Electron Detachment Dissociation (EDD) and Collisionally Activated Dissociation (CAD) for Top-Down Mass Spectrometry of Acidic Proteins

摘要

Ubiquitin was desalted using centrifugal concentrators, and electrosprayed from 1 (mu)M solutions (1:1 H_(2)O/CH_(3)OH) with 0.1percent vol. 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),0.1percent vol. 7-methyl-1,5,7-triazabicyclo [4.4.0]dec-1-ene (m-TBD), 1percent vol. triethylamine (TEA), 20 mM 1-cyclohexylpiperzine, 20 mM piperidine or 20 mM imidazole as additives. Experiments were performed on a 7 Tesla Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer equipped with a collision cell and a hollow dispenser cathode for low-energy CAD and EDD experiments, respectively. Argon gas was used for CAD, and 20-30 eV electrons for EDD.