Conformational changes of ubiquitin during electrospray ionization as determined by in-ESI source H/D exchange combined with high-resolution MS and ECD fragmentation

Yury Kostyukevich, Alexey Kononikhin, Igor Popov, Eugene Nikolaev

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

In the paper, we have demonstrated the possibility of performing hydrogen/deuterium (H/D) exchange of proteins in the region of gas-phase ion formation in an electrospray ion source by saturating the electrospray ionization source with vapors of a deuterating agent (D2O or MeOD). In this region, charged droplets are shrinking and the protein ions transfer into the gas phase. As a model protein, we have used ubiquitin whose ion mobility spectrometry and gas-phase H/D exchange in the vacuum part of a mass spectrometer demonstrated the presence of gas-phase conformers with different cross sections and H/D exchange rates. In our experiments, we observed monomodal deuterium distributions for all solvents, charge states, desolvating capillary temperature and types of deuterating agent. Also, we found that the number of H/D exchanges increases with an increasing desolvating capillary temperature and decreasing charge state. We observed that solution composition (49: 50: 1 H2O: MeOH: formic acid or 99: 1 H2O: formic acid) influences the charge-state distribution but did not change the degree of H/D exchange for the same charge state. Electron-capture dissociation fragmentation shows that higher charge states contain a segment that is protected from access by the deuterating agent.

Original languageEnglish
Pages (from-to)989-994
Number of pages6
JournalJournal of Mass Spectrometry
Volume49
Issue number10
DOIs
Publication statusPublished - 1 Oct 2014
Externally publishedYes

Keywords

  • ECD fragmentation
  • electrospray ionization
  • FT ICR
  • hydrogen/deuterium exchange
  • in-ESI source H/D exchange
  • protein structure

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