Thermodynamic analysis of duplex formation of the heterochiral DNA with L-deoxyadenosine
Thermodynamic analysis of duplex formation of the heterochiral DNA with L-deoxyadenosine
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DOI：
10.2116/analsci.21.77
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发表时间：
2005-02-01
影响因子：
1.6
通讯作者：
Sugimoto, N
中科院分区：
文献类型：
--
作者：
Kawakami, J;Tsujita, K;Sugimoto, N
L脱氧核糖核酸是天然脱氧核糖核酸的镜像异构体，具有很强的抗核酸酶活性，在反义技术等方面具有广阔的应用前景。然而，对含有这种修饰核苷酸的DNA的结构和热力学性质知之甚少。在本研究中，我们制备了L核苷酸(L-大)，并将其引入到寡核苷酸中，以评估L-核苷酸作为一种功能分子在DNA杂交中的应用能力。合成了两个以L大分子为中心的十聚体，并对其进行了结构和热力学分析。圆二色谱的结构研究表明，两种修饰的“L/D-D”双链均为典型的B型结构。这一结果表明，DNA的全球结构并没有因为L-DNA的引入而崩溃。UV熔融实验测定的双链形成的热力学参数(DeltaH度、DeltaS度和DeltaG度(37))表明，引入的L-da在2.5kcal-3.0kcal摩尔(-1)附近使两个双链不稳定，主要是由于不利的热效应。结合其他研究人员的资料，这些结果表明，L对双链结构的影响和稳定性的局部变化，因此，修饰的L/D-D双链的热力学稳定性应该由最近邻热力学参数来预测。
An L-DNA, the mirror-image isomer of natural DNA, has extraordinary nuclease resistance, and thus the molecules should be promising reagents for many applications, such as antisense technology. However, little is known about the structural and thermodynamic properties of DNAs with this modified nucleotide. In this study, we prepared the L-nucleotide (L-dA) and introduced it into oligodeoxyribonucleotides to assess the ability of the L-nucleotide as a functional molecule for many applications based on the DNA hybridization. Two decamers with an L-dA at the center were synthesized and duplexes with the complementary DNA strand were applied to structural and thermodynamic analyses. The structural study by CD spectra showed that the structures of both modified "L/D-D" duplexes were the typical B-form. This result suggests that the global structure of DNA was not,collapsed by the introduction of an L-DNA. Thermodynamic parameters (DeltaHdegrees, DeltaSdegrees, and DeltaGdegrees(37)) of the duplex formation, determined by UV melting experiments, indicated that the both duplexes were destabilized at about 2.5 to 3.0 kcal mol(-1) by the introduced L-dA, mainly due to an unfavorable enthalpic effect. In conjunction with information by other researchers, these results suggest that the L-DNA affect on the duplex structure and the stability vary locally; thus, the thermodynamic stability of modified L/D-D duplexes should be predictable by the nearest-, neighbor thermodynamic parameters.