title: Effects of Solution Structure on the Folding of Lysozyme Ions in the Gas Phase.
abstract: The fidelity between the structures of proteins in solution and protein ions in the gas phase is critical to experiments that use gas-phase measurements to infer structures in solution. Here we generate ions of lysozyme, a 129-residue protein whose native tertiary structure contains four internal disulfide bonds, from three solutions that preserve varying extents of the original native structure. We then use cation-to-anion proton-transfer reactions (CAPTR) to reduce the charge states of those ions in the gas phase and ion mobility to probe their structures. The collision cross section (Ω) distributions of each CAPTR product depends to varying extents on the original solution, the charge state of the product, and the charge state of the precursor. For example, the Ω distributions of the 6+ ions depend strongly on the original solutions conditions and to a lesser extent on the charge state of the precursor. Energy-dependent experiments suggest that very different structures are accessible to disulfide-reduced and disulfide-intact ions, but similar Ω distributions are formed at high energy for disulfide-intact ions from denaturing and from aqueous conditions. The Ω distributions of the 3+ ions are all similar but exhibit subtle differences that depend more strongly on the original solutions conditions than other factors. More generally, these results suggest that specific CAPTR products may be especially sensitive to specific elements of structure in solution.
authors.affiliation: Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Laszlo
authors.affiliation: Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States.
authors.forename: Eleanor B
authors.initials: EB
authors.lastname: Munger
authors.affiliation: Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States.
authors.forename: Matthew F
authors.identifier: 0000-0003-3526-4973
authors.initials: MF
authors.lastname: Bush
mesh_terms: D000818:Animals; D002645:Chickens; D004529:Egg White / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D012996:Solutions
chemical_list: D005740:Gases; D007477:Ions; D012996:Solutions; D009113:Muramidase