Womble D D, Rownd R H
J Bacteriol. 1977 Jul;131(1):145-52. doi: 10.1128/jb.131.1.145-152.1977.
Some properties of the supercoiled deoxyribonucleic acid (DNA)-protein relaxation complex of the R plasmid NR1, which contains more than one origin for DNA replication, were examined. The percentage of complexed NR1 molecules that can be converted to the relaxed (nicked) form appeared to be unaffected by the conditions under which the host cells were cultured. However, the percentage of supercoiled NR1 DNA that can be relaxed was highly dependent on the method used to prepare the DNA and the agents used to induce relaxation. Our data suggest that 100% of NR1 molecules may exist in situ as DNA-protein relaxation complexes. An RTF-Tc segregant of NR1, which has deleted the r-determinants component of the NR1 and therefore does not contain the two origins of replication located in the r-determinants, has indistinguishable relaxation properties in comparison with NR1 itself.
对含有多个DNA复制起点的R质粒NR1的超螺旋脱氧核糖核酸（DNA）-蛋白质松弛复合体的一些特性进行了研究。可转化为松弛（带切口）形式的复合NR1分子的百分比似乎不受宿主细胞培养条件的影响。然而，能够被松弛的超螺旋NR1 DNA的百分比高度依赖于制备DNA所使用的方法以及用于诱导松弛的试剂。我们的数据表明，100%的NR1分子可能以DNA-蛋白质松弛复合体的形式原位存在。NR1的一个RTF-Tc分离株，它删除了NR1的r-决定簇成分，因此不包含位于r-决定簇中的两个复制起点，与NR1本身相比，具有难以区分的松弛特性。
