Konishi Yasuo, Kiyota Taira, Draghici Cristina, Gao Jin-Ming, Yeboah Faustinus, Acoca Stephane, Jarussophon Suwatchai, Purisima Enrico
Biotechnology Research Institute, National Research Council Canada, 6100 Royalmount Avenue, Montréal, Québec, Canada H4P 2R2.
Anal Chem. 2007 Feb 1;79(3):1187-97. doi: 10.1021/ac061391o.
A facile and sensitive mass spectrometric method has been developed for the dereplication of natural products. The method provides information about the molecular formula and substructure of a precursor molecule and its fragments, which are invaluable aids in dereplication of natural products at their early stages of purification and characterization. Collision-induced MS/MS technique is used to fragment a precursor ion into several product ions, and individual product ions are selected and subjected to collision-induced MS/MS/MS analysis. This method enables the identification of the fragmentation pathway of a precursor molecule from its first-generation fragments (MS/MS), through to the nth generation product ions (MSn). It also allows for the identification of the corresponding neutral products released (neutral losses). Elements used in the molecular formula analysis include C, H, N, O, and S, as most natural products are constituted by these five elements. High-resolution mass separation and accurate mass measurements afforded the unique identification of molecular formula of small neutral products. Through sequential add-up of the molecular formulas of the small neutral products, the molecular formula of the precursor ion and its productions were uniquely determined. The molecular formula of the precursor molecule was then reversely used to identify or confirm the molecular formula of the neutral products and that of the productions. The molecular formula of the neutral fragments allowed for the identification of substructures, leading to a rapid and efficient characterization of precursor natural product. The method was applied to paclitaxel (C47H51NO14; 853 amu) to identify its molecular formula and its substructures, and to characterize its potential fragmentation pathways. The method was further validated by correctly identifying the molecular formula of minocycline (C23H27N3O7; 457 amu) and piperacillin (C23H27N5O7S; 517 amu).
已开发出一种简便且灵敏的质谱方法用于天然产物的去重复研究。该方法可提供前体分子及其碎片的分子式和子结构信息，这些信息在天然产物纯化和表征的早期阶段对于去重复研究是非常宝贵的辅助手段。碰撞诱导MS/MS技术用于将前体离子裂解为多个产物离子，然后选择单个产物离子并进行碰撞诱导MS/MS/MS分析。该方法能够确定前体分子从第一代碎片（MS/MS）到第n代产物离子（MSn）的裂解途径。它还能识别释放出的相应中性产物（中性损失）。分子式分析中使用的元素包括C、H、N、O和S，因为大多数天然产物由这五种元素组成。高分辨率质量分离和精确质量测量可对小中性产物的分子式进行独特识别。通过依次累加小中性产物的分子式，可唯一确定前体离子及其产物的分子式。然后反向使用前体分子的分子式来识别或确认中性产物及其产物的分子式。中性碎片的分子式有助于识别子结构，从而快速有效地表征前体天然产物。该方法应用于紫杉醇（C47H51NO14；853原子质量单位）以确定其分子式和子结构，并表征其潜在的裂解途径。通过正确识别米诺环素（C23H27N3O7；457原子质量单位）和哌拉西林（C23H27N5O7S；517原子质量单位）的分子式，进一步验证了该方法。
