Fast Fragmentation During Surface-Induced Dissociation: An Examination of Peptide Size and Structure

We present the results of direct dynamics simulations of surface-induced dissociation for protonated versions of A$_\mathrm{n}$K, KA$_\mathrm{n}$ (n = 1, 3, and 5), AcA$_\mathrm{7}$K, and AcKA$_\mathrm{7}$ for collisions with a fluorinated self-assembled monolayer surface. We focus on elucidating fast fragmentation events, which takes place in coincidence with the collision event. Such events generate a large number of products, and hence, are not easily understood through chemical intuition. Our simulations show distinct differences between the A$_{\mathrm{n}}$K/AcA$_\mathrm{7}$K and KA$_{\mathrm{n}}$/AcKA$_7$ series of peptides, with the former being more reactive, and the latter more selective. Backbone rearrangements and sidechain fragmentation are also seen.