Gas phase RNA and DNA ions 2. Conformational dependence of the gas-phase H/D exchange of nucleotide-5'-monophosphates.
Gas phase RNA and DNA ions 2. Conformational dependence of the gas-phase H/D exchange of nucleotide-5'-monophosphates.
复制标题
气相 RNA 和 DNA 离子 2. 5-单磷酸核苷酸气相 H/D 交换的构象依赖性。
DOI：
10.1016/s1044-0305(01)00260-4
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发表时间：
2001
影响因子：
3.2
通讯作者：
Marshall,AG
中科院分区：
文献类型：
--
作者：
Freitas,MA;Marshall,AG
报道了核苷酸-5-单磷酸阴离子与H/D交换试剂D2-S与H/D交换的构象依赖关系。电喷雾生成的腺苷-5‘-一磷酸、腺苷-5’-羧酸、核糖醇-5-磷酸和2-脱氧-核糖醇-5-磷酸的[M-−H]−阴离子与D2 S在气相中发生反应。它们的反应性(腺苷-5‘-单磷酸交换了5个不稳定氢中的2个，腺苷-5’-羧酸交换了4个中的1个，核糖醇-5-磷酸交换了3个中的2个，2-脱氧核糖醇-5-磷酸交换了1个)表明核糖2位上的羟基和碱基上的氨基氢不容易与D2S交换，半经验分子轨道计算表明，这些位置上的不稳定氢在热力学上很容易交换，但作为一种构象不能被推定的磷酸阴离子访问，与磷酸阴离子与交换试剂络合并在邻近位置辅助H/D交换的机制一致。
The conformational dependence of the gas-phase hydrogen/deuterium (H/D) exchange of nucleotide-5-monophosphate anions with the H/D exchange reagent D 2 S is reported here. The electrospray-generated [M− H]− anions of adenosine-5′-monophosphate, adenosine-5′-carboxylic acid, ribitol-5-phosphate, and 2-deoxy-ribitol-5-phosphate were reacted with D 2 S in the gas phase. Their reactivity (adenosine-5′-monophosphate exchanged 2 of 5 labile hydrogens, adenosine-5′-carboxylic acid exchanged 1 of 4, ribitol-5-phosphate exchanged 2 of 3, and 2-deoxy-ribitol-5-phosphate exchanged 1 of 2) suggests that the hydroxyl group in the 2 position of the ribose sugar and the amino hydrogen on the nucleobase do not exchange readily with D 2 S. Semiempirical molecular orbital calculations suggest that the labile hydrogens in these positions are thermodynamically facile to exchange but as a conformation inaccessible to the presumed phosphate anion, consistent with a mechanism in which the phosphate anion complexes with the exchange reagent and assists H/D exchange at a neighboring site.