McCormack P L, Edlind T D, Ihler G M
Anal Biochem. 1983 Oct 15;134(2):272-83. doi: 10.1016/0003-2697(83)90297-x.
A comparison was made of three procedures used for measuring the locations of long range base pairing in single-stranded DNA. All three procedures gave equivalent results for the location of a transposon, Tn903, and for a loop created by pairing between the nut and operator segments on an EcoRI restriction fragment of lambda DNA. DNA molecules prepared by a T4 gene 32 protein procedure had the best contrast. The highest frequency of measurable loops resulted from a procedure which utilized ammonium acetate/formamide spreading conditions. This procedure also appeared to be the simplest and most satisfactory procedure. Only one procedure revealed the fact that the nutR and oR regions are separated by several hundred bases, but this procedure, which involves crosslinking with trioxsalen, gave generally unsatisfactory DNA morphology. None of the procedures revealed the existence of a short "bulge" loop of single-stranded DNA located between nutL and oL and a longer "bulge" loop located between nutR and oR.
对用于测量单链DNA中远距离碱基配对位置的三种方法进行了比较。对于转座子Tn903的位置以及由λDNA的EcoRI限制片段上的nut和操纵子片段之间配对形成的环，所有这三种方法都给出了等效的结果。通过T4基因32蛋白方法制备的DNA分子具有最佳的对比度。可测量环的最高频率来自一种利用醋酸铵/甲酰胺铺展条件的方法。该方法似乎也是最简单且最令人满意的方法。只有一种方法揭示了nutR和oR区域被数百个碱基隔开这一事实，但该方法涉及与三氧沙林交联，总体上给出的DNA形态并不令人满意。没有一种方法揭示在nutL和oL之间存在一个短的单链DNA“凸起”环以及在nutR和oR之间存在一个更长的“凸起”环。
