POLYCYCLIC AROMATIC-HYDROCARBONS PHYSICALLY INTERCALATE INTO DUPLEX REGIONS OF DENATURED DNA
POLYCYCLIC AROMATIC-HYDROCARBONS PHYSICALLY INTERCALATE INTO DUPLEX REGIONS OF DENATURED DNA
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DOI：
10.1021/bi00394a013
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发表时间：
1987-10-06
期刊：
影响因子：
2.9
通讯作者：
MEEHAN, T
中科院分区：
文献类型：
--
作者：
WOLFE, A;SHIMER, GH;MEEHAN, T
我们研究了芘和苯并[a]芘衍生物与变性DNA的物理结合。当与变性小牛胸腺DNA结合时，这些化合物在其吸收光谱中显示出9 nm的红移，而当与天然DNA结合时，其吸收光谱发生10 nm的位移。当与天然和变性DNA结合时，来自烃的荧光被严重淬灭。增加钠离子浓度会降低中性多环芳烃与天然DNA的结合，并增加与变性DNA的结合。与变性DNA的结合和盐浓度之间的直接关系似乎是中性多环芳烃的一般性质。在260 nm处的吸收测量用于确定变性DNA的双链体含量。当基于双链体结合位点计算时，7，8，9，10-四羟基-7，8，9，10-四氢苯并[a]芘与变性DNA结合的平衡常数比与天然DNA结合的平衡常数大一个数量级。盐对结合常数的影响用于计算每个结合配体的钠离子释放，其对于天然和变性DNA均为0.36。增加盐浓度增加变性DNA的双链体含量，并且似乎多环芳烃的物理结合包括插入到这些位点中。
We have investigated the physical binding of pyrene and benzo[a]pyrene derivatives to denatured DNA. These compounds exhibit a red shift in their absorbance spectra of 9 nm when bound to denatured calf thymus DNA, compared to a shift of 10 nm when binding occurs to native DNA. Fluorescence from the hydrocarbons is severely quenched when bound to both native and denatured DNA. Increasing sodium ion concentration decreases binding of neutral polycyclic aromatic hydrocarbons to native DNA and increases binding to denatured DNA. The direct relationship between binding to denatured DNA and salt concentration appears to be a general property of neutral polycyclic aromatic hydrocarbons. Absorption measurements at 260 nm were used to determine the duplex content of denatured DNA. When calculated on the basis of duplex binding sites, equilibrium constants for binding of 7,8,9,10-tetrahydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene to denatured DNA are an order of magnitude larger than for binding to native DNA. The effect of salt on the binding constant was used to calculate the sodium ion release per bound ligand, which was 0.36 for both native and denatured DNA. Increasing salt concentration increases the duplex content of denatured DNA, and it appears that physical binding of polycyclic aromatic hydrocarbons consists of intercalation into these sites.