Equilibrium binding of benzo[a]pyrene tetrol to synthetic polynucleotides: sequence selectivity, thermodynamic properties, and ionic strength dependence.
Equilibrium binding of benzo[a]pyrene tetrol to synthetic polynucleotides: sequence selectivity, thermodynamic properties, and ionic strength dependence.
复制标题
苯并[a]芘四醇与合成多核苷酸的平衡结合：序列选择性、热力学性质和离子强度依赖性。
DOI：
10.1021/bi00420a055
复制
发表时间：
1988
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：
ShimerJr,GH;Wolfe,AR;Meehan,T
1988年6月8日收到的修订稿摘要：我们研究了外消旋7R，8/，9T，10C-四羟基-7，8，9，10-四氢苯并[a]芘在低结合率下与双链合成多核苷酸多聚[d(AT)]、多聚(GC)和多聚[d(G-M5C)]的平衡结合。差示吸收光谱显示与聚[d(AT)]结合的红移为10 nm，与聚[d(GC)]或聚[d(G-M5C)]结合的红移为11 nm。对于所有三个烃-多核苷酸复合体，AT结合的值大致相同。中性多环芳烃衍生物与这些多核苷酸的结合取决于离子强度和温度。用聚电解质理论对络合物形成的分析表明，与聚[d(AT)]结合相关的反离子释放比与其他两个多核苷酸结合的反离子(分别为0.5和约0.36)更大。因此，这种碳氢化合物在DNA中的序列选择性结合预计会随着盐浓度的变化而改变。在100 mM Na+下研究了结合的温度依赖性，其中聚[d(AT)]和聚[d(G-M5C)]的平衡结合常数大致相等，比聚[d(GC)]的结合亲和力大6倍。聚[d(AT)]和聚[d(GC)]的结合用AH0=-7.0kcal/mol表示，亲和常数的较大差异源于负熵贡献的不同。碳氢多[d(G-M5C)]络合物的形成伴随着H=-9.1kcal/mol。然而，由于与聚[d(G-M5C)]的结合具有更大的负熵，因此与聚[d-(G-M5C)]的亲和力与聚[d(AT)]的亲和力相同。苯并[a]芘(BP)1是一种重要的环境前致癌物，需要代谢活化才能使DNA碱化(Heidelberger，1975)。前致癌物的活化形式已被确定为7R，8/-二羟基-9í，10iepoxy-7，8，9，10-四氢苯并[<；z]芘(<；zün“-BPDE)(Sims等人，1974；Huberman等人，1976；King等人，1976；Korea eda等人，1976；Meehan等人，1976；Weinstein等人，1976)。形成的主要病变是与鸟嘌呤的外环氨基的加合物(Straub等人，1977)。加合物导致多种突变(魏等人，1984；Burgess等人，1985)。在烷基化之前，-BPDE与DNA形成物理络合物，预计这将影响共价结合反应的过程。许多BP衍生物和其他多环芳烃与DNA形成类似的物理络合物(Craig&Isenberg，1970；Abramovich等人，1985)。主要的结合模式是由于平面烃在堆叠的碱基对之间的插层，这从BPDE存在下超螺旋DNA的解离明显可见(Meehan等人，1982)，结合烃的最大吸收峰红移
Revised Manuscript Received June 8, 1988 abstract: We have investigated the equilibrium binding of racemic 7r, 8/, 9t, 10c-tetrahydroxy-7, 8, 9, 10-tetrahydrobenzo [a] pyrene to thedouble-stranded, synthetic polynucleotides poly [d (AT)], polyfd (GC)], and poly [d (G-m5C)] at low binding ratios. Difference absorption spectroscopy shows a 10-nm red shift for binding to poly [d (AT)] and an 11-nm red shift for binding to either poly [d (GC)] or poly [d (G-m5C)]. The value of At forbinding is approximately the same for all three hydrocarbon-polynucleotide complexes. Binding of this neutral polycyclic aromatic hydrocarbon derivative to these polynucleotides is dependent upon ionic strength and temperature. Analysis of complex formation employing polyelectrolyte theory shows a greater release of counterions associated with binding to poly [d (AT)] than with the other two poly-nucleotides (0.5 and ca. 0.36, respectively). Thus, sequence-selective binding of this hydrocarbon in DNA would be expectedto change depending on salt concentration. The temperature dependence of binding was studied at 100 mM Na+ where the equilibrium binding constants for poly [d (AT)] and poly [d (G-m5C)] are roughly equivalent and 6-fold greater than the binding affinity for poly [d (GC)]. The binding to poly [d (AT)] and poly [d (GC)] is characterized by a AH0=-7.0 kcal/mol, and the large difference in affinity constants arises from differences in negative entropic contributions. Formation of hydrocarbonpoly [d (G-m5C)] complexes is accompanied by a AH=-9.1 kcal/mol. However, the affinity for poly [d-(G-m5C)] is the same as that for poly [d (AT)] due to the much more negative entropy associated with binding to poly [d (G-m5C)].Benzo [a] pyrene (BP) 1 is an important environmental procarcinogen that requires metabolic activation in order to al-kylate DNA (Heidelberger, 1975). The activated form of the procarcinogen has been identified as 7r, 8/-dihydroxy-9í, 10iepoxy-7, 8, 9, 10-tetrahydrobenzo [< z] pyrene (< z «n"-BPDE)(Sims et al., 1974; Huberman et al., 1976; King et al., 1976; Koreeda et al., 1976; Meehan et al., 1976; Weinstein et al., 1976). The principal lesion formed is an adduct with the exocyclic amino group of guanine (Straub et al., 1977). The adducts lead to a variety of mutations (Wei et al., 1984; Burgess et al., 1985). Prior to alkylation,-BPDE forms a physical complex with the DNA, which would be expected to affect the course of the covalent binding reaction. Many BP derivatives and other polycyclic aromatic hydrocarbons form similar physical complexes with DNA (Craig & Isenberg, 1970; Abramovich et al., 1985). The principal binding mode results from intercalation of the planar hydrocarbons between the stacked base pairs as is evident from the unwinding of supercoiled DNA in the presence of BPDE (Meehan et al., 1982), the red shift of the absorption maximum of the bound hydrocarbon
登录
查看更多内容
芳香烃与合成多核苷酸结合的碱基序列选择性。
DOI：
10.1016/0006-291x(83)91586-3
发表时间：
1983
影响因子：
3.1
作者：
Yang,NC;Hrinyo,TP;Petrich,JW;Yang,DD
通讯作者：
Yang,DD
多鸟苷酸在 2-氨基和磷酸酯上被强效诱变剂 (i-)-7β,8α-二羟基-9β,10β-环氧-7,8,9,10-四氢苯并[a]芘烷基化。
影响因子：
15
作者：
M. Koreeda*;P. Moore;H. Yagi;H. Yeh;D. Jerina
通讯作者：
D. Jerina
奎纳克林与 DNA 相互作用的协同性和离子效应分析
影响因子：
2.9
作者：
W. Wilson;I. Lopp
通讯作者：
I. Lopp
DNA-碳氢化合物结合的 A 尺寸标准测试
影响因子：
2.9
作者：
Morrie Craig;I. Isenberg
通讯作者：
I. Isenberg
含有 5-甲基胞嘧啶的合成 DAN 的物理研究
DOI：
--
发表时间：
1974
期刊：
影响因子：
--
作者：
J. Gill;J. Mazrimas;C. C. Bishop
通讯作者：
C. C. Bishop