Department of Chemistry and Biochemistry, Department of Medicine, and Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093.
Proc Natl Acad Sci U S A. 2013 Sep 10;110(37):14855-60. doi: 10.1073/pnas.1310618110. Epub 2013 Aug 22.
There is immense cellular and molecular heterogeneity in biological systems. Here, we demonstrate the utility of integrating an inverted light microscope with an ambient ionization source, nanospray electrospray desorption ionization, attached to a high-resolution mass spectrometer to characterize the molecular composition of mouse spinal cords. We detected a broad range of molecules, including peptides and proteins, as well as metabolites such as lipids, sugars, and other small molecules, including S-adenosyl methionine and glutathione, through top-down MS. Top-down analysis revealed variation in the expression of Hb, including the transition from fetal to adult Hb and heterogeneity in Hb subunits consistent with the genetic diversity of the mouse models. Similarly, temporal changes to actin-sequestering proteins β-thymosins during development were observed. These results demonstrate that interfacing microscopy with ambient ionization provides the means to perform targeted in situ ambient top-down mass spectral analysis to study the pattern of proteins, lipids, and sugars in biologically heterogeneous samples.
生物系统中存在巨大的细胞和分子异质性。在这里，我们展示了将倒置显微镜与环境电离源（纳米喷雾电喷雾解吸电离）集成，并连接到高分辨率质谱仪，以用于分析小鼠脊髓的分子组成的方法的实用性。我们通过自上而下的 MS 检测到了广泛的分子，包括肽和蛋白质，以及代谢物，如脂质、糖和其他小分子，包括 S-腺苷甲硫氨酸和谷胱甘肽。自上而下的分析揭示了 Hb 表达的变化，包括从胎儿 Hb 向成人 Hb 的转变，以及与小鼠模型遗传多样性一致的 Hb 亚基异质性。同样，在发育过程中观察到肌动蛋白结合蛋白β-胸腺素的时间变化。这些结果表明，将显微镜与环境电离相结合，为进行靶向原位环境自上而下的质谱分析提供了手段，以研究生物异质样品中蛋白质、脂质和糖的模式。
