Recent News

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Upcoming Presentations: September 2013

Prof. Bush will present the following talks:

  • Native Mass Spectrometry: Ionization, Ion Mobility, and the Mammalian Circadian Clock. Matthew F. Bush. Greater Boston Mass Spectrometry Discussion Group, Boston, MA, 9/19/13. (Additional Information|Flyer)
  • Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA, 9/18/13.
  • Ion mobility mass spectrometry of a mammalian circadian clock protein complex reveals a ligand-dependent conformational switch. Samuel T. Marionni, Weiman Xing, Ning Zheng, Matthew F. Bush. American Chemical Society National Meeting, Indianapolis, IN, 9/11/13. (Additional Information)
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Bush Lab at the 2013 Cascadia Proteomics Symposium

Cascadia Proteomics Symposium

The Bush Lab and collaborators are presenting the following talks at the Cascadia Proteomics Symposium, which takes place at the Institute for Systems Biology in Seattle from July 15-16.

  • Ion Mobility Mass Spectrometry of Native Protein Complex Anions Samuel J. Allen, Alicia M. Schwartz, Matthew F. Bush (Tuesday @ 10:15 AM)
  • Selected Cation to Anion Proton Transfer Kenneth J. Laszlo, Matthew F. Bush (Tuesday @ 10:50 AM)
  • Assembly of the Type II Secretion ATPase Probed by Native Mass Spectrometry Samuel T. Marionni, Connie Lu, Stewart Turley, Young-Jun Park, Kelly Lee, Marcella Patrick, Ripal Shah, Maria Sandkvist, Wim G.J. Hol, Matthew F. Bush (Tuesday @ 1:00 PM)
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Upcoming Presentations: June

  • Prof. Bush will present a talk at the Yale Biological Mass Spectrometry Symposium on June 25th. MFB thanks Prof. Andrew Philips and Suzanne Decatur for organizing this symposium.
  • Prof. Bush will present the University of Minnesota Particle Technology Seminar  on June 20th. MFB thanks Prof. Chris Hogan for hosting this visit.
  • Ion Mobility Mass Spectrometry of Small Molecule, Polymer, and Native Protein Complex Anions Samuel J. Allen; Alicia M. Schwartz; Matthew F. Bush. American Society for Mass Spectrometry Conference. Wednesday, June 12, Poster #737.
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Ion Mobility MS Workshop Program

Ion Mobility Mass Spectrometry: New Instrumentation & Enabling TechnologiesASMS
Matthew F. Bush presiding
Tuesday, June 11th at 5:45 PM | Room 205 AB

The performance of conventional and differential ion mobility mass spectrometers has escalated dramatically in recent years, which can be attributed to improved separations, more efficient ion transfer, and tighter integration of ion mobility devices into hybrid instruments. These improvements enable intricate and sensitive experiments probing mobility selected or separated ions, which has led to the adoption of ion mobility technologies in a wide range of applications, including challenges in gas-phase ion structure determination, native mass spectrometry, proteomics, and systems biology. We will showcase the latest developments in ion mobility mass spectrometry instrumentation and discus remaining challenges.

Prof. Stephen Valentine (West Virginia University)
Miniaturization of Overtone Ion Mobility Spectrometry

Dr. Guillermo Vidal-de-Miguel (SEADM)
Developments in Transversal Modulation IMS (TMIMS): an Add-on enabling absolute IMS-IMS pre-filtration in tandem with MS, and providing 100% DC

Dr. Dimitris Papanastasiou (Fasmatech)
Implementation of a novel Differential Mobility Spectrometry Platform in the Fore Vacuum Region of a Mass Spectrometer

Dr. Melvin Park (Bruker)
High Resolution Trapped Ion Mobility Spectrometry and the Beginnings of a Theory

Dr. Yehia Ibrahim (Pacific Northwest National Laboratory)
The development of the PNNL IMS platform: challenges and solutions

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New Publications: Electron Transfer Dissociation of Photolabeled Peptides

hydrazine_loosGas-phase conformations and electron transfer dissociations of pentapeptide ions containing the photo-Leu residue (L*) were studied. Exhaustive conformational search including molecular dynamics force-field, semi-empirical, ab initio, and density functional theory calculations established that the photo-Leu residue did not alter the gas-phase conformations of (GL*GGK  +  2H)2+ and (GL*GGK-NH2 + H)+ ions, which showed the same conformer energy ranking as the unmodified Leu-containing ions. This finding is significant in that it simplifies conformational analysis of photo-labeled peptide ions. Electron transfer dissociation mass spectra of (GL*GGK  +  2H)2+, (GL*GGK-NH2 + 2H)2+,(GL*GGKK + 2H)2+, (GL*GLK + 2H)2+, and (GL*LGK + 2H)2+ showed 16 %–21 % fragment ions originating by radical rearrangements and cleavages in the diazirine ring. These side-chain dissociations resulted in eliminations of N2H3, N2H4, [N2H5], and [NH4O] neutral fragments and were particularly abundant in long-lived charge-reduced cation-radicals. Deuterium labeling established that the neutral hydrazine molecules mainly contained two exchangeable and two nonexchangeable hydrogen atoms from the peptide and underwent further H/D exchange in an ion–molecule complex. Electron structure calculations on the charge-reduced ions indicated that the unpaired electron was delocalized between the diazirine and amide π* electronic systems in the low electronic states of the cation-radicals. The diazirine moiety in GL*GGK-NH2was calculated to have an intrinsic electron affinity of 1.5 eV, which was further increased by the Coulomb effect of the peptide positive charge. Mechanisms are proposed for the unusual elimination of hydrazine from the photo-labeled peptide ions.

Electron Transfer Dissociation of Photolabeled Peptides. Backbone Cleavages Compete with Diazirine Ring Rearrangements Aleš Marek, Robert Pepin, Bo Peng, Kenneth J. Laszlo, Matthew F. Bush, František Tureček. J. Am. Soc. Mass Spectrom. 2013, DOI:10.1007/s13361-013-0630-0. (Link|PUBMED)