AtPng1p.: The first plant transglutaminase
AtPng1p.: The first plant transglutaminase
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DOI：
10.1104/pp.104.042549
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发表时间：
2004-08-01
期刊：
影响因子：
7.4
通讯作者：
Rigau, J
中科院分区：
文献类型：
--
作者：
Della Mea, M;Caparrós-Ruiz, D;Rigau, J
研究表明，在植物叶绿体、线粒体、细胞壁和细胞质中存在转氨酶（TGase）活性，类似于动物和原核生物中已知的主要具有结构作用的活性，但在植物中没有蛋白质与这种类型的活性相关。最近的计算分析表明，在拟南芥中存在一个基因，AtPng 1 p，它编码一个假定的N-聚糖酶。AtPng 1 p含有存在于TGase催化结构域中的Cys-His-Asp三联体。AtPng 1 p是在植物中普遍表达的单一基因，但在所有光测定条件下均以低水平表达。重组AtPng 1 p蛋白可以用动物TGase抗体进行免疫检测。此外，使用针对重组AtPng 1 p蛋白的抗体的蛋白质印迹分析导致其在微粒体组分中的检测。纯化的蛋白质以钙依赖的方式将多胺-精胺（Spm）、亚精胺（Spd）、腐胺（Put）和生物素-尸胺连接到二甲基酪蛋白。γ-谷氨酰衍生物的分析表明，蛋白质和多胺之间的共价键的形成是通过底物的γ-谷氨酰残基的转酰胺作用发生的，这证实了AtPng 1 p基因产物作为TGase。AtPng 1 p蛋白质的Ca 2+和GTP依赖性交联活性可以通过牛血清白蛋白的聚合来可视化，所述牛血清白蛋白像商业TGase一样在碱性pH和二硫苏糖醇的存在下获得。据我们所知，这是第一个报道的植物蛋白，其特征在于在分子水平上，显示TGase活性，因为迄今为止分析的所有参数与动物TGases通常表现出的参数一致。
Studies have revealed in plant chloroplasts, mitochondria, cell walls, and cytoplasm the existence of transglutaminase (TGase) activities, similar to those known in animals and prokaryotes having mainly structural roles, but no protein has been associated to this type of activity in plants. A recent computational analysis has shown in Arabidopsis the presence of a gene, AtPng1p, which encodes a putative N-glycanase. AtPng1p contains the Cys-His-Asp triad present in the TGase catalytic domain. AtPng1p is a single gene expressed ubiquitously in the plant but at low levels in all light-assayed conditions. The recombinant AtPng1p protein could be immuno-detected using animal TGase antibodies. Furthermore, western-blot analysis using antibodies raised against the recombinant AtPng1p protein have lead to its detection in microsomal fraction. The purified protein links polyamines-spermine (Spm) > spermidine (Spd) > putrescine (Put)-and biotin-cadaverine to dimethylcasein in a calcium-dependent manner. Analyses of the gamma-glutamyl-derivatives revealed that the formation of covalent linkages between proteins and polyamines occurs via the transamidation of gamma-glutamyl residues of the substrate, confirming that the AtPng1p gene product acts as a TGase. The Ca2+- and GTP-dependent cross-linking activity of the AtPng1p protein can be visualized by the polymerization of bovine serum albumine, obtained, like the commercial TGase, at basic pH and in the presence of dithiotreitol. To our knowledge, this is the first reported plant protein, characterized at molecular level, showing TGase activity, as all its parameters analyzed so far agree with those typically exhibited by the animal TGases.