Chen L, Cai L, Zhang X, Rich A
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Biochemistry. 1994 Nov 22;33(46):13540-6. doi: 10.1021/bi00250a005.
The crystal structure of d(C4) solved at 2.3-A resolution reveals a four-stranded molecule composed of two interdigitated or intercalated duplexes. The duplexes are held together by hemiprotonated cytosine-cytosine base pairs and are parallel stranded, but the two duplexes point in opposite directions. The molecule has a slow right-handed twist of 12.4 degrees between covalently linked cytosine base pairs, and the base stacking distance is 3.1 A. This is in general agreement with the NMR studies. A biological role for DNA in this conformation is suggested.
以2.3埃分辨率解析的d(C4)晶体结构揭示了一个由两个相互交错或插入的双链体组成的四链分子。双链体通过半质子化的胞嘧啶-胞嘧啶碱基对结合在一起，并且是平行链的，但两个双链体指向相反的方向。该分子在共价连接的胞嘧啶碱基对之间具有12.4度的缓慢右手扭转，碱基堆积距离为3.1埃。这与核磁共振研究总体一致。有人提出了这种构象的DNA的生物学作用。
