Circular dichroism of acridine orange bound to DNA
Circular dichroism of acridine orange bound to DNA
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吖啶橙与 DNA 结合的圆二色性
DOI：
10.1002/bip.1970.360090106
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发表时间：
1970
期刊：
影响因子：
--
通讯作者：
S. Ichimura
中科院分区：
文献类型：
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作者：
M. Zama;S. Ichimura
在DNA磷酸染料比（P/D）为1 ~ 550时，测定了DNA -吖啶橙（DNA - ao）复合物在可见光区的圆二色性（CD）光谱。在P/D比值为1 ~约40范围内，DNA-AO复合物的CD谱由4个部分组成，即位于510 ~ 480 μ m的正CD谱带和位于497 ~ 468 μ m的负CD谱带。当P/D = 4时，510和468 μ的CD谱带最优，ε1 - εr随P/D的变化表明两者都是由相邻DNA结合位点上的染料分子相互作用引起的，每个染料分子由4个核苷酸组成。随着温度的升高或配合物中亚甲基蓝浓度的增加，ε1−εr值均降低。在较大的P/D比（~ 8）下，497 μ m的负棉花效应最受欢迎，建议的分配是两个染料分子之间的相互作用，它们之间有一个空位点。当P/D比小于4时，在480 μ m下棉花产生正向效应，P/D比为1时效果最佳。在P/D比为40以上时，配合物的CD光谱不能被分解成其组分，即使在足够高的P/D比（550）下，配合物也表现出很小的棉花效应。
The circular dichroism (CD) spectra of DNA–acridine orange (DNA–AO) complex in the visible region were measured at DNA phosphate‐to‐dye ratios (P/D) from 1 to 550. The CD spectrum of DNA–AO complex in the P/D ratio between 1 and approximately 40 consists of four components, i.e., positive CD bands centered at 510 and 480 mμ, and negative CD bands at 497 and 468 mμ. The CD bands at 510 and 468 mμ are optimum at P/D = 4, and the change of ε1 − εr with P/D suggests that both of them are induced from the interaction between dye molecules bound to adjacent DNA binding sites, each of which is composed of four nucleotides. This is supported by the fact that the values of ε1 − εr for both decrease with increasing temperature or increasing methylene blue concentration added to the complex. The negative Cotton effect at, 497 mμ is most favored at larger P/D ratio (∼8), and the suggested assignment is to the interaction between two dye molecules bound with an empty site between them. A positive Cotton effect at 480 mμ is observed at P/D ratio of less than 4 and is optimum at 1. Above P/D ratio of 40, the CD spectrum of the complex can not be resolved into its components and even at sufficiently high P/D ratio (550) the complex shows a small Cotton effect.