Identifying the interactions of small molecules with biomolecules in complex cellular environments is a significant challenge. As one important example, despite being widely used for decades, much is still not understood regarding the cellular targets of Pt(II)-based anticancer drugs. In this study we introduce a novel method for isolation of Pt(II)-bound biomolecules using a DNA hybridization pull-down approach. Using a modified Pt reagent, click-ligation of a DNA oligonucleotide to both a Pt(II)-bound DNA hairpin and bovine serum albumin (BSA) are demonstrated. Subsequent hybridization to a biotin-labeled oligonucleotide allows for efficient isolation of Pt(II)-bound species by streptavidin pulldown. We also find that platinated bovine serum albumin readily crosslinks to DNA in the absence of click ligation, and that a fraction of BSA-bound Pt(II) can transfer to DNA over time. Interestingly, in in vitro studies, fragmented mammalian DNA that is crosslinked to BSA through Pt(II) exhibits significantly increased protection from degradation by serum nucleases.

识别小分子与生物分子在复杂细胞环境中的相互作用是一项重大挑战。作为一个重要的例子，尽管已被广泛使用了几十年，但对于基于Pt（II）的抗癌药物的细胞靶点仍然知之甚少。在这项研究中，我们介绍了一种使用DNA杂交下拉法分离结合Pt（II）的生物分子的新方法。使用修饰的Pt试剂，证明了DNA寡核苷酸与Pt（II）结合的DNA发夹和牛血清白蛋白（BSA）的点击连接。随后与生物素标记的寡核苷酸杂交，可通过抗生蛋白链菌素下拉有效分离Pt（II）结合的物种。我们还发现，在没有单击连接的情况下，铂化的牛血清白蛋白很容易与DNA交联，并且一部分BSA结合的Pt（II）可以随时间转移到DNA。有趣的是在体外研究中，片段化的哺乳动物DNA通过Pt（II）与BSA交联，表现出显着增强的保护作用，可防止血清核酸酶降解。