Gasior E, Herrera F, Sadnik I, McLaughlin C S, Moldave K
J Biol Chem. 1979 May 25;254(10):3965-9.
A cell-free protein-synthesizing system has been prepared from Saccharomyces cerevisiae by differential centrifugation of lysed spheroplasts. The preparation, a modified 100,000 x g supernatant fraction, contains ribosomes and monosomes, ribosomal subunits, translation factors, and aminoacyl-tRNA synthetases, but no polysomes. After removal of small amounts of remaining mRNA with micrococcal nuclease, protein synthesis is stringently dependent on the addition of mRNA, as well as amino acids and an energy-generating system. The 5'-cap analogue, 7-methylguanosine 5'-phosphate, inhibits translation of several natural mRNAs, but has no effect on chain elongation. Incubation of the polysome-free extract with natural mRNA leads to the formation of protein-synthesizing polysomes and eventually, to the release of protein; the molecular weight of the protein synthesized in the presence of BMV (brome mosaic virus) RNA is consistent with that of BMV coat protein.
通过对裂解的球状体进行差速离心，从酿酒酵母中制备了一种无细胞蛋白质合成系统。该制剂是一种经过改良的100,000×g上清液组分，含有核糖体和单核糖体、核糖体亚基、翻译因子以及氨酰-tRNA合成酶，但不含多核糖体。用微球菌核酸酶去除少量残留的mRNA后，蛋白质合成严格依赖于mRNA、氨基酸和能量产生系统的添加。5'-帽类似物7-甲基鸟苷5'-磷酸抑制几种天然mRNA的翻译，但对链延伸没有影响。将无多核糖体提取物与天然mRNA一起孵育会导致形成蛋白质合成多核糖体，并最终释放蛋白质；在BMV（雀麦花叶病毒）RNA存在下合成的蛋白质的分子量与BMV外壳蛋白的分子量一致。
