title: Tuning a High Transmission Ion Guide to Prevent Gas-Phase Proton Exchange During H/D Exchange MS Analysis.
abstract: Hydrogen/deuterium exchange (HDX) mass spectrometry (MS) for protein structural analysis has been adopted for many purposes, including biopharmaceutical development. One of the benefits of examining amide proton exchange by mass spectrometry is that it can readily resolve different exchange regimes, as evidenced by either binomial or bimodal isotope patterns. By careful analysis of the isotope pattern during exchange, more insight can be obtained on protein behavior in solution. However, one must be sure that any observed bimodal isotope patterns are not artifacts of analysis and are reflective of the true behavior in solution. Sample carryover and certain stationary phases are known as potential sources of bimodal artifacts. Here, we describe an additional undocumented source of deuterium loss resulting in artificial bimodal patterns for certain highly charged peptides. We demonstrate that this phenomenon is predominantly due to gas-phase proton exchange between peptides and bulk solvent within the initial stages of high-transmission conjoined ion guides. Minor adjustments of the ion guide settings, as reported here, eliminate the phenomenon without sacrificing signal intensity. Such gas-phase deuterium loss should be appreciated for all HDX-MS studies using such ion optics, even for routine studies not focused on interpreting bimodal spectra. Graphical Abstract ᅟ.
authors.affiliation: Department of Medicinal Chemistry, University of Washington, Seattle, WA, 98195, USA. mguttman@uw.edu.
authors.forename: Miklos
authors.initials: M
authors.lastname: Guttman
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Wales
authors.affiliation: Department of Medicinal Chemistry, University of Washington, Seattle, WA, 98195, USA.
authors.forename: Dale
authors.initials: D
authors.lastname: Whittington
authors.affiliation: Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Engen
authors.affiliation: Waters Corporation, Stamford Avenue, Wilmslow, SK9 4AX, UK.
authors.forename: Jeffery M
authors.initials: JM
authors.lastname: Brown
authors.affiliation: Department of Medicinal Chemistry, University of Washington, Seattle, WA, 98195, USA.
authors.forename: Kelly K
authors.initials: KK
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D003903:Deuterium / Q000737:chemistry; D041961:Deuterium Exchange Measurement / Q000379:methods; D005740:Gases / Q000737:chemistry; D006678:HIV / Q000737:chemistry; D015658:HIV Infections / Q000821:virology; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D010455:Peptides / Q000737:chemistry*; D011522:Protons; D054299:env Gene Products, Human Immunodeficiency Virus / Q000737:chemistry
chemical_list: D005740:Gases; D010455:Peptides; D011522:Protons; D054299:env Gene Products, Human Immunodeficiency Virus; D003903:Deuterium
keywords: Bimodal; Binomial; Conjoined ion guide; Deuterium exchange; Deuterium loss; Envelope broadening; Gas-phase proton exchange; HDX; Intermolecular proton exchange; StepWave
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