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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 ?.

SUBMITTER: Schennach M

PROVIDER: S-EPMC4863917 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature

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Unfolding and Folding of the Three-Helix Bundle Protein KIX in the Absence of Solvent.

Schennach Moritz M Schneeberger Eva-Maria EM Breuker Kathrin K

Journal of the American Society for Mass Spectrometry 20160302 6

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 t ...[more]

PMID: 26936183

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