Scientific article
OA Policy
English

Native Ion Mobility Mass Spectrometry: When Gas-Phase Ion Structures Depend on the Electrospray Charging Process

Published inJournal of the American Society for Mass Spectrometry, vol. 30, no. 6, p. 1069-1081
Publication date2019-06
First online date2019-03-28
Abstract

Ion mobility spectrometry (IMS) has become popular to characterize biomolecule folding. Numerous studies have shown that proteins that are folded in solution remain folded in the gas phase, whereas proteins that are unfolded in solution adopt more extended conformations in the gas phase. Here, we discuss how general this tenet is. We studied single-stranded DNAs (human telomeric cytosine-rich sequences with CCCTAA repeats), which fold into an intercalated motif (i-motif) structure in a pH-dependent manner, thanks to the formation of C-H+ -C base pairs. As i-motif formation is favored at low ionic strength, we could investigate the ESI-IMS-MS behavior of i-motif structures at pH ~ 5.5 over a wide range of ammonium acetate concentrations (15 to 100 mM). The control experiments consisted of either the same sequence at pH ~ 7.5, wherein the sequence is unfolded, or sequence variants that cannot form i-motifs (CTCTAA repeats). The surprising results came from the control experiments. We found that the ionic strength of the solution had a greater effect on the compactness of the gas-phase structures than the solution folding state. This means that electrosprayed ions keep a memory of the charging process, which is influenced by the electrolyte concentration. We discuss these results in light of the analyte partitioning between the droplet interior and the droplet surface, which in turn influences the probability of being ionized via a charged residue-type pathway or a chain extrusion-type pathway.

Keywords
  • Electrospray mechanisms
  • Fundamentals
  • Ion mobility
  • Native MS
  • Nucleic acids
  • Top 10
Affiliation entities Not a UNIGE publication
Funding
  • FP7 Ideas: European Research Council [616551]
  • Associazione Italiana per la Ricerca sul Cancro [IG-18695]
Citation (ISO format)
KHRISTENKO, Nina et al. Native Ion Mobility Mass Spectrometry: When Gas-Phase Ion Structures Depend on the Electrospray Charging Process. In: Journal of the American Society for Mass Spectrometry, 2019, vol. 30, n° 6, p. 1069–1081. doi: 10.1007/s13361-019-02152-3
Main files (1)
Article (Accepted version)
Secondary files (1)
Supplemental data
Identifiers
Journal ISSN1044-0305
25views
73downloads

Technical informations

Creation03/01/2025 13:58:42
First validation09/01/2025 13:12:04
Update09/01/2025 13:12:04
Status update09/01/2025 13:12:04
Last indexation10/06/2025 21:58:33
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack