Experimental and theoretical investigation of overall energy deposition in surface-induced unfolding of protein ions

Abstract

Overall energy deposition in surface-induced unfolding of protein ions is studied with a combination of experimental and theoretical methods.

Structure and effective charge characterization of proteins by a mobility capillary electrophoresis based method

“…With decreased pH, the net charge of BSA increases dramatically from ∼–3.93 to ∼+15.45. The increased number of charged residues would induce intense electrostatic forces within a BSA molecule, causing the collapse and/or unfolding of the molecule 83. As the solvent pH decreases to 3.4, it is found that this “Y” shaped “dish” like BSA would transform into a “V” shaped “rugby” like spheroid.…”

Higher-order structural characterisation of native proteins and complexes by top-down mass spectrometry

“…100 The energy deposition could be affected depending on how the protein ions interact with the surface. 101 In addition to the differences in activation techniques, the charge of protein complexes is another important factor in complex-up experiments. 66,67,98,102 Charge reduction through solution additives and gas-phase reactions can supress protein unfolding, and generally help SID by increasing the percentage of structurally informative products.…”

Computational insights into compaction of gas-phase protein and protein complex ions in native ion mobility-mass spectrometry

“…Gas-phase techniques that probe detailed ion structure, including infrared photodissociation spectroscopy [12], indicate that "memory" of solution-phase structure, such as charge sites in small dibasic organic ions [13], can sometimes be preserved in the gas phase under suitably gentle ionization and transfer conditions. Deliberate heating of biomolecular ions in the gas phase via energetic collisions with background gas, by contrast, can cause extensive unfolding driven by electrostatic repulsion of charge sites ("Collision Induced Unfolding", CIU) [14,15], which has been used to infer structural information about proteins and protein complexes [14].…”