Hydration of short DNA, RNA and 2′-OMe oligonucleotides determined by osmotic stressing
Hydration of short DNA, RNA and 2′-OMe oligonucleotides determined by osmotic stressing
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DOI：
10.1093/nar/gkh175
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发表时间：
2004-01-01
影响因子：
14.9
通讯作者：
Moulder, J
中科院分区：
文献类型：
--
作者：
Rozners, E;Moulder, J
核酸水合作用的研究对于更好地理解核酸的结构和功能具有重要意义。我们使用渗透胁迫方法比较了自互补DNA、RNA和2 '-O-甲基（2'-OMe）寡核苷酸GCGAAUUCGC、（UA）（6）和（CG）（3）的水合作用。在寡核苷酸双链体解链时释放的水分子的数目Deltan（W）由解链温度对水活度和焓的依赖性计算，两者均用UV热解链实验测量。通过添加乙二醇、甘油和乙酰胺作为小的有机共溶质来改变水活度。对于RNA双链体，Δ tan（W）为3-4，对于DNA和2 '-OMe双链体，Δ tan（W）为2-3。因此，RNA双链体比DNA和2 '-OMe寡核苷酸双链体多水合约1至2个水分子，这取决于序列。与先前的研究一致，GC碱基对在RNA中比Au对水合更多，而在DNA和2 '-OMe寡核苷酸中，这两个碱基对之间的水合差异相对较小。我们的数据表明，更好的水合作用的RNA有助于增加的双链体的RNA与DNA的双链体相比，双链体的结晶稳定性。
Studies on hydration are important for better understanding of structure and function of nucleic acids. We compared the hydration of self-complementary DNA, RNA and 2'-O-methyl (2'-OMe) oligonucleotides GCGAAUUCGC, (UA)(6) and (CG)(3) using the osmotic stressing method. The number of water molecules released upon melting of oligonucleotide duplexes, Deltan(W), was calculated from the dependence of melting temperature on water activity and the enthalpy, both measured with UV thermal melting experiments. The water activity was changed by addition of ethylene glycol, glycerol and acetamide as small organic co-solutes. The Deltan(W) was 3-4 for RNA duplexes and 2-3 for DNA and 2'-OMe duplexes. Thus, the RNA duplexes were hydrated more than the DNA and the 2'-OMe oligonucleotide duplexes by approximately one to two water molecules depending on the sequence. Consistent with previous studies, GC base pairs were hydrated more than AU pairs in RNA, whereas in DNA and 2'-OMe oligonucleotides the difference in hydration between these two base pairs was relatively small. Our data suggest that the better hydration of RNA contributes to the increased enthalpic stability of RNA duplexes compared with DNA duplexes.