Nada S, Chang P K, Dignam J D
Department of Biochemistry and Molecular Biology, Medical College of Ohio, Toledo 43699-0008.
J Biol Chem. 1993 Apr 15;268(11):7660-7.
The primary structure of the gene encoding Bombyx mori glycyl-tRNA synthetase was determined by sequence analysis of one cDNA and two genomic clones. The sequence of the protein deduced from the nucleotide sequence was verified by sequence analysis of eight peptides. The M(r) 77,667 protein is encoded in a single open reading frame of 2061 nucleotides. There are no introns in the gene. The deduced protein sequence has no obvious similarity to Escherichia coli glycyl-tRNA synthetase but contains a sequence in its amino terminus that is similar to a sequence found in the Drosophila melanogaster and human glutamyl-tRNA synthetases, the hamster and human histidyl-tRNA synthetases, bovine tryptophanyl-tRNA synthetase, and the mammalian peptide chain release factor. The B. mori glycyl-tRNA synthetase also has sequence similarity with the Saccharomyces cerevisiae (cytoplasmic and mitochondrial), E. coli, and human threonyl-tRNA synthetases. This sequence similarity occurs in a sequence motif that is characteristic of other class II aminoacyl-tRNA synthetases. Two transcription start sites approximately 100 nucleotides apart were identified by ribonuclease mapping. One of the transcription start sites is used preferentially in the posterior silk gland. The peak in mRNA accumulation occurs 80-100 h prior to the peak in glycyl-tRNA synthetase activity and enzyme protein.
通过对一个cDNA和两个基因组克隆进行序列分析，确定了家蚕甘氨酰 - tRNA合成酶编码基因的一级结构。从核苷酸序列推导的蛋白质序列通过八个肽段的序列分析得到验证。该77,667 Mr的蛋白质由一个2061个核苷酸的单一开放阅读框编码。该基因中没有内含子。推导的蛋白质序列与大肠杆菌甘氨酰 - tRNA合成酶没有明显的相似性，但在其氨基末端含有一个与黑腹果蝇和人类谷氨酰胺 - tRNA合成酶、仓鼠和人类组氨酰 - tRNA合成酶、牛色氨酰 - tRNA合成酶以及哺乳动物肽链释放因子中发现的序列相似的序列。家蚕甘氨酰 - tRNA合成酶与酿酒酵母（细胞质和线粒体）、大肠杆菌和人类苏氨酰 - tRNA合成酶也有序列相似性。这种序列相似性出现在其他II类氨酰 - tRNA合成酶特有的序列基序中。通过核糖核酸酶图谱鉴定出两个相距约100个核苷酸的转录起始位点。其中一个转录起始位点在后丝腺中优先使用。mRNA积累的峰值出现在甘氨酰 - tRNA合成酶活性和酶蛋白峰值之前80 - 100小时。
