Analysis of Native-Like Proteins and Protein Complexes Using Cation to Anion Proton Transfer Reactions (CAPTR). Kenneth J. Laszlo; Matthew F. Bush. J. Am. Soc. Mass Spectrom. 2015, in press. (Link)
Mass spectra of native-like protein complexes often exhibit narrow charge-state distributions, broad peaks, and contributions from multiple, coexisting species. These factors can make it challenging to interpret those spectra, particularly for mixtures with significant heterogeneity. Here we demonstrate the use of ion/ion proton transfer reactions to reduce the charge states of m/z-selected, native-like ions of proteins and protein complexes, a technique that we refer to as cation to anion proton transfer reactions (CAPTR). We then demonstrate that CAPTR can increase the accuracy of charge state assignments and the resolution of interfering species in native mass spectrometry. The CAPTR product ion spectra for pyruvate kinase exhibit ~30 peaks and enable unambiguous determination of the charge state of each peak, whereas the corresponding precursor spectra exhibit ~6 peaks and the assigned charge states have an uncertainty of ±3%. 15+ bovine serum albumin and 21+ yeast enolase dimer both appear near m/z 4450 and are completely unresolved in a mixture. After a single CAPTR event, the resulting product ions are baseline resolved. The separation of the product ions increases dramatically after each subsequent CAPTR event; 12 events resulted in a 3000-fold improvement in separation relative to the precursor ions. Finally, we introduce a framework for interpreting and predicting the figures of merit for CAPTR experiments. More generally, these results suggest that CAPTR strongly complements other mass spectrometry tools for analyzing proteins and protein complexes, particularly those in mixtures.
Prof. Bush is excited to present the following talks next month:
- Korean Society for Mass Spectrometry Conference, Busan, Korea, 8/20/15.
- POSTECH Ion Chemistry Mini-Symposium, Pohang, Korea, 8/17/15.
- Young Chemists Symposium, IUPAC World Chemistry Congress, Busan, Korea, 8/14/15. (9:40-10:00 in Hall 107)
- New Development in MS Fundamentals and Instrumentation Symposium, IUPAC World Chemistry Congress, Busan, Korea, 8/10/15. (11:35-11:55 in Hall 103)
Prof. Bush thanks the IUPAC-2015 Organizing Committee, the Korean Chemical Society, and the Korean Society for Mass Spectrometry for supporting various parts of this visit.
Collision cross section calibrants for negative ion mode traveling wave ion mobility-mass spectrometry. Jay G. Forsythe, Anton S. Petrov, Chelsea A. Walker, Samuel J. Allen, Jarrod S. Pellissier, Matthew F. Bush, Nicholas V. Hud, Facundo M. Fernández. Analyst 2015, 140, 6853-6861. (Link|PUBMED)
Abstract. Unlike traditional drift-tube ion mobility-mass spectrometry, traveling-wave ion mobility-mass spectrometry typically requires calibration in order to generate collision cross section (CCS) values. Although this has received a significant amount of attention for positive-ion mode analysis, little attention has been paid for CCS calibration in negative ion mode. Here, we provide drift-tube CCS values for [M − H]− ions of two calibrant series, polyalanine and polymalic acid, and evaluate both types of calibrants in terms of the accuracy and precision of the traveling-wave ion mobility CCS values that they produce.
- For a perspective on this work, please see the feature that appeared on the main page for NASA Astrobiology (Link)
Rachael (Rae) Eaton, a first year graduate student in the Bush Lab, was recently awarded a National Science Foundation Graduate Research Fellowship! From the NSF:
The NSF Graduate Research Fellowship Program recognizes and supports outstanding graduate students in NSF-supported science, technology, engineering, and mathematics disciplines who are pursuing research-based Master’s and doctoral degrees at accredited United States institutions. (For additional information, click here.)
Prof. Bush will present the following talks this Spring:
- Colorado Mass Spectrometry Discussion Group, Colorado State University, Fort Collins, CO, 4/8/15. (Link)
- Uppsala Conference on Electron Capture and Transfer Dissociation, Lake Arrowhead, CA, 3/22/15. (Link)
- Triangle Area Mass Spectrometry Discussion Group, NC, 3/18/15. (Link)
- Pittcon Conference, New Orleans, LA, 3/9/15. (Pittcon | Symposium)
Rachael (Rae) Eaton, a first year graduate student in the Bush Lab, was one of three graduate students selected to be the first-ever PNNL Graduate Fellows! From the UW Department of Chemistry announcement:
The PNNL Graduate Fellowship Program provides recipients with valuable research experiences complementary to their graduate education at the University of Washington. This program was recently established by the Department of Chemistry and Pacific Northwest National Laboratory with the goal of generating new opportunities for collaboration, accelerating progress in research areas of mutual interest, and strengthening existing ties between the Department and PNNL.
Congratulations to Ken Laszlo, who just passed his General Exam and has advanced to candidacy!
From UW Chemistry website (link):
Assistant Professor Matthew F. Bush has been selected to receive the 2014 Eli Lilly and Company Young Investigator Award in Analytical Chemistry. The award is given by the Analytical Chemistry Academic Contacts Committee at Eli Lilly and Company based upon Dr. Bush’s outstanding research, publication record, and the impact they feel he is making in the field of analytical chemistry.
Prof. Bush will present the following seminars this Winter:
- Department of Chemistry, University of Idaho, Moscow, ID, 12/2/14.
- Department of Chemistry, Washington State University, Pullman, WA, 12/1/14.
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, 11/17/14.
- Department of Chemistry, Kalamazoo College, Kalamazoo, MI, 11/17/14.
- Molecular Engineering & Sciences Institute, University of Washington, Seattle, WA, 11/10/14.
- American Society for Mass Spectrometry Fall Workshop, Seattle, WA, 11/7/14. (Link)
Prof. Bush will present the following seminars this September:
- Department of Chemistry, Gustavus Aldolphus College, Saint Peter, MN. 9/26/14.
- Minnesota Mass Spectrometry Discussion Group, University of Minnesota, Minneapolis, MN, 9/25/14. (Seminar at 7:00 PM at the Department of Food Science and Nutrition, Room 15, 1334 Eckles Ave., St. Paul, 55108.)
- Department of Chemistry, Macalester College, Saint Paul, MN. 9/24/14.
- Applications of Time of Flight Mass Spectrometry Meeting, Waters Co. / University of California at Los Angeles, Long Beach, CA, 9/15/14. (Link)
- Proteomics Resource Seminar, University of Washington, Seattle, WA, 9/9/14.
MFB thanks the American Society for Mass Spectrometry Local Area Discussion Group Speaker Support Program for support for his trip to Minnesota.