Ion/Ion Proton-Transfer Reaction for Improved Negative-Ion Electron Capture Dissociation Efficiency in the Structural Characterization of Nucleic Acids and Proteins

摘要

Proton-transfer reaction increases signal abundance of electrospray-generated ions with m/z ratios well beyond 3,000 in a 7-Tesla FT-ICR mass spectrometer; an m/z range that should be ideal for niECD. The abundance of the proton transfer products increases as PTR reagent accumulation times are increased. Also, multiple proton transfer events were observed with increasing reagent accumulation. Successful electron capture was observed when niEC(D) was performed on the proteins cytochrome c and myoglobin. The niEC(D) reactions resulted in charge increased radical species but no backbone fragments were generated. Multiple electron detachment events were also observed. Additional activation, such as infrared irradiation, may be added to aid in the fragmentation of large biomolecular anionic species.