1B-O1-1605 PDF
Structural analysis of low-charged peptide ions using Hydrogen Attachment/Abstraction Dissociation (HAD)
Hydrogen attachment/abstraction dissociation (HAD) was applied to singly charged and multiply charged ions generated by MALDI and ESI, respectively. HAD spectrum of +13 charged ubiquitin (8.6 kDa) provided abundant c-/z-type fragment ions, while that of singly charged substance P peptide showed poor fragmentation with HAD efficiency of only ≈ 5 %, which was calculated as the ratio between the sum of all HAD product abundances and the initial precursor ion abundance. To increase HAD efficiency, IR laser beam was irradiated to the precursor ion together with the H radical irradiation to activate the non-dissociative ions. The fragmentation efficiency of over 15 % was obtained with the sequence coverage exceeding 90% for singly charged substance P. Meanwhile, the optimum IR laser power for PTM peptide was quite sensitive to the reaction time, the background gas pressure and the peptide sequence, since PTMs are readily lost by the activation. To realize a soft activation, ion trap electrodes were heated up to 200 oC (HAthD). As a result, HAthD spectrum of a singly charged modified glycopeptide (MUC5AC-3/13) showed abundant c-/z-type ions preserving labile PTMs with the sequence coverage exceeding 80%. The HAD efficiency improvement was observed in both positive and negative ion modes.