Abstract
We have enabled parallel ion parking on a modified Orbitrap Elite™ as a way to control ion-ion proton transfer reactions via selective activation of a range of ions. The result is the concentration of the majority of ion current from multiple charge states of each precursor proteoform into a single charge state, maximizing signal intensity and increasing effective sensitivity compared to conventional MS1 spectra. These techniques were applied in an on-line HPLC, data-dependent MS/MS analysis of intact E. coli ribosomal proteins with HCD fragmentation. With one injection, all but two ribosomal proteins were selected for fragmentation and subsequently identified. The techniques described facilitate rapid identification of intact proteins in complex mixtures and an enhanced ability to observe proteins of low abundance.
Highlights
S tudies involving mass spectrometric analysis of intact proteins in complex mixtures are subject to many analytical challenges owing to the low abundance of many of these proteins and to the complexity of the samples analyzed
We found that such parallel ion parking (PIP) AC waveforms were not highly effective at selectively suppressing further ion-ion reactions for the relatively high charge state product ions derived from intact proteins
Attempts to increase the amplitude of the PIP waveform and thereby increase product ion kinetic excitation within the PIP m/z range resulted in collision-induced fragmentation of the charge-reduced protein product ions rather than improved suppression of further charge reduction
Summary
S tudies involving mass spectrometric analysis of intact proteins in complex mixtures are subject to many analytical challenges owing to the low abundance of many of these proteins and to the complexity of the samples analyzed. Continued IIPT reactions will eventually generate charge-reduced products that fall outside of the available m/z range of typical mass analyzers (Supplemental Figure 1 d-e). If the reaction time is sufficiently extended, most of the product ions are “parked” at the highest product ion charge state that falls within the PIP m/z range
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of the American Society for Mass Spectrometry
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
