Hermann Andrea, Schmitt Sigrid, Jeltsch Albert
Institut für Biochemie, FB 8, Heinrich-Buff-Ring 58, Justus-Liebig-Universität, 35392 Giessen, Germany.
J Biol Chem. 2003 Aug 22;278(34):31717-21. doi: 10.1074/jbc.M305448200. Epub 2003 Jun 6.
The human Dnmt2 protein is one member of a protein family conserved from Schizosaccharomyces pombe and Drosophila melanogaster to Mus musculus and Homo sapiens. It contains all of the amino acid motifs characteristic for DNA-(Cytosine-C5) methyltransferases, and its structure is very similar to prokaryotic DNA methyltransferases. Nevertheless, so far all attempts to detect catalytic activity of this protein have failed. We show here by two independent assay systems that the purified Dnmt2 protein has weak DNA methyltransferase activity. Methylation was observed at CG sites in a loose ttnCGga(g/a) consensus sequence, suggesting that Dnmt2 has a more specialized role than other mammalian DNA methyltransferases.
人类Dnmt2蛋白是一个从粟酒裂殖酵母、黑腹果蝇到小家鼠和智人都保守的蛋白家族成员。它包含了DNA-（胞嘧啶-C5）甲基转移酶的所有特征性氨基酸基序，其结构与原核DNA甲基转移酶非常相似。然而，到目前为止，所有检测该蛋白催化活性的尝试均告失败。我们在此通过两个独立的检测系统表明，纯化的Dnmt2蛋白具有微弱的DNA甲基转移酶活性。在松散的ttnCGga（g/a）共有序列中的CG位点观察到甲基化，这表明Dnmt2具有比其他哺乳动物DNA甲基转移酶更特殊的作用。
