Experimental and Computational Study of the Group 1 Metal Cation Chelates with Lysine: Bond Dissociation Energies, Structures, and Structural Trends
Experimental and Computational Study of the Group 1 Metal Cation Chelates with Lysine: Bond Dissociation Energies, Structures, and Structural Trends
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DOI：
10.1021/acs.jpcb.8b11967
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发表时间：
2019-03-07
影响因子：
3.3
通讯作者：
Armentrout, P. B.
中科院分区：
文献类型：
--
作者：
Clark, Amy A.;Yang, Bo;Armentrout, P. B.
利用引导离子束串联质谱仪，通过阈值碰撞诱导解离（CID）测量了第1族金属阳离子（M+ = Li+，Na+，K+，Rb+，Cs+）与氨基酸赖氨酸（Lys）螯合的碰撞诱导解离（CID）的动能依赖性。中性赖氨酸的简单损失是用较重的碱金属阳离子观察到的唯一解离通道，而Li+（Lys）的CID产生其他竞争通道，包括NH3的损失（在低能量下的主导通道）和八个其他反应。对动能依赖截面的分析得出，Li+、Na+、K+、Rb+和Cs+的实验M+（Lys）键离解能（BDE）分别为376 +/- 30、219 +/- 13、160 +/- 10、141 +/- 6和128 +/- 4 kJ/mol。计算搜索产生了18个不同的，低能量的结构家庭有关的网站M+结合M+（赖氨酸）复合物和10个不同的，低能量的结构家庭中性赖氨酸。在四个理论水平和三个基组中，发现了四种不同的M+（Lys）和赖氨酸的基态构象，包括K+（Lys）和Cs+（Lys）的基态构象，[N-H2O，CO（OH）]，以及其更高能量的两性离子类似物，[N-H2O，CO2-]，这更好地解释了最近的红外多光子解离作用光谱的结果。预测的地面结构的M+（赖氨酸）复合物的计算结果产生了合理的协议与实验计算BDE。
The kinetic energy dependence of the collision-induced dissociation (CID) of Group 1 metal cations (M+ = Li+, Na+, K+, Rb+, and Cs+) chelated to the amino acid lysine (Lys) was measured by threshold CID using a guided ion beam tandem mass spectrometer. The simple loss of neutral lysine is the only dissociation channel observed with the heavier alkali metal cations, whereas CID of Li+(Lys) yields other competing channels including loss of NH3 (the dominant channel at low energy) and eight other reactions. Analysis of the kinetic energy-dependent cross sections yields experimental M+(Lys) bond dissociation energies (BDEs) of 376 +/- 30, 219 +/- 13, 160 +/- 10, 141 +/- 6, and 128 +/- 4 kJ/mol for Li+, Na+, K+, Rb+, and Cs+, respectively. Computational searches yielded 18 distinct, low-energy structural families related to sites of M+ binding in M+(Lys) complexes and 10 distinct, low-energy structural families for neutral lysine. Among the four levels of theory and three basis sets used, four different ground conformers of M+(Lys) and four different ground conformers of lysine were found, including a ground conformer of K+(Lys) and Cs+(Lys), [N-epsilon,CO(OH)], and its higher energy zwitterionic analogue, [N-epsilon,CO2-], that better explains recent infrared multiple photon dissociation action spectroscopy results. Computational results for predicted ground structures of M+(Lys) complexes yielded computed BDEs in reasonable agreement with experiment.