Bioactive Recognition Sites May Not Be Energetically Preferred in Protein−Carbohydrate Complexes in the Gas Phase

Arrhenius parameters, obtained with the blackbody infrared radiative dissociation technique, are reported for the dissociation of a gaseous protonated complex of an antibody single chain fragment and its native trisaccharide antigen originating from nonspecific interactions during the nanoelectrospray process. It is shown that the nonspecific complex is kinetically more stable and, at the +10 charge state, energetically more stable than the corresponding specific complex originating from interactions in solution. This is the first demonstration that a bioactive recognition site is not energetically preferred in a protein-ligand complex in the gas phase.