scholarly journals Assessing a commercial capillary electrophoresis interface (ZipChip) for shotgun proteomic applications

2019 ◽  
Author(s):  
Aimee Rinas ◽  
Conor Jenkins ◽  
Ben Orsburn

Capillary electrophoresis coupled electrospray ionization mass spectrometry (CE-MS) has long existed as a theoretical alternative to liquid chromatography coupled mass spectrometry (LC-MS). Until recently, however, the coupling of these technologies has occupied only a small niche within specific applications. A recent innovation in CE-MS is the ZipChip interface system from 908 devices that was pioneered by the Ramsay lab at NC State. This newly available source offers advantages over previous CE-MS interfaces including both relative ease of use and direct compatibility to thousands of mass spectrometers currently in use throughout the world with no hardware alterations. The ZipChip CE-MS has been demonstrated in recent studies to provide high resolution and rapid separations for the analysis of intact proteins, glycoproteins and glycosylated peptides, with more applications likely on the way. In this study we assess the capabilities of the ZipChip system in the context of high throughput global shotgun proteomics experiments. We find that on a high field Orbitrap system we can repeatedly identify as many as 800 unique protein groups in an experiment using a run time of 12 minutes. We find the ZipChip CE-MS system to be widely applicable for both data dependent and data independent acquisition experiments as well as targeted experiments. We conclude that the ZipChip is an attractive alternative solution to traditional nanoflow ESI-MS/MS for the analysis of the genomes of single celled organisms and for offline fractionation of eukaryotic proteomes.

2020 ◽  
Author(s):  
Danye Qiu ◽  
Miranda S. Wilson ◽  
Verena B. Eisenbeis ◽  
Robert K. Harmel ◽  
Esther Riemer ◽  
...  

AbstractThe analysis of myo-inositol phosphates (InsPs) and myo-inositol pyrophosphates (PP-InsPs) is a daunting challenge due to the large number of possible isomers, the absence of a chromophore, the high charge density, the low abundance, and the instability of the esters and anhydrides. Given their importance in biology, an analytical approach to follow and understand this complex signaling hub is highly desirable. Here, capillary electrophoresis (CE) coupled to electrospray ionization mass spectrometry (ESI-MS) is implemented to analyze complex mixtures of InsPs and PP-InsPs with high sensitivity. Stable isotope labeled (SIL) internal standards allow for matrix-independent quantitative assignment. The method is validated in wild-type and knockout mammalian cell lines and in model organisms. SIL-CE-ESI-MS enables for the first time the accurate monitoring of InsPs and PP-InsPs arising from compartmentalized cellular synthesis pathways, by feeding cells with either [13C6]-myo-inositol or [13C6]-D-glucose. In doing so, we uncover that there must be unknown inositol synthesis pathways in mammals, highlighting the unique potential of this method to dissect inositol phosphate metabolism and signalling.


2020 ◽  
Vol 20 ◽  
Author(s):  
Bryan Fonslow ◽  
Gabor Jarvas ◽  
Marton Szigeti ◽  
Andras Guttman

Aims: Demonstrating the capabilities of our new capillary electrophoresis – mass spectrometry method, which facilitates highly accurate relative quantitation of modification site occupancy of antibody-ligand (e.g., antibody-drug) conjugates. Background: Antibody-drug conjugates play important roles in medical discovery for imaging and therapeutic intervention. The localization and stoichiometry of the conjugation can affect the orientation, selectivity, specificity, and strength of molecular interactions, influencing biochemical function. Objective: To demonstrate the option to analyze the localization and stoichiometry of antibody-ligand conjugates by using essentially the same method at all levels including ligand infusion, peptide mapping, as well as reduced and intact protein analysis. Materials and Methods: Capillary electrophoresis coupled to electrospray ionization mass spectrometry was used to analyze the antibodyligand conjugates. Results: We identified three prevalent ligand conjugation sites with estimated stoichiometries of 73, 14, and 6% and an average ligand-antibody ratio of 1.37, illustrating the capabilities of CE-ESI-MS for rapid and efficient characterization of antibody-drug conjugates. Conclusion: The developed multilevel analytical method offers a comprehensive way to determine the localization and stoichiometry of antibody-drug conjugates for molecular medicinal applications. In addition, a significant advantage of the reported approach is that small, hydrophilic, unmodified peptides well separated from the neutrals, which is not common with other liquid phase separation methods such as LC.


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