Xia Shuangluo, Konigsberg William H
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, 06520-8114.
Protein Sci. 2014 Apr;23(4):508-13. doi: 10.1002/pro.2434.
Recent structures of DNA polymerase complexes with dGMPCPP/dT and dCTP/dA mispairs at the insertion site have shown that they adopt Watson-Crick geometry in the presence of Mn(2+) indicating that the tautomeric or ionization state of the base has changed. To see whether the tautomeric or ionization state of base-pair could be affected by its microenvironment, we determined 10 structures of an RB69 DNA polymerase quadruple mutant with dG/dT or dT/dG mispairs at position n-1 to n-5 of the Primer/Template duplex. Different shapes of the mispairs, including Watson-Crick geometry, have been observed, strongly suggesting that the local environment of base-pairs plays an important role in their tautomeric or ionization states.
近期DNA聚合酶复合物在插入位点与dGMPCPP/dT和dCTP/dA错配的结构表明,在Mn(2+)存在的情况下它们采用了沃森-克里克几何结构,这表明碱基的互变异构或电离状态发生了变化。为了探究碱基对的互变异构或电离状态是否会受到其微环境的影响,我们测定了RB69 DNA聚合酶四重突变体在引物/模板双链体第n-1至n-5位存在dG/dT或dT/dG错配时的10种结构。观察到了错配的不同形状,包括沃森-克里克几何结构,这强烈表明碱基对的局部环境在其互变异构或电离状态中起着重要作用。