Comparison of the thermodynamic stabilities and solution conformations of DNA center dot RNA hybrids containing purine-rich and pyrimidine-rich strands with DNA and RNA duplexes
Comparison of the thermodynamic stabilities and solution conformations of DNA center dot RNA hybrids containing purine-rich and pyrimidine-rich strands with DNA and RNA duplexes
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DOI：
10.1021/bi960948z
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发表时间：
1996-09-24
期刊：
影响因子：
2.9
通讯作者：
Brown, T
中科院分区：
文献类型：
--
作者：
Gyi, JI;Conn, GL;Brown, T
含有嘌呤丰富（GAAGAGAAGC）和嘧啶丰富（GCTTCTCTTC或GCUUCUUC）的DNA和RNA链的双链体的构象和热力学稳定性已通过UV熔解，电泳，圆二色性和NMR光谱测定。稳定化自由能（-Δ G）为rR级。rY > rR。dY > dR。dY > dR。rY.两个DNA。RNA杂交双链体显示出介于DNA之间的构象特性。DNA和RNA。RNA双链体也彼此不同。两个杂交双链体中DNA链的H-1化学位移与DNA双链体的H-1化学位移之间的差异大于RNA质子的类似位移差异，并且DNA链中嘌呤的差异大于嘧啶。利用NOE和标量耦合数据对核苷酸构象的详细分析表明，核糖核苷酸的糖构象都靠近C3 '-endo。脱氧核糖核苷酸在"S“结构域中，即，在DNA双链体中靠近C2 ′-endo，在两个杂种中C1 ′-exo靠近CY-endo。然而，两个杂交体中的脱氧核糖似乎比DNA双链体中的更灵活，处于“N”（C3“-endo）状态的部分以dR的顺序增加。dY < dR。rY < rR。dY。在全球范围内，纯DNA双链体为B型，纯RNA双链体为A型。两个DNA。RNA杂交体既不是A型也不是B型，但总体上比B型更接近A型。dR越不稳定。rY双链体具有与rR显著不同的构象。dY在局部核苷酸水平和全局上。
The conformations and thermodynamic stabilities of duplexes containing purine-rich (GAAGAGAAGC) and pyrimidine-rich (GCTTCTCTTC or GCUUCUCUUC) DNA and RNA strands have been measured by UV melting, electrophoresis, circular dichroism, and NMR spectroscopy. The free energies of stabilization (-Delta G) were in the order rR . rY > rR . dY > dR . dY > dR . rY. The two DNA . RNA hybrid duplexes showed conformational properties intermediate between those of DNA . DNA and RNA . RNA duplexes and also different from one another. Differences between H-1 chemical shifts of the DNA strands in the two hybrid duplexes and those of the DNA duplex were larger than analogous shift differences for the RNA protons, and the differences were larger for the purine than the pyrimidines in the DNA strands. Detailed analysis of the nucleotide conformations using both NOE and scalar coupling data showed that the sugar conformations of the ribonucleotides are all near C3'-endo. The deoxyribo-nucleotides were in the ''S'' domain, i.e., near C2'-endo in the DNA duplex, and C1'-exo to CY-endo in the two hybrids. However, the deoxyriboses in the two hybrids appear more flexible than in the DNA duplex, with the fraction in the ''N'' (C3'-endo) state increasing in the order dR . dY < dR . rY < rR . dY. Globally, the pure DNA duplex was B-form and the pure RNA duplex A form. The two DNA . RNA hybrids were neither A nor B, but closer globally to the A than the B form. The less stable dR . rY duplex has a significantly different conformation from rR . dY both at the local nucleotide level and globally.