Magee B B, Paoletti J, Magee P T
Proc Natl Acad Sci U S A. 1975 Dec;72(12):4830-4. doi: 10.1073/pnas.72.12.4830.
When chromatin prepared from WI-L2 lymphocytes by low salt extraction and shearing is centrifuged on a glycerol gradient, one area of the gradient yields chromatin enriched in template activity for Escherichia coli DNA-dependent RNA polymerase (EC 2.7.7.6; nucleosidetriphosphate:RNA nucleotidyltransferase) as compared to Saccharomyces cerevisiae RNA polymerase II (or B). Another area yields chromatin preferred by the eukaryotic enzyme. Kinetic studies indicate that the differences in activity cannot be explained by differences in affinity of the enzymes for the various templates. The DNA isolated from either fraction has a molecular weight of 8.5 X 106. The "yeast active" fraction seems enriched in proteins. Mixing experiments indicate that the yeast enzyme does not alter the template in such a way as to improve it for the bacterial enzyme.
当通过低盐提取和剪切从WI-L2淋巴细胞制备的染色质在甘油梯度上离心时,与酿酒酵母RNA聚合酶II(或B)相比,梯度的一个区域产生的染色质富含对大肠杆菌DNA依赖性RNA聚合酶(EC 2.7.7.6;核苷三磷酸:RNA核苷酸转移酶)具有模板活性的物质。另一个区域产生真核酶偏好的染色质。动力学研究表明,活性差异不能用酶对各种模板的亲和力差异来解释。从任何一个组分中分离出的DNA分子量为8.5×10⁶。“酵母活性”组分似乎富含蛋白质。混合实验表明,酵母酶不会以改善细菌酶对模板作用的方式改变模板。