Liu J, Subirana J A
Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Diagonal 647, E-08028, Barcelona, Spain.
J Biol Chem. 1999 Aug 27;274(35):24749-52. doi: 10.1074/jbc.274.35.24749.
The dodecamer d(CGCGAATTCGCG) was the first oligonucleotide to be crystallized as a B-DNA duplex. Its structure was analyzed in detail in the early 1980s. Here we show that, in the presence of Ca(2+), it crystallizes in a different way (R3 space group). The dodecamers form parallel columns of straight duplexes with ten base pairs in the B form. The terminal cytosines in each molecule are disordered, whereas the terminal guanines are placed in the minor groove of neighbor duplexes. The central GAATTC region is practically identical to that found in the classic structure of the same dodecamer crystallized in the P2(1)2(1)2(1) space group in the presence of Mg(2+) and spermine. Its structure is thus independent of the crystallization conditions which have been used.
十二聚体d(CGCGAATTCGCG)是首个以B - DNA双链形式结晶的寡核苷酸。其结构在20世纪80年代早期得到了详细分析。在此我们表明，在Ca(2+)存在的情况下，它以不同的方式结晶（R3空间群）。十二聚体形成了具有十个B型碱基对的直链双链平行柱。每个分子中的末端胞嘧啶无序，而末端鸟嘌呤位于相邻双链的小沟中。中央GAATTC区域实际上与在Mg(2+)和精胺存在下于P2(1)2(1)2(1)空间群中结晶的相同十二聚体的经典结构中发现的区域相同。因此，其结构与所使用的结晶条件无关。
