ION-ELECTRON REACTIONS IN VIBRATIONALLY COOLED MALDI FTICR MS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。由于ECD和EDD可以提供有趣的新碎片模式，因此人们对在MALDI FTMS仪器中实现离子-电子反应非常感兴趣。波士顿大学医学院NCRR质谱资源中心建造的振动冷却（VC） MALDI用于冷却离子的振动运动，从而增加MALDI中多电荷物质的丰度。用低能电子和电子捕获照射swift分离的多电荷离子，检测氢原子损失和c，a片段离子（所有自由基反应中预期的离子）。由于母离子丰度较低，碎片的效率较低，但碎片离子产率与电喷雾光谱大致相当。因此，我们得到了双荷电MALDI离子的ECD。然而，由于丰度大得多，人们也尝试与1+和1-离子进行离子电子反应。用9-14 eV的电子辐照带单电荷的正离子母离子，产生进一步电离的小峰，以及c、z、b、y、a离子的广泛破碎。这种新技术因此被命名为电子诱导解离，在高压MALDI FTMS中对肽进行测序似乎非常有前途。特别是，新技术将对具有PTM¿s的肽测序有用，因为已经注意到这些片段保留了不稳定的基团，如磷酸化位点。首次在高压MALDI FTMS中获得了电子捕获解离和电子诱导解离（EID）技术。这些数据在田纳西州纳什维尔举行的第52届美国质谱学会上发表，目前正在撰写科学论文，提交给同行评议的期刊。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Because of the interesting new fragmentation patterns available with ECD and EDD, there's a strong interest in implementation of ion-electron reaction in the MALDI FTMS instrument. The Vibrationally Cooled (VC) MALDI built at the NCRR Mass Spectrometry Resource at Boston University School of Medicine is required for cooling of the vibrational motion of the ions and thus increases the abundance of multiply charged species in MALDI. SWIFT-isolated multiply charged ions were irradiated with low energy electrons and electron capture, hydrogen atom loss, and c,a fragment ions (all species that are expected for radical reactions) were detected. Efficiency of fragments is low due to the low abundance of the parent ion, but the fragment ion yield is rougly comparable to electrospray spectra. Thus, we have shown ECD of doubly charged MALDI ions. However, due to the much greater abundance, ion electron reactions were also attempted with the 1+ and 1- ion species. Irradiation of singly charged positive parent ions using electrons of 9-14 eV produced small peaks of further ionized species as well as extensive fragmentation of c,z,b,y,a ions. This new technique is thus named electron induced dissociation, and appears to be very promising for sequencing peptides in high pressure MALDI FTMS. Particularly the new technique will be useful for sequencing peptides with PTM¿s since the fragments have been noted to preserve labile groups such as phosphorylation sites. Electron capture dissociation and electron induced dissociation (EID) techniques were obtained for the first time for High pressure MALDI FTMS. These data were presented at the 52d American Society of Mass Spectrometry in Nashville, TN and are currently being written up for submission as a scientific paper in a peer-reviewed journal.