The orientation and dynamics of the C2′-OH and hydration of RNA and DNA-RNA hybrids
The orientation and dynamics of the C2′-OH and hydration of RNA and DNA-RNA hybrids
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DOI：
10.1093/nar/26.13.3104
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发表时间：
1998-07-01
影响因子：
14.9
通讯作者：
Brown, T
中科院分区：
文献类型：
--
作者：
Gyi, JI;Lane, AN;Brown, T
本文用核磁共振法测定了几种DNA、RNA杂交体中C2'羟基的立体化学和动力学性质，并与同源RNA双链体作了比较。鉴定了RNA链的C2 '-OH NMR信号，并进行了许多特定的分配。羟基质子与水交换的速率常数在5 ℃下测定，并发现取决于特定序列内的位置和双链体的性质。平均而言，交换速率常数对于组成rR.dY的杂交体是最慢的，并且对于RNA双链体是最快的，总体范围类似于10-50/s。在DNA.RNA杂交体中，在相同糖的OH和H1'之间观察到强NOE和ROE，明确地表明OH质子大多数时间指向H1'，而不是指向相同糖的O3'。在ROESY和NOESY实验中发现了DNA、RNA杂交体和DNA双链体两个凹槽中显著水合的证据。平均而言，DNA.RNA杂合体的小沟显示出比DNA更动力学显著的水合作用，这可以归因于RNA中羟基的亲水性衬里。
The stereochemical and dynamic properties of the C2' hydroxyl group in several DNA.RNA hybrids have been measured by NMR and compared with the homologous RNA duplex. The C2'-OH NMR signals of the RNA strands were identified, and numerous specific assignments were made. The rate constants for exchange of the hydroxyl protons with water were determined at 5 degrees C, and were found to depend on both the position within a particular sequence and the nature of the duplex. On average, the exchange rate constants were slowest for the hybrids of composition rR.dY, and fastest for the RNA duplex, with an overall range of similar to 10-50/s. In the DNA.RNA hybrids, strong NOEs and ROEs were observed between the OH and the H1' of the same sugar, unambiguously showing that the OH proton points toward the H1' most of the time, and not toward the O3' of the same sugar. Evidence for significant hydration in both grooves of the DNA.RNA hybrids and the DNA duplex was found in ROESY and NOESY experiments. On average, the minor groove of the DNA.RNA hybrids showed more kinetically significant hydration than the DNA, which can be attributed to the hydrophilic lining of hydroxyl groups in RNA.