Grimm Günther N, Boutorine Alexandre S, Lincoln Per, Nordén Bengt, Hélène Claude
Laboratoire de Biophysique, INSERM 201-CNRS UMR 8646, Muséum National d'Histoire Naturelle, 43 rue Cuvier, 75231 Paris Cedex 05, France.
Chembiochem. 2002 Apr 2;3(4):324-31. doi: 10.1002/1439-7633(20020402)3:4<324::AID-CBIC324>3.0.CO;2-7.
A conjugate of a triple helix forming oligonucleotide (TFO) and the Lambda and Delta enantiomers of the ruthenium diphenanthroline dipyridophenazine complex Ru(phen)(2)dppz was synthesized. The ruthenium complex was attached to the 5'-end of the TFO through the dppz moiety. This conjugate formed a stable triple helix with the polypurine tract (PPT) sequence from HIV proviral DNA. The thermal denaturation temperature of the triplex was increased by 12 degrees C. One remarkable property of the Delta-Ru(phen)(2)dppz complex is a strong increase in its fluorescence when it intercalates into DNA. While the fluorescence of the oligonucleotide conjugate was very weak, the formation of a duplex with a complementary sequence or of a triple helix with a target duplex resulted in a large increase in fluorescence of the Delta enantiomer. The increase in fluorescence allowed us to follow the kinetics of duplex and triplex formation by fluorescence spectrometry. In contrast, the Lambda enantiomer gave a much smaller fluorescence change when a triplex was formed, even though the stability of the triplex was comparable to that of the Delta enantiomer. The property was ascribed to intercalation of the dipyridophenazine moiety of the Delta enantiomer into DNA and subsequent threading of the ruthenium complex through the DNA double helix. Salt effects were consistent with the involvement of DNA breathing in the formation of the intercalating complex.
合成了一种三链螺旋形成寡核苷酸（TFO）与钌二菲咯啉二吡啶菲嗪配合物Ru(phen)(2)dppz的λ和δ对映体的共轭物。钌配合物通过dppz部分连接到TFO的5'端。该共轭物与HIV前病毒DNA的聚嘌呤序列（PPT）形成了稳定的三链螺旋。三链体的热变性温度提高了12℃。δ-Ru(phen)(2)dppz配合物的一个显著特性是，当它插入DNA时，其荧光会强烈增强。虽然寡核苷酸共轭物的荧光非常微弱，但与互补序列形成双链体或与靶双链体形成三链螺旋会导致δ对映体的荧光大幅增加。荧光的增加使我们能够通过荧光光谱法追踪双链体和三链体形成的动力学。相比之下，即使三链体的稳定性与δ对映体相当，但形成三链体时λ对映体的荧光变化要小得多。该特性归因于δ对映体的二吡啶菲嗪部分插入DNA以及随后钌配合物穿过DNA双螺旋的穿线过程。盐效应与DNA呼吸参与插入配合物的形成一致。
