探討酵母菌Glycyl-tRNA合成酵素之生化活性

• Main Author: 賴志昌
• Other Authors: 王健家
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/00950848662259268008

碩士 === 國立中央大學 === 生命科學研究所 === 90 === 英文摘要 In the yeast Saccharomyces cerevisiae, protein synthesis takes place in two subcellular compartments: the cytosol and the mitochondria. Each of these two compartments requires a complete set of tRNA synthetases for function. Generally, these two sets of tRNA synthetases are encoded by distinct nuclear genes. An recent report provided evidence that GRS1 encodes both the cytoplasmic and mitochondrial GlyRS activities, while GRS2 is a pseudogene. The specific aims of this thesis are to explore the biochemical activities of GlyRS1 and GlyRS2 and to further dissect the evolutionary relationship between these two homologous genes. Interestingly, although GRS2 is nonfuncuional in vivo, purified GlyRS2 , when used at high concentration, charges yeast tRNA at a significant rate. Moreover, GlyRS2 cannot discriminate between yeast and E.coli tRNAs, while GlyRS1 strongly prefers yeast tRNAs. Thus, our results provide an evolutionary basis that ancient GRS1and GRS2 encode the cytoplasmic and mitochondrial GlyRS activities, respectively.