Jeffrey D. Steill

Publications (65) View all

• Article: Non-equilibrium isomer distribution of the gas-phase Photoactive Yellow Protein chromophore

  M. Almasian, J. Grzetic, J. van Maurik, J.D. Steill, G. Berden, S. Ingemann, W.J. Buma, J. Oomens
  Journal of Physical Chemistry Letters 01/2012; 3:2259. · 6.21 Impact Factor
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  Article: Spectroscopically resolved competition between dissociation and detachment from nitrobenzene radical anion

  Jeffrey D. Steill, Jos Oomens
  International Journal of Mass Spectrometry 12/2011; · 2.55 Impact Factor
• Article: Cyclic peptide as reference system for b ion structural analysis in the gas phase.

  Xian Chen, Marcus Tirado, Jeffrey D Steill, Jos Oomens, Nick C Polfer
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  ABSTRACT: Infrared multiple photon dissociation spectroscopy and hydrogen/deuterium exchange methods are used to confirm the macrocylic structure of a b(6) peptide fragment by direct comparison with a synthetically made cyclic peptide. The acetylation of the peptide N-terminus results in the inhibition of the macrocyclic formation, supporting the "head-to-tail" cyclization mechanism. Differences in hydrogen/deuterium exchange rates for macrocyclic and oxazalone structure peptide fragments are interpreted to be a result of the complex interplay of multiple basic sites in the peptide fragment, supporting the relay mechanism for deuterium exchange with CH(3)OD.
  Biological Mass Spectrometry 10/2011; 46(10):1011-5. · 3.41 Impact Factor
• Article: Infrared multiple photon dissociation action spectroscopy and computational studies of mass-selected gas-phase fluorescein and 2',7'-dichlorofluorescein ions.

  Huihui Yao, Jeffrey D Steill, Jos Oomens, Rebecca A Jockusch
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  ABSTRACT: Fluorescein (FL) and its derivative 2',7'-dichlorofluoroescein (DCF) are well-known fluorescent dyes used in many biological and biochemical applications. Although extensive studies have been carried out to investigate their chemical and photophysical properties in different solvent media, little is known about their intrinsic behaviors in the gas phase. Here, infrared multiple photon dissociation (IRMPD) action spectra are reported for the three charged prototropic forms of FL and DCF and compared with computed IR spectra from electronic structure calculations. In each case, the measured spectra show good agreement with the calculated spectra of the lowest energy computed conformer. Moreover, the major bands of the monoanion IRMPD spectra show striking similarities to those of the dianions and are quite different from those of the cations. These experimental results clearly indicate that the gaseous monoanions are predominantly deprotonated on the xanthene chromophore, rather than the benzoate deprotonation site favored in solution. Investigations such as this, which provide a better understanding of intrinsic properties of ionic dyes, forms a baseline from which to elucidate solvent effects and will aid the rational design of dyes possessing desirable fluorescence properties.
  The Journal of Physical Chemistry A 09/2011; 115(34):9739-47. · 2.95 Impact Factor
• Article: Infrared multiple-photon dissociation spectroscopy of group II metal complexes with salicylate.

  Ryan P Dain, Gary Gresham, Gary S Groenewold, Jeffrey D Steill, Jos Oomens, Michael J van Stipdonk
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  ABSTRACT: Ion trap tandem mass spectrometry with collision-induced dissociation, and the combination of infrared multiple-photon dissociation (IRMPD) spectroscopy and density functional theory (DFT) calculations, were used to characterize singly charged, 1:1 complexes of Ca(2+), Sr(2+) and Ba(2+) with salicylate. For each metal-salicylate complex, the CID pathways are: (a) elimination of CO(2) and (b) formation of [MOH](+) where M = Ca(2+), Sr(2+) or Ba(2+). DFT calculations predict three minima for the cation-salicylate complexes which differ in the mode of metal binding. In the first, the metal ion is coordinated by O atoms of the (neutral) phenol and carboxylate groups of salicylate. In the second, the cation is coordinated by phenoxide and (neutral) carboxylic acid groups. The third mode involves coordination by the carboxylate group alone. The infrared spectrum for the metal-salicylate complexes contains a number of absorptions between 1000 and 1650 cm(-1), and the best correlation between theoretical and experimental spectra is found for the structure that features coordination of the metal ion by phenoxide and the carbonyl O of the carboxylic acid group, consistent with the calculated energies for the respective species.
  Rapid Communications in Mass Spectrometry 07/2011; 25(13):1837-46. · 2.79 Impact Factor