Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195, Berlin, Germany.
Abteilung Molekülphysik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany.
Angew Chem Int Ed Engl. 2020 Aug 3;59(32):13638-13642. doi: 10.1002/anie.202002459. Epub 2020 May 18.
1-Deoxysphingolipids are a recently described class of sphingolipids that have been shown to be associated with several disease states including diabetic and hereditary neuropathy. The identification and characterization of 1-deoxysphingolipids and their metabolites is therefore highly important. However, exact structure determination requires a combination of sophisticated analytical techniques due to the presence of various isomers, such as ketone/alkenol isomers, carbon-carbon double-bond (C=C) isomers and hydroxylation regioisomers. Here we demonstrate that cryogenic gas-phase infrared (IR) spectroscopy of ionized 1-deoxysphingolipids enables the identification and differentiation of isomers by their unique spectroscopic fingerprints. In particular, C=C bond positions and stereochemical configurations can be distinguished by specific interactions between the charged amine and the double bond. The results demonstrate the power of gas-phase IR spectroscopy to overcome the challenge of isomer resolution in conventional mass spectrometry and pave the way for deeper analysis of the lipidome.
1-脱氧鞘脂类是最近发现的一类鞘脂，已被证明与多种疾病状态有关，包括糖尿病性和遗传性神经病。因此，鉴定和表征 1-脱氧鞘脂及其代谢物非常重要。然而，由于存在各种异构体，如酮/烯醇异构体、碳-碳双键 (C=C) 异构体和羟基化区域异构体，因此需要结合复杂的分析技术来进行准确的结构测定。在这里，我们证明了离子化 1-脱氧鞘脂的低温气相红外 (IR) 光谱学可以通过其独特的光谱指纹来识别和区分异构体。特别是，通过带电荷的胺和双键之间的特定相互作用，可以区分 C=C 键的位置和立体化学构型。这些结果证明了气相 IR 光谱学的强大功能，可以克服传统质谱中异构体分辨率的挑战，并为脂质组学的深入分析铺平道路。
