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Effect of protein stabilization on charge state distribution in positive- and negative-ion electrospray ionization mass spectra

Watt, Stephen J; Sheil, Margaret; Beck, Jennifer; Prosselkov, Pavel; Dixon, Nicholas; Otting, Gottfried

Description

Changes in protein conformation are thought to alter charge state distributions observed in electrospray ionization mass spectra (ESI-MS) of proteins. In most cases, this has been demonstrated by unfolding proteins through acidification of the solution. This methodology changes the properties of the solvent so that changes in the ESI-MS charge envelopes from conformational changes are difficult to separate from the effects of changing solvent on the ionization process. A novel strategy is...[Show more]

dc.contributor.authorWatt, Stephen J
dc.contributor.authorSheil, Margaret
dc.contributor.authorBeck, Jennifer
dc.contributor.authorProsselkov, Pavel
dc.contributor.authorDixon, Nicholas
dc.contributor.authorOtting, Gottfried
dc.date.accessioned2015-12-08T22:46:14Z
dc.identifier.issn1044-0305
dc.identifier.urihttp://hdl.handle.net/1885/38059
dc.description.abstractChanges in protein conformation are thought to alter charge state distributions observed in electrospray ionization mass spectra (ESI-MS) of proteins. In most cases, this has been demonstrated by unfolding proteins through acidification of the solution. This methodology changes the properties of the solvent so that changes in the ESI-MS charge envelopes from conformational changes are difficult to separate from the effects of changing solvent on the ionization process. A novel strategy is presented enabling comparison of ESI mass spectra of a folded and partially unfolded protein of the same amino acid sequence subjected to the same experimental protocols and conditions. The N-terminal domain of the Escherichia coli DnaB protein was cyclized by in vivo formation of an amide bond between its N- and C-termini. The properties of this stabilized protein were compared with its linear counterpart. When the linear form was unfolded by decreasing pH, a charge envelope at lower m/z appeared consistent with the presence of a population of unfolded protein. This was observed in both positive-ion and negative-ion ESI mass spectra. Under the same conditions, this low m/z envelope was not present in the ESI mass spectrum of the stable cyclized form. The effects of changing the desolvation temperature in the ionization source of the Q-TOF mass spectrometer were also investigated. Increasing the desolvation temperature had little effect on positive-ion ESI mass spectra, but in negative-ion spectra, a charge envelope at lower m/z appeared, consistent with an increase in the abundance of unfolded protein molecules.
dc.publisherElsevier
dc.sourceJournal of the American Society for Mass Spectrometry
dc.subjectKeywords: Amino acids; Electrospray ionization; Escherichia coli; Mass spectrometry; Charge state distributions; Desolvation temperature; Proteins; amide; helicase; solvent; acidification; amino acid sequence; amino terminal sequence; article; carboxy terminal sequ
dc.titleEffect of protein stabilization on charge state distribution in positive- and negative-ion electrospray ionization mass spectra
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume18
dc.date.issued2007
local.identifier.absfor069999 - Biological Sciences not elsewhere classified
local.identifier.ariespublicationu4005981xPUB157
local.type.statusPublished Version
local.contributor.affiliationWatt, Stephen J, University of Wollongong
local.contributor.affiliationSheil, Margaret, University of Wollongong
local.contributor.affiliationBeck, Jennifer, University of Wollongong
local.contributor.affiliationProsselkov, Pavel, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationOtting, Gottfried, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationDixon, Nicholas, College of Physical and Mathematical Sciences, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.issue9
local.bibliographicCitation.startpage1605
local.bibliographicCitation.lastpage1611
local.identifier.doi10.1016/j.jasms.2007.06.004
dc.date.updated2015-12-08T10:59:43Z
local.identifier.scopusID2-s2.0-34548124523
CollectionsANU Research Publications

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