Targeted MultiNotch MS3 Approach for Relative Quantification of N-Glycans Using Multiplexed Carbonyl-Reactive Isobaric Tags Article Swipe
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· 2017
· Open Access
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· DOI: https://doi.org/10.1021/acs.analchem.7b03289
· OA: W2769300889
The recently developed and commercially available carbonyl-reactive tandem mass tags (aminoxyTMT) enable multiplexed quantification of glycans through comparison of reporter ion intensities. However, challenges still exist for collision activated dissociation (CAD) MS/MS based quantification of aminoxyTMT due to the relatively low reporter ion yield especially for glycans with labile structures. To circumvent this limitation, we utilized the unique structural features of N-glycan molecules, the common core sugar sequence (HexNAc)<sub>2</sub>(Man)<sub>3</sub>, and common m/z of Y<sub>n</sub> ions generated from different types of precursors by MS/MS and designed a Y<sub>1</sub> ion triggered, targeted MultiNotch MS<sup>3</sup> relative quantification approach based on aminoxyTMT labeling. This approach was implemented on a nanoHILIC-Tribrid quadrupole-ion trap-Orbitrap platform, which enables prescreening of aminoxyTMT labeled N-glycan precursor ions by Y<sub>1</sub> ion fragment ion mass in a higher-energy collisional dissociation (HCD) MS/MS scan and coisolation and cofragmentation of multiple Y<sub>n</sub> fragment ions that carry the isobaric tags from the inclusion list in the MS/MS/MS scan. Through systematical optimization and evaluation using N-glycans released from several glycoprotein standards and human serum proteins, we demonstrated that the Y<sub>1</sub> ion triggered, targeted MultiNotch MS<sup>3</sup> approach offers improved accuracy, precision, and sensitivity for relative quantification compared to traditional data-dependent MS<sup>2</sup> and Y<sub>1</sub> ion MS<sup>3</sup> quantification methods.