DIFFERENTIATION OF ALPHA- VS BETA- ASPARTIC ACID USING ETD

点击翻译按钮获取中文摘要

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. Our recent success in showing that ECD can easily differentiate alpha- and beta- aspartic acid residues in peptides and proteins raised the obvious question as to whether or not the same methods could be used with Electron Transfer Dissociation (ETD). However, ETD instrumentation does not exist at the resource. Thus, following ASMS 2005, a collaboration was started with Prof. Scott McLuckey's group in Purdue. Samples of specific, labeled peptides were sent to Purdue, and spectra were returned which shows that this technique does indeed work with ETD as well. The manuscript was published in the Journal of the American Society for Mass Spectrometry. This data was reproduced on the Agilent ETD ion trap in collaboration with Paul Goodley. The net result was that, while ETD does work to distinguish aspartic and isoaspartic acids, unlike ECD, it has a competing "proton transfer" or "charge stripping" channel which reduces ion abundance. This may be dependent on reaction parameters, and it is hoped that ETD can be "tuned-in" as it was on the model peptides to improve detection of these diagnostic ions.