Top-down proteomic approach to protein identification using tandem MS, ion/ion reactions and low-mass analysis
Abstract
Tandem mass spectrometry has been utilized in the field of proteomics to identify and characterize proteins and peptides using two main strategies: bottom-up and top-down. A top-down proteomic approach over a narrow m/z range was studied within a modified AB Sciex QTRAP linear quadrupole ion trap mass spectrometer using beam type collision-induced dissociation and ion/ion proton transfer reactions. A proton transfer reagent, PFO, was injected and transferred to the q2 cell where it reacted with the CID fragment ions from a preselected charge state of a protein, and charge reduced the fragments to singly charged ions. The resulting spectra were analyzed by submitting all m/z peak values and intensities above a set threshold to a variety of proteomics software databases for protein identification. Utilizing only the low mass fragmentation patterns in addition to the intact mass, determined by deconvolution of the charge state distribution, to identify a protein allows for the application of most commercial quadrupole instruments to proteomic research. This work demonstrates how protein identification using this approach is successful by the investigation of myoglobin, ubiquitin and cytochrome c.
Degree
M.S.
Advisors
McLuckey, Purdue University.
Subject Area
Analytical chemistry
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