Sam Allen is named an ACS Division of Analytical Chemistry Graduate Fellow!

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AnalACSlogo10Congratulations to Sam Allen, who just received a Graduate Fellowship from the American Chemical Society Division of Analytical Chemistry! This award is sponsored by Agilent Technologies.

Congratulations to Ken Laszlo!

Congratulations to Ken Laszlo, who just passed his second-year exam! ken_webpage

Matt Bush is named a Sloan Research Fellow

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The Sloan Research Fellowships seek to stimulate fundamental research by early-career scientists and scholars of outstanding promise.  These two-year fellowships are awarded yearly to 126 researchers in recognition of distinguished performance and a unique potential to make substantial contributions to their field. (Description from the Alfred P. Sloan Foundation)

  • New York Times announcement (PDF)
  • Sloan Foundation Press Release (PDF)
  • UW Announcement (Link)
  • The Daily Article (Link)

Mercer University Visit Featured in JASMS

ASMSProf. Bush’s recent visit to Mercer University was featured in the New & Views section of the Journal of the American Society for Mass Spectrometry. Prof. Bush thanks the American Society for Mass Spectrometry for sponsoring his visit.

  • New & Views (PDF)

New Lab Member: Myung Cha

myungThe Bush Lab welcomes Myung Cha! Click here to learn more about Myung.

Congratulations to Kim Davidson!

Congratulations to Kim Davidson, who just passed her second-year exam!IMG_0284 copy

Upcoming Presentations: February 2014

Prof. Bush will present the following seminars this February:

  • Department of Chemistry, Carleton College, Northfield, MN, 2/21/14.
  • Minnesota Mass Spectrometry Discussion Group, University of Minnesota, Minneapolis, MN, 2/20/14.
  • Department of Chemistry, St. Olaf College, Northfield, MN, 2/20/14.

MFB thanks the American Society for Mass Spectrometry Local Area Discussion Group Speaker Support Program for supporting this trip.

New Publication: Comprehensive Analysis of Gly-Leu-Gly-Gly-Lys Peptide Dication Structures and Cation-Radical Dissociations Following Electron Transfer

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Comprehensive Analysis of Gly-Leu-Gly-Gly-Lys Peptide Dication Structures and Cation-Radical Dissociations Following Electron Transfer: From Electron Attachment to Backbone Cleavage, Ion-Molecule Complexes, and Fragment Separation Robert Pepin, Kenneth J. Laszlo, Bo Peng, Aleš Marek, Matthew F. Bush, František Tureček. J. Phys. Chem. A 2014, 118, 308–324. (Link|PUBMED)

Experimental data from ion mobility measurements and electron transfer dissociation were combined with extensive computational analysis of ion structures and dissociation energetics for Gly-Leu-Gly-Gly-Lys cations and cation radicals. Experimental and computational collision cross sections of (GLGGK + 2H)2+ ions pointed to a dominant folding motif that is represented in all low free-energy structures. The local folding motifs were Continue reading

Sam Allen wins Graduate Student Merit Fellowship

DSC_5970Congratulations to Sam Allen, who has been selected as one of the recipients of the Department of Chemistry’s Graduate Student Merit Fellowships.

New Publication: Effects of Polarity on the Structures and Charge States of Native-like Proteins and Protein Complexes in the Gas Phase

toc_polarity_120-01Native mass spectrometry and ion mobility spectrometry were used to investigate the gas-phase structures of selected cations and anions of proteins and protein complexes with masses ranging from 6–468 kDa. Under the same solution conditions, the average charge states observed for all native-like anions were less than those for the corresponding cations. Using an RF-confining drift cell, similar collision cross sections were measured in positive and negative ion mode suggesting that anions and cations have very similar structures. This result suggests that for protein and protein complex ions within this mass range, there is no inherent benefit to selecting a specific polarity for capturing a more native-like structure. For peptides and low-mass proteins, polarity and charge-state dependent structural changes may be more significant. The charged-residue model is most often used to explain the ionization of large macromolecules based on the Rayleigh limit, which defines the upper limit of charge that a droplet can hold. Because ions of both polarities have similar structures and the Rayleigh limit does not depend on polarity, these results cannot be explained by the charged-residue model alone. Rather, the observed charge-state distributions are most consistent with charge-carrier emissions during the final stages of analyte desolvation, with lower charge-carrier emission energies for anions than the corresponding cations. These results suggest that the observed charge-state distributions in most native mass spectrometry experiments are determined by charge-carrier emission processes; although the Rayleigh limit may determine the gas-phase charge states of larger species, e.g., virus capsids.

Effects of Polarity on the Structures and Charge States of Native-like Proteins and Protein Complexes in the Gas Phase Samuel J. Allen, Alicia M. Schwartz, Matthew F. Bush. Anal. Chem. 2013, 85, 12055–12061. (Link|PUBMED)