Schmidt F, Besemer J, Starlinger P
Mol Gen Genet. 1976 May 7;145(2):145-54. doi: 10.1007/BF00269586.
DNA of the IS-elements IS1 and IS2 was prepared by digestion of appropriate heteroduplex molecules with endonuclease S1, followed by sucrose gradient centrifugation or gel electrophoresis. The material obtained is homogeneous with regard to size. The length of IS1 DNA is 820 +/- 65 nucleotides, the length of IS2 DNA is 1,350 +/- 70 nucleotides. IS1 DNA is not cleaved by the restriction endonucleases Eco R1, Hind II or Hind III. IS2 DNA is cleaved once by each of the two latter enzymes. The buoyand density determined by equilibrium centrifugation of Hg-complexes in Cs2so4 corresponds to a GC content of approximately 50%. Labelling with polynucleotide kinase indicates that both IS DNA's have a guanosyl residue at both of their 5'-termini.
通过用核酸酶S1消化合适的异源双链分子，然后进行蔗糖梯度离心或凝胶电泳，制备了IS元件IS1和IS2的DNA。所获得的材料在大小方面是均匀的。IS1 DNA的长度为820±65个核苷酸，IS2 DNA的长度为1350±70个核苷酸。IS1 DNA不能被限制性内切酶Eco R1、Hind II或Hind III切割。IS2 DNA被后两种酶中的每一种切割一次。通过在Cs2so4中对汞复合物进行平衡离心测定的浮力密度对应于约50%的GC含量。用多核苷酸激酶标记表明，两种IS DNA在其5'末端都有一个鸟苷残基。
