Conformational changes of ubiquitin during electrospray ionization as determined by in‐ESI source H/D exchange combined with high‐resolution MS and ECD fragmentation. (29th September 2014)

• Record Type: Journal Article
• Authors: Kostyukevich, Yury; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene
• Is Part Of: Journal of mass spectrometry. Volume 49:Number 10(2014:Oct.)
• Page Start: 989
• Page End: 994
• Publication Date: 2014-09-29
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/jms.3409
• Languages: English
• ISSNs: 1076-5174

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>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. Copyright © 2014 John Wiley &amp; Sons, Ltd.</p> </abstract>