Ott J, Eckstein F
Abteilung Chemie, Max-Planck-Institut für experimentelle Medizin, Göttingen, FRG.
Biochemistry. 1987 Dec 15;26(25):8237-41. doi: 10.1021/bi00399a032.
By use of a mutational assay employing an octadecamer with a mismatch in the center, it is shown that the introduction of phosphorothioate groups near the 5'-end can protect the mismatch against degradation by the 5'-3'-exonuclease activity of Escherichia coli DNA polymerase I. An optimal level of protection is achieved when the phosphorothioate groups are incorporated in at least the second and third internucleotidic linkages from the 5'-end. However, gel electrophoretic analysis as well as the use of an octadecamer with a mismatch closer to the 5'-end in the mutational assay reveals that degradation of the oligonucleotide is not completely blocked but only slowed down.
通过使用一种突变分析方法，该方法采用在中心位置存在错配的十八聚体，结果表明在5'-末端附近引入硫代磷酸酯基团可以保护错配结构不被大肠杆菌DNA聚合酶I的5'-3'-核酸外切酶活性降解。当硫代磷酸酯基团至少掺入到从5'-末端起的第二个和第三个核苷酸间连接中时，可实现最佳保护水平。然而，凝胶电泳分析以及在突变分析中使用错配位置更靠近5'-末端的十八聚体表明，寡核苷酸的降解并未被完全阻断，只是速度减慢。
