Dobrikov M I, Gaĭdamakov S A, Gaĭnutdinov T I, Tenetova E D, Shishkin G V, Vlasov V V
Novosibirsk Institute of Bioorganic Chemistry, Siberian Division, Russian Academy of Sciences, Russia.
Bioorg Khim. 1999 Jan;25(1):31-9.
The photomodification of single-stranded DNA sensitized to visible light (450-580 nm) by a binary system of oligonucleotide conjugates complementary to adjacent DNA sequences was studied. One oligonucleotide carries a residue of the photoreagent p-azidotetrafluorobenzaldehyde hydrazone at its 3'-terminal phosphate, and the other has a residue of the sensitizer, perylene or 1,2-benzanthracene, at the 5'-terminal phosphate. The rate of photomodification sensitized by the perylene derivative is 300,000-fold higher than the rate of photomodification in the absence of the sensitizer. Since the excitation energy of perylene is lower than the energy necessary for the initiation of azide photodecomposition, it is likely that the sensitization in the complementary complex occurs by electron transfer from the azido group of the photoreagent to the excited sensitizer. The sensitization by the 1,2-benzanthracene oligonucleotide derivative occurs by means of singlet-singlet energy transfer, which enables this sensitizer to act as a unconsumable catalyst each molecule of which is able to initiate the photomodification of more than 20 DNA molecules. By both mechanisms, the photomodification occurs with high specificity on the G11 residue of the target DNA. The degree of sensitized photomodification reaches 72%.
研究了由与相邻DNA序列互补的寡核苷酸缀合物二元体系敏化的单链DNA在可见光（450 - 580 nm）下的光修饰作用。一种寡核苷酸在其3'-末端磷酸处带有光试剂对叠氮基四氟苯甲醛腙的残基，另一种在5'-末端磷酸处带有敏化剂苝或1,2-苯并蒽的残基。苝衍生物敏化的光修饰速率比无敏化剂时的光修饰速率高300,000倍。由于苝的激发能低于叠氮化物光分解起始所需的能量，互补复合物中的敏化作用可能是通过光试剂的叠氮基向激发敏化剂的电子转移发生的。1,2-苯并蒽寡核苷酸衍生物的敏化作用是通过单重态-单重态能量转移发生的，这使得该敏化剂能够作为一种不可消耗的催化剂，其每个分子能够引发20多个DNA分子的光修饰。通过这两种机制，光修饰在靶DNA的G11残基上具有高度特异性地发生。敏化光修饰的程度达到72%。
