Renbaum P, Razin A
Department of Cellular Biochemistry, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
FEBS Lett. 1992 Nov 30;313(3):243-7. doi: 10.1016/0014-5793(92)81201-v.
The cytosine DNA methylase from the wall-less prokaryote, Spiroplasma strain MQ1 (M.SssI) methylates completely and exclusively CpG-containing sequences, thus showing sequence specificity which is similar to that of mammalian DNA methylases. M.SssI is shown here to methylate duplex DNA processively as judged by kinetic analysis of methylated intermediates. The cytosine DNA methylases, M.HpaII and M.HhaI, from other prokaryotic organisms, appear to methylate in a non-processive manner or with a very low degree of processivity. The Spiroplasma enzyme interacts with duplex DNA irrespective to the presence of CpG sequences in the substrate DNA. The enzyme proceeds along a CpG-containing DNA substrate molecule methylating one strand of DNA at a time.
来自无壁原核生物螺原体菌株MQ1的胞嘧啶DNA甲基化酶（M.SssI）完全且仅对含CpG的序列进行甲基化，因此显示出与哺乳动物DNA甲基化酶相似的序列特异性。通过对甲基化中间体的动力学分析判断，此处显示M.SssI以持续方式甲基化双链DNA。来自其他原核生物的胞嘧啶DNA甲基化酶M.HpaII和M.HhaI似乎以非持续方式或极低的持续程度进行甲基化。无论底物DNA中是否存在CpG序列，螺原体酶都能与双链DNA相互作用。该酶沿着含CpG的DNA底物分子前进，每次甲基化一条DNA链。
