A COMPONENT OF THE MULTISYNTHETASE COMPLEX IS A MULTIFUNCTIONAL AMINOACYL-TRANSFER RNA-SYNTHETASE
A COMPONENT OF THE MULTISYNTHETASE COMPLEX IS A MULTIFUNCTIONAL AMINOACYL-TRANSFER RNA-SYNTHETASE
复制标题
DOI：
10.1002/j.1460-2075.1991.tb05005.x
复制
发表时间：
1991-12-01
期刊：
影响因子：
11.4
通讯作者：
SEMERIVA, M
中科院分区：
文献类型：
--
作者：
CERINI, C;KERJAN, P;SEMERIVA, M
在高等真核生物中，9个氨酰-tRNA合成酶与一个多酶复合物相关联，该复合物由11个分子量范围为18至150 kDa的多肽组成。我们已经从果蝇中克隆并测序了编码这种复合物的最大多肽的cDNA。我们在这里证明，相应的蛋白质是一个多功能的氨酰-tRNA合成酶。它由三个主要领域组成。其中两个说明了不同的合成酶活性。氨基和羧基末端结构域分别在大肠杆菌中表达，并被发现分别催化谷氨酸和脯氨酸tRNA种类的氨酰化。中心结构域由6个46个氨基酸重复组成。在原核生物中，这两种氨酰-tRNA合成酶由不同的基因编码。通过基因融合事件出现的多功能合成酶似乎是所有高等真核细胞的一个特定但普遍的属性。这种类型的结构组织，与多合成酶复合物的发生有关，可能是在同一颗粒内整合几个催化域的机制。参与内部重复在介导复杂的组装进行了讨论。
In higher eukaryotes, nine aminoacyl-tRNA synthetases are associated within a multienzyme complex which is composed of 11 polypeptides with molecular masses ranging from 18 to 150 kDa. We have cloned and sequenced a cDNA from Drosophila encoding the largest polypeptide of this complex. We demonstrate here that the corresponding protein is a multifunctional aminoacyl-tRNA synthetase. It is composed of three major domains. two of them specifying distinct synthetase activities. The amino and carboxy-terminal domains were expressed separately in Escherichia coli, and were found to catalyse the aminoacylation of glutamic acid and proline tRNA species, respectively. The central domain is made of six 46 amino acid repeats. In prokaryotes, these two aminoacyl-tRNA synthetases are encoded by distinct genes. The emergence of a multifunctional synthetase by a gene fusion event seems to be a specific, but general attribute of all higher eukaryotic cells. This type of structural organization, in relation to the occurrence of multisynthetase complexes, could be a mechanism to integrate several catalytic domains within the same particle. The involvement of the internal repeats in mediating complex assembly is discussed.