Yang Mei Monica, Thompson Richard, Hall Gene
Merck and Company, Rahway, New Jersey 07065, USA.
J Am Soc Mass Spectrom. 2004 Sep;15(9):1354-9. doi: 10.1016/j.jasms.2004.06.008.
The relative stability of RNA duplexes were determined in both solution and gas phase. Solution stability as determined by a spectrophotometric method indicated that the Watson-Crick duplexes were more stable than duplexes containing one GA mismatch or two tandem GA mismatches. Gas phase stability was determined using ESI-MS through variation of the collision energy in an ion trap. Stability curves similar to the melting curves obtained in solution were observed. The relative stability in gas phase differed, however, from that in solution. The duplexes with two tandem GA mismatches were found to be more stable than the Watson-Crick and single GA mismatch duplexes. The different trends observed in solution versus gas phase can be attributed to the primary means of interaction. In solution, stacking is expected to be the dominant interaction mode. In the gas phase, hydrogen bonding is expected to be the dominant interaction mode. Duplexes with tandem GA mismatches have the potential to undergo additional hydrogen bonding relative to the other duplexes which could account for their increased stability in the gas phase.
在溶液和气相中都测定了RNA双链体的相对稳定性。通过分光光度法测定的溶液稳定性表明，沃森-克里克双链体比含有一个GA错配或两个串联GA错配的双链体更稳定。使用电喷雾电离质谱（ESI-MS）通过改变离子阱中的碰撞能量来测定气相稳定性。观察到与在溶液中获得的熔解曲线相似的稳定性曲线。然而，气相中的相对稳定性与溶液中的不同。发现具有两个串联GA错配的双链体比沃森-克里克双链体和单个GA错配双链体更稳定。在溶液和气相中观察到的不同趋势可归因于主要的相互作用方式。在溶液中，堆积预计是主要的相互作用模式。在气相中，氢键预计是主要的相互作用模式。与其他双链体相比，具有串联GA错配的双链体有可能发生额外的氢键作用，这可以解释它们在气相中稳定性增加的原因。
