Tsybin Yury O, He Huan, Emmett Mark R, Hendrickson Christopher L, Marshall Alan G
Biomolecular Mass Spectrometry Laboratory, Swiss Federal Institute of Technology in Lausanne, Lausanne, CH-1015, Switzerland.
Anal Chem. 2007 Oct 15;79(20):7596-602. doi: 10.1021/ac071165u. Epub 2007 Sep 18.
We present a method to distinguish N-terminal from C-terminal product ions in electron capture dissociation (ECD) MS/MS due to the change in relative abundances of even-electron (prime) and odd-electron (radical) product ions produced in consecutive ECD and activated ion-ECD mass spectra. The method is based on the rate and direction of hydrogen atom transfer between N-terminal and C-terminal ECD products and its dependence on ion internal energy. We demonstrate that increasing ion internal energy by vibrational activation prior to ECD results in decreased ratio of radical/prime N-terminal product ions (c*/c' ratio), but increased ratio of radical/prime C-terminal product ions (z*/z' ratio) in many cases. The combination of AI-ECD and ECD promises to increase the confidence of mass spectrometry-based peptide sequencing and protein identification.
我们提出了一种方法，可根据连续电子捕获解离（ECD）和活化离子ECD质谱中产生的偶电子（主）离子和奇电子（自由基）产物离子相对丰度的变化，区分电子捕获解离（ECD）串联质谱（MS/MS）中的N端和C端产物离子。该方法基于N端和C端ECD产物之间氢原子转移的速率和方向及其对离子内能的依赖性。我们证明，在ECD之前通过振动活化增加离子内能，在许多情况下会导致自由基/主N端产物离子的比率（c*/c'比率）降低，但自由基/主C端产物离子的比率（z*/z'比率）增加。人工智能ECD（AI-ECD）和ECD相结合，有望提高基于质谱的肽测序和蛋白质鉴定的可信度。
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