Using positive-ion electrospray ionization mass spectrometry and H/D exchange study phosphoryl group transfer reactions involved in amino acid ester isopropyl phosphoramidates of Brefeldin A.
Using positive-ion electrospray ionization mass spectrometry and H/D exchange study phosphoryl group transfer reactions involved in amino acid ester isopropyl phosphoramidates of Brefeldin A.
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DOI：
10.1016/j.aca.2014.09.053
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发表时间：
2015
影响因子：
6.2
通讯作者：
M. Fang;He Zhang;C. Liao;Y. Qiu;H. Fang;Zhenyu Zheng;Xiang Gao;Yufen Zhao;Zhen Wu
中科院分区：
文献类型：
--
作者：
M. Fang;He Zhang;C. Liao;Y. Qiu;H. Fang;Zhenyu Zheng;Xiang Gao;Yufen Zhao;Zhen Wu
作为微型化学模型，合成了布雷菲德菌素 A 的氨基酸酯异丙基氨基磷酸酯（化合物 2a-2d），并通过电喷雾电离串联质谱结合 H/D 交换进行了研究。为了进一步确认片段的结构，还进行了离线傅里叶变换共振串联质谱（FT-ICR-MS/MS）。总结了化合物2a-2d的碎裂规则，并提出了碎裂途径的合理方案。在本研究中，在化合物 2a–2d 的 [M + Na]+ 离子的 ESI-MS2 光谱中观察到一个去磷酸化离子和两个磷酸化离子。提出并通过H/D交换证实了磷酸化和去磷酸化的可能机制。对于“去磷酸化”重排，氮原子从磷酰基迁移到 Brefeldin A 主链的碳原子，同时失去 C3H7PO3(122 Da) 分子。对于“磷酸化”重排，一个磷酰基的氧原子攻击侧向的磷原子，形成九元环中间体，然后经过两步C单键H共价键断裂以及氢原子的连续迁移，失去一个C16H20O2(244 Da)分子。提出的两种关于磷酰基转移的重排机制可能对其他类似物的结构分析有价值，并为阐明蛋白质磷酸化-去磷酸化的动态过程提供见解。
As mini-chemical models, amino acid ester isopropyl phosphoramidates of Brefeldin A (compounds2a–2d) were synthesized and investigated by electrospray ionization tandem mass spectrometry in combination with H/D exchange. To further confirm the fragments’s structures, off-line Fourier transform resonance tandem mass spectrometry (FT-ICR-MS/MS) was also performed. The fragmentation rules of compounds2a–2dhave been summarized and the plausible schemes for the fragmentation pathways were proposed. In this study, one dephosphorylated ion and two phosphorylated ions were observed in ESI-MS2spectra of [M + Na]+ions for compounds2a–2d. The possible mechanisms about phosphorylation and dephosphorylation were proposed and confirmed by H/D exchange. For the “dephosphorylation” rearrangement, a nitrogen atom was migrated from the phosphoryl group to the carbon atom of Brefeldin A’s backbone with losing a molecule of C3H7PO3(122 Da). For the “phosphorylation” rearrangement, an oxygen atom of one phosphoryl group attacked the sideward phosphorus atom to form a nine-member ring intermediate, then two steps of Csingle bondH covalent bond cleavage with consecutive migration of hydrogen atom to lose a molecule of C16H20O2(244 Da). The two proposed rearrangement mechanisms about phosphoryl group transfer might be valuable for the structure analysis of other analogs and provide insights into elucidating the dynamic process of the phosphorylation–dephosphorylation of proteins.