Thermal denaturation of the DNA-ethidium complex. Redistribution of the intercalated dye during melting.
Thermal denaturation of the DNA-ethidium complex. Redistribution of the intercalated dye during melting.
复制标题
DNA-乙锭复合物的热变性。
作者：
S. Aktipis;W. W. Martz;A. Kindelis
DNA-溴化乙锭络合物在高温下的圆二向色性随温度的变化提供了证据，表明该络合物在307 nm附近的光学活性来源于插层染料分子之间的相互作用，而在515 nm附近的光学活性来自单一的插层溴化乙锭分子。高温下络合物的圆二色行为也解释了307 nm附近较高的椭圆度，这是溴化乙锭与变性DNA形成的络合物的特征。圆二色谱数据表明，络合物的熔融是以一种逐步的方式进行的，一些DNA区域，可能是富含AT的区域，首先解离。这些发现对溴化乙锭对DNA聚合酶功能的抑制作用的影响进行了研究。
The temperature dependence of the circular dichroism of the DNA-ethidium bromide complex at elevated temperatures provides evidence that the optical activity of the complex near 307 nm originates from interactions between intercalated dye molecules while the optical activity near 515 nm results from singly intercalated ethidium bromide molecules. The behavior of the circular dichroism of the complex at elevated temperatures also explains the higher ellipticities near 307 nm which characterize complexes formed between ethidium bromide and denaturated DNA. Finally the circular dichroism data indicate that the melting of the complex takes place in a stepwise manner with some DNA regions, probably AT-rich regions, dissociating first. The implications of these findings regarding the inhibiting effect of ethidium bromide on the function of DNA polymerase are examined.