title: Unfolding and Folding of the Three-Helix Bundle Protein KIX in the Absence of Solvent.
abstract: Electron capture dissociation was used to probe the structure, unfolding, and folding of KIX ions in the gas phase. At energies for vibrational activation that were sufficiently high to cause loss of small molecules such as NH3 and H2O by breaking of covalent bonds in about 5% of the KIX (M + nH)(n+) ions with n = 7-9, only partial unfolding was observed, consistent with our previous hypothesis that salt bridges play an important role in stabilizing the native solution fold after transfer into the gas phase. Folding of the partially unfolded ions on a timescale of up to 10 s was observed only for (M + nH)(n+) ions with n = 9, but not n = 7 and n = 8, which we attribute to differences in the distribution of charges within the (M + nH)(n+) ions. Graphical Abstract ᅟ.
authors.affiliation: Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria.
authors.forename: Moritz
authors.initials: M
authors.lastname: Schennach
authors.affiliation: Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Schneeberger
authors.affiliation: Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria. kathrin.breuker@uibk.ac.at.
authors.forename: Kathrin
authors.identifier: 0000-0002-4978-0883
authors.initials: K
authors.lastname: Breuker
mesh_terms: D007477:Ions; D017510:Protein Folding; D011506:Proteins; D012997:Solvents
chemical_list: D007477:Ions; D011506:Proteins; D012997:Solvents
keywords: Electron capture dissociation; Gas phase; Native mass spectrometry; Protein; Protein folding