Helices Formation of Polyadenylic Acid and Polydeoxyadenylic Acid with Oligo-2'-O-methyluridylic Acid with Ethyl Phosphotriester

含乙基磷酸三脂之2'-O-甲基之寡尿核酸與聚腺核酸和聚去氧腺核酸形成雙螺旋及三螺旋之研究

甘魯生(L. S. Kan) ； 矢野純一(J. Yano)

《中央研究院化學研究所集刊》 42期 (1995/03) Pp. 87-93

https://doi.org/10.6522/BICAS.1995.42.10

摘要

本篇所研究之2'-O-甲基之寡尿核酸乙基磷酸三脂之通式是（Um）_k/（Et）_n，這裡k = 8，9，10；n = 0，1，2，3，4，7。以紫外光譜偵測到（Um）_k/（Et）_n與聚腺核酸成雙螺旋，和聚去氧腺核酸成三螺旋。其穩定度是和寡尿酸之長度成正比，與含乙基磷酸三脂之數目成反比。這種特性可以在反意義核酸的結合強度和吻合度之間選擇時的一個控制因子。

並列摘要

The study of helices formation of polyadenylic acid (polyA) and polydeoxyadenylic acid (polydA) with (Um)_k/(Et)_n was performed in 0.1 M sodium cacodylate solution (pH 6.9), where Um is 2'-O-methyluridine, Et represents the ethyl phosphotriester linkage, and k and n are integers. The k and n range from 8 to 10 and 0 to 7, respectively. The result of UV mixing titration shows that (Um)_k/(Et)_n forms only duplex with polyA and triplex with polydA. The stability of these helices can be measured by UV melting temperature (Tm) experiment. The Tm's were measured as 26, 20, and 13 ℃ of (Um)_k/(Et)_n with polyA when k = 10, 9, 8 and n = 0. Thus, the stability of duplexes formed from (Um)_k and polyA decreases as the chainlength of oligouridylic acid decreases. However, The Tm's of (Um)_(10)/(Et)_n with polyA are 23, 21, and 16 ℃ when n = 1, 2 and 3, respectively. Thus, the stability of (Um)_k/(Et)_n and polyA duplex decrease as the number of ethyl phosphotriester increases. We conclude that ethyl phosphotriester linkage of oIigo (2'-O-methyluridylic acid) has a destabilizing effect to the duplex. Only Tm's (7, 4, and 3 °C) of triplexes of (Um)_(10)/(Et)_n (n = 0 - 2) and polydA can be measured in the temperature range studied. Similarly, we also observed that the ethyl phosphotriester linkage decreases the stability of the triplex. A quantitative destability effect of each ethyl phosphotriester linkage to (Um)_k/(Et)_n and polyA duplex and (Um)_k/(Et)_n and polydA triplex will be reported.