Kind Tobias, Fiehn Oliver
West Coast Metabolomics Center, UC Davis, Davis 95616, California, U.S.A.
Biochemistry Department, King Abdulaziz University, Jeddah, Saudi-Arabia.
Phytochem Lett. 2017 Sep;21:313-319. doi: 10.1016/j.phytol.2016.11.006. Epub 2016 Nov 17.
Complete structural elucidation of natural products is commonly performed by nuclear magnetic resonance spectroscopy (NMR), but annotating compounds to most likely structures using high-resolution tandem mass spectrometry is a faster and feasible first step. The CASMI contest 2016 (Critical Assessment of Small Molecule Identification) provided spectra of eighteen compounds for the best manual structure identification in the natural products category. High resolution precursor and tandem mass spectra (MS/MS) were available to characterize the compounds. We used the Seven Golden Rules, Sirius2 and MS-FINDER software for determination of molecular formulas, and then we queried the formulas in different natural product databases including DNP, UNPD, ChemSpider and REAXYS to obtain molecular structures. We used different in-silico fragmentation tools including CFM-ID, CSI:FingerID and MS-FINDER to rank these compounds. Additional neutral losses and product ion peaks were manually investigated. This manual and time consuming approach allowed for the correct dereplication of thirteen of the eighteen natural products.
天然产物的完整结构解析通常通过核磁共振光谱法（NMR）进行，但使用高分辨率串联质谱法将化合物注释为最可能的结构是更快且可行的第一步。2016年的CASMI竞赛（小分子鉴定关键评估）提供了18种化合物的光谱，用于天然产物类别中最佳的手动结构鉴定。高分辨率前体和串联质谱（MS/MS）可用于表征这些化合物。我们使用“七条黄金法则”、Sirius2和MS-FINDER软件来确定分子式，然后在包括DNP、UNPD、ChemSpider和REAXYS在内的不同天然产物数据库中查询这些分子式以获得分子结构。我们使用不同的计算机辅助裂解工具，包括CFM-ID、CSI:FingerID和MS-FINDER对这些化合物进行排名。另外还手动研究了额外的中性丢失和产物离子峰。这种手动且耗时的方法使得18种天然产物中的13种得以正确的去重复鉴定。
