寡聚脱氧核苷酸d(G-C)_3的激光喇曼谱及其分析

用改进的固相磷酰三酯法合成了oligo-d(G-C)_3。以氩离子激光为激发光源,波长488nm.,在室温条件下,分别测定了纯化后的oligo-d(G-C)_3和其组分单体5’-dGMP和5’-dCMP的激光喇曼谱。观察到被测定的物质在300-2500cm~(-1)频率区间,各自都有其特征的谱形和喇曼峰。5’-dGMP和5’-dCMP谱中大多数特征峰在寡聚体的谱中消失,而在oligo-d(G-C)_3谱中出现了几处新的喇曼峰。经查证,峰832,851和899cm~(-1)系糖-磷酸主链的特征喇曼峰,另外几处峰与DNA的构象有关。实验结果表明oligo-d(G-C)_3在水溶液中(室温)主要以B-构象存在。

Studies on Left-handed DNA, Character's Ties of Raman Spectra of Synthesized Oligo-d (G-C)_3Having 5'-, 3'-bishyd-roxy Groups and Analysis

To study the DNA conformation of B-Z transition, oligodeoxynucleotide with an alternating dG-dC sequence was synthesized by Solid-phase-phosphite-triester method and purified by PAGE.Using Argon ion laser we studied the oligo-d(G-C)3 having 5'-, 3'-bishydroxy groups and its components,5'-dGMP and 5'-dCMP,at 488nm,ranging from 300-2500 cm-1, at room temperature.It was found that the Raman spectrum of oligod(G-C)3 having 5'-,3'-hishydroxy groups was very different from that of either 5'-dGMP or 5'-dCMP in regard to Raman spectra pattern (e.g.peak forms and peak values) many of the characteristic Raman peaks seen in the spectra of 5'-dGMP and 5'-dCMP, disappeared in the spectrum of oligo-d(G-C)3 containing 5'-,3'-hishydroxy groups, while some new Raman peaks appeared in the latter.Three of them at 832, 851 and 899cm-1, attributed to the sugar-phosphate main chain and others related directly to the B-Z transition of DNA conformation.The oligo-d(G-C)3 was in B-conformation resolved in the destilled water at room temperature.