Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden.
J Phys Chem B. 2011 Oct 27;115(42):12192-201. doi: 10.1021/jp205374t. Epub 2011 Sep 30.
We investigate how DNA interacts with drugs in humid polyvinyl alcohol (PVA) films by using a homologous set of cyanine dyes (YO(+), YO-PRO(2+), and YOYO(4+)) known to intercalate into DNA with increasing affinity with increasing charge. UV-vis spectroscopy shows that the PVA matrix destabilizes all three DNA-dye complexes compared to aqueous solution but to a lesser degree as the dye charge increases. The monovalent YO is fully dissociated from DNA within minutes, whereas the dissociation of the divalent YO-PRO takes about one hour and occurs by a two-step mechanism. The tetravalent homodimer YOYO is even less affected by the PVA environment and remains intercalated in the B-form DNA also in the PVA films. The reduced stability of the DNA-dye complexes is discussed in terms of steric and dielectric properties of the PVA matrix. After being kept in dry PVA films for 48 h the DNA-YOYO complexes can be reformed reversibly by rehumidifying the films for 30 min. The ability to store aligned and confined DNA intercalated with ligand complexes may be useful in studies on structural properties of nucleic acids.
我们通过使用一组同源的花青染料（YO(+)、YO-PRO(2+)和 YOYO(4+)）研究了 DNA 在潮湿的聚乙烯醇（PVA）薄膜中与药物的相互作用，这些染料已知具有与带电量增加而增加的与 DNA 插入的亲和力。紫外-可见光谱表明，与水溶液相比，PVA 基质使所有三种 DNA-染料复合物都不稳定，但随着染料电荷的增加，其不稳定程度降低。单价 YO 在数分钟内完全从 DNA 中解离，而二价 YO-PRO 的解离则需要大约一个小时，并且通过两步机制发生。四价同型二聚体 YOYO 受 PVA 环境的影响更小，在 PVA 薄膜中也保持插入 B 型 DNA。DNA-染料复合物稳定性的降低是根据 PVA 基质的空间和介电性质来讨论的。将 DNA-YOYO 复合物保存在干燥的 PVA 薄膜中 48 小时后，通过重新润湿薄膜 30 分钟可以可逆地重新形成。这种储存与配体复合物插入的对齐和受限 DNA 的能力可能对研究核酸的结构性质有用。
