High-field fourier transform ion cyclotron resonance mass spectrometry for simultaneous trapping and gas-phase hydrogen/deuterium exchange of peptide ions

M. A. Freitas, C. L. Hendrickson, M. R. Emmett, A. G. Marshall

Research output: Contribution to journalArticle

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Gas-phase hydrogen/deuterium exchange of D2O with [M + H]+ ions of angiotensin II, angiotensin I, [Sar1]-angiotensin II, bradykinin, des-Arg1-bradykinin, des-Arg9-bradykinin, luteinizing hormone releasing hormone (LH-RH), and substance P has been examined by Fourier transform ion cyclotron resonance mass spectrometry at 9.4 tesla. Because the FTICR dynamic range increases quadratically with magnetic field, parent ions from a mixture of several peptides may be confined simultaneously for long periods at high pressure (e.g., 1 h at 1 × 10-5 torr) without quadrupolar axialization (and its attendant ion heating), for faster data acquisition and better controlled comparisons between different peptides. A high magnetic field also facilitates stored waveform inverse Fourier transform (SWIFT) isolation of monoisotopic [M + H]+ parent ions, so that deuterium incorporation patterns may be determined directly without the need for isotopic distribution deconvolution. Finally, a higher magnetic field provides for a greatly extending trapping period, for measurement of much slower rates. Angiotensin I, angiotensin II, and [Sar1]-angiotensin II are found to undergo a rapid exchange. Angiotensin II and [Sar1]-angiotensin II exhibit multiple deuterium uptake distributions, corresponding to multiple gas-phase conformations. In contrast, substance P exchanges slowly and LH-RH displays no observable exchange. Comparison of the relative H/D exchange rates for bradykinin and its des-Arg-derivatives supports the hypothesis that bradykinin adopts a folded gas-phase conformation that unfolds upon removal of either terminal arginine residue.

Original languageEnglish (US)
Pages (from-to)1012-1019
Number of pages8
JournalJournal of the American Society for Mass Spectrometry
Issue number10
StatePublished - Dec 1 1998
Externally publishedYes


ASJC Scopus subject areas

  • Structural Biology
  • Spectroscopy

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