Garret M, Pajot B, Trézéguet V, Labouesse J, Merle M, Gandar J C, Benedetto J P, Sallafranque M L, Alterio J, Gueguen M
Institut de Biochimie Cellulaire et Neurochimie du CNRS, Université de Bordeaux II, France.
Biochemistry. 1991 Aug 6;30(31):7809-17. doi: 10.1021/bi00245a021.
Determination of the amino acid sequence of beef pancreas tryptophanyl-tRNA synthetase was undertaken through both cDNA and direct peptide sequencing. A full-length cDNA clone containing a 475 amino acid open reading frame was obtained. The molecular mass of the corresponding peptide chain, 53,728 Da, was in agreement with that of beef tryptophanyl-tRNA synthetase, as determined by physicochemical methods (54 kDa). Expression of this clone in Escherichia coli led to tryptophanyl-tRNA synthetase activity in cell extracts. The open reading frame included two sequences analogous to the consensus sequences, HIGH and KMSKS, found in class I aminoacyl-tRNA synthetases. The homology with prokaryotic and yeast mitochondrial tryptophanyl-tRNA synthetases was low and was limited to the regions of the consensus sequences. However, a 90% homology was observed with the recently described rabbit peptide chain release factor (eRF) [Lee et al. (1990) Proc. Natl. Acad. Sci. 87, 3508-3512]. Such a strong homology may reveal a new group of genes deriving from a common ancestor, the products of which could be involved in tRNA aminoacylation (tryptophanyl-tRNA synthetase) or translation termination (eRF).
通过cDNA和直接肽测序对牛胰腺色氨酰 - tRNA合成酶的氨基酸序列进行了测定。获得了一个包含475个氨基酸开放阅读框的全长cDNA克隆。通过物理化学方法测定，相应肽链的分子量为53,728 Da，与牛色氨酰 - tRNA合成酶的分子量（54 kDa）一致。该克隆在大肠杆菌中的表达导致细胞提取物中出现色氨酰 - tRNA合成酶活性。开放阅读框包含两个与I类氨酰 - tRNA合成酶中发现的共有序列HIGH和KMSKS类似的序列。与原核生物和酵母线粒体色氨酰 - tRNA合成酶的同源性较低，且仅限于共有序列区域。然而，与最近描述的兔肽链释放因子（eRF）[Lee等人（1990年）《美国国家科学院院刊》87, 3508 - 3512]观察到90%的同源性。如此高的同源性可能揭示了一组源自共同祖先的新基因，其产物可能参与tRNA氨酰化（色氨酰 - tRNA合成酶）或翻译终止（eRF）。
