Mirande M, Waller J P
Laboratoire d'Enzymologie du Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
J Biol Chem. 1989 Jan 15;264(2):842-7.
A cDNA clone encoding rat liver aspartyl-tRNA synthetase was isolated by probing a lambda gt11 recombinant cDNA expression library with antibodies directed against the corresponding polypeptide from sheep liver. The 1930-base pairs-long cDNA insert allowed the expression in Escherichia coli of an active enzyme of mammalian origin. The nucleotide sequence of that cDNA, corresponding to the DRS1 gene, was determined. The open reading frame of DRS1 corresponds to a protein of Mr = 57,061, in good agreement with the previously determined molecular weight of the purified enzyme. The deduced amino acid sequence shows extensive homologies with that of yeast cytoplasmic aspartyl-tRNA synthetase, more than 50% of the residues being identical. In rat liver, aspartyl-tRNA synthetase occurs in two distinct forms: a dimeric enzyme and a component of a multienzyme complex comprising the nine aminoacyl-tRNA synthetases specific for arginine, aspartic acid, glutamic acid, glutamine, isoleucine, leucine, lysine, methionine, and proline. The primary structure of the DRS1 gene product is discussed in relation to the occurrence of two distinct forms of that enzyme.
通过用针对羊肝中相应多肽的抗体探测λgt11重组cDNA表达文库，分离出了编码大鼠肝脏天冬氨酰 - tRNA合成酶的cDNA克隆。这个1930个碱基对长的cDNA插入片段使得源自哺乳动物的活性酶在大肠杆菌中得以表达。测定了对应于DRS1基因的该cDNA的核苷酸序列。DRS1的开放阅读框对应于一个分子量为57,061的蛋白质，这与先前测定的纯化酶的分子量高度一致。推导的氨基酸序列与酵母细胞质天冬氨酰 - tRNA合成酶的序列显示出广泛的同源性，超过50%的残基相同。在大鼠肝脏中，天冬氨酰 - tRNA合成酶以两种不同形式存在：一种二聚体酶和一种多酶复合物的组分，该多酶复合物包含对精氨酸、天冬氨酸、谷氨酸、谷氨酰胺、异亮氨酸、亮氨酸、赖氨酸、甲硫氨酸和脯氨酸具有特异性的九种氨酰 - tRNA合成酶。结合该酶的两种不同形式的存在情况，讨论了DRS1基因产物的一级结构。
