Hamada H, Kakunaga T
Nature. 1982 Jul 22;298(5872):396-8. doi: 10.1038/298396a0.
Recent analyses of the three-dimensional structure of synthetic DNA molecules has revealed the existence of a left-handed double-helical conformation of DNA, called Z-DNA. The Z-DNA structure was first observed in molecules having alternating guanine and cytosine bases, but has now also been shown for molecules of sequence poly(dT-dG) . poly(dC-dA) (refs 4-7). If Z-DNA occurs naturally then it might have quite different reactivities with molecules such as proteins or carcinogens from right-handed B-DNA. The interconversion of sequences between B and Z forms, under the influence, for example, of DNA binding proteins or chemical modification, may be important in regulating DNA function. So far, little data have been published on the occurrence of potential Z-DNA forming sequences in eukaryotic DNA. Here we report the presence of a sequence of 50 alternating dT and dG residues within one of the introns of a human cardiac muscle actin gene. Also, using a probe specific for poly(dT-dG) sequences, we have also found that potential Z-DNA forming sequences are highly repeated in the human genome.
近期对合成DNA分子三维结构的分析揭示了一种左手双螺旋DNA构象的存在，即Z-DNA。Z-DNA结构最初是在含有交替鸟嘌呤和胞嘧啶碱基的分子中观察到的，但现在也已在聚（dT-dG）.聚（dC-dA）序列的分子中得到证实（参考文献4-7）。如果Z-DNA天然存在，那么它与诸如蛋白质或致癌物等分子的反应性可能与右手B-DNA有很大不同。例如，在DNA结合蛋白或化学修饰的影响下，B型和Z型序列之间的相互转换可能对调节DNA功能很重要。到目前为止，关于真核生物DNA中潜在Z-DNA形成序列的存在情况，几乎没有公开的数据。在此我们报告，在人类心肌肌动蛋白基因的一个内含子中存在一段由五十个交替的dT和dG残基组成的序列。此外，使用针对聚（dT-dG）序列的探针，我们还发现潜在的Z-DNA形成序列在人类基因组中高度重复。
