Development of novel spin-labeled nucleic acids for detection of DNA internal dynamics

我们合成了含有2-N-叔丁基氨基氧基腺苷(1)的寡核苷酸(ODN、15-聚和18-聚)，并测定了它们的单链和双链ESR谱。计算2Azz值和h_+/h_0值(h_+；低场峰高度h_0；中心峰高度)来评价ODN的迁移率。在形成双链后，2Azz值增大，h+/h0值减小，表明ODN的流动性降低。单链寡核苷酸在25℃时的2Azz和h/h0值与10℃时相同。相反，在25和10℃时，双链的2Azz和h_+/h_0值发生变化。这表明双链的迁移率对温度比单链ODN更敏感。含有1的ODN与与1位置相反的A、C、GT互补链之间的双链的ESR谱表明有可能报告双链稳定性。含有1的ODN与含有错配的互补链之间的双链的ESR谱表明有可能报告双链稳定性。

We synthesized oligodeoxynucleotides (ODN, 15-mer and 18-mer) containing 2-N-tert-butylaminoxyladenosine (1) and measured their ESR spectra in single-and double-strand forms. We calculated 2Azz values and h_+/h_0, values (h_+; height of the low field peak, h_0; height of the center peak) to evaluate mobility of ODNs. Upon formation of duplex, increase of 2Azz value and decrease of h_+/h_0 value were observed to indicate the mobility of ODN decreased. The 2Azz and h/h_0 values of single-stranded ODN at 25℃ were identical with those at 10 ℃. In contrast, the 2Azz and h_+/h_0 values of duplex at 25 and 10 ℃ changed. That indicated the mobility of duplex is more sensitive to temperature than single-stranded ODN.ESR spectra of duplex between ODN containing 1 and complementary strands which contain A, C, G T at the opposite position to 1 indicated possibilities to report duplex stabilities.ESR spectra of duplex between ODN containing 1 and complementary strands which contain mismatches indicated possibilities to report duplex stabilities.