Valence anions of N-acetylproline in the gas phase: Computational and anion photoelectron spectroscopic studies
Valence anions of N-acetylproline in the gas phase: Computational and anion photoelectron spectroscopic studies
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DOI：
10.1063/1.3625957
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发表时间：
2011-09-21
影响因子：
4.4
通讯作者：
Bowen, Kit H.
中科院分区：
文献类型：
--
作者：
Chomicz, Lidia;Rak, Janusz;Bowen, Kit H.
本文报道了用3.49 eV光子测量的阴离子N-乙酰脯氨酸（N-AcPro）（-）的光电子能谱。该光谱由以1.4 eV的电子结合能为中心的带和更高能量的光谱尾部组成，证实了N-乙酰脯氨酸在气相中形成价阴离子。在B3 LYP/6-31++G（d，p）水平上计算了N-AcPro的中性和阴离子。计算结果表明，光电子能谱是由电子附着在N-乙酰基脯氨酸的π * 轨道上引起的质子转移产生的阴离子引起的。我们还表征了导致吡咯烷开环的反应路径的能量学。这些数据表明，包含脯氨酸的肽/蛋白质的电子诱导分解强烈依赖于脯氨酸残基附近质子供体的存在。(C)2011年美国物理学会。[doi：10.1063/1.3625957]
We report the photoelectron spectrum of anionic N-acetylproline, (N-AcPro)(-), measured with 3.49 eV photons. This spectrum, which consists of a band centered at an electron binding energy of 1.4 eV and a higher energy spectral tail, confirms that N-acetylproline forms a valence anion in the gas phase. The neutrals and anions of N-AcPro were also studied computationally at the B3LYP/6-31++G(d,p) level. Based on the calculations, we conclude that the photoelectron spectrum is due to anions which originated from proton transfer induced by electron attachment to the pi* orbital localized at the acetyl group of N-AcPro. We also characterized the energetics of reaction paths leading to pyrrolidine ring opening in the anionic N-AcPro. These data suggest that electron induced decomposition of peptides/proteins comprising proline strongly depends on the presence of proton donors in the close vicinity to the proline residue. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3625957]