Broadband Quadrupolar Axialization of Large Multiply Charged Ions to Enhance Measurement and Minimize Conformational Restrictions

O’Connor, Peter B.; Speir, J. Paul; Wood, Troy D.; Chorush, Russell; Guan, Ziqiang; McLafferty, Fred W.

doi:10.1002/(sici)1096-9888(199605)31:5<555::aid-jms324>3.0.co;2-f

Cited by 15 publications

(23 citation statements)

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“…Conformations and folding of proteins in the gas phase have recently been reported by McLafferty and co-workers (Suckau et al, 1993;O'Connor et al, 1996). These studies have used electrospray ionization coupled with FTMS to study the protein folding of cytochrome c by monitoring 'H/D exchange in the gas phase.…”

Section: 'H/d Exchangementioning

confidence: 91%

Fourier transform mass spectrometry—advancing years (1992-mid. 1996)

Dienes

Pastor

Schürch

et al. 1996

Mass Spectrom. Rev.

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This article is one of a series of Fourier transform mass spectrometry (FTMS) reviews that has appeared in this journal at ca. 3–4 year intervals. A comprehensive review of the recent theoretical developments, instrumental developments, electrospray ionization (ESI), and MALDI is given. Ion dissociation techniques are also discussed because of their contributions to gaining insight into chemical structure. Special sections have been devoted to discussing the emerging fields of surface analysis, polymer analysis, Buckminsterfullerenes (buckyballs), and hydrogen/deuterium exchange studies. This review, although not all‐inclusive, is intended to be a starting point for those wishing to learn more about the current status of FTMS, and also as a representative cross‐section of the literature for those familiar with the technique. © 1997 John Wiley & Sons, Inc.

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Section: 'H/d Exchangementioning

confidence: 91%

Fourier transform mass spectrometry—advancing years (1992-mid. 1996)

Dienes

Pastor

Schürch

et al. 1996

Mass Spectrom. Rev.

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“…For example, substituting acetonitrile for water can severely reduce enzymatic activity, even though the α-helix content and crystalline enzyme structure are little changed . Even with the complete removal of water and its concomitant hydrophobic stabilization, gaseous protein cations can exist in several conformational states that can be folded and unfolded. , In a critical mechanistic examination of such data for cytochrome c ,10b Wolynes pointed out 2 that van der Waals packing forces would have to be unusually important for native structures to survive in vacuo, without solvent stabilization, so that many other structures should be competitive energetically. Although the absence of water should increase the stability of classical secondary structures such as the α-helix and β-sheet, the apolar vacuum could even stabilize hydrophobic residues on the exterior to produce an “inside out” conformation .…”

Section: Introductionmentioning

confidence: 99%

Gaseous Conformational Structures of Cytochrome c

et al. 1998

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Solution folding of a protein removes major sections of it from their aqueous environment. Complete removal, by forming water-free gaseous protein ions with electrospray ionization/mass spectrometry, profoundly changes the conformation of cytochrome c. Of these ions' exchangeable hydrogen atoms, gaseous D2O replaces 30% to 70% in distinct values indicative of at least six conformational states. Although this is increased to >95% by colliding ions with D2O, colliding instead with N2 and subsequent D2O exposure gives the same H/D exchange values, although in different proportions; on solvent removal, denatured ions spontaneously refold. Deuterated State I, II, and V ions of a range of charge values up to 17+ when charge stripped to 9+ ions do not fold appreciably, even though their cross section decreases by 20%, confirming that each has a characteristic conformational structure insensitive to electrostatic repulsion; the charge solvation of an added protonated side chain also protects additional exchangeable sites. Dramatic temperature effects on H/D exchange also support unique State I, II, IV, and V conformers with a variety of charge values. Despite extensive H/D scrambling, dissociation to locate D sites of State I, II, IV, and V ions indicates that four small α-helical regions are maintained even in the most open ionic conformations; these regions are consistent with salt bridge stabilization. In the more open conformers the α-helical regions could be partially converted to either β-sheet or denatured structures. No close similarities were found between the gaseous conformer structures and those in solution, a cautionary note for the use of ESI/MS gas-phase data to characterize noncovalent interactions in solution.

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“…After its introduction at ISOLTRAP [1] as a preparatory step for precision mass spectrometry of short-lived radionuclei [2,3], the method has quickly been transferred [4] to (Fourier transform) ion cyclotron resonance (FT-ICR) cells. In analytical chemistry applications it is often implemented as part of the standard procedure of complex event sequences, either for axialization of particular species [5] or broader ranges of mass-over-charge ratios [6].…”

Section: Introductionmentioning

confidence: 99%

A study of octupolar excitation for mass-selective centering in Penning traps

Rosenbusch

Bohm

Borgmann

et al. 2012

International Journal of Mass Spectrometry

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Octupolar excitation has been investigated with respect to mass-selective ion centering in buffer-gas filled Penning traps for the isolation of an ion species of interest. To this end, off-line test measurements have been performed with the preparation Penning trap of the mass spectrometer ISOLTRAP located at ISOLDE/CERN including a comparison with the conventional quadrupolar excitation. The experimental results are compared to numerical simulations of ions under influence of quadrupolar and octupolar excitation. (c) 2012 Elsevier B.V. All rights reserved

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Broadband Quadrupolar Axialization of Large Multiply Charged Ions to Enhance Measurement and Minimize Conformational Restrictions

Cited by 15 publications

References 1 publication

Fourier transform mass spectrometry—advancing years (1992-mid. 1996)

Fourier transform mass spectrometry—advancing years (1992-mid. 1996)

Gaseous Conformational Structures of Cytochrome c

A study of octupolar excitation for mass-selective centering in Penning traps

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