CHARACTERIZATION OF INTERACTION BETWEEN DNA AND 4',6-DIAMIDINO-2-PHENYLINDOLE BY OPTICAL SPECTROSCOPY
CHARACTERIZATION OF INTERACTION BETWEEN DNA AND 4',6-DIAMIDINO-2-PHENYLINDOLE BY OPTICAL SPECTROSCOPY
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DOI：
10.1021/bi00388a057
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发表时间：
1987-07-14
期刊：
影响因子：
2.9
通讯作者：
NORDEN, B
中科院分区：
文献类型：
--
作者：
KUBISTA, M;AKERMAN, B;NORDEN, B
用流动线性二色性（LD）、圆二色性（CD）和荧光光谱技术研究了4“，6-二脒基-2-苯基吲哚（DAPI）与DNA的相互作用。我们表明存在两个光谱上不同的结合位点，在低结合率与饱和值分别为0.025和0.17。在这两个位点中，DAPI以其长轴大致平行于DNA螺旋的凹槽结合。CD光谱的分辨率表明，激子组件是存在于较高的结合比，我们归因于两个偶然的紧密说谎的DAPI分子的相互作用。我们还发现证据表明，DAPI，至少在高亲和力的网站，优先结合AT丰富的地区。从光谱结果，由结构考虑支持，我们可以完全排除DAPI通过嵌入结合到DNA。结合几何形状和位点密度与DAPI在DNA凹槽中的位置一致，高亲和力位点最可能在小沟中。
We have examined the interaction between 4'',6-diamidino-2-phenylindole (DAPI) and DNA using flow linear dichroism (LD), circular dichroism (CD), and fluorescence techniques. We show the presence of two spectroscopically distinct binding sites at low binding ratios with saturation values of 0.025 and 0.17, respectively. In both sites DAPI is bound with its long axis approximately parallel to the grooves of the DNA helix. Resolution of CD spectra shows that an exciton component is present at higher binding ratios, which we attribute to the interaction of two accidentally close-lying DAPI molecules. We also find evidence that DAPI, at least in the high-affinity site, binds preferentially to AT-rich regions. From the spectroscopic results, supported by structural considerations, we can completely exclude that DAPI is bound to DNA by intercalation. Binding geometries and site densities are consistent with a location of DAPI in the grooves of DNA, with the high-affinity site most probably in the minor groove.