摘要
质谱分析技术已广泛应用于蛋白质组学的分析、鉴定等工作中.近年来,由于自由基解离在蛋白质结构鉴定中可提供额外的特征碎片以及特殊信息等优势,自由基多肽离子解离分析也逐渐引起人们的广泛关注.因此,深入理解质谱测试条件下自由基诱导解离机制,对进一步发展蛋白质测序策略以及领悟生命过程都有十分重要的意义.采用基于有限温度密度泛函理论的第一性原理分子动力学方法模拟研究了N-乙酰甘氨酸自由基在电子捕获解离质谱条件下的裂解过程.模拟结果显示,仅分子中的氮原子接受质子的动力学轨迹中有共价键的断裂,其中,90.5%的轨迹中观察到键长较长的肽键断裂,而另外9.5%的轨迹中则观察到了自由基诱导N-Cɑ键均裂.进一步分析显示,该解离过程为动力学控制.希望本研究结果能够为人们认识电子捕获解离条件下多肽自由基的解离过程提供帮助.
Mass spectrometry has been widely used in the analysis and identification of proteomics.In recent years,due to the advantages of free radical dissociation in the identification of protein structures and special information,the dissociation analysis of radical peptide ions has gradually caused people’s extensive attention.Therefore,a deep understanding of the free radical-induced dissociation mechanisms in mass spectrometric conditions is of great significance for further development of protein sequencing strategies and understanding of life processes.In this paper,the first-principles molecular dynamics method based on finite temperature density functional theory was used to simulate the dissociation process of N-acetylglycine radicals under electron electron capture mass spectrometric conditions.The simulation results show that the cleavage of covalent bonds is observed in the trajectories of all the molecules with an extra hydrogen atom attached to the nitrogen,and the cleavage of the peptide bond is observed in 90.5%of these trajectories.Other 9.5%trajectories are attributed to the free radical induced N—Cɑbond cleavage.Further analysis shows that the dissociation process is a dynamics control process.It is hoped that these results can help people understand the dissociation processes of peptide free radicals under electron capture dissociation conditions.
作者
李朝明
姜笑楠
郝强
LI Chaoming;JIANG Xiaonan;HAO Qiang(School of Chemistry and Chemical Engineering,Liaoning Normal University,Dalian 116029,China)
出处
《辽宁师范大学学报（自然科学版）》
CAS
2019年第4期493-497,共5页
Journal of Liaoning Normal University:Natural Science Edition
基金
辽宁省自然科学基金资助项目（20170540580）
辽宁省教育厅科学技术研究一般项目（L201683671）
关键词
质谱
N-乙酰甘氨酸
解离机制
第一性原理
分子动力学
mass spectrometry
N-acetylglycine
cleavage mechanism
firstprinciple
molecular dynamics
作者简介
李朝明(1980-),男,吉林省吉林市人,辽宁师范大学博士研究生.
