Giglione C, Serero A, Pierre M, Boisson B, Meinnel T
Institut des Sciences Végétales, UPR40, Centre National de la Recherche Scientifique, Bâtiment 23, 1 avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France.
EMBO J. 2000 Nov 1;19(21):5916-29. doi: 10.1093/emboj/19.21.5916.
The N-terminal protein processing pathway is an essential mechanism found in all organisms. However, it is widely believed that deformylase, a key enzyme involved in this process in bacteria, does not exist in eukaryotes, thus making it a target for antibacterial agents such as actinonin. In an attempt to define this process in higher eukaryotes we have used Arabidopsis thaliana as a model organism. Two deformylase cDNAs, the first identified in any eukaryotic system, and six distinct methionine aminopeptidase cDNAs were cloned. The corresponding proteins were characterized in vivo and in vitro. Methionine aminopeptidases were found in the cytoplasm and in the organelles, while deformylases were localized in the organelles only. Our work shows that higher plants have a much more complex machinery for methionine removal than previously suspected. We were also able to identify deformylase homologues from several animals and clone the corresponding cDNA from human cells. Our data provide the first evidence that lower and higher eukaryotes, as well as bacteria, share a similar N-terminal protein processing machinery, indicating universality of this system.
N端蛋白质加工途径是所有生物体中都存在的一种基本机制。然而，人们普遍认为，细菌中参与这一过程的关键酶去甲酰化酶在真核生物中不存在，因此它成为了诸如放线菌素等抗菌剂的作用靶点。为了确定高等真核生物中的这一过程，我们以拟南芥作为模式生物。克隆了两个去甲酰化酶cDNA（这是在任何真核系统中首次鉴定出的）以及六个不同的甲硫氨酸氨肽酶cDNA。对相应的蛋白质进行了体内和体外特性分析。发现甲硫氨酸氨肽酶存在于细胞质和细胞器中，而去甲酰化酶仅定位于细胞器中。我们的研究表明，高等植物去除甲硫氨酸的机制比之前认为的要复杂得多。我们还能够从几种动物中鉴定出去甲酰化酶同源物，并从人类细胞中克隆出相应的cDNA。我们的数据首次证明，低等和高等真核生物以及细菌都共享类似的N端蛋白质加工机制，这表明该系统具有普遍性。
