脂质作为六大营养素之一,与细胞膜构建、信号传导和能量代谢等多种生物学过程密切相关。然而,脂质分子结构多样性给分析带来了挑战。基于碰撞诱导解离(collision-induced dissociation,CID)的传统串联质谱(tandem mass spectrometry,MS/...脂质作为六大营养素之一,与细胞膜构建、信号传导和能量代谢等多种生物学过程密切相关。然而,脂质分子结构多样性给分析带来了挑战。基于碰撞诱导解离(collision-induced dissociation,CID)的传统串联质谱(tandem mass spectrometry,MS/MS)技术仅可以鉴定分子种类和脂肪酰基链组成,难以分析C C位置、sn-位置、官能团取代及位置等精细结构。近年来,在多种结构层次上分辨脂质异构体的质谱方法迅速发展,其中,自由基的引入在脂质气相离子活化和引发化学反应等方面发挥着独特作用。本文综述了近10年来自由基化学结合串联质谱技术在脂质精细结构解析方面的应用进展,主要包括气相的自由基诱导解离(radical-induced dissociation,RID)和自由基参与反应的衍生化-串联质谱技术。展开更多
提出一种基于路径优化的非平衡自由能预测方法。首先,通过建立蛋白质复合物解离的多目标优化模型找出一条能耗小、速度快的拉伸分子动力学SMD(Steered Molecular Dynamics)解离路径,然后,沿此路径计算解离自由能。与Jarzynski按平均力势...提出一种基于路径优化的非平衡自由能预测方法。首先,通过建立蛋白质复合物解离的多目标优化模型找出一条能耗小、速度快的拉伸分子动力学SMD(Steered Molecular Dynamics)解离路径,然后,沿此路径计算解离自由能。与Jarzynski按平均力势PMF(Potentials of Mean Force)的外推方法相比,本文方法有较高的预测效率,数值算例也给出了与实验值比较的预测精度。通过拉伸分子动力学模拟还可以揭示小配体与蛋白质之间的解离全过程,为药物设计提供重要的结构信息。展开更多
Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the...Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the OH radical on the 22Π and B2Σ+repulsive states, respectively, from sequential two-photon excitation via the A2Σ+(v′=2, J′=0.5-2.5)state. Both H+O product channels have anisotropic angular distributions, with β=-0.97 for H(2 S)+O(1 D) and 1.97 for H(2 S)+O(1 S). The anisotropic angular distributions are consistent with a mechanism of OH direct dissociation on the repulsive potential energy curves(PECs) leading to the H+O products. The OH bond dissociation energy D0(O-H) is determined to be 35580±15 cm-1.展开更多
文摘提出一种基于路径优化的非平衡自由能预测方法。首先,通过建立蛋白质复合物解离的多目标优化模型找出一条能耗小、速度快的拉伸分子动力学SMD(Steered Molecular Dynamics)解离路径,然后,沿此路径计算解离自由能。与Jarzynski按平均力势PMF(Potentials of Mean Force)的外推方法相比,本文方法有较高的预测效率,数值算例也给出了与实验值比较的预测精度。通过拉伸分子动力学模拟还可以揭示小配体与蛋白质之间的解离全过程,为药物设计提供重要的结构信息。
基金supported by the US National Science Foundation (grant number CHE-1566636)UC MEXUS-CONACYT Collaborative Grant (CN-1668)DGAPA-UNAM for support through Project PAPIIT IN-115916.
文摘Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the OH radical on the 22Π and B2Σ+repulsive states, respectively, from sequential two-photon excitation via the A2Σ+(v′=2, J′=0.5-2.5)state. Both H+O product channels have anisotropic angular distributions, with β=-0.97 for H(2 S)+O(1 D) and 1.97 for H(2 S)+O(1 S). The anisotropic angular distributions are consistent with a mechanism of OH direct dissociation on the repulsive potential energy curves(PECs) leading to the H+O products. The OH bond dissociation energy D0(O-H) is determined to be 35580±15 cm-1.
