Controlling the higher order structure of single DNA molecule with attention to environmental stress

1.以定量的方式评价了水溶性类黄酮衍生物对光和γ射线诱导的DNA双链断裂的保护作用。这一观察结果表明，这些化合物的抗氧化潜力依赖于辐射源。2.结果发现，四唑桥联双核铂（II）配合物诱导大基因组DNA的不可逆压缩，这是伴随着从B到C形式的二级结构的变化。3.巨碱基DNA中的相分离态的出现与单个亚巨碱基DNA中折叠转变的全或无特征明显不同。4.研究了四价多胺的新型立体异构体诱导单个DNA分子压缩的能力。发现异构体（R，S-R，S）在诱导DNA压缩和二级结构变化方面更有效。

1. The protective effects of water-soluble derivatives of flavonoids on photo- and gamma ray-induced DNA double-strand breaks were evaluated in a quantitative manner. This observation demonstrated the dependence of the antioxidant potentials of these compounds on the source of irradiation. 2. It was found that tetrazolato-bridged dinuclear platinum(II) complexes induced the irreversible compaction of large genomic DNA, which was accompanied by a change in the secondary structure from the B to C form. 3.The appearance of the phase-segregated state in megabase-size DNA is markedly different from the all-or-none characteristics on the foldingtransition in a single sub-megabase-size DNA. 4. Novel stereoisomers of tetravalent polyamines were examined their ability to induce the compaction of single DNA molecules. It was found that Isomer (R,S-R,S) is more potent at inducing both DNA compaction and changes in the secondary structure.