Gabelica V, De Pauw E, Rosu F
Mass Spectrometry Laboratory, Chemistry Institute B6c, University of Liège, B-4000 Liège, Belgium.
J Mass Spectrom. 1999 Dec;34(12):1328-37. doi: 10.1002/(SICI)1096-9888(199912)34:12<1328::AID-JMS889>3.0.CO;2-F.
Electrospray ionization mass spectrometry was used to investigate the complex formation between a double-stranded oligonucleotide and various antitumor drugs belonging to two categories: intercalators (ethidium bromide, amsacrine and ascididemin) and minor groove binders (Hoechst 33258, netropsin, distamycin A, berenil and DAPI). The goal of this study was to determine whether the relative intensities in the mass spectra reflect the relative abundances of the species in the solution phase. The full-scan mass spectra suggest non-specific binding for the intercalators and specific binding for the minor groove binders. The preferential stoichiometries adopted by each minor groove binder were determined by studying the influence of the drug concentration on the spectra. We obtained 2:1 > 1:1 for distamycin, 1:1 > 2:1 for Hoechst 33258 and DAPI and only the 1 : 1 complex for netropsin and berenil. These features reflect their known behavior in solution. The compared tandem mass spectra of the 1 : 1 complexes with Hoechst 33258 and netropsin, when correlated with published crystallographic data, suggest the possibility of inferring some structural information. The relative binding affinities of the drug for the considered duplex were deduced with two by two competition experiments, assuming that the relative intensities reflect the composition of the solution phase. The obtained affinity scale is netropsin > distamycin A > DAPI > Hoechst 33258 > berenil. These examples show some of the potential uses of mass spectrometry as a useful tool for the characterization of specific drug binding to DNA, and possibly a rapid drug screening method requiring small amounts of materials.
嵌入剂（溴化乙锭、安吖啶和海鞘素B）和小沟结合剂（Hoechst 33258、纺锤菌素、偏端霉素A、贝尼尔和4',6-二脒基-2-苯基吲哚）。本研究的目的是确定质谱中的相对强度是否反映溶液相中各物种的相对丰度。全扫描质谱表明嵌入剂存在非特异性结合，而小沟结合剂存在特异性结合。通过研究药物浓度对光谱的影响，确定了每种小沟结合剂优先采用的化学计量比。我们得到：偏端霉素为2:1 > 1:1，Hoechst 33258和4',6-二脒基-2-苯基吲哚为1:1 > 2:1，而纺锤菌素和贝尼尔只有1:1的复合物。这些特征反映了它们在溶液中的已知行为。与Hoechst 33258和纺锤菌素形成的1:1复合物的串联质谱，与已发表的晶体学数据相关联时，表明有可能推断出一些结构信息。通过两两竞争实验，在假设相对强度反映溶液相组成的情况下，推导出了药物对所考虑双链体的相对结合亲和力。得到的亲和力顺序为：纺锤菌素 > 偏端霉素A > 4',6-二脒基-2-苯基吲哚 > Hoechst 33258 > 贝尼尔。这些例子展示了质谱作为一种用于表征特定药物与DNA结合的有用工具的一些潜在用途，并且可能是一种需要少量材料的快速药物筛选方法。
