Smith S S, Hardy T A, Baker D J
Division of Surgery, City of Hope National Medical Center, Duarte, CA 91010.
Nucleic Acids Res. 1987 Sep 11;15(17):6899-916. doi: 10.1093/nar/15.17.6899.
The presence of the C.C mispair in a defined duplex oligodeoxynucleotide enhanced its capacity to serve as a substrate for highly purified human DNA methyltransferase. Analysis of tritiated reaction products showed that the C.C mispair acted as a "methylation acceptor" in that it was itself rapidly methylated. The m5C.G base pair also enhanced the capacity of the oligodeoxynucleotide to serve as a substrate for the enzyme. However, this complementary base pair was found to act as a "methylation director". That is, the presence of the m5C in one strand induced the enzyme to rapidly methylate at the cytosine residue on the opposite strand in an adjacent C.G base pair.
在特定的双链寡脱氧核苷酸中，C.C错配的存在增强了其作为高度纯化的人DNA甲基转移酶底物的能力。对氚标记反应产物的分析表明，C.C错配作为“甲基化受体”，因为它自身会迅速被甲基化。m5C.G碱基对也增强了寡脱氧核苷酸作为该酶底物的能力。然而，发现这种互补碱基对起到“甲基化导向”作用。也就是说，一条链中m5C的存在会诱导该酶在相邻C.G碱基对的互补链上的胞嘧啶残基处迅速甲基化。
