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很多耐高温的DNA聚合酶,如Taq DNA聚合酶,因其具有非模板依赖性末端转移酶活性,因而常在PCR产物的3’末端加上一个多余的碱基,通常为3’-dA,从而使通过平端连接克隆PCR产物的效率很低。有几种方法可以解决这个问题。①在dNTP存在的情况下,用T_4DNA聚合酶除去3’末端突出的碱基。②利用具有3’-dT突出末端的载体进行克隆,这种载体有商品。③利用其它的DNA聚合酶,如pfu DNA聚合酶进行PCR得到具平头末端的PCR产物。在本文中,作者介绍了二种对Taq DNA聚合
Many thermostable DNA polymerases, such as Taq DNA polymerase, often have an extra base at the 3 ’end of the PCR product, usually 3’-dA, because of their non-template-dependent terminal transferase activity. Thus, the efficiency of cloning PCR products by blunt-end ligation is low. There are several ways to solve this problem. ① In the presence of dNTP, remove the 3’-terminal protruding base with T_4 DNA polymerase. ② Cloning using a vector having a 3’-dT overhang, this vector is commercially available. ③ PCR using other DNA polymerases such as pfu DNA polymerase gives blunt-ended PCR products. In this article, the authors describe two kinds of Taq DNA polymerizations