FLUORESCENCE STUDY OF THE PHYSICO‐CHEMICAL PROPERTIES OF A BENZO(A)PYRENE7,8‐DIHYDRODIOL9,10‐OXIDE DERIVATIVE BOUND COVALENTLY TO DNA
FLUORESCENCE STUDY OF THE PHYSICO‐CHEMICAL PROPERTIES OF A BENZO(A)PYRENE7,8‐DIHYDRODIOL9,10‐OXIDE DERIVATIVE BOUND COVALENTLY TO DNA
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与 DNA 共价结合的苯并(A)芘7,8-二氢二醇9,10-氧化物衍生物的物理化学性质的荧光研究
DOI：
10.1111/j.1751-1097.1979.tb07043.x
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发表时间：
1979
影响因子：
3.3
通讯作者：
I. Weinstein
中科院分区：
文献类型：
--
作者：
T. Prusik;N. Geacintov;Christopher Tobiasz;V. Ivanović;I. Weinstein
摘要：在体外制备了7,8 -二氢二醇9.10 -氧化物苯并(a)芘（BPDE）与DNA之间的共价配合物，每1000个DNA碱基修饰一个BPDE分子。与先前报道的人类和牛支气管外植体一样，观察到BPDE与天然DNA具有相同的立体选择性和化学均匀性结合。利用体外BPDE与DNA结合的类芘芳香族部分的荧光作为BPDE分子微环境的探针，以获得水溶液中BPDE - DNA复合物的结构信息。基于金属离子（如Ag+）、碘离子和分子氧对单线态激发态猝灭的荧光技术，为区分多环芳香族分子与DNA的外部和内部（插层）结合提供了一种方法。特异性结合DNA碱基的银离子对非共价结合的插层苯并(a)芘表现出强烈的猝灭作用；另一方面，共价DNA加合物对BPDE的荧光没有猝灭作用。猝灭剂，如O2和碘离子，不特异性地与DNA结合，溶解在DNA分子外的溶液中，对BPDE发色团表现出猝灭作用。此外，BPDE - DNA复合物的荧光产额随着DNA浓度的增加而降低，这种效应在非共价结合的插层苯并芘- DNA复合物中没有观察到，这归因于分子间DNA - DNA相互作用。这些研究结果表明，共价BPDE - DNA复合体中的芘样发色团并没有嵌入碱基对之间，而是位于DNA螺旋外的可接近区域。讨论了可能的结构。
Abstract— Covalent complexes between7,8‐dihydrodiol 9.10‐oxide benzo(a)pyrene (BPDE) and DNA with a modification of one BPDE molecule per 1000 DNA bases were prepared in vitro. The same stereoselective and chemically homogeneous binding of BPDE to native DNA was observed, as reported earlier for human and bovine bronchial explants. The fluorescence of the pyrene‐like aromatic moiety of BPDE bound to DNA in vitro was used as a probe of the microenvironment of the BPDE molecule in order to obtain information about the structure of the BPDE‐DNA complex dissolved in aqueous solution. Fluorescence techniques, based on the quenching of the singlet excited states by metal ions such as Ag+, by iodide ions, and by molecular oxygen are described, which provide a method for differentiating between external and internal (intercalation) binding of polycyclic aromatic molecules to DNA. Silver ions, which bind specifically to DNA bases, exhibit a strong quenching effect on noncovalently bound, intercalated benzo(a)pyrene; on the other hand, there is no quenching effect on the fluorescence of BPDE in the covalent DNA adduct. Quenchers such as O2 and iodide ions, which do not specifically bind to DNA and are dissolved in the solution external to the DNA molecule, exhibit a quenching effect on the BPDE chromophore. Furthermore, the fluorescence yield of the BPDE‐DNA complex decreases with increasing DNA concentration, an effect which is not observed with non‐covalently bound intercalated benzo(a)pyrene‐DNA complexes, and which is attributed to intermolecular DNA‐DNA interactions. The results of these studies indicate that the pyrene‐like chromophore in the covalent BPDE‐DNA complex is not intercalated between the base pairs, and that it is located in an accessible region external to the DNA helix. Possible structures are discussed.