Matsugami Akimasa, Tsuchibayashi Hiroaki, Xu Yan, Noguchi Yuuki, Sugiyama Hiroshi, Katahira Masato
Supramolecular Biology, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
Nucleic Acids Symp Ser (Oxf). 2006(50):45-6. doi: 10.1093/nass/nrl023.
The structure of human telomeric DNA has been controversial: the solution structure in the presence of Na(+) has been reported to be antiparallel basket-type quadruplex by NMR, while the crystal structure in the presence of K(+) has been reported to be parallel propeller-type quadruplex. The solution structure in the presence of K(+) has drawn intense interest, as the intracellular K(+) concentration is higher than that of Na(+), but the structure is still open to address. Recently Sugiyama et al. has suggested that the DNA exists as a mixture of mixed-parallel/antiparallel quadruplex and antiparallel chair-type quadruplex on the basis of the combination of a series of 8-bromoguanine mutations and CD analysis. Here, we have started NMR analysis of the DNAs with the mutations to evaluate the proposed model. So far, NMR analysis is qualitatively consistent with the proposal. The structure determination is in progress to evaluate the model at atomic resolution.
人类端粒DNA的结构一直存在争议：据核磁共振（NMR）报道，在存在Na(+)的情况下其溶液结构为反平行篮状四链体，而在存在K(+)的情况下其晶体结构为平行螺旋桨状四链体。由于细胞内K(+)浓度高于Na(+)，因此在存在K(+)的情况下的溶液结构引起了人们的浓厚兴趣，但该结构仍有待确定。最近，杉山等人基于一系列8-溴鸟嘌呤突变和圆二色性（CD）分析的结合，提出DNA以混合平行/反平行四链体和反平行椅型四链体的混合物形式存在。在此，我们开始对具有这些突变的DNA进行NMR分析，以评估所提出的模型。到目前为止，NMR分析在定性上与该提议一致。正在进行结构测定以在原子分辨率下评估该模型。
