FOM Institute AMOLF, Amsterdam, The Netherlands.
Proteomics. 2014 May;14(10):1283-9. doi: 10.1002/pmic.201300306. Epub 2014 Feb 12.
Laser ablation ESI (LAESI) is a recent development in MS imaging. It has been shown that lipids and small metabolites can be imaged in various samples such as plant material, tissue sections or bacterial colonies without any sample pretreatment. Further, LAESI has been shown to produce multiply charged protein ions from liquids or solid surfaces. This presents a means to address one of the biggest challenges in MS imaging; the identification of proteins directly from biological tissue surfaces. Such identification is hindered by the lack of multiply charged proteins in common MALDI ion sources and the difficulty of performing tandem MS on such large, singly charged ions. We present here top-down identification of intact proteins from tissue with a LAESI ion source combined with a hybrid ion-trap FT-ICR mass spectrometer. The performance of the system was first tested with a standard protein with electron capture dissociation and infrared multiphoton dissociation fragmentation to prove the viability of LAESI FT-ICR for top-down proteomics. Finally, the imaging of a tissue section was performed, where a number of intact proteins were measured and the hemoglobin α chain was identified directly from tissue using CID and infrared multiphoton dissociation fragmentation.
激光烧蚀电喷雾（LAESI）是 MS 成像领域的一项新技术。已经证明，无需任何样品预处理，就可以对植物材料、组织切片或细菌菌落等各种样品中的脂质和小代谢物进行成像。此外，LAESI 已被证明可以从液体或固体表面产生多电荷蛋白质离子。这为解决 MS 成像中最大的挑战之一提供了一种手段；直接从生物组织表面鉴定蛋白质。由于常见 MALDI 离子源中缺乏多电荷蛋白质，以及对如此大的单电荷离子进行串联 MS 分析的困难，这种鉴定受到了阻碍。我们在这里介绍了使用 LAESI 离子源和混合离子阱傅里叶变换离子回旋共振质谱仪从组织中进行自上而下的完整蛋白质鉴定。该系统的性能首先通过电子俘获解离和红外多光子解离碎裂的标准蛋白质进行了测试，以证明 LAESI FT-ICR 用于自上而下蛋白质组学的可行性。最后，进行了组织切片的成像，其中测量了许多完整的蛋白质，并直接使用 CID 和红外多光子解离碎裂从组织中鉴定出血红蛋白α链。
