Uclacyanins, stellacyanins, and plantacyanins ape distinct subfamilies of phytocyanins: Plant-specific mononuclear blue copper proteins
Uclacyanins, stellacyanins, and plantacyanins ape distinct subfamilies of phytocyanins: Plant-specific mononuclear blue copper proteins
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DOI：
10.1002/pro.5560070907
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发表时间：
1998-09-01
期刊：
影响因子：
8
通讯作者：
Valentine, JS
中科院分区：
文献类型：
--
作者：
Nersissian, AM;Immoos, C;Valentine, JS
从菠菜中分离并鉴定了编码植物花青苷的cDNA。此外，四个新的cDNA序列从拟南芥EST被确定为编码类似于植物蓝蛋白的多肽，植物特异性蛋白质构成一个独特的单核蓝铜蛋白家族。其中一个编码拟南芥中的plantacyanin，而另外三个，命名为uclacyanin 1，2和3，编码的蛋白质前体与来自豌豆豆荚的stellacyanins和蓝铜蛋白的前体密切相关。与已知的植物蓝蛋白的比较分析允许这些蛋白质进一步分类为三个不同的亚家族，命名为uclacyanins，stellacyanins，和plantacyanins。本说明书基于（1）其光谱特性，（2）其糖基化状态，（3）其前体的结构域组织，以及（4）其铜结合氨基酸。表达、纯化了重组的拟南芥uclacyanin 1的铜结合结构域，并显示出以称为“蓝色”或1型的方式结合铜原子。黄瓜stellacyanin的突变体，其中谷氨酰胺轴向配体取代甲硫氨酸（Q99 M）进行了纯化，并显示具有光谱性质类似uclacyanin I，而不是plantacyanins。通过循环伏安法测定其氧化还原电位为+420 mV，该值显著高于野生型蛋白质测定的值（+260 mV）。现有的结构数据表明，星蓝素和其他可能的植物蓝素可能不是参与远程电子转移过程的可扩散电子转移蛋白。可以想象的是，它们参与了植物初级防御反应和/或木质素形成过程中发生的氧化还原反应。
The cDNAs encoding plantacyanin from spinach were isolated and characterized. In addition, four new cDNA sequences from Arabidopsis ESTs were identified that encode polypeptides resembling phytocyanins, plant-specific proteins constituting a distinct family of mononuclear blue copper proteins. One of them encodes plantacyanin from Arabidopsis, while three others, designated as uclacyanin 1, 2, and 3, encode protein precursors that are closely related to precursors of stellacyanins and a blue copper protein from pea pods. Comparative analyses with known phytocyanins allow further classification of these proteins into three distinct subfamilies designated as uclacyanins, stellacyanins, and plantacyanins. This specification is based on (1) their spectroscopic properties, (2) their glycosylation state, (3) the domain organization of their precursors, and (4) their copper-binding amino acids. The recombinant copper binding domain of Arabidopsis uclacyanin 1 was expressed, purified, and shown to bind a copper atom in a fashion known as "blue" or type 1. The mutant of cucumber stellacyanin in which the glutamine axial ligand was substituted by a methionine (Q99M) was purified and shown to possess spectroscopic properties similar to uclacyanin I rather than to plantacyanins. Its redox potential was determined by cyclic voltammetry to be +420 mV, a value that is significantly higher than that determined for the wild-type protein (+260 mV). The available structural data suggest that stellacyanins land possibly other phytocyanins) might not be diffusible electron-transfer proteins participating in long-range electron-transfer processes. Conceivably, they are involved in redox reactions occurring during primary defense responses in plants and/or in lignin formation.