Functionalization of oligonucleotides capable to form alternate-stranded triplex containing stereoisomeric nucleotide units

制备了一种新型的二核苷磷酸三酯单元的磷酸酰胺衍生物，该磷酸三酯单元在其核苷酸间链上以立体特异性的方式插入了一个片段，并成功地嵌入到α-β嵌合寡核苷酸的中间部分。其中一种立体异构体嵌合体DNA强烈增强了在嵌合体和双链DNA之间形成的交替链三联体的热稳定性。另一方面，含有相同单元的低聚物的双相化合物没有表现出任何Tm增量（稳定）效应，而与含有插入部分的磷原子的立体化学无关。因此，当前二核苷单位的稳定作用似乎是特异性的DNA三联体。合成了一种与2,2-二（羟甲基）丙酸缀合的蒽醌衍生物，作为一种新型的非核苷类化合物，并通过磷酸酰胺法成功地结合到14聚三聚体寡核苷酸（TFO）的内区。所得到的新型TFO在与含有嘧啶间隙的多嘌呤序列结合后，对DNA三联体的热稳定性有显著的增强作用。合成了一种新型的α-β嵌合寡脱氧核苷酸，其核碱基位于内部4-nt连接区域，并对其三联体稳定性进行了研究。修饰嵌合体DNA与双链DNA之间形成的三螺旋DNA表现出显著的热稳定性；插入物共轭核碱基的位置对其稳定性影响不大。在被检测的嵌合体DNA中，在相邻位置携带两个插入物共轭核碱基的修饰嵌合体DNA表现出最高的稳定性。合成了一种新型的非对映体α-β嵌合寡脱氧核苷酸，其“连接”区域含有蒽醌-多胺缀合物的丙酸衍生物。与双链DNA杂交后，修饰的嵌合体DNA即使在接近生理ph时也能形成相当稳定的交替链三联体。此外，衍生物的加入所带来的三联体稳定效应几乎与衍生物的立体化学无关。制备了由插层剂-金属配体-2,2-双（羟甲基）丙酸组成的新型共轭物。共轭物与Fe^<2+>、Cu^<2+>、Zn^<2+>等二价金属离子形成配合物。其中，Fe^<2+>复合物能高效地切割双链DNA。一项利用带有该复合体的功能性嵌合体DNA作为序列特异性基因调节因子的研究正在进行中。少

A novel phosphoramidite derivative of a dinucleoside phosphotriester unit bearing an intercalative moiety at its internucleotide linkage in a stereospecific manner was prepared and successfully incorporated into the middle portion of α-β chimeric oligoDNA. One of the resulting stereoisomeric chimera DNAs strongly enhances the thermal stability of an alternate-stranded triplex formed between the chimera and a double-stranded DNA. On the other hand, the duplexes containing the oligomers bearing the same unit failed to show any Tm increment (stabilization) effect regardless of the stereochemistry of the phosphorous atom bearing the intercalative moiety. Thus, the stabilizing effect of the current dinucleoside unit seems to be specific to the DNA triplex.An anthraquinone derivative conjugated with 2,2-bis(hydroxymethyl)propionic acid as a novel non-nucleosidic component was synthesized and successfully incorporated into an internal region of 14-mer triplex-forming oligonucleotide (TFO) via … More the phosphoramidite method. The resulted novel TFO exhibits remarkable enhancement effect on the thermal stability of a DNA triplex upon binding to a pyrimidine-gap containing polypurine sequence.Novel α-β chimeric oligodeoxynucleotides bearing an intercalator-conjugated nucleobase located at the internal 4-nt linker region were synthesized, and their triplex-stabilizing property was examined. The triple helical DNA formed between the modified chimera DNA and double-stranded DNA exhibited remarkable thermal stability ; however, the position of the intercalator-conjugated nucleobase had little influence on the stability. Among the examined, modified chimera DNA bearing the two intercalator-conjugated nucleobases at adjacent positions exhibited the highest stability.Novel diastereomeric α-β chimeric oligodeoxynucleotides bearing a propionic acid derivative of an anthraquinone-polyamine conjugate in the "linker" region were synthesized. Upon hybridization with double-stranded DNA, the modified chimera DNAs formed substantially stable alternate-stranded triplex even at near physiological pH. Furthermore, the triplex-stabilizing effect brought about by the incorporation of the derivative was almost regardless of the stereochemistry of the derivative.Novel conjugate composed of an intercalator-metal ligand-2,2-bis(hydroxymethyl)propionic acid was prepared. The conjugate forms complexes with divalent metal ions such as Fe^<2+>, Cu^<2+>, Zn^<2+>, etc. Among them, the Fe^<2+> complex cleaves double-stranded DNA, efficiently. A study to utilize a functional chimera DNA bearing the complex as a sequence specific gene regulator is now under way. Less