Gas-phase hydrogen/deuterium exchange of 5'- and 3'-mononucleotides in a quadrupole ion trap: exploring the role of conformation and system energy.
Gas-phase hydrogen/deuterium exchange of 5'- and 3'-mononucleotides in a quadrupole ion trap: exploring the role of conformation and system energy.
复制标题
四极离子阱中 5- 和 3- 单核苷酸的气相氢/氘交换：探索构象和系统能量的作用。
DOI：
10.1016/j.jasms.2006.12.007
复制
发表时间：
2007
影响因子：
3.2
通讯作者：
Brodbelt,JenniferS
中科院分区：
文献类型：
--
作者：
Chipuk,JosephE;Brodbelt,JenniferS
用四极杆离子阱质谱仪研究了去质子化的2′-脱氧-5 ′-单磷酸和2′-脱氧-3 ′-单磷酸核苷酸与D2 O的气相氢/氘（H/D）交换反应。为了增强这些实验，分子建模也进行了识别可能的去质子化位点和潜在的气相构象的阴离子。大多数5 '-单磷酸盐与几种完全掺入氘代替其不稳定氢原子的化合物进行了广泛交换。相比之下，大多数3′-单磷酸异构体交换相对较少的氢原子，尽管前两次交换的速率大于5′-单磷酸异构体。通常发现在默认反应条件下未能掺入两个以上氘原子的单核苷酸在较高能量条件下进行反应时交换更广泛。实验和理论结果的整合支持中继交换机制的使用，并表明交换行为高度依赖于核碱基的身份和方向以及去质子化磷酸部分的位置和柔性。这些观测结果还突出了不同参与组之间的距离以及它们的气相酸碱度的重要性。
Gas-phase hydrogen/deuterium (H/D) exchange reactions for deprotonated 2′-deoxy-5′-monophosphate and 2′-deoxy-3′-monophosphate nucleotides with D2O were performed in a quadrupole ion trap mass spectrometer. To augment these experiments, molecular modeling was also conducted to identify likely deprotonation sites and potential gas-phase conformations of the anions. A majority of the 5′-monophosphates exchanged extensively with several of the compounds completely incorporating deuterium in place of their labile hydrogen atoms. In contrast, most of the 3′-monophosphate isomers exchanged relatively few hydrogen atoms, even though the rate of the first two exchanges was greater than observed for the 5′-monophosphates. Mononucleotides that failed to incorporate more than two deuterium atoms under default reaction conditions were often found to exchange more extensively when reactions were performed under higher energy conditions. Integration of the experimental and theoretical results supports the use of a relay exchange mechanism and suggests that the exchange behavior depends highly on the identity and orientation of the nucleobase and the position and flexibility of the deprotonated phosphate moiety. These observations also highlight the importance of the distance between the various participating groups in addition to their gas-phase acidity and basicity.