Mikelsons Larisa, Carra Claudio, Shaw Michelle, Schweitzer Claude, Scaiano J C
Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Photochem Photobiol Sci. 2005 Oct;4(10):798-802. doi: 10.1039/b508720a. Epub 2005 Aug 18.
The photophysical properties of an intercalating unsymmetrical monomethine cyanine dye and single-stranded DNA homopolymers show strong association for poly(dA) and poly(dG), but not for poly(dC) and poly(dT), as determined by several spectroscopic techniques and molecular dynamics calculations. While poly(dA) and poly(dG) appear to bind the dye as a monomer (with dramatic increase in fluorescence), poly(dC) and poly(dT) bind only very weakly, and seem to promote dye aggregation. Only in the case of poly(dA) there seems to be a unique, well defined form of intercalation, that molecular dynamics calculations suggest involve the quinoline ring between two bases, in an arrangement that should favor pi-stacking; consistently with this, the decay of the fluorescence shows a single exponential, the absorption spectrum shows a shift in the dye maximum, the fluorescence is strong, and the induced circular dichroism follows a simple pattern.
一种插入式不对称单甲川花菁染料与单链DNA均聚物的光物理性质表明，通过几种光谱技术和分子动力学计算确定，该染料与聚（dA）和聚（dG）有很强的缔合，但与聚（dC）和聚（dT）没有。虽然聚（dA）和聚（dG）似乎以单体形式结合染料（荧光显著增加），但聚（dC）和聚（dT）仅非常弱地结合，并且似乎促进染料聚集。仅在聚（dA）的情况下，似乎存在一种独特的、定义明确的插入形式，分子动力学计算表明这种形式涉及两个碱基之间的喹啉环，其排列应有利于π-堆积；与此一致的是，荧光衰减呈现单指数形式，吸收光谱显示染料最大值发生位移，荧光很强，并且诱导圆二色性遵循简单模式。
