are present in the asymmetric unit. Although the tertiary structure of LeACX1 is essentially similar to the previously determined structures of ACX enzymes, the packing within the unit cells is distinctly different.