Cherepanova Natalia A, Minero Antonio S, Rakhimova Alina R, Gromova Elizaveta S
Department of Chemistry, Moscow State University, Moscow, Russia.
Nucleosides Nucleotides Nucleic Acids. 2011 Jul-Aug;30(7-8):619-31. doi: 10.1080/15257770.2011.583973.
Murine DNA methyltransferases Dnmt3a-CD and M.SssI from Spiroplasma methylate cytosines at CpG sites. The role of 6-oxo groups of guanines in DNA methylation by these enzymes has been studied using DNA substrates, which contained 2-aminopurine at different positions. Removal of the 6-oxo group of the guanine located adjacent to the target cytosine in the CpG site dramatically reduces the stability of the methyltransferase-DNA complexes and leads to a significant decrease in the methylation. Apparently, O6 of this guanine is involved in the recognition of CpG sites by the enzymes. Cooperative binding of Dnmt3a-CD to 2-aminopurine-containing DNA and the formation of nonproductive enzyme-substrate complexes were observed.
小鼠DNA甲基转移酶Dnmt3a-CD和来自螺原体的M.SssI在CpG位点使胞嘧啶甲基化。使用在不同位置含有2-氨基嘌呤的DNA底物，研究了鸟嘌呤的6-氧代基团在这些酶介导的DNA甲基化中的作用。去除CpG位点中与目标胞嘧啶相邻的鸟嘌呤的6-氧代基团，会显著降低甲基转移酶-DNA复合物的稳定性，并导致甲基化显著减少。显然，该鸟嘌呤的O6参与了酶对CpG位点的识别。观察到Dnmt3a-CD与含2-氨基嘌呤的DNA的协同结合以及非生产性酶-底物复合物的形成。
