Collision-induced dissociation pathways of protonated Gly(2)NH(2) and Gly(3)NH(2) in the short time-scale limit by chemical dynamics and ion spectroscopy

摘要

In this work we have studied the collision induced dissociation (CID) of C-terminally amidated, protonated di- and tri-glycine by means of chemical dynamics simulations from on-the-fly electronic structure calculations using a semi-empirical Hamiltonian. The simulations represent a collision event between the peptide and an Ar-atom addressing the reactivity at "short" time-scales, i.e. up to 5 ps. Simulations were performed for different protonation sites, greatly influencing the reactivity in agreement with what Is known from the "mobile proton" model of peptide dissociation. Results are then combined with ESI-MS/MS experiments to determine the fragmentation patterns. Additionally, we used IRMPD spectra to elucidate the structure of these peptides before collisional activation and the structures of some of the CID products. Results are also compared with threshold CID experiments reported in the literature for the non-amidated peptides.