Maastricht MultiModal Molecular Imaging (M4I) Institute, Division of Imaging Mass Spectrometry, Maastricht University , Maastricht, 6229 ER, The Netherlands.
Physical Electronics Inc. , Chanhassen, Minnesota 55317, United States.
Anal Chem. 2017 Aug 15;89(16):8223-8227. doi: 10.1021/acs.analchem.7b02573. Epub 2017 Aug 3.
Matrix-enhanced secondary ion mass spectrometry (ME-SIMS) has overcome one of the biggest disadvantages of SIMS analysis by providing the ability to detect intact biomolecules at high spatial resolution. By increasing ionization efficiency and minimizing primary ion beam-induced fragmentation of analytes, ME-SIMS has proven useful for detection of numerous biorelevant species, now including peptides. We report here the first demonstration of tandem ME-SIMS for de novo sequencing of endogenous neuropeptides from tissue in situ (i.e., rat pituitary gland). The peptide ions were isolated for tandem MS analysis using a 1 Da mass isolation window, followed by collision-induced dissociation (CID) at 1.5 keV in a collision cell filled with argon gas, for confident identification of the detected peptide. Using this method, neuropeptides up to m/z 2000 were detected and sequenced from the posterior lobe of the rat pituitary gland. These results demonstrate the potential for ME-SIMS tandem MS development in bottom-up proteomics imaging at high-spatial resolution.
基质增强二次离子质谱（ME-SIMS）通过提供在高空间分辨率下检测完整生物分子的能力，克服了 SIMS 分析的最大缺点之一。通过提高离子化效率和最小化分析物的初级离子束诱导碎裂，ME-SIMS 已被证明对检测许多生物相关物种有用，现在包括肽。我们在这里首次报告了串联 ME-SIMS 用于从原位组织（即大鼠垂体）中从头测序内源性神经肽的演示。使用 1 Da 质量隔离窗口对肽离子进行串联 MS 分析，然后在充满氩气的碰撞池中进行碰撞诱导解离（CID），在 1.5 keV 下进行，以对检测到的肽进行可靠鉴定。使用该方法，可从大鼠垂体后叶检测和测序高达 m/z 2000 的神经肽。这些结果表明，在高空间分辨率下进行从头蛋白质组学成像的 ME-SIMS 串联 MS 发展具有潜力。
