Appleby D W, Rall S C, Hearst J E
Biophys Chem. 1976 Jul;5(1-2):271-83. doi: 10.1016/0301-4622(76)80040-3.
We present measurements of the sedimentation coefficients of DNA present in whole cell lysates of E. coli. The method used is a preparative version of the band sedimentation experiment of Bruner and Vinograd. We show that in order to obtain reliable data on the time dependence of sedimentation, it is necessary to accelerate and decelerate the rotor over much longer times than the standard centrifuge allows. We describe the necessary modifications to the preparative centrifuge and use them to determine the So20,W of unsheared E. coli DNA. The value for the fastest moving components in the lysate is 220 S. The molecular weight of the DNA corresponding to this sedimentation coefficient is probably 1.7 X 10(9) g/mole. However, alternative values cannot be ruled out.
我们展示了大肠杆菌全细胞裂解物中DNA沉降系数的测量结果。所使用的方法是布鲁纳和维诺格拉德带状沉降实验的制备版本。我们表明，为了获得关于沉降时间依赖性的可靠数据，有必要在比标准离心机允许的长得多的时间内加速和减速转子。我们描述了对制备型离心机的必要修改，并使用它们来确定未剪切的大肠杆菌DNA的S020,W。裂解物中移动最快的组分的值为220 S。对应于该沉降系数的DNA分子量可能为1.7×109 g/摩尔。然而，不能排除其他值。
